Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors

NUCLEAR REGULATORY COMMISSION

10 CFR Part 50

RIN 3150-AF00

Primary Reactor Containment Leakage Testing for Water-Cooled

Power Reactors

AGENCY: Nuclear Regulatory Commission.

ACTION: Final rule.

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SUMMARY: The Nuclear Regulatory Commission is amending its regulations

to provide a performance-based option for leakage-rate testing of

containments of light-water-cooled nuclear power plants. This option is

available for voluntary adoption by licensees in lieu of compliance

with the prescriptive requirements contained in the current regulation.

This action improves the focus of the regulations by eliminating

prescriptive requirements that are marginal to safety. The final rule

allows test intervals to be based on system and component performance

and provides licensees greater flexibility for cost-effective

implementation methods of regulatory safety objectives.

EFFECTIVE DATE: October 26, 1995.

FOR FURTHER INFORMATION CONTACT: Dr. Moni Dey, Office of Nuclear

Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC

20555, telephone (301) 415-6443, e-mail [email protected]

SUPPLEMENTARY INFORMATION:

Background--Development of Proposed Rule

NRC's Marginal-to-Safety Program

In 1984, the NRC staff initiated a program to make regulatory

requirements more efficient by eliminating those with marginal impact

on safety. The NRC's initiative to eliminate requirements marginal to

safety recognizes both the dynamic nature of the regulatory process and

that the importance and safety contribution of some existing regulatory

requirements may not have been accurately predicted when adopted or may

have diminished with time. The availability of new technical

information and methods justify a review and modification of existing

requirements.

The NRC solicited comments from industry on specific regulatory

requirements and associated regulatory positions that needed

reevaluation. The Atomic Industrial Forum conducted a survey providing

most of industry's input, published for the NRC as NUREG/CR-4330

1, ``Review of Light Water Reactor Regulatory Requirements,'' Vol.

1, April 1986. A list of 45 candidates for potential regulatory

modification were identified. The NRC's review of the list selected

Appendix J as one of seven areas requiring further analysis (NUREG/CR-

4330, Vols. 2 and 3, dated June 1986 and May 1987). The NRC also

conducted a survey of its staff on the same issue. The NRC staff survey

identified 54 candidates for regulatory modification, a number of which

were previously identified in the industry survey. The NRC's assessment

of this list also selected Appendix J as a potential candidate for

modification.

\1\ Copies of NUREGs may be purchased from the Superintendent of

Documents, U.S. Government Printing Office, P. O. Box 37082,

Washington, DC 20013-7082. Copies are also available from the

National Technical Information Service, 5285 Port Royal Road,

Springfield, VA 22161. A copy is available for inspection and/or

copying in the NRC Public Document Room, 2120 L Street, NW. (Lower

Level), Washington, DC.

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The NRC published in the Federal Register, for comment, a proposed

revision to Appendix J on October 29, 1986 (51 FR 39538) to update

acceptance criteria and test methods based on experience in applying

the existing requirements and advances in containment leak testing

methods, to resolve interpretive questions, and to reduce the number of

exemption requests. This proposed rule was withdrawn from further

consideration and superseded with a more comprehensive revision of

Appendix J.

The NRC published a notice in the Federal Register on February 4,

1992 (57 FR 4166), presenting its conclusion that Appendix J was a

candidate whose requirements may be relaxed or eliminated based on

cost-benefit considerations. On the basis of NRC staff analyses of

public comments on the proposal, the Commission approved and announced

on November 24, 1992 (57 FR 55156) its plans to initiate rulemaking for

developing a performance-oriented and risk-based regulation for

containment leakage-testing requirements. On January 27, 1993, (58 FR

6196) the NRC staff published a general framework for developing

performance-oriented and risk-based regulations and, at a public

workshop on April 27 and 28, 1993, invited discussions of specific

proposals for modifying containment leakage-testing requirements.

Industry and public comments on the proposals, and other

recommendations and innovative ideas raised at the public workshop,

were documented in the proceedings of the workshop (NUREG/CP-0129,

September 1993). Specifically, the NRC concluded that the allowable

containment leakage rate utilized in containment testing may be

increased and other Appendix J requirements need not be as prescriptive

as the current requirements. To increase flexibility, the detailed and

prescriptive technical requirements contained in Appendix J regulations

could be improved and replaced with performance-based requirements and

supporting regulatory guides. The regulatory guides would allow

alternative approaches, although compliance with existing regulatory

requirements would continue to be acceptable. The performance-based

requirements would reward superior operating practices.

The present rulemaking is part of this overall effort and

initiative for eliminating requirements that are marginal to safety and

is guided by the policies, framework and criteria for the

[[Page 49496]]

program. A more comprehensive proposed rule than that proposed in 1986

that accounts for the latest technical information and regulatory

framework, using performance-oriented and risk-based approaches, was

published by the NRC in the Federal Register on February 21, 1995. The

public comment period for the proposed rule closed May 8, 1995.

NRC's Regulatory Improvement Program

The NRC's marginal-to-safety initiative is part of a broader NRC

initiative for regulatory improvement. Through its Program for

Regulatory Improvement, the NRC has institutionalized an ongoing effort

to eliminate requirements marginal to safety and to reduce the

regulatory burden on its licensees. The NRC staff's plan, summarized in

SECY-94-090, dated March 31, 1994, satisfies the requirement for a

periodic review of existing regulations given in Executive Order 12866

of September 30, 1993. This plan was approved by the Commission on May

18, 1994. The Regulatory Improvement Program is aimed at the

fundamental principle adopted by the Commission that all regulatory

burdens must be justified and that its regulatory process must be

efficient. In practice, this means the elimination or modification of

requirements for which burdens are not commensurate with their safety

significance. The activities of the Regulatory Improvement Program

should result in enhanced regulatory focus in areas that are more

safety significant. As a result, an overall net increase in safety is

expected from the program.

The Regulatory Improvement Program will include, whenever feasible

and appropriate, the consideration of performance-oriented and risk-

based approaches. The program will review requirements or license

conditions that are identified as a significant burden on licensees. If

review and analysis find that the requirements are marginal to safety,

they will be eliminated or relaxed. By performance-oriented, the NRC

means establishing regulatory objectives without prescribing the

methods or hardware necessary to accomplish the objective, and allowing

licensees the flexibility to propose cost-effective methods for

implementation. By risk-based, the NRC means regulatory approaches that

use probabilistic risk analysis (PRA) as the systematic framework for

developing or modifying requirements.

In institutionalizing the Regulatory Improvement Program and

adopting a performance-based regulatory approach, the NRC has

formulated the following framework for revisions to its regulations:

(1) The new performance-based regulation will be less prescriptive

and will allow licensees the flexibility to adopt cost-effective

methods for implementing the safety objectives of the original rule.

(2) The regulatory safety objectives will be derived, to the extent

feasible and practical, from risk considerations with appropriate

consideration of uncertainties, and will be consistent with the NRC's

Safety Goals.

(3) Detailed technical methods for measuring or judging the

acceptability of a licensee's performance relative to the regulatory

safety objectives will be, to the extent practical, provided in

industry standards and guidance documents which are endorsed in NRC

regulatory guides.

(4) The new regulation will be optional for current licensees so

that licensees can decide to remain in compliance with current

regulations.

(5) The regulation will be supported by necessary modifications to,

or development of, the full body of regulatory practice including, for

example, standard review plans, inspection procedures, guides, and

other regulatory documents.

(6) The new regulation will be formulated to provide incentives for

innovations leading to improvements in safety through better design,

construction, operating, or maintenance practices.

Current Appendix J Requirements

Appendix J to 10 CFR Part 50, ``Primary Reactor Containment Leakage

Testing for Water-Cooled Power Reactors,'' became effective on March

16, 1973. The regulatory safety objective of reactor containment design

is stated in 10 CFR Part 50, Appendix A, ``General Design Criteria for

Nuclear Power Plants,'' Criterion No. 16, ``Containment Design.'' GDC

Criterion 16 mandates ``an essentially leak-tight barrier against the

uncontrolled release of radioactivity to the environment * * *'' for

postulated accidents. Appendix J to 10 CFR Part 50 implements, in part,

General Design Criterion No. 16 and specifies containment leakage-

testing requirements, including the types of tests required. For each

type of test required, Appendix J specifies how the tests should be

conducted, the frequency of testing, and reporting requirements.

Appendix J requires the following types of containment leak tests:

(1) Measurement of the containment integrated leakage rate (Type A

tests, often referred to as ILRTs).

(2) Measurement of the leakage rate across each pressure-containing

or leakage-limiting boundary for various primary reactor containment

penetrations (Type B tests).

(3) Measurement of the containment isolation valves leakage rates

(Type C tests).

Type B and C tests are referred to as local leakage-rate tests

(LLRTs).

Leak-Tightness Requirements

Compliance with 10 CFR Part 50, Appendix J, requirements is

determined by comparing the measured containment leakage rate with the

maximum allowable leakage rate. Maximum allowable leakage rates are

calculated in accordance with 10 CFR Part 100, ``Reactor Site

Criteria,'' and are incorporated into the technical specifications.

Typical allowable leakage rates are 0.1 percent of containment volume

per day for pressurized water reactors (PWRs) and one volume percent

per day for boiling water reactors (BWRs).

Test Frequency Requirements

Schedules for conducting containment leakage-rate tests are

specified in Appendix J for both preoperational and periodic tests.

Periodic leakage-rate test schedules are as follows:

Type A Tests

(1) After the preoperational leakage-rate test, a set of three Type

A tests must be performed at approximately equal intervals during each

10-year service period. The third test of each set must be conducted

when the plant is shut down for the 10-year plant in-service

inspection.

(2) The performance of Type A tests must be limited to periods when

the plant facility is nonoperational and secured in the shutdown

condition under administrative control and in accordance with the

safety procedures defined in the license.

(3) If any periodic Type A test fails to meet the applicable

acceptance criteria, the test schedule applicable to subsequent Type A

tests will be reviewed and approved by the Commission. If two

consecutive periodic Type A tests fail to meet the applicable

acceptance criteria, a Type A test must be performed at each plant

shutdown for refueling or approximately every 18 months, whichever

occurs first, until two consecutive Type A tests meet the

[[Page 49497]]

acceptance criteria, after which time the regular retest schedule may

be resumed.

Type B Tests

(1) Except for airlocks, Type B tests must be performed during

reactor shutdown for refueling, or other convenient intervals, but in

no case at intervals greater than 2 years. If opened following a Type A

or B test, containment penetrations subject to Type B testing must be

tested prior to returning the reactor to an operating mode requiring

containment integrity. For primary reactor containment penetrations

employing a continuous leakage monitoring system, Type B tests, except

for tests of airlocks, may be performed at every other reactor shutdown

for refueling but in no case at intervals greater than 3 years.

(2) Airlocks must be tested prior to initial fuel loading and at

six-month intervals thereafter. Airlocks opened during periods when

containment integrity is not required by the plant's technical

specifications must be tested at the end of such periods. Airlocks

opened during periods when containment integrity is required by the

plant's technical specifications must be tested within 3 days after

being opened. For airlock doors opened more frequently than once every

3 days, the airlock must be tested at least once every 3 days during

the period of frequent openings. For airlock doors having testable

seals, testing the seals fulfills the 3-day test requirement. Airlock

door-seal testing must not be substituted for the 6-month test of the

entire airlock at not less than Pa, the calculated peak

containment pressure related to the design basis accident.

Type C Tests

Type C tests must be performed during each reactor shutdown for

refueling, but in no case at intervals greater than 2 years.

There have been two amendments to this Appendix since 1973. The

first amendment, published September 22, 1980 (45 FR 62789), modified

the Type B penetration test requirements to conform to what had become

accepted practice through the granting of exemptions. The second

amendment, published November 15, 1988 (53 FR 45890), incorporated the

Mass Point Statistical Analysis Technique as a permissible alternative

to the Total Time and Point-to-Point techniques specified in Appendix

J.

International Experience

A combination of Type A tests and an on-line monitoring (OLM)

capability is being actively pursued in Canada and Europe, notably in

France and Belgium, and is currently being considered in Sweden. OLM is

used to identify a ``normal'' containment pressurization pattern and to

detect deviations from that pattern. With on-line, low-pressure

testing, Hydro-Quebec's Gentilly-2 station is able to monitor the

change in containment leaktightness between Type A tests. The Belgians

conduct a leakage test using OLM during reactor operation after each

cold shutdown longer than 15 days with the objective of detecting gross

leaks. The objective of the Belgian approach to Type A testing is to

reduce the frequency and duration of the tests. The Type A test is

conducted at a containment pressure (Pt) not less than half of the

peak pressure (0.5 Pa). It is performed once every 10 years. In

France, containment leaktightness is continuously monitored during

reactor operation in all of the French PWR plants using the SEXTEN

system. It is also being evaluated by the Swedes for their PWR units.

Leaks may be detected during the positive or negative pressure periods

in the containment by evaluating the air mass balance in the

containment. Type A tests are conducted at containment peak pressure

(loss-of-coolant accident pressure) before initial plant startup,

during the first refueling, and thereafter every 10 years unless a

degradation in containment leaktightness is detected. In that case,

tests are conducted more frequently.

Further details of international approaches to containment testing

are provided in NUREG-1493.

Advance Notices for Rulemaking

Over time, it has become apparent that variations in plant design

and operation frequently make it difficult to meet some of the

requirements contained in Appendix J because of its prescriptive

nature. Economic and occupational exposure costs are directly related

to the frequency of containment testing. Containment integrated

leakage-rate tests (Type A) preclude any other reactor maintenance

activities and thus are on the critical path for return to service from

reactor outages. In addition to the costs of the tests, integrated leak

tests impose the added burden of the cost of replacement power.

Containment-penetration leak tests (Type B and C) can be conducted

during reactor shutdowns in parallel with other activities and thus

tend to be less costly; however, the large number of penetrations

impose a significant burden on the utilities. Additionally, risk

assessments performed to date indicate that the allowable leakage rate

from containments can be increased, and that control of containment

leakage at the current low rates is not as risk significant as

previously assumed.2 3

\2\ ``Severe Accident Risks: An assessment for five U. S.

Nuclear Power Plants, Final Summary Report.'' NUREG-1150, December

1990. Copies of NUREGs may be purchased from the Superintendent of

Documents, U.S. Government Printing Office, P. O. Box 37082,

Washington, DC 20013/7082. Copies are also available from the

National Technical Information Service, 5285 Port Royal Road,

Springfield, VA 22161. A copy is available for inspection and/or

copying in the NRC Public Document Room, 2120 L Street, NW. (Lower

Level), Washington, DC.

\3\ ``Performance-Based Containment Leak Test Program,'' NUREG-

1493, July 1995.

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In August of 1992, the NRC initiated a rulemaking to modify

Appendix J to make it less prescriptive and more performance-oriented.

The Commission also initiated a plan to relax the allowable containment

leakage rate used to define performance standards for containment

tests. In the Federal Register of January 27, 1993 (58 FR 6196), the

NRC indicated the following potential modifications to Appendix J of 10

CFR Part 50 would be considered:

(1) Increase allowable containment leakage rates based on Safety

Goals and PRA technology (i.e., define a new performance standard); and

(2) Modify Appendix J to be a performance-based regulation:

A. Limit the revised rule to a new regulatory objective. In order

to ensure the availability of the containment during postulated

accidents, licensees should either:

(i) Test overall containment leakage at intervals not longer than

every 10 years, and test pressure-containing or leakage-limiting

boundaries and containment isolation valves on an interval based on the

performance history of the equipment; or

(ii) Provide on-line (i.e., continuous) monitoring of containment

isolation status.

B. Remove prescriptive requirements from Appendix J and preserve

useful portions as guidance in an NRC regulatory guide.

C. Endorse industry standards on:

(i) Guidance for calculating plant-specific allowable leakage rates

based on new NRC performance standards;

(ii) Guidance on the conduct of containment tests; and

(iii) Guidance for on-line monitoring of containment isolation

status.

D. Continue to accept compliance with the current detailed

requirements in Appendix J (i.e., licensees presently in compliance

with Appendix J will not need to do anything if they do not wish to

change their practice).

[[Page 49498]]

A public workshop on the subject was held by the NRC on April 27

and 28, 1993.4

\4\ ``Workshop on Program for Elimination of Requirements

Marginal to Safety,'' NUREG/CP-0129, September 1994.

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February 1995 Proposed Revision

Based on several advance notices for rulemaking and significant

public comment and discussion, evaluation of risks and costs, and

consideration of which modifications have become feasible and

practical, in the February 21, 1995, Federal Register the NRC proposed

two phases for modifications of requirements to containment leakage

testing. The first phase allowed leakage-rate testing intervals to be

based on the performance of the containment system structures and

components. The second phase will further examine the needed

requirements of the containment function (i.e. structural and leak-

tight integrity of containment system structures and components, and

prevention of inadvertent bypass), and include consideration of the

potential for on-line monitoring of containment integrity to verify

certain functions. Public comments were solicited to guide this future

work.

The February 21, 1995, proposed rule applies to all NRC licensees

who operate light-water-cooled power reactors. The proposed rule allows

licensees the option of continuing to comply with the current Appendix

J or to adopt the new performance-based standards.

The NRC's analyses are based upon the insight gained through the

use of probabilistic risk assessment techniques and the significant

data base of practical, hands-on operating experience gained since

Appendix J was promulgated in 1973. This operating experience provides

solid evidence of the activities necessary to conduct Appendix J

testing, and the costs of those activities both in monetary terms and

occupational radiation exposure.

The proposed rule is based on analytical efforts documented in

NUREG-1493 which, like NUREG-1150, confirms previous observations of

insensitivity of population risks from severe reactor accidents to

containment leakage rates.

The current Appendix J requirements continue to achieve the

regulatory criterion of assuring an essentially leak-tight boundary

between the power reactor system and the external environment (General

Design Criterion 16). Costs associated with complying with current

Appendix J requirements are estimated to be $165,000 for a complete

battery of Type B/C tests and $1,890,000 for Type A tests. Over the

average reactor's remaining lifetime of 20 years, the present value of

all remaining containment leakage testing at a 5 percent discount rate

is estimated to be about $7 million per reactor. Estimates of the

remaining industry-wide costs of implementing current Appendix J

requirements ranged from $720 to $1,080 million, approximately 75

percent of which could be averted with a performance-based rule.

The Regulatory Analysis for the proposed rule finds that by

allowing requirements to remain in effect with marginal impact on

safety, but which impose a significant cost on licensees, is to have

missed an opportunity to improve regulatory coherence and to focus

NRC's regulations to areas where the return in terms of added public

safety is higher.

Specific alternatives for modifying the current Appendix J were

identified by the public in response to the NRC's Federal Register

notice published on January 27, 1993 (58 FR 6196). Those whose

characteristics matched the NRC's established criteria for the marginal

to safety program were selected for further review.

Modifications of Advance NRC Proposal

Allowable Leakage Rate

The NRC had initially planned to establish, by rulemaking, a risk-

based allowable leakage rate commensurate with its significance to

total public risk. Specific findings from NUREG-1493 on the allowable

leakage rate include:

1. Allowable leakage could be increased approximately two orders of

magnitude (100-200 fold) with marginal impact on population dose

estimates from reactor accidents.

2. Calculated risks to individuals are several orders of magnitude

below the NRC's Safety Goals for all reactors considered.

3. Increases in the allowable leakage rate are estimated to have a

negligible impact on occupational exposure.

Relaxing the allowable leakage rate is estimated to reduce future

industry testing costs by $50 to $110 million, a 10 percent decrease in

overall leakage-rate testing costs.

A risk-based allowable leakage rate would be based on an

evaluation, using PRA, of the sensitivity and significance of

containment leakage to risk, and the determination of an appropriate

containment leakage limit commensurate with its significance to the

risk to the public and plant control-room operators. However, this

would have entailed a major change in policy and restructuring of the

current licensing basis and a more complete understanding of the

uncertainties associated with the threat of severe accidents to the

containment, and therefore, the NRC planned to develop a modification

of the performance standard (allowable leakage level) in the second

phase separate from modifications of testing requirements. This

modification would be part of a broader effort to further examine the

risk significance of various attributes of containment performance,

i.e., structural and leak-tight integrity of containment-system

structures and components, and inadvertent bypass.

On-Line Monitoring (OLM) Systems

Currently, there is no NRC requirement for systems which

continuously monitor the containment to detect unintentional breaches

of containment integrity.

Studies discussed in NUREG-1493, ``Performance-Based Containment

Leak Test Program,'' found that, based on operating experience, OLM

would not significantly reduce the risk to the public from nuclear

plant operation and, thus, could not be justified solely on the basis

of risk-based considerations. Specific findings include:

1. Existing continuous monitoring methods appear technically

capable of detecting leaks in reactor containments within 1 day to

several weeks. OLM systems are in use or planned in several European

countries and Canada.

2. OLM systems are capable of detecting leaks only in systems that

are open to the containment atmosphere during normal operation

(approximately 10 percent of the mechanical penetrations).

3. The technical and administrative objectives of OLM systems and

Type A tests are different.

4. OLM could not be considered as a complete replacement for Type A

tests because it cannot challenge the structural and leak-tight

integrity of the containment system at elevated pressures.

5. Analysis of the history of operating experience indicated a

limited need for, and benefit of, OLM in the U.S.

Although OLM can not be justified solely based on risk

considerations, a plant already possessing such a system has a greater

assurance of achieving certain attributes of containment integrity.

Therefore, OLM systems could contribute towards an overall leakage-

monitoring scheme. Some capability for on-line monitoring already

exists as a byproduct of specific containment designs. For example,

licensees with

[[Page 49499]]

inerted BWR containments, or subatmospheric PWR containments, could

possibly detect gross leakages that develop during normal operation.

Given that the application of on-line monitoring is specific to

containment design, and generic application can not be justified solely

on risk considerations, the NRC did not propose a requirement for OLMs.

However, licensees with such a capability (e.g. inerted BWR

containments, and subatmospheric PWR containments) were encouraged to

propose plant-specific application of such a capability, and to take

credit for any added assurance of containment integrity provided by

such a system compared to other testing methods. The NRC proposed to

reconsider the role of OLM in the second phase of modifications in this

area along with the allowable leakage rate.

Proposed Modification of Type A, B, and C Test Intervals

In the February 1995 proposed rule, the NRC proposed a new risk-

based regulation based on the performance history of components

(containment, penetrations, valves) as the means to justify an increase

in the interval for Type A, B, and C tests. The revised regulation

requires tests to be conducted on an interval based on the performance

of the containment structure, penetrations and valves without

specifying the interval in the regulation. Currently, three Type A

tests are conducted in every 10 year period. Type B (except airlocks,

which are tested more frequently) and C tests are conducted on a

frequency not to exceed 2 years.

The NRC proposed to base the frequency of Type A tests (ILRTs) on

the historical performance of the overall containment system. Specific

findings documented in NUREG-1493 that justify the proposal include:

1. The fraction of leakages detected only by ILRTs is small, on the

order of a few percent.

2. Reducing the frequency of ILRT testing from 3 every 10 years to

1 every 10 years leads to a marginal increase in risk.

3. ILRTs also test the strength of the containment structure. No

alternative to ILRTs has been identified to provide assurance that the

containment structure would meet allowable leakage rates during design-

basis accidents.

4. At a frequency of 1 test every 10 years, industry-wide

occupational exposure would be reduced by 0.087 person-sievert (8.7

person-rem) per year.

Based on specific, detailed analyses of data from the North Anna

and Grand Gulf nuclear power plants, and data from twenty-two nuclear

plants (see NUREG-1493), performance-based alternatives to current LLRT

methods are feasible with marginal impact on risk. Specific findings

include:

1. Type B and C tests are capable of detecting over 97 percent of

containment leakages.

2. Of the 97 percent, virtually all leakages are identified by

LLRTs of containment isolation valves (Type C tests).

3. Based on the detailed evaluation of the experience of a single

two-unit station, no correlation of failures with type of valve or

plant service could be found.

4. For the 20 years of remaining operations, changing the Type B/C

test frequency to once every 5 years for good-performing components is

estimated to reduce industry-wide occupational radiation exposure by

0.72 person-sievert (72 person-rem) per year. If 20-year license

extension is assumed, the estimate is 0.75 person-sievert (75 person-

rem) per year.

Future industry testing costs are reduced by approximately $330 to

$660 million if ILRT tests are conducted once every 10 years rather

than the current 3 per 10 years. ILRT savings represent about 65

percent of the remaining costs of current Appendix J requirements.

Performance-based LLRT alternatives are estimated to reduce future

industry testing costs by $40 million to $55 million. LLRT savings

represent about 5 percent of the total remaining costs of Appendix J

testing.

Therefore, based on the risks and costs evaluated, and other

considerations discussed above, a performance-based Appendix J was

proposed which encompassed the following principles, which differ

moderately from those first described in the Federal Register (January

27, 1993 58 FR 6197).

General (1) Make Appendix J less prescriptive and more performance-

oriented; (2) Move details of Appendix J tests to a regulatory guide as

guidance; (3) Endorse in a regulatory guide the industry guideline (NEI

94-01) on the conduct of containment tests (The methods for testing are

contained in an industry standard (ANSI/ANS 56.8-1994) which is

referenced in the NEI guideline); and (4) Allow voluntary adoption of

the new regulation, i.e., current detailed requirements in Appendix J

will continue to be acceptable for compliance with the modified rule.

Leakage Limits Acknowledge the less risk-significant nature of

allowable containment leakage but pursue its modification as a separate

action.

Type A Test Interval (1) Based on the limited value of integrated

leakage-rate tests (ILRTs) in detecting significant leakages from

penetrations and isolation valves, establish the test interval based on

the performance of the containment system structure; (2) The

performance criterion of the test will continue to be the allowable

leakage rate (La); (3) The industry guideline allows extension of the

Type A test interval to once every 10 years based on satisfactory

performance of two previous tests, inclusive of the pre-operational

ILRT; (4) In the regulatory guide, the NRC takes exception to industry

guidance for the extension of the interval of the general visual

inspection of the containment system, and limits the interval to 3

times every 10 years, in accordance with current practice.

Type B & C Test Interval (1) Allow local leakage-rate test (LLRTs)

intervals to be established based on the performance history of each

component; (2) The performance criterion for the tests will continue to

be the allowable leakage rate (La); (3) Specific performance factors

for establishing extended test intervals (up to 10 years for Type B

components, and 5 years for Type C components) are contained in the

regulatory guide and industry guideline. In the regulatory guide, the

NRC has taken exception to the NEI guideline allowing the extension of

Type C test intervals up to 10 years, and limits such extensions to 5

years.

Summary of Public Comments

Twenty-six letters were received that addressed the policy,

technical, and cost aspects of the proposed rulemaking, including the

nine questions posed by the NRC in the February 21, 1995 proposed rule.

All comments, including the ones received by the NRC after the deadline

were considered. The commenters included 4 private citizens, 1 public

interest group, 18 utilities, 1 nuclear utility industry group, 1 State

regulatory agency, and 1 foreign regulator.

Although the proposed rule did not generate a significant number of

public comments, the commenters did align themselves into two distinct

groups: those who supported publishing the rule and those against.

Those who supported publishing the rule comprise the vast majority of

the commenters (22) and included the Nuclear Energy Institute (NEI),

which represents the nuclear utility licensees, eighteen individual

nuclear power plant licensee respondents, a Spanish regulatory

authority and two private citizens (Mr.

[[Page 49500]]

Hill and Mr. Barkley). This group is very supportive of the

Commission's risk-based regulatory program, and supports proceeding

with the rule in an expeditious manner, despite having reservations

about three specific provisions. The issues of most concern to this

group are: (1) Licensee commitments to certain requirements of the

regulatory guide implementing Appendix J testing via use of the

technical specifications (industry would prefer using a plant's final

safety analysis report); (2) requirements to conduct visual internal

and external inspections of the containment on a frequency of 3 times

per 10 years (industry would prefer once per 10 years to coincide with

Type A tests); (3) making Option B of the proposed rule mandatory

(industry would prefer to retain the optional feature); and (4) Type C

test frequency (industry would prefer a 10-year test interval for

certain Type C valves). Industry supports a future rulemaking to

increase the allowable leakage rate.

Two private citizens (Mr. Arndt and Dr. Reytblatt) are opposed to

the proposed rule. The issues of most concern to these citizens are:

(1) Type A test frequency (Mr. Arndt would prefer that frequencies be

held at current levels); (2) Type A test methodology (Dr. Reytblatt

wants to halt Type A testing until the test accuracy is improved); (3)

Type C test frequencies (Mr. Arndt believes the existing database does

not support 10-year test intervals, and suggests 5-years as an upper

limit at the present time); and (4) Leakage rate (a future rulemaking

to increase the allowable leakage rate should not be undertaken).

Two organizations are opposed to the proposed rule. The Bureau of

Nuclear Engineering of the state of New Jersey and the Ohio Citizens

for Responsible Energy (OCRE, represented by Ms. Hiatt), a public

interest group, expressed skepticism in the risk-based approach to

regulation as embodied in the philosophy of the Marginal-to-Safety

Program. The issues of most concern to this group are that: (1)

Increases in public risk are not acceptable, no matter how marginal;

and (2) A future rulemaking to increase the allowable leakage rate

should not be undertaken.

NRC Position. With respect to the areas of disagreement between the

NRC and those who generally support the proposed rule, no new

information has been provided in the public comments that was not

already addressed in ongoing dialogue. Accordingly, the NRC has not

made any substantive changes to its proposed regulation. Specifically,

the NRC has retained: (1) Its position of requiring the use of

technical specifications; (2) The intervals established for visual

examinations of containment; and (3) The 5-year Type C test interval.

With respect to the optional feature of the rule, the NRC agrees

with the industry and has retained this feature. With respect to Mr.

Arndt and Dr. Reytblatt, the NRC agrees in part with Mr. Arndt and has

decided not to alter the LLRT test interval as noted in item (3). The

other issues raised by Mr. Arndt and Dr. Reytblatt contain no

information that has not been considered previously in a public forum.

Therefore, the NRC has decided to make no substantive changes to its

proposed rule as a result of the issues raised. With respect to the two

organizations opposed to the proposed rule (OCRE and the NJ Bureau of

Nuclear Engineering), neither has provided new information or a

compelling reason to abandon the risk-based approach to regulation.

In its preliminary criteria for developing performance-based

regulations, the NRC identified several issues to be addressed by the

rulemaking process as a measure of the viability of the revised rule.

These issues were addressed in the proposed rule and the NRC sought

further public input on them. Comments were received on these topics in

addition to other areas of interest to the public. The following is a

summary of comments received on these issues and areas, and NRC's

response. A complete discussion of all comments is included in the

Public Comment Resolution Document.5

\5\ Copies are available for inspection or copying for a fee

from the NRC Public Document Room at 2120 L Street NW., Washington,

DC; the PDR's mailing address is Mail Stop LL-6, Washington, DC

20555; telephone (202) 634-3273; fax (202) 634-3343.

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

1. Can the new rule and its implementation yield an equivalent

level of, or would it only have a marginal impact on safety?

Twenty-four commenters addressed this issue, offering a wide

variety of opinions. Twenty commenters believe that implementation of

the proposed rule will provide an equivalent level of safety to that

provided by the current rule. A majority of commenters, representing

for the most part nuclear utilities, believe that the proposed

regulation will reduce the testing burden currently imposed on the

nuclear industry, and will result in more efficient use of utility

resources, while ensuring the health and safety of the public. They

believe that the practical experience gained from more than 1,500

reactor-years of commercial nuclear power-plant operation provides an

appropriate basis to adjust the Appendix J testing intervals which were

established over 20 years ago on the basis of engineering judgment.

Further, these commenters believe that a significant reduction in

occupational exposures can be achieved with reduced testing frequency.

Mr. E. Gunter Arndt, a private citizen, believes that the NRC has

neither sufficient objective data nor perspective to justify increasing

containment leakage rates, decreasing test frequencies, relaxing

testing criteria, and reducing containment-system maintenance

standards. Dr. Reytblatt, a private citizen, believes that Type A

testing must be immediately suspended because the current testing

methodology is flawed. Mr. Kent W. Tosch, Manager of New Jersey's

Bureau of Nuclear Engineering, points out that the containment is an

extremely important barrier to a release of radioactivity, but the

philosophy reflected in this rulemaking is that this barrier can be

allowed to become less reliable, even when some nuclear plants are

showing signs of aging. Ms. Susan L. Hiatt, Director of Ohio Citizens

for Responsible Energy, notes that relaxing the frequency of Appendix J

tests leads to an increase in overall reactor risk of approximately 2

percent and, while the NRC may deem this to be marginal, it nonetheless

is an increase in risk.

The NRC believes it has collected sufficient subjective and

independent data to conduct its risk analysis. Detailed data from two

independent power plants, representing four units, data supplied by the

NEI representing approximately 30 additional units, and approximately

180 ILRT and licensee event reports were analyzed. These data produced

consistent results. Dr. Reytblatt's views, while technically correct,

have been opposed by several technically competent organizations

including the American National Standards Institute, and Oak Ridge

National Laboratory because the improvements he suggests will have an

insignificant effect on measured containment leakage rates in practice

and thus have no safety significance. The NRC believes there has been

ample opportunity for public discussion of the basis for the Appendix J

revisions.

Based on the foregoing, the NRC reaffirms its prior conclusion

(stated in the February 21, 1995, Federal Register notice) that its

safety objective for containment integrity can be maintained while at

the same time reducing the burden on licensees. Additionally, the final

rule provides a greater level of worker safety than that provided by

the previous rule.

[[Page 49501]]

2. Can the regulatory/safety objective (qualitative or

quantitative) be established in an objective manner to allow a common

understanding between licensees and the NRC on how the performance or

results will be measured or judged?

To avoid repetition, the NRC incorporated responses to this

question with those of Question 3.

3. Can the regulation and implementation documents be developed in

such a manner that they can be objectively and consistently inspected

and enforced against?

Approximately 20 commenters expressed opinions on Questions #2 and

#3. The majority of the commenters believe that regulatory/safety

objectives can be established objectively, and can be consistently

enforced, although opinions differ on the optimum enforcement

mechanism. Mr. Fernando Robledo of the Spanish nuclear regulatory

agency states that the use of probabilistic risk assessment in the

regulatory process provides a more realistic and objective assessment

of nuclear safety, and thus supports its increased use in the

regulatory process. The NEI believes the use of technical

specifications for inspection and enforcement is neither necessary nor

warranted and that, rather than a licensee commitment in the plant

technical specification, future licensee commitments to implement

Option B should be provided by documentation in the updated Final

Safety Analysis Report.

To assist in the common understanding of new methods of

establishing Type A, B, and C test frequencies between the NRC and

power reactor licensees, the NRC has had ongoing discussions with

licensees. These discussions included participation in workshops

designed to elicit a common understanding. Also, the NRC wishes to

retain the current practice which requires its review and approval of

changes to Appendix J performance limits and surveillance requirements.

Therefore, the NRC has required that the regulatory guide should be

specified in the technical specifications, an approach not inconsistent

with the Commission's policy on technical specifications.

Based on the foregoing, the NRC reaffirms its prior conclusion

(stated in the February 21, 1995, proposed rule) that it expects that

its activities to date, the review and endorsement of a industry

guideline in a regulatory guide, and the general reference of the

regulatory guide in plant technical specifications, will provide a

common understanding on the measures of compliance.

4. Should the proposed revision be made even less prescriptive?

Except for Mr. Hill and Mr. Barkley, commenters did not explicitly

address this question, which was directed at the possibility of

reducing, even further, the testing frequency of ILRTs based on the

fact that there does seem to be a strong statistical link between

passing or failing successive ILRTs. Mr. Hill believes that there is no

need to make the rule less prescriptive, and it may be inferred that is

no desire on the part of industry to further increase the testing

interval between ILRTs or to eliminate them completely. Richard

Barkley, although strongly supporting an adjustment to the frequency of

Type A testing to once every 10 years, also discourages the NRC from

adopting a Type A surveillance interval any longer than 10 years

because of aging considerations.

The NRC has decided, in general, to maintain the present level of

prescriptiveness in the proposed rule and, in particular, to not

decrease further the test frequency for ILRTs. The NRC's position is

guided by the desire to maintain some conservatism to address

uncertainties and adopt an evolutionary approach wherein incentives

remain for good performance.

5. Should the proposed revisions be made mandatory?

To avoid repetition, the NRC incorporated responses to this

question with those of Question 7.

6. Was the definition of ``backfit'' in Sec. 50.109(a)(1) intended

to encompass rulemakings of the type represented by this proposed rule?

To avoid repetition, the NRC incorporated responses to this

question with those of Question 7.

7. Is it appropriate for the Commission to waive the applicability

of the Backfit Rule?

The majority of the 20 commenters believe that compliance with the

performance-based Appendix J program should not be made mandatory. The

NEI believes that rulemakings that provide relief from a current

regulation but would also contain one or more new requirements (as is

the case here) would be subject to the backfit rule. These commenters

believe that application of the backfit rule would be necessary before

the NRC could promulgate the performance-based Appendix J program as a

requirement, believing some licensees might select, for reasons of

cost, to continue to comply with the existing Appendix J.

The majority of commenters believe that the backfit rule would

apply and should not be waived. Several utilities have no objection to

waiving a backfit analysis when clear relief is available, but are

concerned with the generic implications of waiving the applicability of

the backfit rule. The NEI believes that while the proposed Appendix J

revisions would provide much needed performance-based improvements to

the existing Appendix J, it would also impose new requirements; thus,

the proposed rule constitutes a backfit. Further, this commenter

believes that, as a matter of administrative law, an agency lacks

authority to depart from its own rules, thus, it cannot waive its own

regulations.

The NRC believes that if the rule were made mandatory, all

licensees would incur costs setting up the procedures for implementing

the rule's requirements following the guidance provided in the

regulatory guide and the NEI guidance document. For those utilities

whose circumstances (e.g., remaining plant life) would lead them to

follow the current Appendix J, costs would be incurred with no

additional benefit. Thus, the NRC agrees with the opinions expressed by

the NEI and has decided to retain the proposed rule in its present

form, which provides a non-mandatory alternative to the current

Appendix J requirements. Because the NRC has decided to retain the

optional feature of the proposed rule, the question of backfit is not

addressed.

8. Should NRC pursue a fundamental modification of its regulations

in this area by establishing an allowable leakage rate based on risk

analysis (as presented in draft NUREG-1493, Chapter 5), as compared to

the current practice of using deterministic design basis accidents and

dose guidelines contained in 10 CFR Part 100; or should the NRC modify

the allowable leakage rate within the current licensing basis by

revising source terms and updating regulatory guides (R.G.s 1.3 and

1.4) 6 for calculating doses to the public? What are the

advantages and disadvantages of the two approaches? What are some other

considerations than risk to public, e.g., plant control room

habitability, that might limit the allowable leakage rate?

\6\ Copies may be purchased at current rates from the

Superintendent of Documents, U.S. Government Printing Office, P.O.

Box 37082, Washington, DC 20402-9328 (telephone 202-512-2249 or 202-

512-2171); or from the National Technical Information Service by

writing NTIS at Port Royal Road, Springfield, VA 22161.

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

The 20 commenters who responded to this question consist

predominantly of the utilities endorsing the NEI position. These

respondents encourages the NRC

[[Page 49502]]

to pursue a rulemaking to alter allowable leakage rates using risk-

based analysis, believing that a firm technical basis exists for

relaxing leakage rates up to two orders of magnitude with only a

marginal impact on population risk estimates. It was also suggested

that a review of the present source terms, dose projection models, and

associated assumptions against the revised source terms and dose

methodologies should also be performed to determine if relief can be

achieved while assuring public health and safety. Three commenters

discouraged the NRC from relaxing containment leakage rates ranging

from the opinion that little benefit would result (Mr. E. Gunter Arndt)

to an unequivocal belief that such a move would violate a plant's

licensing basis by eliminating the protection provided for the nearest

public individual by the 10 CFR Part 100 siting criteria (Ms. S.

Hiatt). Ms. Susan Hiatt, representing the Ohio Citizens for Responsible

Energy, believes that containment leak rates should be periodically

reexamined, not for the purpose of relaxing them, but to determine

whether they should be made more stringent given increasing population

density around operating nuclear power plants.

The NRC has decided to continue to pursue further reductions in

regulatory burden with marginal impacts on safety and will address the

complexities noted in the public comments in its future efforts to

relax the allowable leakage rate.

9. If the allowable leakage rate is increased, could on-line

monitoring of containment integrity replace other current containment

tests? Could the results of the on-line monitoring be used to establish

a new performance basis for containment integrity involving less

stringent reporting requirements if there is high assurance there are

no large leakage paths in containment (> 1 in. diameter).

The 18 commenters who responded to this question consist of the NEI

and the utilities endorsing the NEI position, and Mr. Richard Barkley.

The commenters do not believe that on-line monitoring (OLM) of

containment integrity can replace many of the current containment

tests, and state that OLM systems have very limited abilities to

identify breaches in containment integrity. In the experience of Mr.

Barkley, such systems add unnecessary plant complexity and cost.

The NRC acknowledges the public comments rendered and will be

guided by them in decisions yet to be made regarding the Phase 2

effort.

10. Are there any other regulatory approaches and technical methods

by which the NRC can adopt a complete performance and risk basis to its

regulations for containment leak-tight integrity? What are some of the

attributes for performance, and what risk-based methods can be used to

analyze these attributes?

The NEI, speaking for all other utilities, addressed this question

by stating that it had not conducted any analyses to determine whether

any other regulatory approaches and technical methods by which the NRC

can adopt a complete performance and risk basis to its regulations for

containment leak-tight integrity.

11. Rulemaking Documents.

Seventeen commenters expressed opinions about NRC's regulatory

policy decisions and/or specific language in the rule or its supporting

documents. Mr. Hill believes that the NRC's and the NEI's guidance

documents are not developed to the point of establishing a common

understanding of how to meet NRC's regulatory and safety objectives

(e.g., while NEI 94-01 contains a lot of information and solid

guidance, it also contains inconsistencies, contradictions and unclear

passages). The NEI, whose comments were endorsed by most responding

licensees, proposed modifications to several of the rulemaking

documents, including the Federal Register notice and its own guidance

document.

The NRC has amended its rule and accepts most of the revisions to

the implementing documents to clarify language and achieve consistency

between the rulemaking documents.

12. Technical Issues.

Testing Frequency

Twenty-four commenters expressed opinions on test frequency, the

majority were supportive of 10-year intervals for both Types A, B and C

tests. Regarding ILRTs, the Nuclear Energy Institute, several

individual utilities, and Mr. Howard Hill expressed views that the

proposed rule provides an acceptable testing frequency for ILRTs. Mr.

Fernando Robledo, of the Spanish nuclear regulatory agency, believes

that 10 years is too long a time interval between Type A containment

tests. Mr. E. Gunter Arndt's view is that a preoperational test should

not count as one of the two successful ILRT tests required to go to a

10-year test interval because preoperational conditions are not at all

representative of operating conditions. The citizens' group, Ohio

Citizens for Responsible Energy, believes the frequency of containment

leak-rate testing should remain unchanged from the current practice.

Several commenters also expressed opinions on the NRC's position on

LLRT testing frequency. Mr. Fernando Robledo, while agreeing in general

with the test frequency for type B and C tests proposed in the draft

regulatory guide, believes that certain mechanical penetrations

particularly important for plant safety should be leak tested every 24

months. Mr. E. Gunter Arndt's view is that the testing history of

penetrations, and especially of valves, does not support leaving them

untested for 10 years and suggested that an upper limit should be once

every 5 years. One utility in particular, and the Nuclear Energy

Institute in general believe that the NRC does not go far enough in

citing that several sets of data justify 10-year LLRT intervals. In

contrast, Mr. Richard Barkley, who also endorses Type B & C testing

frequency based on performance, strongly supports the NRC's proposal to

prohibit the adoption of Type C surveillance intervals longer than 60

months.

In establishing the 5-year test interval for LLRTs, the NRC has

designed a cautious, evolutionary approach as data are compiled to

minimize the uncertainty now believed to exist with respect to LLRT

data. The NRC's judgment, based on risk assessment and deterministic

analysis, continues to be that the limited database on unquantified

leakages and common mode and repetitive failures introduces significant

uncertainties into the probabilistic risk analysis. The NRC will be

open to submittals from licensees as more performance-based data are

developed. The extension of LLRT test interval to 5 years is a prudent

first step. By allowing a 25 percent margin in testing frequency

requirements, the NRC has provided the flexibility to accommodate

longer fuel cycles. With respect to the 10-year interval for ILRTs, the

NRC believes its technical support document (NUREG-1493) is persuasive

by demonstrating that testing intervals could be increased up to once

every 20 years with an imperceptible increase in risk, using actual

ILRT data which accounted for random and plant-specific failures and

plant aging effects.

Based on the foregoing discussion, the NRC has decided to retain

the 60-month Type C test interval and the 120-month interval for Type A

and B tests. In response to public comments, the NRC has revised the

regulatory guide to limit the extension of test intervals for main

steam and feedwater isolation valves in BWRs, and containment purge and

vent valves in PWRs and BWRs beyond 30 months given their operating

experience and/or safety significance.

[[Page 49503]]

Test Pressures

Two commenters expressed opinions on the magnitude of the pressures

used in conducting Type A leakage tests. Northern States Power Company

believes that Type A testing at full pressure is unnecessary and

believes that visual inspection coupled with a reduced pressure test

will adequately assure that the containment structural members are

leak-tight, especially since reduced pressure Type A tests are legally

acceptable tests as prescribed in the current 10 CFR Part 50, Appendix

J. Mr. E. Gunter Arndt states that while Type A tests performed at

reduced pressure rather than peak accident pressure are economically

advantageous to the industry, the results of these tests are not

necessarily indicative of leakage rates during accidents.

The NRC believes that extrapolating low pressure leakage-test

results to full pressure leakage-test results has turned out to be

unsuccessful. The NRC believes that the peak calculated accident

pressure: (1) Is consistent with the typical practice for NRC staff

evaluations of accident pressure for the first 24 hours in accordance

with Regulatory Guides 1.3 and 1.4; (2) Provides at least a nominal

check for gross leak paths which might exist at high test pressures,

but not at low test pressures; and (3) Directly represents technical

specification leakage-rate limits, and provides greater confidence in

containment system leak-tight integrity.

Based on the foregoing, the NRC has decided to retain the

calculated design basis loss-of-coolant accident peak pressure as the

ILRT test pressure.

Containment Inservice Visual Inspection

Eighteen commenters expressed opinions on this issue. The NEI and

most utilities oppose the NRC's proposal to require visual examination

of containment be performed 3 times every 10 years. These commenters

suggest that this issue be taken up in a parallel rulemaking.

The NRC finds the industry's arguments for relaxing the frequency

of containment visual inspections to be unpersuasive. Because the

visual examination is not integral to the ILRT (i.e., may be performed

independently) and because the NRC sees benefits to the early detection

of unknown aging mechanisms which may be active, the NRC considers it

prudent to conduct visual inspections on a frequency greater than the

ILRT. Further, the NRC believes it is inappropriate to defer a

requirement pertaining to containment structural integrity to an

ongoing rulemaking to incorporate ASME Section XI, IWE and IWL until

its form and substance is finalized.

Based on the foregoing, the NRC has decided to retain its frequency

for the inservice visual inspection.

Reporting Requirements

Only one comment was received on this issue. Dr. Z. Reytblatt noted

that the proposed rule's reporting requirements consist only of a cover

letter to the NRC and suggested this is intended to conceal information

from the public. Dr. Reytblatt suggests that utilities should be

required to submit all computer files related to testing to the NRC

immediately after the tests have been completed to prevent their

alteration or destruction.

It is not the intent of the NRC's reporting requirements to conceal

information from the public; if tests fail, the information is required

to be reported to the NRC, and the NRC will make such data available to

the public. The NRC has decided to retain its reporting requirements as

stated in the proposed rule.

Modifications to the Proposed Rule in Response to Public Comments

The NRC has decided to amend its proposed rule and its implementing

documents to clarify language. The NRC has concluded that its

regulatory analysis and its technical support document, NUREG-1493, do

not require corrections to its technical or cost analyses or its

findings. Modifications to all documents will be restricted to

clarifications and enhancements to assist in communications with the

reader, specifically in areas discussed in the public comments.

The proposed rule has been modified by changing ``Acceptance

criteria'' to ``Performance criteria'' in Section II, Definitions, and

various conforming text changes to reflect consistent use of that term.

Other similar redundant terms in the proposed rule, e.g. goals, have

been deleted to establish clear and concise language in the rule.

Specific changes to the draft regulatory guide, Section C,

Regulatory Position, include (1) in paragraph number 2, the inclusion

of the rationale for denying the ``3 refueling cycle'' change requested

in the public comments; (2) the inclusion of a new paragraph number 4,

taking exception to the NEI Industry Guideline, Section 10.2.3.3, which

provides guidance that an as-found Type C test or an alternative test

or analysis (emphasis added) shall be performed prior to any

maintenance, repair, modification, or adjustment activity if it could

affect a valve's leak-tightness. ``Alternate test or analysis'' are not

endorsed as appropriate substitutes for an as-found test, since the

latter provides clear and objective evidence of performance of

isolation components; and (3) limitation of the extension of test

intervals for main steam and feedwater isolation valves in BWRs, and

containment purge and vent valves in PWRs and BWRs beyond 30 months

given their operating experience and/or safety significance.

Regulatory Guide; Issuance, Availability

The Nuclear Regulatory Commission has issued a new guide in its

Regulatory Guide Series. This series has been developed to describe and

make available to the public such information as methods acceptable to

the NRC staff for implementing specific parts of the Commission's

regulations, techniques used by the staff in evaluating specific

problems or postulated accidents, and data needed by the staff in its

review of applications for permits and licenses.

Regulatory Guide 1.163, ``Performance-Based Containment Leakage-

Test Program,'' endorses an industry standard which contains guidance

on an acceptable performance-based leakage-test program, leakage rate

test methods, procedures, and analyses that may be used to implement

the final regulation published in this notice.

Comments and suggestions in connection with items for inclusion in

guides currently being developed or improvements in all published

guides are encouraged at any time. Written comments may be submitted to

the Rules Review and Directives Branch, Division of Freedom of

Information and Publications Services, Office of Administration, U.S.

Nuclear Regulatory Commission, Washington, DC 20555. The NRC staff's

response to public comments received on the draft version of this guide

(DG-1037, issued in February 1995) are available for inspection or

copying for a fee in the NRC Public Document Room, 2120 L Street NW.,

Washington, DC.

Regulatory guides are available for inspection at the Commission's

Public Document Room, 2120 L Street NW., Washington, DC. Single copies

of regulatory guides may be obtained free of charge by writing the

Office of Administration, Attention: Distribution and Services Section,

U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001; or by

fax at (301) 415-2260. Issued guides may also be purchased from the

National Technical Information Service on a standing order basis.

Details on this service may be

[[Page 49504]]

obtained by writing NTIS, 5285 Port Royal Road, Springfield, VA 22161.

Regulatory guides are not copyrighted, and Commission approval is not

required to reproduce them.

Implementation

The proposed Option B to Appendix J will become effective 30 days

after publication. At any time thereafter, a licensee or applicant may

notify the NRC of its desire to perform containment leakage-rate

testing according to Option B. Accompanying this notification, a

licensee must submit proposed technical specifications changes which

would eliminate those technical specifications which implement the

current rule and propose a new technical specification referencing the

NRC regulatory guide or, if the licensee desires, an alternative

implementation guidance. Implementation must await NRC review and

approval of the licensee's proposal. The NRC anticipates that a generic

communication will be issued shortly which will provide the

implementation procedure to all power reactor licensees.

Finding of No Significant Environmental Impact: Availability

The Commission has determined under the National Environmental

Policy Act of 1969, as amended, and the Commission's regulations in

Subpart A of 10 CFR Part 51, that this rule, if adopted, would not be a

major Federal action significantly affecting the quality of the human

environment, and therefore an environmental impact statement is not

required. There will be a marginal radiological environmental impact

offsite, and the occupational exposure onsite is expected to decrease

by about 0.8 person-rem per year of plant operation for plant personnel

if licensees adopt the performance-based testing scheme provided in the

revised regulation. Alternatives to issuing this revision of the

regulation were considered. One alternative would also entail complex

revisions to other NRC regulations and therefore the NRC has decided to

pursue it separately in the future. A third alternative would add

regulatory burden without a commensurate safety benefit and therefore

was found not to be acceptable. The environmental assessment is

available for inspection or copying for a fee in the NRC Public

Document Room, 2120 L Street NW, (Lower Level), Washington, DC; the

PDR's mailing address is Mail Stop LL-6, Washington, DC 20555; phone

(202) 634-3273; fax (202) 634-3343.

Paperwork Reduction Act Statement

This final rule amends information collection requirements that are

subject to the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et

seq.). These requirements were approved by the Office of Management and

Budget, approval number 3150-0011.

Because the rule will relax existing information collection

requirements by providing an option to the existing requirements, the

public burden for this collection of information is expected to be

reduced by approximately 400 hours per licensee per year. This

reduction includes the time required for reviewing instructions,

searching existing data sources, gathering and maintaining the data

needed and completing and reviewing the collection of information. Send

comments regarding the estimated burden reduction or any aspect of this

collection of information, including suggestions for reducing this

burden, to the Information and Records Management Branch (T-6 F33),

U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001; and to

the Desk Officer, Office of Information and Regulatory Affairs, NEOB-

10202, (3150-0011), Office of Management and Budget, Washington, DC

20503.

Regulatory Analysis

The Commission has prepared a final regulatory analysis on this

regulation. The analysis examines the costs and benefits of the

alternatives considered by the Commission. The analysis is available

for inspection or copying for a fee in the NRC Public Document Room,

2120 L Street NW, (Lower Level), Washington, DC; the PDR's mailing

address is Mail Stop LL-6, Washington, DC 20555; phone (202) 634-3273;

fax (202) 634-3343.

Regulatory Flexibility Certification

In accordance with the Regulatory Flexibility Act of 1980, (5

U.S.C. 605(b)), the Commission certifies that this rule will not, if

promulgated, have a significant economic impact on a substantial number

of small entities. This rule affects only the licensing and operation

of nuclear power plants. The companies that own these plants do not

fall within the scope of the definition of ``small entities'' set forth

in the Regulatory Flexibility Act or the Size standard adopted by the

NRC (10 CFR 2.810).

Backfit Analysis

This final rule amends a current regulation by establishing

alternative requirements which may be voluntarily adopted by licensees.

Therefore, the final rule does not constitute a backfit as defined in

10 CFR 50.109(a)(1). Therefore, a backfit analysis is not necessary.

List of Subjects in 10 CFR Part 50

Antitrust, Classified information, Criminal penalties, Fire

protection, Incorporation by reference, Intergovernmental relations,

Nuclear power plants and reactors, Radiation protection, Reactor siting

criteria, Reporting and recordkeeping requirements.

For the reasons set out in the preamble and under the authority of

the Atomic Energy Act of 1954, as amended, the Energy Reorganization

Act of 1974, as amended, and 5 U.S.C. 552 and 553, the NRC is adopting

the following amendments to 10 CFR Part 50.

PART 50--DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION

FACILITIES

1. The authority citation for Part 50 is revised to read as

follows:

Authority: Secs. 102, 103, 104, 105, 161, 182, 183, 186, 189, 68

Stat. 936, 937, 938, 948, 953, 954, 955, 956, as amended, sec. 234,

83 Stat. 1244, as amended (42 U.S.C. 2132, 2133, 2134, 2135, 2201,

2232, 2233, 2236, 2239, 2282); secs. 201, as amended, 202, 206, 88

Stat. 1242, as amended, 1244 1246 (42 U.S.C. 5841, 5842, 5846).

Section 50.7 also issued under Pub. L. 95-601, sec. 10, 92 Stat.

2951, as amended by Pub. L. 102-486, sec. 2902, 106 Stat. 3123, (42

U.S.C. 5851). Sections 50.10 also issued under secs. 101, 185, 68

Stat. 936, 955, as amended (42 U.S.C. 2131, 2235); sec. 102, Pub. L.

91-190, 83 Stat. 853 (42 U.S.C. 4332). Sections 50.13, 50.54(dd),

and 50.103 also issued under sec. 108, 68 Stat. 939, as amended (42

U.S.C. 2138). Sections 50.23, 50.35, 50.55, and 50.56 also issued

under sec. 185, 68 Stat. 955 (42 U.S.C. 2235). Sections 50.33a,

50.55a and Appendix Q also issued under sec. 102, Pub. L. 91-190, 83

Stat. 853 (42 U.S.C. 4332). Sections 50.34 and 50.54 also issued

under sec. 204, 88 Stat. 1245 (42 U.S.C. 5844). Sections 50.58,

50.91, and 50.92 also issued under Pub. L. 97-415, 96 Stat. 2073 (42

U.S.C. 2239). Section 50.78 also issued under sec. 122, 68 Stat. 939

(42 U.S.C. 2152). Sections 50.80 50.81 also issued under sec. 184,

68 Stat. 954, as amended (42 U.S.C. 2234). Appendix F also issued

under sec. 187, 68 Stat. 955 (42 U.S.C. 2237).

2. Appendix J to 10 CFR Part 50 is amended by adding the following

language between the title and the Table of Contents and adding the

language for Option B after Section V.B3.

Appendix J--Primary Reactor Containment Leakage Testing for Water-

Cooled Power Reactors

This appendix includes two options, A and B, either of which can

be chosen for meeting the requirements of this appendix.

[[Page 49505]]

Option A--Prescriptive Requirements

* * * * *

Option B--Performance-Based Requirements

Table of Contents

I. Introduction.

II. Definitions.

III. Performance-based leakage-test requirements.

A. Type A test.

B. Type B and C tests.

IV. Recordkeeping.

V. Application.

I. Introduction

One of the conditions required of all operating licenses for

light-water-cooled power reactors as specified in Sec. 50.54(o) is

that primary reactor containments meet the leakage-rate test

requirements in either Option A or B of this appendix. These test

requirements ensure that (a) leakage through these containments or

systems and components penetrating these containments does not

exceed allowable leakage rates specified in the Technical

Specifications and (b) integrity of the containment structure is

maintained during its service life. Option B of this appendix

identifies the performance-based requirements and criteria for

preoperational and subsequent periodic leakage-rate testing.3

\3\ Specific guidance concerning a performance-based leakage-

test program, acceptable leakage-rate test methods, procedures, and

analyses that may be used to implement these requirements and

criteria are provided in Regulatory Guide 1.163, ``Performance-Based

Containment Leak-Test Program.''

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II. Definitions

Performance criteria means the performance standards against

which test results are to be compared for establishing the

acceptability of the containment system as a leakage-limiting

boundary.

Containment system means the principal barrier, after the

reactor coolant pressure boundary, to prevent the release of

quantities of radioactive material that would have a significant

radiological effect on the health of the public.

Overall integrated leakage rate means the total leakage rate

through all tested leakage paths, including containment welds,

valves, fittings, and components that penetrate the containment

system.

La (percent/24 hours) means the maximum allowable leakage rate

at pressure Pa as specified in the Technical Specifications.

Pa (p.s.i.g) means the calculated peak containment internal

pressure related to the design basis loss-of-coolant accident as

specified in the Technical Specifications.

III. Performance-Based Leakage-Test Requirements

A. Type A Test

Type A tests to measure the containment system overall

integrated leakage rate must be conducted under conditions

representing design basis loss-of-coolant accident containment peak

pressure. A Type A test must be conducted (1) after the containment

system has been completed and is ready for operation and (2) at a

periodic interval based on the historical performance of the overall

containment system as a barrier to fission product releases to

reduce the risk from reactor accidents. A general visual inspection

of the accessible interior and exterior surfaces of the containment

system for structural deterioration which may affect the containment

leak-tight integrity must be conducted prior to each test, and at a

periodic interval between tests based on the performance of the

containment system. The leakage rate must not exceed the allowable

leakage rate (La) with margin, as specified in the Technical

Specifications. The test results must be compared with previous

results to examine the performance history of the overall

containment system to limit leakage.

B. Type B and C Tests

Type B pneumatic tests to detect and measure local leakage rates

across pressure retaining, leakage-limiting boundaries, and Type C

pneumatic tests to measure containment isolation valve leakage

rates, must be conducted (1) prior to initial criticality, and (2)

periodically thereafter at intervals based on the safety

significance and historical performance of each boundary and

isolation valve to ensure the integrity of the overall containment

system as a barrier to fission product release to reduce the risk

from reactor accidents. The performance-based testing program must

contain a performance criterion for Type B and C tests,

consideration of leakage-rate limits and factors that are indicative

of or affect performance, when establishing test intervals,

evaluations of performance of containment system components, and

comparison to previous test results to examine the performance

history of the overall containment system to limit leakage. The

tests must demonstrate that the sum of the leakage rates at accident

pressure of Type B tests, and pathway leakage rates from Type C

tests, is less than the performance criterion (La) with margin, as

specified in the Technical Specification.

IV. Recordkeeping

The results of the preoperational and periodic Type A, B, and C

tests must be documented to show that performance criteria for

leakage have been met. The comparison to previous results of the

performance of the overall containment system and of individual

components within it must be documented to show that the test

intervals established for the containment system and components

within it are adequate. These records must be available for

inspection at plant sites.

If the test results exceed the performance criteria (La) as

defined in the plant Technical Specifications, those exceedances

must be assessed for Emergency Notification System reporting under

Secs. 50.72 (b)(1)(ii) and Sec. 50.72 (b)(2)(i), and for a Licensee

Event Report under Sec. 50.73 (a)(2)(ii).

V. Application

A. Applicability

The requirements in either or both Option B, III.A for Type A

tests, and Option B, III.B for Type B and C tests, may be adopted on

a voluntary basis by an operating nuclear power reactor licensee as

specified in Sec. 50.54 in substitution of the requirements for

those tests contained in Option A of this appendix. If the

requirements for tests in Option B, III.A or Option B, III.B are

implemented, the recordkeeping requirements in Option B, IV for

these tests must be substituted for the reporting requirements of

these tests contained in Option A of this appendix.

B. Implementation

1. Specific exemptions to Option A of this appendix that have

been formally approved by the AEC or NRC, according to 10 CFR 50.12,

are still applicable to Option B of this appendix if necessary,

unless specifically revoked by the NRC.

2. A licensee or applicant for an operating license may adopt

Option B, or parts thereof, as specified in Section V.A of this

Appendix, by submitting its implementation plan and request for

revision to technical specifications (see paragraph B.3 below) to

the Director of the Office of Nuclear Reactor Regulation.

3. The regulatory guide or other implementation document used by

a licensee, or applicant for an operating license, to develop a

performance-based leakage-testing program must be included, by

general reference, in the plant technical specifications. The

submittal for technical specification revisions must contain

justification, including supporting analyses, if the licensee

chooses to deviate from methods approved by the Commission and

endorsed in a regulatory guide.

4. The detailed licensee programs for conducting testing under

Option B must be available at the plant site for NRC inspection.

Dated at Rockville, Maryland this 20th day of September, 1995.

For the Nuclear Regulatory Commission.

John C. Hoyle,

Secretary of the Commission.

[FR Doc. 95-23803 Filed 9-25-95; 8:45 am]

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