Changes, Tests, and Experiments

NUCLEAR REGULATORY COMMISSION

10 CFR Parts 50, 52 and 72

RIN 3150-AF94

Changes, Tests, and Experiments

AGENCY: Nuclear Regulatory Commission.

ACTION: Proposed rule.

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SUMMARY: The Nuclear Regulatory Commission is proposing to amend its

regulations concerning the authority for licensees of production or

utilization facilities, such as nuclear reactors, and independent spent

fuel storage facilities, to make changes to the facility or procedures,

or to conduct tests or experiments, without prior NRC approval. The

proposed rule would clarify which changes, tests and experiments

conducted at a licensed facility require evaluation, and the criteria

that determine when NRC approval is needed before such changes to a

licensed facility can be implemented. The proposed rule would also add

definitions for terms that have been subject to differing

interpretations, reorganize the rule language for clarity, and revise

the criteria for when prior NRC approval is needed. The Commission is

also seeking comment on several specific issues as discussed below.

DATES: Submit comments by December 21, 1998. Comments received after

this date will be considered if it is practical to do so, but the

Commission is able to assure consideration only for comments received

on or before this date.

ADDRESSES: Send comments to: Secretary, U.S. Nuclear Regulatory

Commission, Washington, DC 20555-0001. ATTN: Rulemakings and

Adjudications Staff.

Hand deliver comments to: 11555 Rockville Pike, Rockville,

Maryland, between 7:45 a.m. and 4:15 p.m. Federal workdays.

FOR FURTHER INFORMATION CONTACT: Eileen McKenna, Office of Nuclear

Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC

20555-0001, telephone (301) 415-2189. ([email protected]) or Naiem Tanious,

Office of Nuclear Materials Safety and Safeguards, U.S. Nuclear

Regulatory Commission, Washington DC 20555-0001, telephone (301) 415-

6103 ([email protected]).

.m. Federal workdays.

FOR FURTHER INFORMATION CONTACT: Eileen McKenna, Office of Nuclear

Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC

20555-0001, telephone (301) 415-2189. ([email protected]) or Naiem Tanious,

Office of Nuclear Materials Safety and Safeguards, U.S. Nuclear

Regulatory Commission, Washington DC 20555-0001, telephone (301) 415-

6103 ([email protected]).

SUPPLEMENTARY INFORMATION:

I. Background

II. Proposed Rule Topics and Issues

A. Organization of the rule requirements

B. Change to the facility as described in the Safety Analysis

Report

C. Change to the procedures as described in the Safety Analysis

Report

D. Tests and experiments not described in the Safety Analysis

Report

E. Safety Analysis Report

F. Probability of occurrence or consequences of an accident or

malfunction of equipment important to safety previously evaluated in

the safety analysis report may be increased

G. More than a minimal increase in probability or consequences

H. Possibility of an accident of a different type from any

previously evaluated in the Safety Analysis Report may be created

I. Possibility of a malfunction of a different type from any

previously evaluated in the Safety Analysis Report may be created

J. Margin of safety as defined in the basis for any technical

specification is Reduced

K. Safety Evaluation

L. Reporting and record keeping requirements

M. Part 72 changes

III. Section by Section Analysis

IV. Commission Voting Record on SECY-98-171

V. Rule Language Proposed by the Nuclear Energy Institute

VI. Request for Public Comments

VII. Availability of Documents and Electronic Access

VIII. Finding of No Significant Environmental Impact

IX. Paperwork Reduction Act Statement

X. Regulatory Analysis

XI. Regulatory Flexibility Certification

XII. Backfit Analysis

XIII. Criminal Penalties

XIV. Compatibility Agreement State Regulations

I. Background

e Language Proposed by the Nuclear Energy Institute

VI. Request for Public Comments

VII. Availability of Documents and Electronic Access

VIII. Finding of No Significant Environmental Impact

IX. Paperwork Reduction Act Statement

X. Regulatory Analysis

XI. Regulatory Flexibility Certification

XII. Backfit Analysis

XIII. Criminal Penalties

XIV. Compatibility Agreement State Regulations

I. Background

The existing requirements governing the authority of production and

utilization facility licensees to make changes to their facilities and

procedures, or to conduct tests or experiments, without prior NRC

approval are contained in 10 CFR 50.59. (Comparable provisions exist in

10 CFR 72.48 for licensees of facilities for the independent storage of

spent nuclear fuel and high-level radioactive waste. This proposed

rulemaking affects the requirements for 10 CFR parts 50, 52 and 72; for

simplicity, the discussion will focus primarily on the language in 10

CFR 50.59). These regulations provide that licensees may make changes

to the facility or procedures as described in the safety analysis

report, or conduct tests or experiments not described in the safety

analysis report, without prior Commission approval, unless the proposed

change, test or experiment involves a change to the Technical

Specifications incorporated in the license or an unreviewed safety

question. Section 50.59(a)(2), as currently codified, states:

``A proposed change, test or experiment shall be deemed to

involve an unreviewed safety question (i) if the probability of

occurrence or the consequences of an accident or malfunction of

equipment important to safety previously evaluated in the safety

analysis report may be increased; or (ii) if a possibility for an

accident or malfunction of a different type than any evaluated

previously in the safety analysis report may be created; or (iii) if

the margin of safety as defined in the basis for any technical

specification is reduced''.

quences of an accident or malfunction of

equipment important to safety previously evaluated in the safety

analysis report may be increased; or (ii) if a possibility for an

accident or malfunction of a different type than any evaluated

previously in the safety analysis report may be created; or (iii) if

the margin of safety as defined in the basis for any technical

specification is reduced''.

The rule also specifies record keeping and reporting requirements

associated with such changes, tests or experiments.

In order to understand the reasons for the provisions of the

current rule, and how the Commission proposes to revise it, it is

helpful to understand how this process fits within the overall

requirements undergirding licensing and oversight of nuclear reactors.

Overview of Licensing Process

The application for an operating license includes the final safety

analysis report (FSAR) which is to contain: a description of the

facility; the design bases and limits on operation; and the safety

analysis for the structures, systems, and components (SSC) and of the

facility as a whole. The safety analysis emphasizes performance

requirements, analytical bases and technical justifications, and

evaluations that show how safety functions will be accomplished. Design

bases include the specific functions that the SSC need to perform, the

parameters that need to be controlled to assure the function, and the

range of values for these parameters. As part of the FSAR, the

applicant is required to propose, for NRC approval, Technical

Specifications(TS) that will become part of the license.

The NRC issues a license after finding, among other things, that

the plant has been built according to its design and can be operated

within its design limits

need to be controlled to assure the function, and the

range of values for these parameters. As part of the FSAR, the

applicant is required to propose, for NRC approval, Technical

Specifications(TS) that will become part of the license.

The NRC issues a license after finding, among other things, that

the plant has been built according to its design and can be operated

within its design limits. The NRC prepares a safety evaluation report

that documents the basis for its findings, including its review of the

design information provided in the FSAR (and supporting documents) and

the applicable acceptance criteria (established either in regulations,

standards or guidance documents). In some cases, the NRC staff performs

independent analyses to confirm the adequacy of the facility design to

meet regulatory requirements. One example of this practice is the staff

calculation of radiological consequences (doses) for design basis

accidents.

The licensee is required to operate the facility in accordance with

NRC regulations and with requirements contained in the license. The

license describes the facility in general terms, and includes specific

conditions imposed on the facility and the licensee, as well as

incorporates the TS. Section 50.36 of the regulations defines for

inclusion in the TS, those limits and parameters of most immediate

significance for protection of public health and safety: safety limits,

limiting safety system settings, limiting conditions for operation,

surveillance requirements, and design features to which changes would

have a significant effect on safety, and administrative controls. The

TS are derived from the safety analysis, evaluations, and design bases

described in the FSAR. Any changes to the TS must receive NRC review

and approval before they are made.

Engineering evaluations demonstrate that the fundamental safety

principles of the plant design are met. Design basis events play a

central role in plant design

nificant effect on safety, and administrative controls. The

TS are derived from the safety analysis, evaluations, and design bases

described in the FSAR. Any changes to the TS must receive NRC review

and approval before they are made.

Engineering evaluations demonstrate that the fundamental safety

principles of the plant design are met. Design basis events play a

central role in plant design. These are a combination of postulated

challenges and failure events against which plants are designed to

ensure adequate and safe plant response. Design basis events are

defined as conditions of normal operation, anticipated operational

occurrences and design basis accidents, external events and natural

phenomena for which the plant has been designed to ensure the integrity

of the pressure boundary, the capability to shutdown safely, and the

capability to prevent or mitigate the consequences of accidents. For

events with high frequency, NRC requires that consequences be low (such

as by preventing fuel damage). For more severe, but less probable

accidents, the allowable consequences are higher, but must still meet

the regulatory guidelines established in 10 CFR part 100. Adequacy of

the reactor design is evaluated by consideration of postulated design

basis events viewed as sufficiently credible that the facility should

be designed to prevent or mitigate their effects.

During the design process, plant response is evaluated using

assumptions that are intended to be conservative to account for

uncertainties in analysis or data. In the Final Safety Analysis Report

(FSAR), analyses are done conservatively to account for uncertainties

in the design, construction, and operation of nuclear power plants.

These conservatisms are introduced into FSAR analyses in numerous ways.

For example, some computer codes model systems and processes in a

simplified but bounding fashion

to account for

uncertainties in analysis or data. In the Final Safety Analysis Report

(FSAR), analyses are done conservatively to account for uncertainties

in the design, construction, and operation of nuclear power plants.

These conservatisms are introduced into FSAR analyses in numerous ways.

For example, some computer codes model systems and processes in a

simplified but bounding fashion. Analysis input assumptions are

typically worst case values (consistent with the design and operating

limits) of instrument drift or error, temperature, pressure, fluid

volume and enthalpy, flow rate, system response time, heat transfer

rate and heat capacity, reactivity coefficients, power history and

decay heat. An FSAR analysis also typically assumes the worst-case

single-active failure of equipment.

National standards and other regulatory policies, such as defense-

in-depth, constitute additional engineering considerations that

influence plant design and operation. Commensurate with expected

frequency and consequences of challenges to the system, defense-in-

depth could require: (1) Multiple means to accomplish safety functions

and prevent release of radioactive material (multiple barriers); (2)

reasonable balance among prevention of core damage, prevention of

containment failure and consequence mitigation; (3) system redundancy;

(4) independence; and (5) diversity.

Various margins exist in a facility design. These margins are based

on, for example, assumptions of initial conditions, conservatisms in

computer modeling and codes, allowance for instrument drift and system

response time, redundancy and independence of components in safety

trains, and plant response during operating transient and accident

conditions. Margin is provided by meeting codes and standards or

alternatives approved for use by NRC, including the safety analysis

acceptance criteria in the FSAR and in supporting analyses

omputer modeling and codes, allowance for instrument drift and system

response time, redundancy and independence of components in safety

trains, and plant response during operating transient and accident

conditions. Margin is provided by meeting codes and standards or

alternatives approved for use by NRC, including the safety analysis

acceptance criteria in the FSAR and in supporting analyses. Not all

margin that exists falls within the purview of ``reduction in margin of

safety \1\ as defined in the basis for any technical specification.''

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\1\ Margin of safety is not defined in the regulations, although

it is mentioned in Sec. 50.34(a) (``the margins of safety during

normal operations and transient conditions anticipated during the

life of the facility''); Sec. 50.92(c) (``No significant hazards

considerations if the proposed amendment would not involve a

significant reduction in a margin of safety'') as well as

Sec. 50.59.

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When a plant is licensed, the NRC states in its Safety Evaluation

Report (SER) why it found each FSAR analysis acceptable. An FSAR

analysis may be accepted because it was considered to be adequately

conservative and because the NRC's acceptance criteria for that

analysis are met. Frequently, the SER states specific conditions the

NRC relied upon for concluding that the analysis was conservative.

Examples of such conditions may be the use of an NRC-approved computer

code, correlation, or setpoint methodology, specific limitations on one

or more input assumptions, or penalties put into a calculation to

account for uncertainties. In addition to being stated in a plant-

. Frequently, the SER states specific conditions the

NRC relied upon for concluding that the analysis was conservative.

Examples of such conditions may be the use of an NRC-approved computer

code, correlation, or setpoint methodology, specific limitations on one

or more input assumptions, or penalties put into a calculation to

account for uncertainties. In addition to being stated in a plant-

specific SER, these conditions may be found in other safety evaluations

such as for an analysis method proposed by a topical report.

Changes to the basis for licensing occur over the life of the plant

through promulgation of new rules, plant-specific license amendments

and other analyses and reviews that may be conducted, such as in

response to NRC bulletins and generic letters. The NRC prepares a

safety evaluation for many of these issues based upon either licensee

requests for changes or licensee responses to NRC requests for

information. The licensee is required to periodically update the final

safety analysis report to reflect effects of these changes so that the

safety analysis report (as updated) remains a complete and accurate

description and analysis of the facility such that it can serve as the

reference document for evaluation of changes made under 10 CFR 50.59.

10 CFR 50.59 Evaluation Process

Section 50.59 was promulgated in 1962 to allow licensees to make

certain changes that affect systems, structures, components, or

procedures described in the SAR without prior approval provided certain

conditions were met. In 1968, the rule was revised to modify some of

the criteria for when approval was required. The intent of the

Sec. 50.59 process is to permit licensees to make changes to the

facility, provided the changes maintain the level of safety documented

in the original licensing basis, such as in the safety analysis report

ribed in the SAR without prior approval provided certain

conditions were met. In 1968, the rule was revised to modify some of

the criteria for when approval was required. The intent of the

Sec. 50.59 process is to permit licensees to make changes to the

facility, provided the changes maintain the level of safety documented

in the original licensing basis, such as in the safety analysis report.

The process is thus structured around the licensing approach of design

basis events (anticipated operational occurrences and accidents);

safety-related mitigation systems, and consequence calculations for the

design basis accidents. Margins and equipment functionality,

reliability and availability also may be impacted by facility changes.

Therefore, the criteria for requiring NRC approval were directly

related to: (1) Preserving licensing assumptions concerning initiation

of design basis events by not allowing a different type of initiating

event or probability of occurrence larger than previously considered;

(2) preserving effectiveness (reliability) of the mitigation systems by

not allowing introduction of different equipment malfunctions and by

limiting increases in probability of malfunction, or reductions in the

margin of safety (which reflects the capability of the system); and (3)

preserving acceptability of consequences by limiting increases in

consequences of the postulated design basis events.

Implementation Guidance

eliability) of the mitigation systems by

not allowing introduction of different equipment malfunctions and by

limiting increases in probability of malfunction, or reductions in the

margin of safety (which reflects the capability of the system); and (3)

preserving acceptability of consequences by limiting increases in

consequences of the postulated design basis events.

Implementation Guidance

In 1989, an industry guidance document, NSAC-125, ``Guidelines for

10 CFR 50.59 Safety Evaluations'' was published to assist licensees in

the conduct of the evaluations required under Sec. 50.59. The NRC

neither endorsed nor disapproved this document. While the staff

concluded that the evaluation process established in NSAC-125 was

generally sound, the staff was unable to endorse the document because

of some inconsistencies between the implementation guidance and the

language of Sec. 50.59.

On October 31, 1997, the Nuclear Energy Institute (NEI) submitted

for staff review a revised guidance document, NEI 96-07, ``Guidelines

for 10 CFR 50.59 Safety Evaluations.'' This document is an updated

version of NSAC-125 that NEI modified in response to some of the staff

positions, and other implementation issues arising from licensee use of

the NSAC-125 guidance. Along with the submittal of the guidance

document, NEI included an industry-wide initiative that would require

industry adoption and implementation of the revised guidance by June

1998. The NRC provided comments to NEI concerning this guidance in a

letter dated January 9, 1998. This letter noted that certain aspects of

this guidance were unacceptable for implementation of Sec. 50.59 as

presently written.

Staff efforts to develop guidance on implementation of Sec. 50.59

were prompted by a reassessment of the 10 CFR 50.59 evaluation process,

conducted in 1995, that examined existing guidance and practice, with

the goal of identifying how the process could be improved, or where

additional guidance was needed

this guidance were unacceptable for implementation of Sec. 50.59 as

presently written.

Staff efforts to develop guidance on implementation of Sec. 50.59

were prompted by a reassessment of the 10 CFR 50.59 evaluation process,

conducted in 1995, that examined existing guidance and practice, with

the goal of identifying how the process could be improved, or where

additional guidance was needed. The staff provided an action plan to

the Commission on April 15, 1996, outlining the actions the staff

proposed to complete with respect to guidance and oversight of

implementation of Sec. 50.59. The staff review identified a number of

areas in which the meaning of the rule language is not clear, or where

staff and industry interpretations (such as those in NSAC-125) are

different. In SECY-97-035, dated February 12, 1997, the staff forwarded

to the Commission proposed regulatory guidance on implementation of

Sec. 50.59. In this SECY, the staff presented positions on a number of

topic areas. These positions in some cases reaffirmed existing

regulatory practice or clarified staff expectations, and in other

areas, established positions where guidance did not previously exist.

In its proposed guidance, the staff compared its proposed regulatory

guidance to industry guidance contained in NSAC-125. In accordance with

a Commission Staff Requirements Memorandum dated April 25, 1997, the

staff guidance was published in the Federal Register as draft NUREG-

1606 (Proposed Regulatory Guidance Related to Implementation of 10 CFR

50.59), for public comment on May 7, 1997 (62 FR 24947).

In response to the Federal Register notice, many comments were

submitted that voiced strong opposition to a number of the positions

proposed by the staff. These comments were summarized in Attachment 1

to SECY-97-205, Integration and Evaluation of Results from Recent

Lessons-Learned Reviews, dated September 10, 1997

mentation of 10 CFR

50.59), for public comment on May 7, 1997 (62 FR 24947).

In response to the Federal Register notice, many comments were

submitted that voiced strong opposition to a number of the positions

proposed by the staff. These comments were summarized in Attachment 1

to SECY-97-205, Integration and Evaluation of Results from Recent

Lessons-Learned Reviews, dated September 10, 1997. Since that time, the

NRC has conducted a more detailed review of the comments and concludes

that some issues can be resolved through guidance, while in other

areas, rulemaking is necessary to clarify the implementation issues. A

copy of this analysis of comments is available for review in the NRC

Public Document Room. As noted, the staff concluded that rulemaking was

necessary to resolve some of the issues associated with implementation

of the rule.

II. Proposed Rule Topics and Issues

The NRC is proposing rulemaking on Sec. 50.59 (and Sec. 72.48) to

address a number of issues concerning implementation of the current

rule, and suitability of the criteria that determine when an unreviewed

safety question exists. The implementation issues primarily relate to

cases involving judgment as to whether a proposed change requires NRC

approval before it can be implemented. The differing interpretations of

the rule as it relates to an increase in probability of an accident, or

an increase in consequences have contributed to disputed inspection and

enforcement findings. Too stringent an interpretation of the meaning of

the requirements could result in diversion of licensee and staff

resources for review of inconsequential changes. Too high a threshold

for NRC review could lead to erosion of safety margins without NRC

review, particularly from the cumulative effect of more than one

change. In developing the proposed rule, the Commission has carefully

weighed these matters in trying to establish an appropriate threshold

for NRC review

lt in diversion of licensee and staff

resources for review of inconsequential changes. Too high a threshold

for NRC review could lead to erosion of safety margins without NRC

review, particularly from the cumulative effect of more than one

change. In developing the proposed rule, the Commission has carefully

weighed these matters in trying to establish an appropriate threshold

for NRC review.

Conforming changes are proposed in other portions of the rules,

including Sec. 50.66, 50.71(e) for production and utilization

facilities licensed under part 50. Conforming changes are also

required in Sec. 72.212(b)(4) and Appendices A and B to part 52 (Design

Certification Rules for ABWR and System 80+ respectively).

In addition, the Commission is proposing to make parallel changes

applicable to facilities for independent spent fuel storage facilities

licensed in accordance with part 72. These changes are included in the

sections below (in some cases, the discussion of the issue focuses on

Sec. 50.59 for simplicity; except where noted, the discussion is also

applicable to the changes for Sec. 72.48). As part of the proposed

changes to part 72, the Commission is also proposing to extend the

change control process authority granted to ISFSI or MRS license

holders (in Sec. 72.48) to holders of NRC Certificates of Compliance

(CoC) for a spent fuel storage cask design.

In addition to changes to the requirements within Secs. 50.59 and

72.48, the Commission is also proposing to rearrange certain provisions

of these rules to provide a more logical structure. These changes do

not affect the substance of the requirements, but rather affect only

where they are located and how they are stated. These organizational

changes are discussed first, followed by discussion of each of the

issues where revisions to requirements are proposed by this rulemaking.

The proposed rule revisions are presented in the order that the issues

currently arise in the regulations.

A. Organization of the Rule Requirements

e requirements, but rather affect only

where they are located and how they are stated. These organizational

changes are discussed first, followed by discussion of each of the

issues where revisions to requirements are proposed by this rulemaking.

The proposed rule revisions are presented in the order that the issues

currently arise in the regulations.

A. Organization of the Rule Requirements

The organizational changes being proposed include the following:

(1) Applicability

In the existing rule, language concerning applicability to

different facilities is contained in three different paragraphs. These

facilities are: Production and utilization facilities (including power

and non-power reactors) that are authorized to operate, and reactors

(both power and non-power) that have permanently ceased operations. The

Commission proposes to place all of these provisions in one paragraph

that is clearly labeled ``Applicability.'' 2

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\2\ Section 50.59(a) refers to holders of a license authorizing

operation of a production or utilization facility. Section 50.59(d)

explicitly refers to power reactor licensees who have submitted

certification of permanent cessation of operation required under

Sec. 50.82(a)(1)(i). As noted in Sec. 50.82(a)(iii), for power

reactors whose licenses were modified to allow possession but not

operation, before the effective date of this rule (that is of

Sec. 50.82), the certification of Sec. 50.82(a)(1)(i) shall be

deemed to have been submitted. Section 50.59(e) refers to non-power

reactors whose license no longer authorizes operation. The net

effect is that Sec. 50.59 applies to both power and nonpower

reactors, whether authorized to operate or no longer authorized to

operate (and to other production or utilization facilities).

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deemed to have been submitted. Section 50.59(e) refers to non-power

reactors whose license no longer authorizes operation. The net

effect is that Sec. 50.59 applies to both power and nonpower

reactors, whether authorized to operate or no longer authorized to

operate (and to other production or utilization facilities).

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(2) Form of prior Commission approval

Existing Sec. 50.59(a) refers to the need for prior Commission

approval of changes, tests, and experiments under certain conditions,

but the method of receiving that approval is not discussed until

paragraph (c), which states that the licensee shall submit an

application for amendment under Sec. 50.90. The Commission proposes to

combine these two paragraphs and to revise the regulation to state more

clearly that a licensee must apply for and obtain a license amendment,

pursuant to Sec. 50.90, before implementing such changes, tests, or

experiments. This organizational change to the rule of combining

(existing) paragraphs (a) and (c) will also facilitate some of the

other proposed changes, such as the criteria for when approval is

needed.

(3) Criteria for needing Commission approval of changes, tests and

experiments and Unreviewed Safety Question (USQ) designation

The Commission proposes to remove the reference in the rule to the

term ``unreviewed safety question'' and instead to refer to the need to

obtain a license amendment. The Commission believes that the

terminology of ``USQ'' has sometimes led to confusion about the purpose

of the evaluation required by Sec. 50.59. Some licensees have concluded

that if they determined a change was safe, there could be no need for

NRC approval.

The Commission notes that the purpose of performing evaluations

against the criteria specified in Sec

to

obtain a license amendment. The Commission believes that the

terminology of ``USQ'' has sometimes led to confusion about the purpose

of the evaluation required by Sec. 50.59. Some licensees have concluded

that if they determined a change was safe, there could be no need for

NRC approval.

The Commission notes that the purpose of performing evaluations

against the criteria specified in Sec. 50.59 is to identify possible

changes that might affect the basis for licensing of the facility so

that any changes that might pose a safety concern are either reviewed

by the NRC or not implemented by the licensee. This evaluation process

will thus distinguish those changes which by their nature do not raise

safety concerns and therefore do not require prior NRC approval to

confirm their safety, from those that must be reviewed by the NRC to

independently confirm their safety before implementation. To avoid

confusion between a determination of safety and a determination of the

need for NRC approval, the Commission proposes to revise Sec. 50.59 to

delete use of the term ``unreviewed safety question'' and instead to

list the criteria (in new Sec. 50.59(c)(2)) that require prior

Commission approval, in the form of a license amendment. It is also

noted that many facility technical specifications refer to unreviewed

safety question determinations and such TS should ultimately be revised

in accordance with the final wording of Sec. 50.59. The deletion of

reference to USQ also requires a number of conforming changes to other

parts of the regulations, including Part 52 (Appendices A and B), in

which the term is presently used.

This proposed rule would revise the existing compound statements

contained with the evaluation criteria to state each specific criterion

individually. This will make the regulation more consistent with how it

is generally implemented by licensees. Changes to the criteria are

discussed in the sections below.

Finally, the Commission would simplify existing Sec

which the term is presently used.

This proposed rule would revise the existing compound statements

contained with the evaluation criteria to state each specific criterion

individually. This will make the regulation more consistent with how it

is generally implemented by licensees. Changes to the criteria are

discussed in the sections below.

Finally, the Commission would simplify existing Sec. 50.59(c) by

removing the following statement: ``The holder of a license . . . who

desires (1) a change to its technical specifications . . . shall submit

an application for amendment of his license pursuant to Sec. 50.90.''

This statement refers to changes to the TS not associated with a

change, test or experiment. The Commission concludes that a more

suitable place for this provision is within Sec. 50.90, and therefore

as part of this rulemaking, proposes to modify Sec. 50.90 to state that

if a licensee wishes to amend its license (including the TS

incorporated into it), the licensee must file an application as

specified in Sec. 50.90. Revised Sec. 50.59(c)(i) would be revised to

state that if a proposed change, test, or experiment would involve a TS

change, the Sec. 50.90 process must be followed in order to change the

technical specification such that the proposed change, test or

experiment may be implemented.

B. Change to the Facility as Described in the Safety Analysis Report

Section 50.59 states that ``changes to the facility as described in

the safety analysis report'' must be evaluated to determine whether

prior approval is needed before implementation. As discussed in NUREG-

1606 and in the comment discussions, a common understanding between the

NRC and the industry on what constitutes a ``change to the facility as

described in the safety analysis report'' is necessary for effective

functioning of the review process. Guidance on preparation of

Sec

eport'' must be evaluated to determine whether

prior approval is needed before implementation. As discussed in NUREG-

1606 and in the comment discussions, a common understanding between the

NRC and the industry on what constitutes a ``change to the facility as

described in the safety analysis report'' is necessary for effective

functioning of the review process. Guidance on preparation of

Sec. 50.59 evaluations provides the means for review of the effects of

changes, but these reviews are not conducted if the activity is not

considered to be a ``change . . .'' The Commission concludes that

modification of an existing provision (e.g., SSC, design requirement,

analysis method or

parameter), additions, and removals (physical removals or non-reliance

on a system to meet a requirement) are all changes to the facility as

described in the final safety analysis. The Commission believes that

additions to the facility which were not previously evaluated, could

adversely impact facility performance and the bases upon which the NRC

previously determined the acceptability of the design as described in

the SAR. Accordingly, the Commission concludes that additions should be

considered ``changes to the facility as described in the SAR'' in order

to assure that such changes are subject to evaluation using the

Sec. 50.59 criteria for determining whether prior NRC review and

approval are necessary.

Differences in interpretation have occurred about whether changes

that do not actually change the physical plant (the ``hardware'')

require a Sec. 50.59 evaluation. As an example, consider a change being

made to the basis (documented in the SAR) for demonstrating adequacy of

the facility without a physical change to the facility. Such changes

might include changes to evaluative methods, acceptance standards,

procurement specifications, or other information for SSC described in

the FSAR. The Commission believes that Sec

)

require a Sec. 50.59 evaluation. As an example, consider a change being

made to the basis (documented in the SAR) for demonstrating adequacy of

the facility without a physical change to the facility. Such changes

might include changes to evaluative methods, acceptance standards,

procurement specifications, or other information for SSC described in

the FSAR. The Commission believes that Sec. 50.59 does apply to the

requirements for design, construction and operation, and the safety

analyses for the facility that are documented in the FSAR. Section

50.34(b), ``Final safety analysis report,'' requires the FSAR to

contain a presentation of the design bases and the limits on its

operation, a description and analysis of the SSC of the facility, with

emphasis upon performance requirements, the bases, with technical

justifications therefore, upon which such requirements have been

established, and the evaluations required to show that safety functions

will be accomplished. The original licensing decision was based in part

upon the margins provided by performance requirements, analysis methods

and assumptions described in the SAR, and reviewed by the staff in the

SER. Therefore, the Commission concludes that changes to such

information (e.g., performance requirements, methods of operation, the

bases upon which the requirements have been established, and the

evaluations) should be considered to constitute a change to the

``facility as described in the SAR'' in order to assure that such

changes are subject to evaluation using the Sec. 50.59 criteria for

determining whether prior NRC review and approval are necessary.

If changes to methods and assumptions were not controlled, a

licensee might revise its analyses and then subsequently conclude that

a later facility change did not require NRC approval because the

results of the (new) analysis with this change were bounded by the

previous analysis. This proposed rulemaking would add definitions in

Sec

ning whether prior NRC review and approval are necessary.

If changes to methods and assumptions were not controlled, a

licensee might revise its analyses and then subsequently conclude that

a later facility change did not require NRC approval because the

results of the (new) analysis with this change were bounded by the

previous analysis. This proposed rulemaking would add definitions in

Sec. 50.59 of ``change'' and of ``facility as described in the final

safety analysis report(as updated)'' to more explicitly establish that

evaluation is required for changes to the analyses and bases for the

facility as well as for physical or hardware changes to the facility.

Accordingly, the Commission proposes to add the following as

definitions in section Sec. 50.59:

Change means a modification, addition, or removal.

Facility as described in the final safety analysis report (as

updated) means (i) the structures, systems, and components (SSC) that

are described in the final safety analysis report (as updated), (ii)

design or performance requirements or methods of operation for such SSC

required to be included or described in the final safety analysis

report (as updated), and (iii) evaluations or methods of evaluation

required to be included in the FSAR (as updated) for such SSC that

demonstrate that their intended functions will be accomplished or that

their design bases can be met.

The Commission endorses the staff's previously stated position (in

draft NUREG-1606) about what constitutes a single change, as compared

to packaging of several changes with offsetting effects. Interdependent

changes (i.e., where a second change is caused by the first, with

respect to function or performance), can be treated as a single change,

whereas treating as one change the combination of changes (whether to

the facility directly or to the safety analysis) to offset one that

would otherwise require prior approval is not an appropriate

application of Sec. 50.59.

etting effects. Interdependent

changes (i.e., where a second change is caused by the first, with

respect to function or performance), can be treated as a single change,

whereas treating as one change the combination of changes (whether to

the facility directly or to the safety analysis) to offset one that

would otherwise require prior approval is not an appropriate

application of Sec. 50.59.

C. Change to the Procedures as Described in the Safety Analysis Report

The Commission proposes to provide a definition of ``procedures as

described in the safety analysis report'' in order to have definitions

in the rule for all the major terms and criteria. This definition would

include the evaluations demonstrating that requirements are met, such

as assumed operator actions and response times.

The Commission also notes that Sec. 50.34(b) states that the final

SAR is to contain the managerial and administrative controls to be used

to meet Appendix B (Quality Assurance), and plans for coping with

emergencies, per Appendix E. Section 50.59 applies to changes to

procedures as described in the SAR. Quality assurance and emergency

planning program requirements are subject to the change control

provisions of Secs. 50.54(a) and 50.54(q) respectively. Based on this

set of rule provisions, it could be inferred that changes to quality

assurance or emergency plans would require both a Sec. 50.59 evaluation

and a Sec. 50.54 [either (a) or (q)] evaluation. The Sec. 50.54

3 regulations provide criteria and reporting requirements

specific to the plans and which were promulgated after Sec. 50.59. To

reduce duplication of effort, the Commission proposes that changes to

these programs be governed by Sec. 50.54 requirements, and that a

Sec. 50.59 evaluation would not be required unless other information

described in the FSAR is also being changed. The proposed rule would

add language to specifically exclude from the scope of Sec

c to the plans and which were promulgated after Sec. 50.59. To

reduce duplication of effort, the Commission proposes that changes to

these programs be governed by Sec. 50.54 requirements, and that a

Sec. 50.59 evaluation would not be required unless other information

described in the FSAR is also being changed. The proposed rule would

add language to specifically exclude from the scope of Sec. 50.59

changes to procedures where other more specific requirements and

criteria have been established by regulation for controlling these

changes (e.g., for information required by Sec. 50.34(b)(6) (ii) and

(v)), through a provision in the Sec. 50.59(c)(1) of the proposed rule.

---------------------------------------------------------------------------

\3\ Section 50.54(p) establishes change control requirements for

safeguards contingency plans. While these plans are part of the

application submitted pursuant to Sec. 50.34, they are not part of

the FSAR, and thus Sec. 50.59 would not apply to these plans.

---------------------------------------------------------------------------

The proposed definition for ``procedures as described in the final

safety analysis report (as updated)'' is as follows:

Procedures as described in the final safety analysis report (as

updated) means information in the final safety analysis report (as

updated) regarding how systems, structures and components are

operated and controlled (including assumed operator actions and

response times), including assumed operator actions and response

times, and information on conduct of operations.

D. Tests and Experiments Not Described in the Safety Analysis Report

nalysis report (as

updated) means information in the final safety analysis report (as

updated) regarding how systems, structures and components are

operated and controlled (including assumed operator actions and

response times), including assumed operator actions and response

times, and information on conduct of operations.

D. Tests and Experiments Not Described in the Safety Analysis Report

Section 50.59 also discusses the conduct of tests or experiments

not described in the safety analysis report. ``Test'' is, of course,

subject to many meanings including both routine verifications of

function, and also more unusual evolutions. In the former category,

there are many tests that are conducted that are not explicitly

described in the SAR. For example, a licensee conducts tests of

component and system performance that verify the

SSCs perform the functions as described or required. (Performance of

tests is typically controlled by procedure.) However, there also may be

tests of new materials or means of plant operation that may put the

plant in a situation that has not been previously evaluated and that

could affect the capability of SSC to perform their required functions.

The existing rule was designed to ensure that the latter type of tests

would be reviewed before they were conducted. Therefore, to assure that

there is clear definition with respect to the tests that are subject to

prior NRC review and approval before they are conducted, the Commission

proposes that a definition of ``tests and experiments not described in

the safety analysis report'' be provided in Sec. 50.59 as follows:

d to ensure that the latter type of tests

would be reviewed before they were conducted. Therefore, to assure that

there is clear definition with respect to the tests that are subject to

prior NRC review and approval before they are conducted, the Commission

proposes that a definition of ``tests and experiments not described in

the safety analysis report'' be provided in Sec. 50.59 as follows:

Tests or experiments not described in the final safety analysis

report (as updated) means any activity where the reactor or any of

its systems, structures, or components are used or controlled in a

manner which cannot be shown to be within (i) the controlling

parameters of their design bases as described in the final safety

analysis report (as updated) or (ii) consistent with the analyses in

the final safety analysis report (as updated).

E. Safety Analysis Report

In developing the proposed rule changes, the Commission noted the

varying references to the safety analysis report within related

sections of part 50. For example, in Sec. 50.59, the phrase used is

``safety analysis report,'' in Sec. 50.66, the reference is to the

``updated final safety analysis report;'' and Sec. 50.71(e) refers to

the updated FSAR. (Other sections and parts generally refer to the

final safety analysis report (e.g. part 55), but this is not

universally true (e.g. Sec. 50.54(a)). For purposes of Sec. 50.59,

``safety analysis report'' refers to the current revision of the FSAR,

so that the changes are evaluated against the most complete and

accurate description of the facility. When performing evaluations, a

licensee needs to consider changes already made for which the FSAR

update has not yet been submitted to the NRC. The Commission emphasizes

the need for as current a reference base as possible for Sec. 50.59

evaluations, in order that the evaluations appropriately consider other

changes already made that may have impacted the facility or procedures

the facility. When performing evaluations, a

licensee needs to consider changes already made for which the FSAR

update has not yet been submitted to the NRC. The Commission emphasizes

the need for as current a reference base as possible for Sec. 50.59

evaluations, in order that the evaluations appropriately consider other

changes already made that may have impacted the facility or procedures.

However, a licensee is not required to submit an update to its FSAR in

the form specified by Sec. 50.71(e) except at the required frequency.

To enhance consistency, the Commission is proposing to revise the rule

language in these sections to add a definition of the final safety

analysis report (as updated) and to clarify in the evaluation criteria

that evaluations need to account for changes made through other

processes that have not yet been included in an update to the FSAR. The

Commission did not use ``Updated FSAR'' for this purpose in order to

take into account two special circumstances: (1) Nonpower reactors, who

are not required to submit updates to the FSAR, although they still

need to consider other changes previously made when performing

Sec. 50.59 evaluations, and (2) a plant licensed to operate, during the

period between initial licensing and the first update. This revision is

reflected in the definitions in the earlier sections and in the

following sections. The definition also refers to ``Final Hazards

Summary Report,'' which is the applicable document for some early

plants whose application was submitted before the regulatory term

``safety analysis report'' was adopted.

The proposed definition is as follows:

Final safety analysis report (as updated) means the final safety

analysis report (or Final Hazards Summary Report) submitted in

accordance with Sec. 50.34, as amended and supplemented, and as

modified as a result of changes made pursuant to Sec. 50.59 and

Sec. 50.90, and, as applicable, Sec. 50.71 (e) and (f).

m

``safety analysis report'' was adopted.

The proposed definition is as follows:

Final safety analysis report (as updated) means the final safety

analysis report (or Final Hazards Summary Report) submitted in

accordance with Sec. 50.34, as amended and supplemented, and as

modified as a result of changes made pursuant to Sec. 50.59 and

Sec. 50.90, and, as applicable, Sec. 50.71 (e) and (f).

F. Probability of Occurrence or Consequences of an Accident or

Malfunction of Equipment Important to Safety Previously Evaluated in

the Safety Analysis Report may be Increased

The current language of the rule states that an unreviewed safety

question exists when the probability of occurrence or consequences of

an accident or malfunction of equipment important to safety previously

evaluated may be increased [emphasis added]. Many of the concerns with

current implementation relate to the appropriate interpretation of the

words ``probability of occurrence . . . or consequences . . . may be

increased.'' In the draft NUREG-1606, the NRC staff stated that the

plain reading of the words would mean that uncertainty about whether

there has been an increase must lead to the conclusion that the

criterion is met. As a result of trying to deal with the question of

uncertainty, licensees were placed in the position of having to prove

there could not be an increase, even when there was no reason to

believe that the proposed change, test or experiment would have that

effect. A similar problem was experienced in considering whether the

possibility of an accident or malfunction of a different type may be

created.

Many of the commenters on the staff's proposed positions viewed

this as overly restrictive and stated that it would result in many

changes requiring prior NRC approval that are below the level of

significance warranting such review

ould have that

effect. A similar problem was experienced in considering whether the

possibility of an accident or malfunction of a different type may be

created.

Many of the commenters on the staff's proposed positions viewed

this as overly restrictive and stated that it would result in many

changes requiring prior NRC approval that are below the level of

significance warranting such review. The position espoused in the

revised industry guidance document (NEI 96-07) is that an increase in

probability or consequences must be discernable in order for approval

to be needed. The Commission concludes that the plain reading of the

existing rule language is not consistent with this interpretation.

Although the current rule language would not permit discernable

increases in probability or consequences, the Commission has concluded

that at minimum, this would be a reasonable standard for requiring

prior approval of changes, tests or experiment for increases in

probability of occurrence of an accident or malfunction. The existing

rule language dates from early in the development of reactor

regulation, where with the knowledge base at the time, the then-AEC

found it appropriate to set a very low threshold for changes. Over the

last thirty years, the Commission has garnered experience with

implementation of Sec. 50.59 and insights from probabilistic risk

assessments, both of which indicate that this threshold can be adjusted

without adversely impacting safety. Further, the analytical

capabilities to calculate probabilities have greatly advanced, such

that the effect of even minor changes on probabilities can be

evaluated. Therefore, the Commission proposes to revise existing

paragraph Sec. 50.59(a)(2)(i) of the rule by replacing ``may be

increased'' with ``would result in more than a minimal increase,'' in

order to provide that there must be a clearly discernable change to

require approval, the ``minimal increase'' concept is described in the

next section

even minor changes on probabilities can be

evaluated. Therefore, the Commission proposes to revise existing

paragraph Sec. 50.59(a)(2)(i) of the rule by replacing ``may be

increased'' with ``would result in more than a minimal increase,'' in

order to provide that there must be a clearly discernable change to

require approval, the ``minimal increase'' concept is described in the

next section. As noted above, the (a)(2) paragraph would be broken into

four statements and renumbered as (c)(2)(i) through (iv).

G. More than a Minimal Increase in Probability or Consequences

The Commission notes that Sec. 50.59 permits changes that do not

otherwise require approval (such as would be the case if the provisions

being changed are in TS or license, quality assurance or emergency

plans, or inservice inspection and testing programs). Because the

information being revised is of less immediate importance to public

health and safety, and in consideration of the conservatisms in NRC

design and analysis requirements, acceptance criteria, and the

precision with which safety analyses are performed, ``minimal''

variations in probability of occurrence or consequences of accidents

and malfunctions should not affect the

basis for the licensing decision. This conclusion is based upon the

qualitative consideration of probability during plant licensing;

accident probabilities were assessed in relative frequencies; equipment

failures were generally postulated to gauge the robustness of the

design, without estimating their likelihood of occurrence. Therefore,

minimal increases in probability could not even have been identifiable,

and could not impact the conclusions reached about acceptability of the

facility design. Radiological consequences for accidents are calculated

and reported at a level of precision such that minimal increases also

would not impact the safety determination

sign, without estimating their likelihood of occurrence. Therefore,

minimal increases in probability could not even have been identifiable,

and could not impact the conclusions reached about acceptability of the

facility design. Radiological consequences for accidents are calculated

and reported at a level of precision such that minimal increases also

would not impact the safety determination. The Commission therefore

concludes that the proposed criteria would provide reasonable assurance

that those changes that would affect the NRC's basis for licensing

would be identified as requiring NRC approval before implementation.

The revised criteria would also provide some degree of flexibility for

licensees to make changes with smaller impacts without the need to

obtain a license amendment.

On the other hand, the Commission intends to limit the amount of

increase in probability or consequences of accidents such that it

remains substantially less than a ``significant increase'' as referred

to in Sec. 50.92 (in accordance with Sec. 50.92, a license amendment

involving a significant increase in the probability or consequences of

an accident previously evaluated involves a ``significant hazards

considerations;'' any hearing for an amendment constituting a

``significant hazards consideration'' must be completed prior to the

grant of the amendment.) The standard in the proposed rule is

qualitative (probability or consequences no more than minimally

increased). The intent of this proposed rule is to allow changes that

are small enough that they would not affect the facility's licensing

basis, or adversely affect safety performance

constituting a

``significant hazards consideration'' must be completed prior to the

grant of the amendment.) The standard in the proposed rule is

qualitative (probability or consequences no more than minimally

increased). The intent of this proposed rule is to allow changes that

are small enough that they would not affect the facility's licensing

basis, or adversely affect safety performance. While the proposed rule

would allow minimal increases, licensee still must meet applicable

regulatory limits and other acceptance criteria to which they are

committed (such as contained in Regulatory Guides, etc.) Because the

``more than minimal'' standard allows for there to be a discernable

increase, NRC needs to establish a point beyond which one would

conclude that the increase is not minimal. The following guidance is

offered, including values as to when the Commission would conclude that

the revised criteria are not met. Quantitative calculations are not

required except for those instances in which a licensee offers other

than qualitative arguments as part of its evaluation.

Probability of Occurrence of an Accident

The current guidance in NEI 96-07 states: ``Where a change in

probability is so small or the uncertainties in determining whether a

change in probability has occurred are such that it cannot be

reasonably concluded that the probability has actually changed (i.e.

there is no clear trend towards increasing the probability), the change

need not be considered an increase in probability.'' The Commission

believes this satisfies the proposed NRC standard.

In order to be considered as a minimal increase, the resulting

probability (considering the change, test or experiment) must still

satisfy the event frequency classification provided in the licensee's

FSAR (as updated), e.g., for an anticipated operational occurrence

(expected once a year) or for a design basis accident (not expected

during life of plant, but sufficiently credible to require mitigation).

be considered as a minimal increase, the resulting

probability (considering the change, test or experiment) must still

satisfy the event frequency classification provided in the licensee's

FSAR (as updated), e.g., for an anticipated operational occurrence

(expected once a year) or for a design basis accident (not expected

during life of plant, but sufficiently credible to require mitigation).

Probability of Equipment Malfunction

The Commission believes that the probability of malfunction is more

than minimally increased if a new failure mode as likely as existing

modes is introduced. The determination should be made either at the

component level, or consistent with the failure modes and effects

analyses, taking into account single failure assumptions, and the level

of the change being made.

Guidance in NEI 96-07 states: ``Where a change in probability is so

small or the uncertainties in determining whether a change in

probability has occurred are such that it cannot be reasonably

concluded that the probability has actually changed (i.e. there is no

clear trend towards increasing the probability), the change need not be

considered an increase in probability.'' The Commission believes this

satisfies this criterion.

The probability of malfunction of equipment important to safety

previously evaluated in the FSAR (as updated) is no more than minimally

increased if ``design bases'' assumptions and requirements are still

satisfied (i.e., the seismic or wind loadings, qualification

specifications, procurement requirements). As part of this guidance,

note that NRC concludes that licensees can treat changes in external

hazard design requirements as potentially affecting equipment

malfunction probability rather than as ``accident probability.''

Consequences of Accident or Malfunction

s and requirements are still

satisfied (i.e., the seismic or wind loadings, qualification

specifications, procurement requirements). As part of this guidance,

note that NRC concludes that licensees can treat changes in external

hazard design requirements as potentially affecting equipment

malfunction probability rather than as ``accident probability.''

Consequences of Accident or Malfunction

Guidance in NEI 96-07 states: ``Where a change in consequences is

so small or the uncertainties in determining whether a change in

consequences has occurred are such that it cannot be reasonably

concluded that the consequences have actually changed (i.e. there is no

clear trend towards increasing the consequences), the change need not

be considered an increase in consequences.'' The NRC believes this

satisfies the revised NRC standard.

If a licensee has performed an analysis with certain bounding

assumptions, and the change would increase a specific parameter from

its present value to a different value that is still bounded by the

value assumed in the analysis, NRC concludes that such a change

satisfies the criteria of no more than a minimal increase in

consequences.

As a quantitative measure, the Commission is considering some

options. One would be to establish that a 0.5 rem increase in

calculated dose as a result of the change be used to assess whether a

minimal increase has occurred. This range of change would generally be

in the decimal place for accident analyses where doses are reported in

rem. The facility must still satisfy applicable acceptance values

(e.g., the SRP) or regulatory requirements (e.g., part 100) for the

particular accident. If a licensee would need to change its design

basis assumptions or analytical methods, or both, to demonstrate that

the change in consequences is less than 0.5 rem, then the NRC does not

view the change as minimal and would expect the licensee to submit a

license amendment for such a change

ptance values

(e.g., the SRP) or regulatory requirements (e.g., part 100) for the

particular accident. If a licensee would need to change its design

basis assumptions or analytical methods, or both, to demonstrate that

the change in consequences is less than 0.5 rem, then the NRC does not

view the change as minimal and would expect the licensee to submit a

license amendment for such a change.

In addition, the Commission is considering a graduated approach,

consistent with the concept of ``minimal'' being small enough so as not

to impact the basis for acceptability. When the facility is far from

the limit, a larger increase can be accommodated without concern about

impact on the basis for acceptability. The values proposed take into

account such factors as differences between licensee calculated values

and staff estimation of existing performance, potential for a single

change with a large increase, or for several ``minimal'' increases to

approach the regulatory limits. The specific proposal offered for

comment is:

Example using 300 rem thyroid dose as the limit.

----------------------------------------------------------------------------------------------------------------

Existing calculated dose ``Minimal'' change Pre-change After the change

----------------------------------------------------------------------------------------------------------------

10% increase..... 140 rem............... 170 rem.

80% of limit............. 5% increase...... 205 rem............... 220 rem.

more than 80%....................... 1% increase (NTE 245 rem............... 248 rem.

limit).

----------------------------------------------------------------------------------------------------------------

------------------------------------------------------------------

10% increase..... 140 rem............... 170 rem.

80% of limit............. 5% increase...... 205 rem............... 220 rem.

more than 80%....................... 1% increase (NTE 245 rem............... 248 rem.

limit).

----------------------------------------------------------------------------------------------------------------

A third option under consideration, similar to option 2, would

limit the fraction of remaining margin that can be consumed by a

particular change. By defining ``minimal'' as being 10% of the

remaining margin between current conditions and acceptance guidelines,

the amount of change would decrease as the limit is approached, and the

limit could not be exceeded.

Cumulative Effect

The Commission is concerned about the cumulative effect of minimal

increases. Since some increases are allowed, the Commission believes

that the proposed process would place greater importance on: (1)

Complete and accurate SAR updating; (2) the licensee's evaluation

process taking into account other changes made since last update; (3)

the licensee's screening process examining plant changes to determine

whether they are indeed changes requiring evaluation; and (4) reporting

requirements so that staff can assess the ongoing nature of cumulative

impact.

The issue then becomes how the NRC can best oversee the process

such that several ``minimal'' changes do not result in unacceptable

results. The Commission has decided to require licensees to report

effects of changes in a different manner to facilitate evaluation of

cumulative effect, as discussed in a later section on reporting

requirements, in which the Commission proposes to require that the SAR

update in accordance with Sec. 50.71(e) discuss the effects of the

changes upon calculated doses and other information.

H. Possibility of an Accident of a Different Type from any Previously

Evaluated in the Safety Analysis Report may be Created

evaluation of

cumulative effect, as discussed in a later section on reporting

requirements, in which the Commission proposes to require that the SAR

update in accordance with Sec. 50.71(e) discuss the effects of the

changes upon calculated doses and other information.

H. Possibility of an Accident of a Different Type from any Previously

Evaluated in the Safety Analysis Report may be Created

As noted in Section F above, the uncertainty connected with

demonstrating that no accident or malfunction may have been created is

a major source of confusion and difficulty in implementing the existing

rule; and is unnecessary for purposes of identifying when NRC review of

a change is needed. Accordingly, the Commission proposes that the

language in existing Sec. 50.59(a)(2)(ii) be revised as discussed below

in this section and the following one. As noted earlier, the Commission

is proposing to separate the requirements into distinct criteria for

clarity. This criterion would now read ``if a possibility for an

accident of a different type from any previously evaluated in the final

safety analysis report (as updated) is created.'' Under the proposed

rule, a license amendment would be needed only if the licensee

reasonably concluded that the possibility of an accident of a different

type is created. This contrasts with the current rule, which would

require a license amendment if the licensee is uncertain or unable to

reasonably conclude that a new accident of a different type is not

created. The Commission concludes that this proposed rule change will

still identify those proposed changes, tests, or experiments that the

NRC should review, without also including other changes of lesser

significance that may be viewed as meeting the existing criteria.

Need for Definition of Accident

uncertain or unable to

reasonably conclude that a new accident of a different type is not

created. The Commission concludes that this proposed rule change will

still identify those proposed changes, tests, or experiments that the

NRC should review, without also including other changes of lesser

significance that may be viewed as meeting the existing criteria.

Need for Definition of Accident

In determining whether a proposed change requires prior NRC

approval under Sec. 50.59, the rule refers to whether ``accidents''

previously evaluated in the SAR are impacted, or whether an accident of

a different type may be created (see also Sec. 50.92 criteria for ``no

significant hazards consideration)''. Those accidents evaluated in the

SAR, that is, those events that a plant must show that it can

withstand, are derived from a number of regulatory requirements, and

the safety analyses are included in the FSAR.

The regulations and NRC guidance documents, refer to ``a design

basis accident'' (Sec. 50.36), to design basis events (Sec. 50.49), to

loss-of-coolant accidents (Appendix A), to anticipated operational

occurrences (Appendix A) and to accidents that could result in release

of significant quantities of radioactive fission products (part 100).

The PSAR, and by extension the FSAR, pursuant to Sec. 50.34, is to

contain ``analysis and evaluation of the design and performance of SSC

of the facility with the objective of assessing the risk to public

health and safety resulting from operation of the facility and

including determination of (i) the margins of safety during normal

operations and transient conditions anticipated during the life of the

facility and (ii) the adequacy of SSC provided for the prevention of

accidents and the mitigation of the consequences of accidents.'' RG

1.70 states that the FSAR is to include postulated anticipated

operational occurrences; postulated off-design transients that induce

fuel failures above those expected for normal operational experience,

and design ba

tions anticipated during the life of the

facility and (ii) the adequacy of SSC provided for the prevention of

accidents and the mitigation of the consequences of accidents.'' RG

1.70 states that the FSAR is to include postulated anticipated

operational occurrences; postulated off-design transients that induce

fuel failures above those expected for normal operational experience,

and design basis accidents. The Standard Review Plan for Chapter 15,

refers to anticipated operational occurrences and to postulated

accidents, and also to ``transients and accidents'' (the SRP notes that

other events, such as response to external phenomena, are covered in

other chapters).

Design basis accident(s) has been used in regulatory practice both

singularly and generally. The regulations also include the concept of a

design basis accident (DBA), for purposes of evaluating siting, which

is an assumed fission product release, based upon a major accident that

would result in potential hazards not exceeded by those from any

accident considered credible. Such accidents have generally been

assumed to result in substantial meltdown of the core with subsequent

release of appreciable quantities of fission products. The set of

``accidents'' that a plant must postulate for purposes of FSAR design

and safety analyses, including LOCA, other pipe ruptures, rod ejection,

etc., are often referred to as ``design basis accidents''.

The terms of accidents and transients are often used in regulatory

documents (as for example in Chapter 15 of the Standard Review Plan),

where transients are viewed as the more likely, low consequence events

and accidents as more serious. In the context of probabilistic risk

assessment, transients are typically viewed as initiating events, and

accidents as the sequences that result from various combinations of

plant and safety system response.

However, the meaning of the term ``accident'' as it is used more

generally in Part 50, is somewhat obscured by the

the more likely, low consequence events

and accidents as more serious. In the context of probabilistic risk

assessment, transients are typically viewed as initiating events, and

accidents as the sequences that result from various combinations of

plant and safety system response.

However, the meaning of the term ``accident'' as it is used more

generally in Part 50, is somewhat obscured by the

use of the term ``design basis event.'' In Sec. 50.49, design basis

event is defined as:

normal operations including anticipated operational occurrences,

design basis accidents, external events, natural phenomena

(earthquakes, tornados, hurricanes, floods, tsunami and seiches),

for which the plant must be designed to ensure safety-related

functions.

In view of the range of language presently used to describe the

types of events evaluated as part of the licensing basis, the

Commission is contemplating the need to clarify its intent as to the

extent of events that are within the purview of the criteria in

Sec. 50.59 and in Sec. 72.48). For purposes of stimulating discussion,

the Commission offers two proposals. One would be to set forth a

definition for the term ``accident'' as follows:

an initiating event or combination of events and/or conditions that

could occur from equipment failure, human error, natural or manmade

hazards which challenges the integrity of one or more fission

product barriers (fuel, reactor coolant system, release of

radionuclides (confinement/containment)), required to be analyzed

and/or accounted for by the Commission and addressed in the

licensee's safety analysis report.

combination of events and/or conditions that

could occur from equipment failure, human error, natural or manmade

hazards which challenges the integrity of one or more fission

product barriers (fuel, reactor coolant system, release of

radionuclides (confinement/containment)), required to be analyzed

and/or accounted for by the Commission and addressed in the

licensee's safety analysis report.

Such a definition would make it clear that the Commission's intent

in referring to ``accidents'' in Sec. 50.59 (and in Sec. 72.48) is to

refer to the design basis accidents that are addressed in the SAR. The

second approach is to add the phrase ``design basis accident'' into the

existing criteria. This could be done for each of the three criteria

that refer to ``accident'' or just for the one on accident of a

different type. Since the criteria on probability and consequences also

contain language about ``previously evaluated in the SAR,'' there may

be less need for a reference to ``design basis accident'' in these

criteria. The proposed rule language includes use of the phrase

``design basis accident'' in the one criterion, for purposes of

obtaining public comment.

I. Possibility of a Malfunction of a Different Type from any Previously

Evaluated in the Safety Analysis Report may be Created

In a similar fashion, the Commission proposes to modify the

remaining part of existing Sec. 50.59(a)(2)(ii), concerning

malfunctions of a different type by creating a new criterion that would

read ``if a possibility for a malfunction of equipment important to

safety with a different result than any evaluated previously in the

final safety analysis report (as updated) is created.'' This criterion

involves three revisions to the existing rule. The first change is the

use of the phrase ``is created'' which would require a determination

that the possibility has been created, rather than uncertainty as to

exclusion

alfunction of equipment important to

safety with a different result than any evaluated previously in the

final safety analysis report (as updated) is created.'' This criterion

involves three revisions to the existing rule. The first change is the

use of the phrase ``is created'' which would require a determination

that the possibility has been created, rather than uncertainty as to

exclusion.

The second change is to insert the words ``of equipment important

to safety.'' The existing rule does not provide this characterization

within paragraph (ii), but it is included in paragraph (i). It has

generally been inferred that the statement in paragraph (ii) is an

abbreviated version of that in paragraph (i). A review of the history

of the 1968 rulemaking adopting revisions to Sec. 50.59 did not

disclose any discussion suggesting that the Commission intended to

distinguish between the (a)(2)(i) and the (a)(2)(ii) criteria with

respect to the scope of equipment covered. Therefore, the Commission

concludes that the rule was intended to apply to the same scope of

equipment in each cases, and therefore, proposes to include the words

in this criterion to eliminate any doubt.

The final change is being proposed in response to the comments on

the staff-proposed guidance (NUREG-1606) on the interpretation of

malfunction (of equipment important to safety) of a different type. The

commenters believe that the cause of the malfunction should be a

consideration in determining whether the probability of the malfunction

may have increased, and that a malfunction of a different type would

only be created if the effects of the malfunction are not already

bounded by the FSAR analysis. The recent industry guidance states that

if a component were subject to failure from a new failure mode but the

failure of the component is already considered in the safety analysis,

then there would not be a failure of a different type

ve increased, and that a malfunction of a different type would

only be created if the effects of the malfunction are not already

bounded by the FSAR analysis. The recent industry guidance states that

if a component were subject to failure from a new failure mode but the

failure of the component is already considered in the safety analysis,

then there would not be a failure of a different type. The Commission

does not agree that the industry interpretation is consistent with the

rule as written, which refers to creation or possibility of a

malfunction of a different type, not of a different result. However,

the Commission recognizes that in its reviews, equipment malfunctions

are generally postulated as potential single failures to evaluate plant

performance; thus, the focus of the NRC review was on the result,

rather than the cause/type of malfunction. Unless the equipment would

fail in a way not already evaluated in the safety analysis, there is no

need for NRC review of the change that led to the new type of

malfunction. Therefore, as the third change in Sec. 50.59(a)(2)(ii),

the Commission is proposing to change the phrase ``of a different

type'' to ``with a different result''. Therefore, this criterion would

read: ``if a possibility for a malfunction of equipment important to

safety with a different result . . . is created.''

In implementing this position, attention must be given to whether

the malfunction is evaluated at the component level or the overall

system level. While the evaluation should take into account the level

that was previously evaluated in terms of malfunctions and resulting

event initiators or mitigation impacts, it also needs to consider the

nature of the change. Thus for instance, if failures were previously

postulated on a train level because the trains were independent, a

change that introduces a cross-tie might need to be evaluated to see

whether new outcomes have been introduced

he level

that was previously evaluated in terms of malfunctions and resulting

event initiators or mitigation impacts, it also needs to consider the

nature of the change. Thus for instance, if failures were previously

postulated on a train level because the trains were independent, a

change that introduces a cross-tie might need to be evaluated to see

whether new outcomes have been introduced. The staff has provided

guidance on this issue in Generic Letter (GL) 95-02, concerning

replacement of analog systems with digital instrumentation. The GL

states that in considering whether new types of failures are created,

this must be done at the level of equipment being replaced--not at the

overall system level. Further, it is not sufficient for a licensee to

state that since failure of a system or train was postulated in the

SAR, any other equipment failure is bounded by this assumption, unless

there is some assurance that the mode of failure can be detected and

that there are no consequential effects (electrical interference,

materials interactions, etc), such that it can be reasonably concluded

that the SAR analysis was truly bounding and applicable. Otherwise, the

Commission would conclude that there was increase in probability of

malfunction or that a malfunction with a different result has been

created.

J. Margin of Safety as Defined in the Basis for any Technical

Specification is Reduced

Two criteria in the current regulations (Sec. 50.59) specifically

focus upon accidents and equipment malfunction (creation, consequences

and likelihood) as the measures for determining when a change requires

prior NRC approval. However, the phrases ``margin of safety'' and ``as

defined in the basis for any technical specification'' in the third

criterion have been the subject of differing interpretations because

the rule does not define what constitutes a margin of safety or a basis

for any technical specification in the context of Secs. 50.59 and

72.48

res for determining when a change requires

prior NRC approval. However, the phrases ``margin of safety'' and ``as

defined in the basis for any technical specification'' in the third

criterion have been the subject of differing interpretations because

the rule does not define what constitutes a margin of safety or a basis

for any technical specification in the context of Secs. 50.59 and

72.48. In addition, some have questioned the need for the third

criterion on ``margin of safety.''

The Commission has under consideration a number of proposals on

margin. In the proposed rule text specifically being offered for

comment, one option has been inserted so that commenters can examine

the

relationship of this aspect of the proposed rule to other changes being

offered. This should not be viewed as meaning that this option is

preferred by the Commission. The range of options under consideration

is discussed in more detail below.

Questions of margin are commonly judged in terms of the degree of

confidence that the response of the facility, or of particular SSC, to

postulated challenges is acceptable. Various margins exist in a

facility design. These margins are based on, for example, assumptions

of initial conditions, conservatisms in computer modeling and codes,

allowance for instrument drift and system response time, redundancy and

independence of components in safety trains, and plant response during

operating transient and accident conditions. Margin to conditions that

might be detrimental to safety is also determined by establishing

acceptance criteria to be met for response to various accidents and

transients. Acceptance criteria are established at a value that

accounts for uncertainty about physical properties and other

variability and thus provides margin to unacceptable plant conditions.

Margins are built into the facility to account for routine plant

fluctuations and transients

ty is also determined by establishing

acceptance criteria to be met for response to various accidents and

transients. Acceptance criteria are established at a value that

accounts for uncertainty about physical properties and other

variability and thus provides margin to unacceptable plant conditions.

Margins are built into the facility to account for routine plant

fluctuations and transients. Margins are also built into the plant to

establish the regulatory envelope within which a plant has demonstrated

its ability to respond to a spectrum of design basis accidents. It is

in this category termed the ``regulatory envelope,'' that the NRC

believes that regulatory oversight of changes in margin may be needed

from the standpoint of Sec. 50.59. Thus the Commission notes that not

all margins fall within the purview in which changes to the margin

require prior NRC approval. As part of this rulemaking, the Commission

wants to clarify which margins fall within the regulatory envelope and

how possible reductions in margin resulting from facility or procedure

changes, or from conduct of tests and experiments should be evaluated.

In defining in the rule a standard for NRC review and approval of

changes to margins in the regulatory envelope, the Commission may want

to preserve the NRC's ability to review changes when there is a

potentially significant reduction in a margin of safety,\4\ but clearly

would not want to unduly affect licensee operations. Therefore, for

this proposed rulemaking, the Commission is offering the public the

opportunity to comment on a range of options for treating margin.

Commenters are requested to present opinions about the merits, or

concerns about the specific proposals, or both, and also to offer any

other suggestions for wording.

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ns. Therefore, for

this proposed rulemaking, the Commission is offering the public the

opportunity to comment on a range of options for treating margin.

Commenters are requested to present opinions about the merits, or

concerns about the specific proposals, or both, and also to offer any

other suggestions for wording.

---------------------------------------------------------------------------

\4\ In accordance with 10 CFR 50.92(c)(3), license amendments

involving a significant reduction in a margin of safety do not meet

the criteria for a ``no significant hazards consideration''

determination; thus, changes involving a significant reduction in a

margin of safety are not to be performed under 10 CFR 50.59.

---------------------------------------------------------------------------

Option 1: Control Inputs to Analyses and Methods that Establish TS

The Commission believes it is reasonable to interpret the specific

reference to ``basis for any technical specification'' in the 1968

rulemaking that added the ``margin of safety'' criterion as preserving

the margins in the analyses that established the TS requirements. For

instance, the minimum plant performance conditions and configurations

stated in the TS are the limiting conditions for operation, limiting

safety system settings, and safety limits. Margins of safety exist

within the safety analyses as a result of the specific input

assumptions, methods, or other limits that were used. These parameters

and methods were proposed by the licensee and reviewed by NRC to

account for uncertainties, instrumentation response, and ranges of

possible operating conditions. Because Sec. 50.59 requires prior NRC

approval for a change to the TS, a change that could invalidate the

basis upon which the TS values were established should also receive

prior approval

er limits that were used. These parameters

and methods were proposed by the licensee and reviewed by NRC to

account for uncertainties, instrumentation response, and ranges of

possible operating conditions. Because Sec. 50.59 requires prior NRC

approval for a change to the TS, a change that could invalidate the

basis upon which the TS values were established should also receive

prior approval. In accordance with this interpretation, changes that

invalidate these specific conditions described in the FSAR for analyses

that established the TS requirement (such as a limiting condition of

operation, or a limiting safety system setting) would reduce the margin

of safety associated with the TS.

Under this option, the Commission would conclude that the analyses

and information in the FSAR establish the basis for the margins of

safety for the TS. Thus, the Commission would propose to add a

definition for ``reduction in margin of safety associated with any

technical specification'' and to conform the criterion for needing a

license amendment in new Sec. 50.59(c)(2). The existing terminology of

``basis for any TS'' would be replaced by ``associated with any TS.''

The following definition would be added:

Reduction in margin of safety associated with any technical

specification means that the input assumptions, analytical methods,

acceptance conditions, criteria and limits of the safety analyses,

presented in the final safety analysis report (as updated), that

established any technical specification requirement, are altered in

a nonconservative manner.

Although this option would maintain the safety analyses that

underlie the TS, this approach would also have the effect of giving

input values and assumptions the weight of TS, which is inconsistent

with the philosophy in Sec. 50.36 of establishing TS only on those

values of most immediate safety importance. In many instances, changes

to inputs can be accommodated by other available margins so that the

licensing envelope is preserved.

ety analyses that

underlie the TS, this approach would also have the effect of giving

input values and assumptions the weight of TS, which is inconsistent

with the philosophy in Sec. 50.36 of establishing TS only on those

values of most immediate safety importance. In many instances, changes

to inputs can be accommodated by other available margins so that the

licensing envelope is preserved.

Option 2: Delete ``margin of safety'' as a Criterion.

Under this option, the Commission would delete any criterion

focusing upon margins. Instead, the Commission would rely upon the

other criteria in Sec. 50.59, as well as the regulatory requirement

that all changes to TS be reviewed and approved by the NRC, to assure

that there are no significant adverse changes to margins in design and

operation. The Commission would argue that there is no need for prior

review of changes that do not satisfy any of the other evaluation

criteria in view of ``risk-informed'' insights and greater

understanding of the margins that exist through meeting the body of

regulatory requirements. The Commission seeks comment on whether any of

the other evaluation criteria should be revised were this approach to

be adopted.

Option 3: Control margins associated with results of analyses

Instead of focusing on the inputs to safety analyses, another

interpretation would be to examine the results of the safety analyses,

and to determine whether changes to operational characteristics or

other information described in the FSAR (as updated) would reduce the

level of protection afforded by the TS (i.e., by the limiting safety

system settings and limiting conditions of operation), as reflected in

the results of safety analyses

alyses, another

interpretation would be to examine the results of the safety analyses,

and to determine whether changes to operational characteristics or

other information described in the FSAR (as updated) would reduce the

level of protection afforded by the TS (i.e., by the limiting safety

system settings and limiting conditions of operation), as reflected in

the results of safety analyses.

As part of the licensing review for a facility, the NRC established

a level of required performance (which will be referred to in this

discussion as acceptance criteria) for certain physical parameters,

such as those that define the integrity of the fission product barriers

(fuel cladding, reactor coolant system boundary and containment).

Satisfying these acceptance criteria (or regulatory limits) produces a

margin of safety to loss of barrier integrity. The safety analyses

presented in the FSAR (as updated) demonstrate that the response of the

barriers to the postulated accidents, transients, and malfunctions

meets the acceptance criteria. For

certain of these parameters, TS safety limits have been established;

these safety limits are limits upon important process variables that

are found necessary to reasonably protect the integrity of physical

barriers that guard against the uncontrolled release of radioactivity.

However, for other parameters, a licensee must determine the

licensing basis of the parameter in question by reviewing the plant-

specific safety analyses. The acceptance criterion is that value

approved by the NRC for a particular parameter or process variable

(e.g., ASME Code stress limits, a departure from nucleate boiling ratio

limit or maximum critical power ratio limit or containment design

pressure). These acceptance criteria may be stated in the FSAR, may be

in NRC regulations, or may be presented in the NRC Standard Review

Plan

spects are separately discussed

in order to amplify upon the issues under consideration. However, any

rule language option would need to include some provision for each of

the three aspects.

(a) Which parameters should be controlled?

The margins of safety that would be controlled by the 10 CFR 50.59

process can be characterized in different ways.

OPTION 3(A)(1)--Safety and Regulatory Limits

The margin between regulatory limits and the failure of physical

barriers is protected in the regulations (and also in the portion of

the Technical Specifications (TSs) called ``safety limits''). The

margin, as reflected in approved safety and accident analyses, between

the protection afforded by the TSs (e.g., the limiting safety system

settings and limiting conditions of operations) and the associated

regulatory limits is a possible interpretation as to ``the margin of

safety as defined in the basis for any TS'', which would be subject to

the 10 CFR 50.59 evaluation process. Thus, one proposal under

consideration would be to define ``margin of safety'' as follows:

The ``margin of safety as defined in any technical

specification'' (margin of safety) is the amount (quantitative or

qualitative) of margin between the operation of the facility as

described in the technical specifications and the exceedance of

safety limits listed in the technical specifications or other

regulatory limits. In relation to accident analysis, the margin of

safety is typically the difference between calculated parameters

(e.g., peak fuel clad temperature, maximum RCS pressure, etc.) and

the associated regulatory or safety limit. The margin of safety is a

product of specific values and limits contained in the technical

specifications (which cannot be changed without NRC approval) and

other values, such as assumed accident or transient initial

conditions or assumed safety system response times, which are not

specifically contained in the technical specifications

re, etc.) and

the associated regulatory or safety limit. The margin of safety is a

product of specific values and limits contained in the technical

specifications (which cannot be changed without NRC approval) and

other values, such as assumed accident or transient initial

conditions or assumed safety system response times, which are not

specifically contained in the technical specifications. Any change

to the values not specifically contained in the technical

specifications must be evaluated for impact on the margin between

the calculated result of an accident or transient and the safety or

regulatory limit.

With this option, before changing operational characteristics

described in the UFSAR (not directly controlled by TS), a safety

evaluation must be performed to determine, among other things, if the

change results in a reduction in the level of protection afforded by

the TS (margin of safety as defined in any TS). Such a reduction would

typically occur only if the operational characteristic had been used as

a bounding condition in the analysis upon which the selection of TS was

based, or in analysis where the acceptability of selected TS values was

demonstrated. Licensees could make desired changes to operational

characteristics without prior NRC approval, provided that the change

does not result in accident analysis results that are nearer the

regulatory, or safety, limits than the corresponding results that the

NRC used in evaluating the acceptability of the TS during licensing of

the facility.

OPTION 3(A)(2)--Fission product barriers--definition

Licensees could make desired changes to operational

characteristics without prior NRC approval, provided that the change

does not result in accident analysis results that are nearer the

regulatory, or safety, limits than the corresponding results that the

NRC used in evaluating the acceptability of the TS during licensing of

the facility.

OPTION 3(A)(2)--Fission product barriers--definition

The NRC notes that Sec. 50.36 (requirements for Technical

Specifications) has criteria for when TS are to be provided that

specifically are tied to design basis accident or transient analysis

that either assumes the failure of or presents a challenge to the

integrity of a fission product barrier. Thus, the margin as defined in

the basis for any TS can be reasonably viewed as that margin associated

with preserving integrity of these barriers. Therefore, the NRC is also

considering a more explicit linkage to the response of the three

fission product barriers generally relied upon to provide protection

from uncontrolled release of radioactive materials from a reactor

facility. Under such a proposal, the text of the rule would explicitly

state that it is the response of fission product barriers (fuel,

reactor coolant system, and containment) to accidents, transients, and

malfunctions that is being controlled.

The following could be given as a definition of margin of safety

and of fission product barrier response. Regulatory guidance would

explicitly list the parameters (for PWRs and BWRs) that are to be

controlled.

The margin of safety for any fission product barrier response is

the difference between the calculated value and its associated

acceptance criteria. Fission product barrier response means those

parameters that must be satisfied in the event of postulated design

basis events to demonstrate integrity of the fuel, reactor coolant

system and containment system barriers.

t are to be

controlled.

The margin of safety for any fission product barrier response is

the difference between the calculated value and its associated

acceptance criteria. Fission product barrier response means those

parameters that must be satisfied in the event of postulated design

basis events to demonstrate integrity of the fuel, reactor coolant

system and containment system barriers.

The following parameters would be included: Fuel and cladding

performance (peak cladding temperature, or energy deposition, DNBR or

MCPR, oxidation), RCS performance (pressure, flows, stress), and

containment performance (peak pressure, containment leakage).

OPTION 3(A)(3)--Specified Parameters

A variant on the previous option would be to actually list the

parameters of interest directly in the criterion for prior review, as

for instance, the criterion could read:

(vii) Result in a change to the FSAR (as updated) calculated

value of RCS peak pressure, containment peak pressure, or fuel

performance (DNBR/MCPR, others), etc.

This variant has the advantage of being more precise, but the rule

language would need to be crafted to account for various reactor types.

OPTION 3(A)(4)--Include Mitigation Capability

The Commission is interested in preserving the integrity of both

prevention and mitigation capabilities available in the plant, and is

therefore considering an option that would include both features within

the ``margin'' criterion if the margin criterion is maintained. If this

approach were adopted, the definition or the list of parameters would

be supplemented with the performance parameters for the

ssion is interested in preserving the integrity of both

prevention and mitigation capabilities available in the plant, and is

therefore considering an option that would include both features within

the ``margin'' criterion if the margin criterion is maintained. If this

approach were adopted, the definition or the list of parameters would

be supplemented with the performance parameters for the

accident mitigation capability of the plant, as for instance, ECCS

performance (pressures, flows, actuation values), engineered safety

feature performance (flows, pressures, spray effectiveness, system

efficiencies).

Finally, in conjunction with any of these approaches, the

Commission is also considering whether there are other parameters

important to preservation of barriers that should be explicitly

defined. For instance, for fuel stored in spent fuel pools, or for the

reactor during periods of shutdown or refueling, there may be other

analysis results (water level, pool temperature) in lieu of reactor

coolant system pressure. Therefore, the Commission seeks input as to

whether there are other parameters of interest beyond those previously

offered that should be included within the ``margin of safety''

criterion if that criterion is maintained, and how should the rule

language be revised to specify what those parameters might be.

(b) Determination of reduction in margin requiring review

Once the parameters of interest are determined, it is also

necessary to define when a reduction in margin warranting NRC review

and approval has occurred

t should be included within the ``margin of safety''

criterion if that criterion is maintained, and how should the rule

language be revised to specify what those parameters might be.

(b) Determination of reduction in margin requiring review

Once the parameters of interest are determined, it is also

necessary to define when a reduction in margin warranting NRC review

and approval has occurred. The Commission is evaluating options ranging

from any ``nonconservative change in calculated values,'' to a

``minimal change'' standard, and ultimately an option that would allow

increases up to ``specified limits (acceptance criteria)'' for those

parameters that may be established in the regulations or NRC guidance

(such approaches to the limits might be controlled in a graduated

fashion as was discussed in the section of this notice relating to

``minimal increases''). An option for the degree of reduction would be

paired with an option (such as one of those listed in (a) above) to

provide the text of the rule.

OPTION 3(B)(1)--No Reduction

One approach would be require that the safety analysis, considering

the effect of the change, must show that the accident analysis results

are not nearer to any safety or regulatory limit, thus, a ``no

reduction in margin'' standard. Possible rule text:

Changes, or the net effect of multiple changes, which result in

a reduction in the margin of safety require prior NRC approval.

Changes, or the net effect of multiple changes, which do not cause a

reduction in the margin of safety do not require prior NRC approval.

OPTION 3(B)(2)--Minimal Amount--Definition of Margin Reduction

thus, a ``no

reduction in margin'' standard. Possible rule text:

Changes, or the net effect of multiple changes, which result in

a reduction in the margin of safety require prior NRC approval.

Changes, or the net effect of multiple changes, which do not cause a

reduction in the margin of safety do not require prior NRC approval.

OPTION 3(B)(2)--Minimal Amount--Definition of Margin Reduction

As discussed in other sections of this notice, the Commission

concludes that the revised rule should allow licensees some flexibility

in making changes, through development of a ``minimal increase''

standard. In considering margins, the Commission is thus weighing how

such a concept could be applied. One option would be that NRC approval

would be required for a change, test, or experiment if the output

values (calculated in the SAR) are altered by more than a minimal

amount. The ``margin'' criterion would be modified to state that a

change in calculated result of ``more than a minimal amount'' would

require prior review and approval. Either in the rule itself, or in

guidance, the Commission would define ``minimal amount'', modeled upon

the options offered for minimal increases in consequences (see section

II.G. of this notice). For example, there could be a fixed amount

(percent change) in margin, as long as regulatory limits are still met.

If guidance itemizes the parameters, such guidance could also customize

how ``minimal'' should be judged for each particular parameter

(allowing greater amounts for certain parameters depending on precision

of calculations, sensitivity of results and other considerations).

For instance, the definition of ``margin of safety reduction * *

*'' might be stated as follows:

Reduction in margin of safety means that as a result of a

change, the [MARGIN] is altered in a nonconservative manner by more

than a minimal amount.

OPTION 3(B)(3)--Minimal Determined With Respect to Acceptance Criteria

(Available Margin)

tions, sensitivity of results and other considerations).

For instance, the definition of ``margin of safety reduction * *

*'' might be stated as follows:

Reduction in margin of safety means that as a result of a

change, the [MARGIN] is altered in a nonconservative manner by more

than a minimal amount.

OPTION 3(B)(3)--Minimal Determined With Respect to Acceptance Criteria

(Available Margin)

It is also possible to achieve this result by removing the language

referring to margin of safety (and to TS), and defining ``minimal'' in

the rule itself in terms of the results or analyses for barrier

response, with respect to meeting the acceptance criteria for those

barriers. For example, rule language could read as follows:

License amendment needed if as a result of a change, test or

experiment:

(vii) there is more than a 10% reduction in the difference

between the calculated value and the acceptance criteria for fission

product barrier response to accidents evaluated in the SAR.

If such an approach is followed, the Commission would propose to

include a definition of acceptance criteria, such as follows:

Acceptance criteria are those values, established by NRC

regulation or review guidance, to which the licensee is committed

through its FSAR (as updated), as the basis for acceptability of

response to the postulated accident, transient or malfunction.

(c) Evaluation of effect of the change upon analysis results.

The Commission also notes that the results of safety analyses are

subject to variance depending upon the assumptions, analysis methods or

analytical techniques used. In many instances, these factors were

reviewed by the NRC during its licensing deliberations, and their use

may have formed part of the basis for the conclusion that acceptable

safety margins were demonstrated. Therefore, the Commission wishes to

ensure that proposed changes by a licensee would not invalidate these

conclusions by requiring a demonstration that the evaluation techniques

and analyses are suitable

hese factors were

reviewed by the NRC during its licensing deliberations, and their use

may have formed part of the basis for the conclusion that acceptable

safety margins were demonstrated. Therefore, the Commission wishes to

ensure that proposed changes by a licensee would not invalidate these

conclusions by requiring a demonstration that the evaluation techniques

and analyses are suitable.

To accomplish this, the Commission is considering having as part of

whichever definition of ``margin of safety reduction'' is selected the

following statement [Option 3(c)]:

All analyses and evaluations for assessing the impacts of

proposed changes must be performed using methodology and analytical

techniques which are either reviewed and approved by the NRC or

which are shown to meet applicable review guidance and standards for

such analyses.

The alternative to this proposed language would be to rely upon a

licensee's design control processes under their quality assurance

requirements and program, to provide the assurance that any evaluative

work has been conducted with methods and techniques commensurate with

the safety significance of the analyses being performed.

Impacts for Part 72 Changes

Certain of the options discussed above may need to be modified for

application to independent spent fuel storage facilities or spent fuel

storage cask designs in Part 72. While the overall philosophy would be

the same, the particular outputs or barriers that would be specified

for reductions in margin would have to be defined in terms of the

barriers against release of radioactivity afforded by fuel storage

facilities. For instance, these might include calculated fuel

temperature or cladding oxidation, and stresses (or pressures) on the

cask structure. Comment is also requested on the appropriate parameters

for facilities licensed under Part 72.

K. Safety Evaluation

Section 50.59(b)(1) requires licensees to maintain records that

must include a written safety evaluation that provides

l storage

facilities. For instance, these might include calculated fuel

temperature or cladding oxidation, and stresses (or pressures) on the

cask structure. Comment is also requested on the appropriate parameters

for facilities licensed under Part 72.

K. Safety Evaluation

Section 50.59(b)(1) requires licensees to maintain records that

must include a written safety evaluation that provides

the bases for the determination that the change, test, or experiment

does not involve an unreviewed safety question. Section 50.59(b)(2)

requires submittal of a report containing a brief description of any

changes, tests, or experiment, including a summary of the safety

evaluation of each. In the interest of emphasizing the regulatory

purpose of the evaluation required under Sec. 50.59, which led the

Commission to propose deletion of the term ``unreviewed safety

question,'' the Commission proposes to delete the word ``safety'' in

referring to the required evaluation for determining whether the

change, test, or experiment requires a license amendment. For purposes

of the summary report of tests and experiments submitted to NRC, the

staff would propose that the rule specify that a summary of the

evaluation be provided (rather than a summary of the safety

evaluation).

A similar change is proposed for Sec. 50.71(e), which presently

refers to safety evaluations either in support of license amendments or

of conclusions that changes did not involve USQs. The Commission

proposes to change ``safety evaluation in support of license

amendments'' to ``safety analysis in support of license amendments,''

to reduce confusion between the information prepared by the licensee

for the amendment (safety analysis) and the NRC review (safety

evaluation). The second part of this phrase would be revised to refer

to the ``evaluation that changes did not require a license amendment in

accordance with Sec. 50.59(c)(2) of this part.'' (In this case, it is a

licensee evaluation against the regulatory criteria in Sec

confusion between the information prepared by the licensee

for the amendment (safety analysis) and the NRC review (safety

evaluation). The second part of this phrase would be revised to refer

to the ``evaluation that changes did not require a license amendment in

accordance with Sec. 50.59(c)(2) of this part.'' (In this case, it is a

licensee evaluation against the regulatory criteria in Sec. 50.59 that

is being referred to). In addition, other minor wording changes are

proposed such as with respect to terminology on ``final safety analysis

report'' and ``effects of'' (see reporting requirements discussion

below). Conforming changes in the appendices to part 52 and in part 72

to revise language to refer to ``evaluation'' are also proposed.

L. Reporting and Recordkeeping Requirements

In view of the ``minimal increase'' criteria in Sec. 50.59, the

Commission concludes that the reporting requirements for the SAR update

should be enhanced to enable the NRC to better understand the potential

cumulative impact of changes that might have been made since the last

update. Therefore, the Commission proposes to supplement the reporting

requirements on ``effects'' of changes to require that in the FSAR

update submittal (with the replacement pages), the licensee shall

include a description of each change affecting that part of the SAR

that provides sufficient information to document the effect of the

change upon the probability or consequences of accidents or

malfunctions, or reductions in margin associated with that part of the

SAR. Accordingly, the Commission proposes to revise Sec. 50.71(e) to

read as follows:

the replacement pages), the licensee shall

include a description of each change affecting that part of the SAR

that provides sufficient information to document the effect of the

change upon the probability or consequences of accidents or

malfunctions, or reductions in margin associated with that part of the

SAR. Accordingly, the Commission proposes to revise Sec. 50.71(e) to

read as follows:

``(e) Each person licensed to operate a nuclear power reactor

pursuant to the provisions of Sec. 50.21 or Sec. 50.22 of this part

shall update periodically, as provided in paragraphs (e)(3) and (4)

of this section, the final safety analysis report (FSAR) originally

submitted as part of the application for the operating license, to

assure that the information included in the FSAR (as updated)

contains the latest information developed. The submittal must

describe the effects \1\ of: (1) All changes made in the facility or

procedures as described in the FSAR; (2) all safety analyses and

evaluations performed by the licensee either in support of requested

license amendments, or in support of conclusions that changes did

not require a license amendment in accordance with Sec. 50.59(c)(2)

of this part; (3) all analyses of new safety issues performed by or

on behalf of the licensee at Commission request; and (4) the net

effect of all changes made since the last update on the safety

analyses, including probabilities, consequences, calculated values,

system or component performance, that are in the FSAR (as updated).

The updated information shall be appropriately located within the

update to the FSAR.

\1\ Effects of changes includes appropriate revisions of

descriptions in the FSAR such that the FSAR (as updated) is complete

and accurate.

---------------------------------------------------------------------------

ces, calculated values,

system or component performance, that are in the FSAR (as updated).

The updated information shall be appropriately located within the

update to the FSAR.

\1\ Effects of changes includes appropriate revisions of

descriptions in the FSAR such that the FSAR (as updated) is complete

and accurate.

---------------------------------------------------------------------------

Finally, the Commission is proposing a change to the record

retention requirements in existing Sec. 50.59 (b)(3) (renumbered by

this rulemaking to (c)(3)). The change would add to the requirement

that the records of changes to the facility be maintained until the

termination of the license, the statement ``or until the termination of

a license issued pursuant to 10 CFR part 54, whichever is later.'' This

change would make more clear the requirement that records must be

maintained through the life of the facility so that they will remain

available until such time as they are no longer needed (that is, when

the license is terminated, not just at the end of the initial licensing

term).

M. Part 72 Changes

In part 72 the Commission is proposing to make conforming changes

to Sec. 72.48 with those made to Sec. 50.59 and to expand the scope of

Sec. 72.48 so that holders of a Certificate of Compliance (CoC) are

also subject to it. In addition to the proposed changes to Sec. 72.48,

the Commission proposes to make changes in other sections of part 72.

When subpart L--Approval of Spent Fuel Storage Casks, was originally

added to part 72, no provisions were included to address potential

amendments of CoCs. However, regulations in this area are necessary to

provide requirements for certificate holders in instances where a

proposed change does not meet the tests of Sec. 72.48, and an amendment

to the CoC is necessary. Therefore Secs. 72.244 and 72.246 would be

added to subpart L, to provide regulations on applying for, and

approving, amendments to CoCs

ed to address potential

amendments of CoCs. However, regulations in this area are necessary to

provide requirements for certificate holders in instances where a

proposed change does not meet the tests of Sec. 72.48, and an amendment

to the CoC is necessary. Therefore Secs. 72.244 and 72.246 would be

added to subpart L, to provide regulations on applying for, and

approving, amendments to CoCs. Section 72.248 would also be added to

provide regulations for the certificate holder submitting an updated

final safety analysis report, which would document the changes it made

to procedures or structures, systems, and components under the

provisions of Sec. 72.48. The Commission notes that a general licensee

is not precluded from loading spent fuel into an approved spent fuel

storage cask during the 90-day period allowed for the certificate

holder to submit a final safety analysis report. This approach is the

same as that required for part 72 license holders to update their final

safety analysis report under Sec. 72.70. The Commission also notes,

that for dual-purpose spent fuel casks (i.e., casks which have been

issued CoCs for transportation and storage under parts 71 and 72,

respectively), no regulation equivalent to Sec. 72.48 exists in part

71. Consequently, a certificate holder could make changes to the design

of a spent fuel storage cask under the authority of Sec. 72.48 (i.e.,

without prior NRC approval); however, if the change also affected the

transportation aspects of the cask's design and involved a modification

to the part 71 certificate, then NRC approval and amendment of the

transportation CoC would be required before the cask could be used to

transport spent fuel to another site. Additionally, a transportation

cask CoC has a term of 5 years, compared to the 20-year term for a

storage CoC

ever, if the change also affected the

transportation aspects of the cask's design and involved a modification

to the part 71 certificate, then NRC approval and amendment of the

transportation CoC would be required before the cask could be used to

transport spent fuel to another site. Additionally, a transportation

cask CoC has a term of 5 years, compared to the 20-year term for a

storage CoC. Consequently, the Commission envisions that most of this

type of change would be captured during the periodic renewal of a

transportation CoC and this delay would not have a significant adverse

impact on a licensee's ability to transport spent fuel in a dual

purpose cask.

In Sec. 72.3 the definition for independent spent fuel storage

installation (ISFSI) would be revised to remove the tests for

evaluation of the acceptability of sharing common utilities and

services between the ISFSI and other facilities. The existing

requirement in Sec. 72.24(a)--Contents of application: Technical

Information,

would be revised to reference shared common utilities and services in

the applicant's assessment of potential interactions between the ISFSI

and another facility. The Commission would remove the existing

requirement in Sec. 72.3 for the applicant to evaluate the impact of

sharing common utilities and services on the ``other facility.'' The

Commission believes that evaluation of the impact on the ``other

facility'' should not be part of the licensing process for an ISFSI.

Rather, such evaluation should be part of the license amendment process

for that ``other facility'' and should be performed under the

regulations used to license that ``other facility.''

Changes to Sec. 72.56 would be conforming changes to those made to

Sec. 50.90. Changes to Sec. 72.70 are also conforming changes to those

made to Sec. 50.71(e); additionally, requirements would be added to

Sec. 72.70 on standards for submitting revised Final Safety Analysis

Report (FSAR) pages. The Commission notes that the proposed Sec

he

regulations used to license that ``other facility.''

Changes to Sec. 72.56 would be conforming changes to those made to

Sec. 50.90. Changes to Sec. 72.70 are also conforming changes to those

made to Sec. 50.71(e); additionally, requirements would be added to

Sec. 72.70 on standards for submitting revised Final Safety Analysis

Report (FSAR) pages. The Commission notes that the proposed Sec. 72.70

would retain the requirement that the site-specific licensee submit a

final safety analysis report at least 90 days prior to the planned

receipt of spent fuel or high-level waste. The Commission has not

received any requests for exemption from this regulation and believes

that this regulation does not impose an undue burden or schedule impact

on licensees. The proposed rule also modifies the requirements for

filing of updates (through reference to Sec. 72.4) to be consistent

with other changes being made to part 72. Changes to Sec. 72.216 for a

general licensee are similar to the changes made to Sec. 72.70 for a

site-specific licensee and are also conforming changes to those made to

Sec. 50.71(e). The Commission also envisions that a general licensee

who wishes to adopt a change to the design of a spent fuel storage cask

it possesses--which was previously made to the generic design by the

certificate holder under the provisions of Sec. 72.48--would be

required to perform a separate evaluation under the provisions of

Sec. 72.48 to determine the suitability of the change for itself. The

changes to Secs. 72.9 and 72.86 are conforming changes due to the

addition of new Secs. 72.244, 72.246, and 72.248.

Changes to part 72 Record keeping requirements would include the

clarification that records required by Sec. 72.48 shall also include

determinations that significant increases in occupational exposure or

unreviewed environmental impacts did not exist, such that a license

amendment would have been required

.86 are conforming changes due to the

addition of new Secs. 72.244, 72.246, and 72.248.

Changes to part 72 Record keeping requirements would include the

clarification that records required by Sec. 72.48 shall also include

determinations that significant increases in occupational exposure or

unreviewed environmental impacts did not exist, such that a license

amendment would have been required. (The existing language linked the

written evaluation only to the ``unreviewed safety question''

determination, and thus did not explicitly require Record keeping for

the determinations of whether the change would cause a significant

increase in occupational exposure or a significant unreviewed

environmental impact). Certificate holders would also be required to

keep records of such changes as would be allowed under Sec. 72.48.

Requirements in Sec. 72.70 would be established for reporting

changes to procedures. The Commission notes that Sec. 72.70 presently

requires that the update include 5 a description and

analysis of changes in the structures, systems, and components with

emphasis upon performance requirements; the bases, with technical

justification therefor, upon which such requirements are based; and

evaluations showing that safety functions will be accomplished. It also

requires an analysis of the significance of any changes to codes,

standards, regulations, or regulatory guides which the licensee has

committed to meeting the requirements of which are applicable to the

design, construction, or operation of the facility. New reporting

requirements for certificate holders would be added in Secs. 72.244 and

72.248, similar to existing requirements imposed on licensees in

Secs. 72.56 and 72.70, respectively. New reporting requirements for

general licensees would be added as Sec. 72.216(d), similar to existing

reporting requirements for site-specific licensees in Sec. 72.70 and

proposed requirements for certificate holders in Sec. 72.248

s for certificate holders would be added in Secs. 72.244 and

72.248, similar to existing requirements imposed on licensees in

Secs. 72.56 and 72.70, respectively. New reporting requirements for

general licensees would be added as Sec. 72.216(d), similar to existing

reporting requirements for site-specific licensees in Sec. 72.70 and

proposed requirements for certificate holders in Sec. 72.248. In both

of these sections, the Commission is adding a requirement that the

entity making a change to the cask, either the general licensee or the

certificate holder, provide a copy of the submittal to the other party

for their information.

---------------------------------------------------------------------------

\5\ The similarity in the language between Secs. 72.24 and

50.34(a) and between Secs. 72.70 and 50.34(b)(2) is noteworthy.

---------------------------------------------------------------------------

III. Section By Section Analysis

10 CFR Part 50

10 CFR 50.59

As discussed in more detail above, Sec. 50.59 would be restructured

and revised to have the following components.

Paragraph (a)--This is a new paragraph that provides definitions of

terms such as ``change'', ``facility as described * * *,'' in order to

specify more clearly which changes, tests and experiments require

further evaluation and how reductions in margin of safety are to be

determined. The references to ``safety analysis report'' are being

revised to ``final safety analysis report (as updated)'' to state that

the evaluations are to be performed that take into account other

changes made that have affected the final safety analysis report since

its original submittal.

Paragraph (b)--Relocation of existing applicability provisions.

Paragraph (c)(1)--Relocation of existing provisions establishing

which changes, tests, or experiments require evaluation, using the

defined terms. The terminology of ``unreviewed safety question'' has

been replaced by referring to the need to obtain a license amendment

e final safety analysis report since

its original submittal.

Paragraph (b)--Relocation of existing applicability provisions.

Paragraph (c)(1)--Relocation of existing provisions establishing

which changes, tests, or experiments require evaluation, using the

defined terms. The terminology of ``unreviewed safety question'' has

been replaced by referring to the need to obtain a license amendment.

This paragraph also clarifies that the licensee must submit its request

for license amendment, and obtain the amendment prior to implementing

those changes, tests or experiments that involve TS or otherwise meet

the criteria for prior NRC approval as specified in (new) paragraph

(c)(2).

Paragraph (c)(2)--Reformatting of the evaluation requirements into

seven distinct statements of the criteria and revision of the criteria

for when prior NRC approval of a change, test or experiment is

required. Specifically, language of ``more than a minimal increase''

was inserted in the criteria concerning increases in probability and

consequences, and revisions to the rule requirements were made

concerning creation of accidents of a different type and malfunctions

of equipment with a different result. Clarification is also being

provided that the margins of safety are those associated with TS

requirements established by the FSAR analyses, and are not confined to

the BASES section of the TS. These revisions clarify the criteria for

when prior approval is needed and allow some flexibility for licensees

to make changes that would not affect the NRC basis for licensing of

the facility.

Paragraph (d)(1)--Renumbered paragraph with record keeping

requirements. Also includes change from ``safety evaluation'' to

``evaluation.''

Paragraph (d)(2)--Renumbered paragraph with reporting requirements.

Paragraph (d)(3)--Renumbered and revised paragraph on retention of

records, to cover the term of any renewed license.

10 CFR 50.66

t affect the NRC basis for licensing of

the facility.

Paragraph (d)(1)--Renumbered paragraph with record keeping

requirements. Also includes change from ``safety evaluation'' to

``evaluation.''

Paragraph (d)(2)--Renumbered paragraph with reporting requirements.

Paragraph (d)(3)--Renumbered and revised paragraph on retention of

records, to cover the term of any renewed license.

10 CFR 50.66

The proposed changes for Sec. 50.66 are to conform existing

language referring to unreviewed safety questions, and references to

updated final safety analysis report, to the language

proposed in revised Sec. 50.59 for consistency.

10 CFR 50.71(e)

The proposed changes to this section are to conform language with

respect to unreviewed safety question, safety evaluation, and reference

to final safety analysis report (as updated), with the proposed

language in Sec. 50.59, and to clarify reporting requirements relating

to ``effects of'' changes such that cumulative effects of minimal

increases in probability and consequences are included in the update to

the FSAR.

10 CFR 50.90

A portion of existing Sec. 50.59(c) would be relocated into this

section. This change would place the requirements for changes to

technical specifications in the rule section on amendments to licenses.

10 CFR Part 52

Appendix A and Appendix B to 10 CFR Part 52

The proposed changes to these sections are to conform references to

unreviewed safety question, safety evaluation and the evaluation

criteria concerning when prior NRC approval is needed, to the language

in the proposed revision to Sec. 50.59.

10 CFR Part 72

10 CFR 72.3

The definition for independent spent fuel storage installation

would be revised to remove the tests for evaluation of the

acceptability of sharing common utilities and services between the

ISFSI and other facilities. (Section 72.24 is also proposed to be

revised to include this evaluation).

10 CFR 72.9

ed, to the language

in the proposed revision to Sec. 50.59.

10 CFR Part 72

10 CFR 72.3

The definition for independent spent fuel storage installation

would be revised to remove the tests for evaluation of the

acceptability of sharing common utilities and services between the

ISFSI and other facilities. (Section 72.24 is also proposed to be

revised to include this evaluation).

10 CFR 72.9

Paragraph (b) would be revised as a conforming change to include in

the list of information collection requirements the new reporting

requirements in Secs. 72.244 and 72.248 for reports of changes made by

CoC holders and for updates to the safety analysis reports by CoC

holders.

10 CFR 72.24

This section would be revised to reference shared common utilities

and services in the applicant's assessment of potential interactions

between the ISFSI and another facility (previously covered by

Sec. 72.3).

10 CFR 72.48

New definitions have been added for terms such as ``change'' and

``facility as described in the Final Safety Analysis Report (as

updated).'' The specific criteria in existing paragraph (a)(2) have

been revised to separate out the various statements, to insert the

language of ``more than a minimal increase,'' and to modify the

criterion from ``malfunction of a different type'' to ``malfunction of

a different result.'' The text for Record keeping requirements was

revised to refer to the need for license or certificate of compliance

(CoC) amendments, rather than involving an unreviewed safety question.

As part of this revision, the Commission is also clarifying that the

records shall also provide a basis for why a proposed change, test, or

experiment did not require a license or CoC amendment with respect to

significant increases in occupational exposure or significant

unreviewed environmental impacts. Additionally, the term ``Final Safety

Analysis Report (FSAR) (as updated)'' has been used to provide greater

clarity and consistency with Sec. 50.59 and other sections of Part 72

rovide a basis for why a proposed change, test, or

experiment did not require a license or CoC amendment with respect to

significant increases in occupational exposure or significant

unreviewed environmental impacts. Additionally, the term ``Final Safety

Analysis Report (FSAR) (as updated)'' has been used to provide greater

clarity and consistency with Sec. 50.59 and other sections of Part 72.

The filing requirements for the summary reports are modified to be

consistent with Sec. 72.4 (Communications).

10 CFR 72.56

Existing Sec. 72.48 (c)(2) is being relocated into this section.

This is a parallel change to that proposed for Sec. 50.59 and

Sec. 50.90, wherein the Commission would place the requirements for

changes to license conditions in the rule section on amendments to

licenses.

10 CFR 72.70

Paragraphs (a) and (b) would be revised to use the terms ``Final

Safety Analysis Report,'' ``FSAR,'' and ``as updated.'' Paragraph

(b)(2) would be revised to add changes to procedures to the annual

updates of the FSAR. New paragraph (c) would be added to provide

requirements on submitting revisions to the FSAR.

10 CFR 72.86

Paragraph (b) currently includes those sections under which

criminal sanctions are not issued. This paragraph would be revised by

adding Secs. 72.244 and 72.246 as a conforming change to reflect that

certificate holders who fail to comply with these new sections would

not be subject to the criminal penalty provisions of section 223 of the

Atomic Energy Act (AEA). New Sec. 72.248 has not been included in

paragraph (b) to reflect that certificate holders who fail to comply

with this new section would be subject to the criminal penalty

provisions of section 223 of the AEA.

10 CFR 72.212(b)(4)

rtificate holders who fail to comply with these new sections would

not be subject to the criminal penalty provisions of section 223 of the

Atomic Energy Act (AEA). New Sec. 72.248 has not been included in

paragraph (b) to reflect that certificate holders who fail to comply

with this new section would be subject to the criminal penalty

provisions of section 223 of the AEA.

10 CFR 72.212(b)(4)

The change to this section is to conform the reference to 10 CFR

50.59 provisions, specifically to change from the terminology of

unreviewed safety question to referring to need for license amendment

for the facility (that is, the reactor facility at whose site the

independent spent fuel storage installation is located).

10 CFR 72.216

New paragraph (d) provides requirements for a general licensee to

submit annual updates to a final safety analysis report (FSAR) for the

cask or casks approved for spent fuel storage cask that are used by the

general licensee. The general licensee is also required to provide a

copy of its submittal to the certificate holder. This section is

similar to the requirements in Secs. 72.70 and 72.248 for submission of

annual updates to the FSAR associated with a site-specific Part 72

licensee or a certificate holder, respectively.

10 CFR 72.244

This new section provides requirements for a certificate holder to

submit an application to amend the certificate of compliance (CoC).

This section is similar to the requirements in Sec. 72.56 for licensees

to apply for an amendment to their license.

10 CFR 72.246

This new section provides requirements for approval of an amendment

to a CoC. This section is similar to the requirements in Sec. 72.58 for

approval of an amendment to a license.

10 CFR 72.248

submit an application to amend the certificate of compliance (CoC).

This section is similar to the requirements in Sec. 72.56 for licensees

to apply for an amendment to their license.

10 CFR 72.246

This new section provides requirements for approval of an amendment

to a CoC. This section is similar to the requirements in Sec. 72.58 for

approval of an amendment to a license.

10 CFR 72.248

This new section provides requirements for submittal of annual

updates to a FSAR associated with the design of a spent fuel storage

cask which has been issued a CoC. This new section also provides that

the changes to procedures and structures, systems, and components

associated with the spent fuel storage cask and which are made pursuant

to Sec. 72.48 would be included in the annual update. The proposed

revisions would also require that the certificate holder provide a copy

of the FSAR submittal to each general licensee using that cask. This

section is similar to the requirements in Sec. 72.70 for submission of

annual updates to the FSAR associated with a site-specific part 72

license and new section 72.216 for general licensees to provide updates

to the FSAR.

IV. Commission Voting Record on SECY-98-171

The staff forwarded to the Commission a proposed rulemaking package

on Sec. 50.59 and related regulations in SECY-98-171, dated July 10,

1998. This document was placed in the Public Document Room on July 29,

1998. Subsequently, the Commission voted to approve issuance of a

proposed rule for public comments with several additions and changes

that are reflected in this notice. The Commission also directed that

the record of their decision on SECY-98-171 be included as part of this

notice to clearly inform stakeholders on preliminary positions taken by

the Commission. The text of the resultant staff requirements memorandum

and of the individual Commissioner vote sheets, is presented below.

Commission SRM on SECY-98-171, Dated September 25, 1998

ected in this notice. The Commission also directed that

the record of their decision on SECY-98-171 be included as part of this

notice to clearly inform stakeholders on preliminary positions taken by

the Commission. The text of the resultant staff requirements memorandum

and of the individual Commissioner vote sheets, is presented below.

Commission SRM on SECY-98-171, Dated September 25, 1998

The Commission has approved publication, for a 60 day public

comment period, the proposed rulemaking that would revise 10 CFR 50.59

and related provisions in parts 50, 52 and 72 concerning the processes

controlling licensee changes, tests and experiments for production and

utilization facilities and for facilities for independent storage of

spent nuclear fuel and high-level radioactive waste. The Voting Record,

which includes the Commissioner votes and this Staff Requirements

Memorandum, should be published in the Federal Register notice to

clearly inform stakeholders on preliminary positions taken by the

Commission (Enclosed).

The Commission also approves the staff's recommendations for

handling violations of 10 CFR 50.59 and 72.48, including staff plans

for exercise of enforcement discretion, while rulemaking is underway.

The Commission requested that the staff specifically solicit public

comment in the Federal Register notice on:

1. A wide array of options for the margin of safety criterion

(50.59(c)(2)(vii) in the proposed rule) and its definition including:

dations for

handling violations of 10 CFR 50.59 and 72.48, including staff plans

for exercise of enforcement discretion, while rulemaking is underway.

The Commission requested that the staff specifically solicit public

comment in the Federal Register notice on:

1. A wide array of options for the margin of safety criterion

(50.59(c)(2)(vii) in the proposed rule) and its definition including:

(a) Deleting the criterion and definition, (b) a new definition as

described in Chairman Jackson's vote, and (c) an option which would

decouple the last criterion from technical specifications and focus

instead on a new criterion relating to performance of fission product

barriers (e.g., reactor coolant system pressure, containment pressure,

etc), with minimal changes being allowed up to specified limits,

perhaps utilizing a graduated approach similar to the approaches

proposed for other criteria.

2. Options for defining ``minimal'' as it pertains to ``probability

of occurrence of an accident'' or ``probability of equipment

malfunction.''

3. The definitions of ``facility,'' ``procedures,'' and ``tests or

experiments,'' including elimination of the definitions.

4. A clear definition of ``accident.''

(This action scheduled for completion October 9, 1998).

The Commission requests the staff to complete the revised 50.59

rule on an expedited schedule.

(This action scheduled for completion February 19, 1999).

All Commissioners approved in part and disapproved in part the

proposed rulemaking on 10 CFR parts 50, 52 and 72 requirements

concerning changes, tests and experiments and staff recommendations on

changes to other regulations and enforcement policy, and provided

additional comments. In their vote sheets, all Commissioners approved

the staff's recommendations to approve publication of the proposed rule

for public comment, and use of the enforcement discretion guidance in

its assessment of severity levels for violations while the rulemaking

is underway, and provided some additional comments

nges to other regulations and enforcement policy, and provided

additional comments. In their vote sheets, all Commissioners approved

the staff's recommendations to approve publication of the proposed rule

for public comment, and use of the enforcement discretion guidance in

its assessment of severity levels for violations while the rulemaking

is underway, and provided some additional comments. In particular, all

Commissioners disapproved the staff's proposed margin of safety

criterion (Sec. 50.59(c)(2)(vii) in the proposed rule) and its

definition and each Commissioner provided an option for evaluation

during the comment period. The Commissioners also specifically

requested comments on a number of other issues. Because of the need to

finalize this rule as expeditiously as possible and because SECY-98-171

has already been publicly available since July 29, 1998, the Commission

agreed to a 60 day comment period, and that the staff complete the

revised Sec. 50.59 rule by February 19, 1999. Subsequently, the

comments of the Commission were incorporated into the guidance to staff

as reflected in the SRM issued on September 25, 1998.

Chairman Jackson's Comments on SECY-98-171

I approve, in part, and disapprove, in part, the staffs proposal

for rulemaking. I approve the staff's proceeding with issuance of the

proposed rule language for public comment in order to support the

expedited finalization of a revision to these processes. I disapprove

of the specific language proposed by the staff for

Sec. 50.59(c)(2)(vii), ``reductions in the margin of safety.''

I agree with the recent letter from ACRS on this rulemaking, in

that: (1) 10 CFR 50.59 can accommodate risk-informed decisionmaking.

(2) the positions, as presented, on margin of safety may add regulatory

burden without a commensurate safety benefit.

I disagree with ACRS in that I believe:

(1) The rulemaking should go out for public comment to foster

comment on this high priority issue, and

I agree with the recent letter from ACRS on this rulemaking, in

that: (1) 10 CFR 50.59 can accommodate risk-informed decisionmaking.

(2) the positions, as presented, on margin of safety may add regulatory

burden without a commensurate safety benefit.

I disagree with ACRS in that I believe:

(1) The rulemaking should go out for public comment to foster

comment on this high priority issue, and

(2) The regulatory guidance can be worked in parallel with the

rulemaking.

I note that a further reason for issuing this package for public

comment at this time is that the paper calls for the proper use of

enforcement discretion as this rulemaking progresses, thereby providing

further stability in the implementation of this rule in the industry.

Further, I propose that the SRM on this SECY, and the voting

record, be placed in the FR notice to clearly inform stakeholders on

preliminary positions taken by the Commission.

Giving Definition to Minimal

Attached to the recent ACRS letter was ``A Proposal for the

Development of a Risk-Informed Framework for 10 CFR 50.59 and Related

Matters.'' The proposal forwarded by the ACRS parallels an existing

risk-informed approach described in Regulatory Guide 1.174. Regulatory

Guide 1.174 describes a method for determining the level of review,

based on severe accident implications, for proposed licensing actions.

The proposal forwarded by the ACRS describes methodology for creating

frequency-consequence curves for Class 1-8 accidents. The proposal

states that existing processes could be extended to provide appropriate

context for whether the results of a change are ``minimal.'' The

proposal also notes that aspects of this type of approach are in use in

the international regulatory community. The approach utilized in the

proposal forwarded by the ACRS is consistent with the Commission

guidance in the Staff Requirements Memorandum of March 24, 1998 on

SECY-97-205

ses could be extended to provide appropriate

context for whether the results of a change are ``minimal.'' The

proposal also notes that aspects of this type of approach are in use in

the international regulatory community. The approach utilized in the

proposal forwarded by the ACRS is consistent with the Commission

guidance in the Staff Requirements Memorandum of March 24, 1998 on

SECY-97-205.

Without commenting on the specifics of the proposal forwarded by

the ACRS, I am convinced that changes to nuclear plants can be

evaluated in a risk-informed context. Any such approach would benefit

from paralleling existing methodology. Careful consideration would be

required to ensure that the ``consequence'' and ``frequency'' standards

are appropriate for a Sec. 50.59 type application. For instance,

``consequences'' could be evaluated at one of the following levels:

Fractional releases, off-site or on-site doses, or

challenges to fission product release barriers. ``Frequency'' could be

evaluated for Class 1-8 accidents or for design basis accidents using

existing guidelines for risk-informed regulation. The level at which

consequences and frequency of events were tracked would also impact the

type of parallel, deterministic (e.g., protection of redundancy,

defense in depth, etc.), considerations against which changes would

have to be evaluated. For instance, evaluating consequences at the

level of the loss of a single barrier, or occurrences of accident

sequence initiators, might allow elimination of parallel,

deterministic, considerations such as ``margin.''

It is of some concern to me that the whole staff has pursued risk-

informed approaches to issues like the review of TSs, the use of Graded

Quality Assurance, and programs like Inservice Inspection and Inservice

Testing, the staff appears to be more reluctant to allow risk-informed

approaches if the result is the relinquishment of review and approval

authority

onsiderations such as ``margin.''

It is of some concern to me that the whole staff has pursued risk-

informed approaches to issues like the review of TSs, the use of Graded

Quality Assurance, and programs like Inservice Inspection and Inservice

Testing, the staff appears to be more reluctant to allow risk-informed

approaches if the result is the relinquishment of review and approval

authority. Because prior NRC review and approval impacts the cost and

schedule of licensed activities, we must ensure that we require such

prior review and approval only when justified or required by mandate.

We should not limit the application of risk-informed regulation as a

means to ensure continued NRC reviews and approvals of licensed

activities. This message is complimentary to my oft repeated message to

industry that the use of risk information is ``double-edged,'' that is

that relief and additional regulatory scrutiny may both result from its

use.

Margin of safety

The staff proposes to provide a specific definition of ``Reduction

in margin of safety associated with any technical specification,'' and

to revise the current provisions of 10 CFR 50.59(a)(2)(iii) to

explicitly refer to this definition. While I commend the staff on its

efforts to provide clear, definitive, requirements in this proposed

rulemaking, I am concerned that the proposed rule is not consistent

with policy direction established by the Commission in the SRM dated

March 24, 1998. I concur that it is important that the staff has the

independence to (and, I believe, has the responsibility to) inform the

Commission when there are concerns with Commission guidance (as it did

in COMSECY 98-013). However, I believe that when the staff proposes to

take action that is inconsistent with Commission direction, it is

obliged to provide a clear and complete rationale for the proposed

departure. I do not feel that the staff has met that obligation for the

``margin of safety'' aspect of this proposed rule

ommission when there are concerns with Commission guidance (as it did

in COMSECY 98-013). However, I believe that when the staff proposes to

take action that is inconsistent with Commission direction, it is

obliged to provide a clear and complete rationale for the proposed

departure. I do not feel that the staff has met that obligation for the

``margin of safety'' aspect of this proposed rule. However, this said,

I do not disagree with the staff's conclusion that we should be careful

to understand, and maintain, a consistent regulatory basis on ``margin

of safety.'' We must proceed in a manner that does not call into

question the existing deterministic basis for ``reasonable assurance''

of public safety embodied in plants Technical Specifications (TSs).

My previous discussions with the staff have indicated that it is

extremely difficult (and probably not legally defensible) to allow

decreases in the ``margin of safety'' when the upper and lower limits

between which ``margin'' may exist are not defined in relation to the

regulatory requirements for safe operation. Based upon these

discussions, I can only assume that the staff is hesitant to allow

direct reductions in margin within the ``basis'' for TSs because some

such changes could create a de-facto change in the TSs themselves. The

staff may also be concerned by the lack of consistency in the ``margin

of safety in the basis for TSs'' associated with the different

generations of existing licenses (e.g., older customized TSs compared

to improved standardized TSs), and associated with the different

methods utilized in the technical review and approval of the TS (e.g.,

some TSs might be based on maintaining margin between accident analysis

results and acceptance limits, while other TSs might be based on margin

which was built into analytical techniques and methodologies used in

the accident and safety analysis, with no ``margin'' between the

results and the acceptance limits, etc.)

rent

methods utilized in the technical review and approval of the TS (e.g.,

some TSs might be based on maintaining margin between accident analysis

results and acceptance limits, while other TSs might be based on margin

which was built into analytical techniques and methodologies used in

the accident and safety analysis, with no ``margin'' between the

results and the acceptance limits, etc.).

The staff's proposed method of requiring prior agency approval to

changes of input assumptions, analytical methods, etc., for those

parameters which affected the selection of TSs, results in the newly

controlled parameters being treated essentially the same way as values

in the TSs. It also appears that implementation of the staffs proposed

control over a broad range of parameters used in the safety analysis

would effectively prevent any change to the facility that would result

in a ``minimal change in consequence,'' a condition allowed elsewhere

in the proposed rule. In other words, it is not clear what type of

changes would successfully pass the 10 CFR 50.59 test for allowed

``minimal increases in consequences,'' without failing the test for

``no reductions in the margin of safety.'' I do not believe that the

potential safety significance of all the parameters to be covered under

the proposed definition of a reduction in the margin of safety always

justify the requirement of prior NRC approval.

The staff should continue to work to establish a technically sound

method for allowing licensees to make plant changes where there is only

``minimal'' impact on safety. If fundamental conflicts exist with

allowing reductions in some ``margins of safety,'' especially those on

which the validity of TSs are based, then staff should provide a clear

explanation of this, and should address how other changes to the

structure of the regulation, which do not create fundamental conflicts,

can be made in a manner which achieves the Commission's objective of

removing unnecessary burdens from licensees

th

allowing reductions in some ``margins of safety,'' especially those on

which the validity of TSs are based, then staff should provide a clear

explanation of this, and should address how other changes to the

structure of the regulation, which do not create fundamental conflicts,

can be made in a manner which achieves the Commission's objective of

removing unnecessary burdens from licensees.

Attachment ``A'' to this vote describes one alternate method for

addressing the issue of ``margin of safety.'' This alternative would

maintain existing margins of safety (associated with TSs), while

providing greater flexibility to licensees in implementing changes to

their facilities. This alternative is based on methodology similar to

that described in NEI 96-07. This methodology requires evaluating the

effect of proposed tests and changes on the accident analysis results

(rather than inputs, as proposed by the staff), in cases where TSs are

based on accident analysis considerations. Prior NRC approval of

changes, tests, and experiments would be limited to those cases where

there was a net effect on the accident analysis results. The

alternative also recognizes the significance of the analytical

techniques used in the safety or accident analysis, and would require

some form of prior approval for analytical methods used to support

changes when the change did not have prior NRC approval. This approach

could provide staff reasonable assurance that the assumptions made by

the license reviews are not invalidated. The staff should evaluate this

option, along with other comments in this area, during the comment

period.

In considering the technical and regulatory underpinning of this

clause of Sec. 50.59, I have become concerned that we are evaluating

incremental changes to a provision which is not well suited to such

changes. I am concerned that the result may be the addition of yet

another layer of regulatory process rather than the elimination of any

unnecessary layers

s area, during the comment

period.

In considering the technical and regulatory underpinning of this

clause of Sec. 50.59, I have become concerned that we are evaluating

incremental changes to a provision which is not well suited to such

changes. I am concerned that the result may be the addition of yet

another layer of regulatory process rather than the elimination of any

unnecessary layers. For this reason, the staff should be receptive to

internal or public comments on feasible alternatives which eliminate

the discussion of ``the margin of safety in the basis of TSs,'' while

maintaining the integrity of the plant's licensing basis. I envision

that it may be possible to eliminate the rule

language criteria on ``margin of safety'' if evaluations of

``frequency'' and ``consequences'' are performed at a level of

significance which bounds allowable ``minimal'' reductions in margin.

Accident of a Different Type

In determining the effect of any proposed change to Sec. 50.59, it

will be necessary to more clearly understand what an ``accident of a

different type'' is. The staff should provide a more definitive

definition of an accident than was included in COMSECY-98-013. The

information provided by the staff should address, as a minimum, the

following:

(1) What is an ``accident'' under this section, and is it

consistent with other existing regulations (e.g., Sec. 50.92,

Sec. 50.34, Appendix A of part 50, etc.)?

(2) Is an ``accident of a different type'' better described as an

``initiating event (e.g., loss of feedwater, loss of offsite power, new

common mode failure mechanism, etc.) of a different Type?''

ess, as a minimum, the

following:

(1) What is an ``accident'' under this section, and is it

consistent with other existing regulations (e.g., Sec. 50.92,

Sec. 50.34, Appendix A of part 50, etc.)?

(2) Is an ``accident of a different type'' better described as an

``initiating event (e.g., loss of feedwater, loss of offsite power, new

common mode failure mechanism, etc.) of a different Type?''

(3) What are the bounds which limit those ``accidents'' which are

the subject of this Section (e.g., only those initiating events which,

when evaluated using approved analytical techniques, result in

transients with the potential to challenge fission product barriers,

etc.)?

Procedures

I commend staff on inserting a definition for the term ``Procedures

as described in the final safety analysis report (as updated).''

However, I am concerned that the definition provided may cloud the

distinction between: (1) Those procedures which must be screened, or

evaluated, under Sec. 50.59, and (2) the criteria which necessitates a

full safety evaluation. I believe that staff seeks to indicate that all

procedures which are described as being required in the FSAR are

subject to a Sec. 50.59 screening. The screening would identify the

need for a full safety evaluation only if a proposed procedure change

created a change to the ``information in the FSAR regarding how

structures, systems, and components are operated and controlled. . .

.'' Staff should solicit comment on this definition and clarify the

proposed definition, as required, in the final rule.

Making the Rule Risk Informed

eening. The screening would identify the

need for a full safety evaluation only if a proposed procedure change

created a change to the ``information in the FSAR regarding how

structures, systems, and components are operated and controlled. . .

.'' Staff should solicit comment on this definition and clarify the

proposed definition, as required, in the final rule.

Making the Rule Risk Informed

I note with interest that members of the ACRS believe that there

are substantial barriers in the existing determinist

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