Disposal of High-Level Radioactive Wastes in Geologic Repositories; Design Basis Events

SUMMARY: The Nuclear Regulatory Commission is proposing to amend its

policy on the protection of public health and safety from activities

conducted at a geologic repository operations area (GROA) before

permanent closure. In particular, the proposed rule would address the

measures that are required to provide defense in depth against the

consequences of ``design basis events.'' These measures include

prescribed design requirements, quality assurance requirements, and the

establishment of a preclosure controlled area from which members of the

public can be excluded.

DATES: Comments must be submitted on or before June 20, 1995. Comments

received after this date will be considered if it is practical to do

so, but the Commission is able to ensure consideration only for

comments received on or before this date.

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

Commission, Washington, DC 20555-0001. Attention: Docketing and Service

Branch.

Hand-deliver comments to: 11555 Rockville Pike, Rockville,

Maryland, between 7:45 am and 4:15 pm Federal workdays.

Examine comments received at the NRC Public Document Room, 2120 L

Street NW (Lower Level), Washington, DC.

FOR FURTHER INFORMATION CONTACT: Dr. Richard A. Weller, Division of

Waste Management, Office of Nuclear Material Safety and Safeguards,

U.S. Nuclear Regulatory Commission, Washington, DC 20555, telephone

(301) 415-7287.

SUPPLEMENTARY INFORMATION:

Background

Under the Nuclear Waste Policy Act of 1982, as amended, the U.S.

Nuclear Regulatory Commission exercises licensing and related

regulatory authority with respect to geologic repositories that are to

be constructed and operated by the U.S. Department of Energy (DOE) for

the disposal of high-level radioactive waste. The Commission's

regulations pertaining to these geologic repositories appear at 10 CFR

part 60. In recent years, NRC, in conjunction with its Federally-Funded

Research and Development Center (the Center for Nuclear Waste

Regulatory Analyses), completed a comprehensive review of the

requirements of part 60, regarding their clarity and sufficiency to

protect public health and safety. NRC focused particular attention on

any matters that may be ambiguous, insufficient for their intended

purpose, or inconsistent with other expressions of its regulatory

policy. The amendments presented in this proposed rule deal with a

matter that was brought to light by this review and by a petition for

rulemaking (PRM) filed by DOE (PRM-60-3).

The issue concerns the protection of public health and safety for a

broad range of normal and accident conditions during the operational

period of a geologic repository (i.e., before permanent closure). The

Commission is concerned that the current requirements of part 60 may be

unclear and may be insufficient to protect public health and safety for

the full range of credible conditions or events that may occur at an

operating repository, including those low-probability events that have

potentially serious consequences. The Commission also notes that

certain elements of existing part 60 differ from counterpart

requirements in other NRC rules, and it believes that greater

consistency in language would be beneficial. NRC is proposing

rulemaking to address these identified concerns. To develop and explain

the changes to the regulatory requirements that appear to be desirable,

it would be useful to review the pertinent provisions of existing part

60. In this review and in subsequent discussions in this notice, unless

the specific context suggests otherwise, the terms ``provisions,''

``requirements,'' ``standards,'' and ``criteria'' are generally used

interchangeably; the term ``limit'' (as in ``dose limit'') is generally

used to refer to a specific type of requirement or criterion; and the

term ``rule'' is generally used to refer to the entire set of

requirements or criteria (e.g., part 60).

The Existing Rule

The provisions of part 60 generally reflect the defense-in-depth

philosophy of the Commission that is commonly embodied in the

requirements and practices for other types of Commission-regulated

facilities, such as commercial nuclear power reactors and independent

spent fuel storage installations (ISFSIs), with the overall intent to

prevent or mitigate the occurrence of serious accidents and, thereby,

to protect the public health and safety. Defense-in-depth is provided

for, during the preclosure period, by conservatism, redundancy, and

diversity in design; the application of a comprehensive quality

assurance program, to facility design, construction, operation, and

maintenance; the imposition of radiation protection standards, for both

workers and members of the public, to limit the potential adverse

consequences of licensed activities to levels that are well within the

bounds of risks accepted in other productive activities in society; and

requirements for radiation safety programs and procedures and emergency

plans. The Commission's radiation protection standards are codified in

10 CFR part 20.

Specifically, defense-in-depth is implemented in Part 60 by

repository performance objectives and by detailed siting and design

criteria. Further, the rule provides that those structures, systems,

and components determined to be ``important to safety'' would be

subject to additional design requirements and to quality assurance

requirements, to add confidence that the repository and its subsystems

will perform satisfactorily in service. However, examination of the

specific provisions of the rule indicates that some elements may be

deficient in terms of their clarity, sufficiency, or consistency with

other NRC rules, resulting in concerns about the adequacy of defense-

in-depth in Part 60. The most significant concerns relate to: (1) The

definition of structures, systems, and components ``important to

safety'' and the ability to identify such features; (2) uncertainties

in the performance objective for radiation protection; and (3) the lack

of consistency with 10 CFR part 72 (``Licensing Requirements for the

Independent Storage of Spent Nuclear Fuel and High-Level Radioactive

Waste'') which applies to ``monitored retrievable storage (MRS)

installations,'' the facilities most similar to a repository, during

the repository's operational period. These concerns are discussed in

turn.

``Important-to-Safety'' Definition

The regulation states (10 CFR 60.2):

``Important to safety,'' with reference to structures, systems,

and components means those engineered structures, systems, and

components essential to the prevention or mitigation of an accident

that could result in a radiation dose to the whole body, or any

organ, of 0.5 rem or greater at or beyond the nearest boundary of

the unrestricted area at any time until the completion of permanent

closure.

[[Page 15181]] Note, first, that the definition refers to

repository features ``essential to the prevention or mitigation of an

accident'' (emphasis added) in the context of a dose limit (0.5 rem)

``* * * equal to the annual dose to the whole body of an individual in

an unrestricted area that would be permitted under 10 CFR Part 20 for

normal operations * * *'' (48 FR 28202; June 21, 1983, Final rule,

``Disposal of High-Level Radioactive Wastes in Geologic

Repositories''). However, the definition is unclear with respect to the

range of ``accidents'' to be considered when it is applied to identify

those structures, systems, and components important to safety. As such,

the uncertainty in the definition raises questions about the adequacy

of the requirements, in the rule, to protect the public health and

safety for the full range of conditions or events that may occur before

closure, including those credible, but unlikely events with potentially

significant radiological consequences. Second, the focus of the

definition is the protection of members of the public in unrestricted

areas and, although supplemental design and quality assurance

requirements for this purpose may also indirectly benefit onsite

workers for some conditions or events, the definition does not

explicitly address protection for the occupational workforce. Lastly,

the value of 5 mSv (0.5 rem) as a dose limit in unrestricted areas for

``accident'' conditions is peculiar to part 60, and lacks consistency

with a corresponding limit in 10 CFR part 72.

Performance Objective for Radiation Protection

As stated previously, the Commission's numerical radiation

protection standards are codified in Part 20. These standards apply to

operations at a geologic repository by virtue of 10 CFR 20.1002 as well

as by 10 CFR 60.111(a), which provides, in part:

Protection against radiation exposures and releases of

radioactive material. The geologic repository operations area shall

be designed so that until permanent closure has been completed,

radiation exposures and radiation levels, and releases of

radioactive materials to unrestricted areas, will at all times be

maintained within the limits specified in Part 20 of this chapter *

* *.

There are two conceptual difficulties with this language and both

issues derive from the language in the rule that requires the limits of

part 20 to be met ``at all times.'' The first issue relates to the

uncertainty about the scope of activities intended in the requirement,

specifically, whether part 20 limits must be observed not only during

planned operations, but also if the emplaced waste has to be retrieved

in accordance with 10 CFR 60.111(b). The Commission previously

addressed this issue in a prior proposed rulemaking, explaining that

the phrase (``at all times'') was included in the regulation so as ``*

* * to emphasize the need to design the geologic repository operations

area so that any waste retrieval found to be necessary in the future

could be carried out in conformance with the radiation protection

requirements of 10 CFR Part 20'' (51 FR 22288; June 19, 1986, proposed

amendments to conform to U.S. Environmental Protection Agency (EPA)

general environmental standards). The Commission adheres to this

interpretation and believes that the application of part 20 limits to

possible retrieval activities is consistent with the policy followed in

the application of part 20 to corresponding activities (e.g., spent

fuel handling) at other facilities regulated by the Commission under 10

CFR parts 50 and 72 (i.e., at commercial power reactors and ISFSIs,

respectively).

The second issue relates to uncertainty about the scope of

conditions intended in Sec. 60.111(a), specifically, whether part 20

limits must be observed for the extreme conditions that may result from

credible, but unlikely, scenarios or events. Here, the Commission

recognizes the desirability of articulating its intentions more

clearly. For this purpose, it is helpful to use a simple classification

scheme for describing the broad range of conditions or events that

effectively provide the design basis for the facility. These so-called

``design basis events'' are defined as being of two categories:

(1) those natural and human-induced events that are reasonably

likely to occur regularly, moderately frequently, or one or more times

before permanent closure of the geologic repository operations area;

and

(2) other natural and human-induced events that are considered

unlikely, but sufficiently credible to warrant consideration, taking

into account the potential for significant radiological impacts on

public health and safety.

Category 1 events have typically been referred to in the rules and

guidance documents (e.g., regulatory guides) for Commission-regulated

facilities (nuclear power plants, MRS installations, geologic

repositories) as those conditions resulting from ``normal operation,

including anticipated operational occurrences.'' Anticipated

operational occurrences, including those of natural origin, are those

conditions expected to occur one or more times during the lifetime of

the facility.

In the administration of its regulatory program for facilities

licensed under parts 50 and 72, it has been the Commission's general

practice, as well as its intent in part 60, to apply the dose limits of

part 20 to Category 1 events. The Commission's intent, in this regard,

is further clarified in the statement of considerations related to

revision of its part 20 standards (56 FR 23360; May 21, 1991, Final

rule, ``Standards for Protection Against Radiation''). Here, the

Commission notes that the revision conforms its regulations to the

``Presidential Radiation Protection Guidance to Federal Agencies for

Occupational Exposure.'' The Commission further notes (56 FR 23365)

that the dose standards in the Presidential guidance only apply to

normal operating conditions. Although it is the Commission's intent

that the regulations in part 20 also be observed to the extent

practicable during emergencies, the Commission also recognizes that, in

an actual emergency, operations that do not conform to the regulations

may be necessary to protect public health and safety. Notwithstanding

the general applicability of these regulations to all operational

situations, it is not the Commission's intent that these requirements

apply to Category 2 events as a design basis for the facility.

Appropriate requirements other than the dose limits of part 20 would be

provided as the design basis for Category 2 events. Some of the

confusion about this matter is no doubt linked to the terminology used

in various Commission rules or guidance documents, where the terms

``accidents'' and ``anticipated operational occurrences'' may have been

used interchangeably. It should be recognized that some accidents''

may, indeed, be ``anticipated operational occurrences,'' if they are

expected to occur one or more times during the lifetime of the

facility. What is important, in this regard, is not the term applied to

the event, but its expected frequency of occurrence, to determine both

its category and whether part 20 limits should apply as a design basis.

Although the foregoing discussion may help to clarify the

Commission's intent regarding the applicability of part 20 limits to

Categories 1 and 2 design basis events, it leaves open the question

about the adequacy, to protect public health and safety, of the

requirements of part 60 for Category 2 events. The Commission now

proposes to address this matter by harmonizing the requirements of part

60, as appropriate, with other parts of its regulations--

[[Page 15182]] particularly art 72, which applies to facilities (MRS

installations) with much in common with repositories, during their

operational period. In this regard, the character and design of the

features of an MRS installation would be expected to be very similar to

the surface facilities of an operating repository. Further, the same

kind of functional activities would be performed at both types of

facilities, namely, receiving, handling, packaging, storing, and

retrieving high-level radioactive waste. As such, the Commission

believes that greater consistency between part 60 and part 72 is both

logical and desirable.

10 CFR Part 72

Part 72 also refers to structures, systems, and components

important to safety. However, instead of defining this concept in

specific quantitative terms, it provides the following (10 CFR 72.3):

``Structures, systems, and components important to safety'' mean

those features of the ISFSI (independent spent fuel storage

installation) or MRS (monitored retrievable storage installation)

whose function is:

(1) to maintain the conditions required to store spent fuel or

high-level radioactive waste safely;

(2) to prevent damage to the spent fuel or the high-level

radioactive waste container during handling and storage; or

(3) to provide reasonable assurance that spent fuel or high-

level radioactive waste can be received, handled, packaged, stored,

and retrieved without undue risk to the health and safety of the

public.

The Commission's concern in singling out this class of structures,

systems, and components is to identify those features that are so

important that it is prudent to warrant the application of special

design and quality assurance criteria. The design elements that are

then to be required are determined in the light of the design bases, a

term that is defined as follows:

``Design bases'' means that information that identifies the

specific functions to be performed by a structure, system, or

component of a facility and the specific values or ranges of values

chosen for controlling parameters as reference bounds for design.

These values may be restraints derived from generally accepted

``state-of-the-art'' practices for achieving functional goals or

requirements derived from analysis (based on calculation or

experiments) of the effects of a postulated event under which a

structure, system, or component must meet its functional goals. The

values for controlling parameters for external events include: (1)

estimates of severe natural events to be used for deriving design

bases that will be based on consideration of historical data on the

associated parameters, physical data, or analysis of upper limits of

the physical processes involved and (2) estimates of severe external

man-induced events to be used for deriving design bases that will be

based on analysis of human activity in the region taking into

account the site characteristics and the risks associated with the

event. (10 CFR 72.3.)

Part 72 provides for a quality assurance program that encompasses a

range of structures, systems, and components of somewhat indefinite

scope. According to 10 CFR 72.140(b), the program ``* * * must cover

the activities identified in 10 CFR 72.24(n),'' which in turn deals

with ``structures, systems, and components important to safety.'' The

application of these provisions relates to the qualitative language of

the definition of ``* * * structures, systems, and components important

to safety.'' In essence, an element is to be placed in this category if

its function is to provide reasonable assurance that there is no undue

risk to the health and safety of the public. Although the definition

lacks specific numerical guidance as to what constitutes ``undue

risk,'' the Commission, nevertheless, regards this as a stringent

test--one that contemplates that the numerical limits set out in part

20 will generally be met for Category 1 design basis events, consistent

with the general practice (as previously discussed) of the Commission

in the application of these standards.

With respect to Category 2 design basis events, numerical guidance

may be inferred from both the ``Siting Evaluation Factors'' (Subpart E)

and ``General Design Criteria'' (Subpart F) of part 72. As specified in

10 CFR 72.106, for each ISFSI or MRS facility, there must be a

``controlled area'' of such size that no individual located on or

beyond its boundary will receive a dose greater than 0.05 Sv (5 rem) to

the whole body, or to any organ, from any ``design basis accident.''

Both external natural events and external man-induced events must be

considered in defining the design bases that would result in the design

basis accident. 10 CFR 72.126(d) specifies that analyses must be made

to show that releases to the general environment from design basis

accidents will be within the exposure limits of 10 CFR 72.106. These

requirements suggest that the 0.05-Sv (5-rem) dose limit cited above

could be used to aid in the identification of structures, systems, and

components ``important to safety.'' However, although the existing

functional definition, in part 72, for ``important-to-safety''

features, has sufficed for identifying those corresponding components

or structures of an ISFSI, the Commission believes that the greater

specificity (i.e., numerical guidance) provided by a quantitative

definition similar in character to the existing part 60 definition

would be more suitable for the licensing of a more complex repository.

In the foregoing discussion, the Commission cited the requirements

of 10 CFR 72.106, which include provisions for the establishment of a

``controlled area'' boundary and dose criteria for limiting exposures

to individuals at or beyond that boundary, during design basis

accidents. The Commission notes that corresponding requirements are not

provided in part 60 which, in turn, raises questions about the adequacy

of the criteria in part 60 to ensure protection of public health and

safety.

There is another matter the Commission wishes to address, in this

action, that relates to another area of inconsistency between part 72

and part 60. Subpart F of part 72 provides the ``general design

criteria'' for an ISFSI or an MRS. These general design criteria

establish the minimum requirements for the design, fabrication,

construction, testing, maintenance, and performance, for the

structures, systems, and components of the facility that are important

to safety. In this regard, subpart F of part 72 is structured similarly

to, and performs the same function as, appendix A of 10 CFR part 50

(``General Design Criteria for Nuclear Power Plants'') in that both

sets of criteria establish minimum requirements for structures,

systems, and components ``important to safety.'' The corresponding

structure for the design criteria for the GROA in part 60 is somewhat

different from the corresponding structures in parts 72 and 50.

The design criteria for the GROA are provided in Secs. 60.130

through 60.134 and include criteria for both preclosure considerations

(i.e., criteria for features ``important to safety''), as well as

postclosure interests (i.e., criteria for features ``important to waste

isolation''). However, only the criteria of Sec. 60.131(b) are

identified as ``structures, systems, and components important to

safety,'' and it is unclear if other criteria specified in

Secs. 60.131(a), 60.132, and 60.133, for operational considerations,

are also ``important to safety.'' In this regard, the Commission notes

that there are some ``important-to-safety'' criteria in part 72 that

are not designated as such, in a corresponding manner, in part 60.

Although the Commission recognizes that this lack of consistency may be

due, in part, to the dual interests, in part 60, of preclosure safety

and postclosure isolation, the [[Page 15183]] Commission also believes

that this structure may contribute to the difficulty in determining

which features of the GROA are ``important to safety'' and subject to

the quality assurance provisions of subpart G.

The Petition for Rulemaking

On April 19, 1990, DOE filed a PRM with the Commission. It was

assigned Docket No. PRM-60-3. A notice of receipt was published in the

Federal Register on July 13, 1990 (55 FR 28771).

In its petition, DOE observed that 10 CFR 60.21(c)(3)(ii) requires

that the safety analysis report for a repository include a description

and analysis that considers ``* * *the adequacy of structures, systems,

and components provided for the prevention of accidents and mitigation

of the consequences of accidents, including those caused by natural

phenomena.'' Yet, part 60 does not provide numerical dose criteria

(i.e., dose limits) to use in identifying the need for engineered

safety features and for determining their adequacy.

DOE noted how similar operations at a geologic repository were to

those carried out at other licensed facilities, including, in

particular, facility operations for independent storage of spent

nuclear fuel. In common with these other facilities, the operations at

a repository would involve receipt, handling, transfer, and storage of

highly radioactive materials.

Under DOE's proposal, part 60 would be amended to include accident

dose limits of 0.05-Sv (5-rem) effective dose equivalent or 0.5-Sv (50-

rem) committed dose equivalent to any organ. These limits would apply

to any individual at the boundary of a newly defined ``preclosure

control area.'' The definition of the term ``important to safety''

would be revised, but would retain the 5-mSv (0.5-rem) dose limit;

however, unlike the present part 60, which relates this value to the

boundary of the unrestricted area, DOE's proposal would apply the dose

limit at the boundary of the preclosure control area. The phrase, ``at

all times,'' would be deleted from 10 CFR 60.111(a), to clarify that

part 20 does not apply to accident conditions. Lastly, DOE proposed

adding definitions of the terms ``preclosure control area,''

``committed dose equivalent,'' ``committed effective dose equivalent,''

and ``effective dose equivalent,'' to support the application of the

accident-dose limits described above.

For a fuller discussion of the PRM, see the July 13, 1990, Federal

Register notice.

Discussion

The Commission agrees with the petitioner that rulemaking is needed

to address the uncertainties related to appropriate accident-dose

limits for those unlikely, but credible, conditions or events (i.e.,

Category 2 design basis events) that might occur. In this regard, the

Commission agrees with the concept proposed by DOE, including the

application of appropriate accident-dose limits at the boundary of a

``preclosure control area.''

Regarding the current definition of ``important to safety,'' the

Commission agrees with DOE that the term should be revised so as to

clarify both its meaning and its intended scope. Although the revision

proposed by DOE captures the Commission's intent, with respect to

identifying those structures, systems, and components necessary to

prevent or mitigate the consequences of credible, but unlikely

accidents (i.e., Category 2 design basis events), it does not address

the Commission's parallel interest in those repository features

necessary to protect workers and members of the public from those

events that occur regularly, moderately frequently, or one or more

times during the lifetime of the GROA (i.e., Category 1 design basis

events). The Commission proposes to address this matter by both

expanding and modifying the current definition in part 60.

With regard to DOE's remaining major item of concern in its

petition, specifically the uncertainty in the language of 10 CFR

60.111(a), the Commission agrees with DOE's proposal to delete the

ambiguous phrase ``at all times'' from the rule, to clarify that the

objective does not apply to radiation exposures, levels, or releases

from those credible, but unlikely conditions or events that are

referred to above as Category 2 design basis events. Notwithstanding

this change, it remains the Commission's intent that this performance

objective applies to all functional activities (e.g., radioactive waste

receiving, handling, packaging, storage, and emplacement) expected to

occur at a repository site, including retrieval, if that becomes

necessary.

Finally, with respect to the new definitions that DOE proposed for

10 CFR 60.2, the Commission agrees that there is a need to define a

boundary for a ``preclosure control area.'' However, the terms

``committed dose equivalent,'' ``committed effective dose equivalent,''

and ``effective dose equivalent'' are all defined terms, in part 20,

and incorporated into part 60 by virtue of 10 CFR 60.111(a). As such,

these terms do not need to be defined in part 60.

Based on the foregoing discussion of DOE's petition and the

interest of greater consistency between part 60 and part 72, as

previously discussed, the Commission proposes to amend part 60 to

ensure the adequacy of its requirements to protect the public health

and safety. In this regard, dose limits are proposed, in the rule, for

protection of members of the public, during Category 1 and Category 2

design basis events, and for protection of workers, during Category 1

design basis events. The Commission notes that dose limits are not

proposed for protection of workers during Category 2 design basis

events, consistent with the policy in practice for facilities regulated

by the Commission under parts 50 and 72.

The Commission has determined that specific standards for the

protection of workers during Category 2 events are not needed for part

60. First, for some design basis events, the repository design and

quality assurance enhancements employed to satisfy the proposed

requirements, for protection of members of the public, during Category

2 events, will also provide a measure of protection for onsite workers.

Second, onsite workers would have access to protective equipment (e.g.,

respirators) and clothing, should the need ever arise. Third, onsite

workers would be trained in emergency response and procedures to deal

with operational problems related to these kinds of events. Fourth,

part 20 should provide adequate worker protection standards.

There is one other matter the Commission would like to note in

relation to this action. During the course of consideration of the DOE

PRM and development of the amendments as proposed herein, the

Commission identified an additional regulatory uncertainty with respect

to part 60 requirements. Specifically, while part 60 includes a

definition for structures, systems, and components ``important to

safety,'' there is no corresponding definition in the rule for

structures, systems, and components ``important to waste isolation.''

These definitions are important as they are the predicates for required

design and quality assurance requirements in the rule. However, the

focus of the amendments proposed in this action is strictly in relation

to the adequacy of part 60 requirements to protect public health and

safety during the operational period of the repository. Recognizing

that the lack of a definition for ``important to waste isolation''

relates solely to the period of isolation following permanent

repository closure, the Commission plans to address this matter

separately in a subsequent rulemaking action. [[Page 15184]]

The proposed amendments are discussed below.

Section-by-Section Analysis

Section 60.2. Definitions

The proposed amendments involve eight definitions needed in part

60.

The term ``preclosure controlled area'' is new. It is essentially

the same as the term ``preclosure control area'' proposed by DOE in its

petition (PRM-60-3) and corresponds closely to the term ``controlled

area,'' as defined in 10 CFR 72.3. The term ``preclosure controlled

area'' is proposed because part 60 already refers to a ``controlled

area'' (within which waste isolation is to be ensured after permanent

closure). The function of the new term is to delimit an area over which

the licensee exercises control of activities to meet regulatory

requirements. Control includes the power to exclude members of the

public, if necessary. Because part 60 (unlike part 72) involves ongoing

underground operations and timeframes of concern over centuries and

millennia, language in the proposed definition is included that,

consistent with its function, limits the area to the surface and limits

the duration to the period up to, and including, permanent closure.

The existing term ``controlled area'' would be renamed

``postclosure controlled area,'' to avoid any confusion or

misunderstanding about this term, in relation to its use in parts 20

and 72. No substantive change, however, is intended for the

``postclosure controlled area,'' as this is a change in nomenclature,

only. Consistent with this change in nomenclature, the term

``controlled area'' would be changed to ``postclosure controlled

area,'' where it appears in the definitions for ``accessible

environment,'' ``disturbed zone,'' and ``site.''

The term ``important to safety'' would be amended to address the

issues previously discussed. The existing provision is unclear and

fails to ensure proper levels of protection of public and worker health

and safety for the broad range of conditions or events that might occur

at a repository site. This is an important term, because it is the

predicate for required design features, as well as required quality

assurance measures that provide defense-in-depth. The Commission

proposes to retain the quantitative features of the existing

definition, but specify different numerical limits for each of the two

categories (1 and 2) of design basis events. The structures, systems,

and components ``important to safety'' would be those necessary: (1) to

provide reasonable assurance that the requirements of Sec. 60.111(a)

would be observed for Category 1 design basis events; or (2) to prevent

or mitigate Category 2 design basis events that could result in doses

equal to, or greater than, the values specified in [new] Sec. 60.136,

to any individual located on or beyond the nearest boundary of the

preclosure controlled area.

Although the term ``design bases'' appears in existing part 60, in

10 CFR 60.21(c)(2), it was not defined. As the discussion above makes

clear, ``design bases'' should be understood in relation to that range

of events, including external natural or man-induced events, that is

taken into account in the design, and, in particular, in relation to

conditions that could result in radiological consequences beyond

specified limits. The definition in part 72 would be inserted, without

change, into the list of defined terms in 10 CFR 60.2.

The inclusion of a definition of ``design basis events'' serves two

purposes. First, it identifies a set of events (referred to elsewhere

as Category 1 design basis events) that must be taken into account in

demonstrating compliance with the requirement to show, with reasonable

assurance, that the provisions of part 20 will be met. (This set of

events is described as ``* * *those natural and human-induced events

that are reasonably likely to occur regularly, moderately frequently,

or one or more times before permanent closure of the geologic

repository operations area.'') Second, it identifies an additional set

of events (previously referred to as Category 2 design basis events)

that must be taken into account in applying the Commission's defense-

in-depth philosophy. (This set of events is described as those ``* *

*other natural and human-induced events that are considered unlikely,

but sufficiently credible to warrant consideration, taking into account

the potential for significant radiological impacts on public health and

safety.'') The Commission recognizes that the criterion of

``sufficiently credible to warrant consideration'' is inexact, leaving

its application to a consideration of the particular site and design

that are the subjects of a license application. Generally, the

Commission would expect that such design basis events would include as

broad a range of external phenomena as would be taken into account in

defining the design basis for other regulated facilities, including

nuclear reactors.

Section 60.8 Information Collection Requirements: OMB Approval

NRC is proposing to update 10 CFR 60.8, ``Information Collection

Requirements: OMB Approval,'' to reflect the fact that subsequent to

the original issuance of part 60, NRC requested, and obtained Office of

Management and Budget (OMB) approval for the part 60 ``Information

Collection Requirements.'' Section 60.8 was to be corrected the first

time other revisions were made.

Section 60.21 Content of Application

The petition for rulemaking suggested that provision for accident

analysis might be accomplished by amendment of 10 CFR 60.111. The

Commission proposes, instead, to provide for an accident analysis as

part of the content of the application section (i.e., 10 CFR 60.21).

The proposed language would require the application to address the

potential dose, to an individual on or beyond the preclosure controlled

area boundary, that is attributable to Category 2 design basis events.

The procedure that is envisaged is that the applicant would address the

critical design basis events, singly, and demonstrate, by its analysis,

that the doses on or beyond the preclosure controlled area boundary

would be in accordance with the applicable requirements. The proposed

language serves the same purpose as the counterpart section of part 72

(namely 10 CFR 72.24(m)).

The proposed rule also reflects the position, as discussed

previously, that the applicant must demonstrate that the requirements

of part 20 will be met, assuming the occurrence of Category 1 design

basis events. For this analysis, the applicant would consider Category

1 design basis events singly, or in appropriate combinations. The

doses, exposures, or releases must be kept within part 20 limits should

less likely events (e.g., moderately frequent events) occur in

combination with events that occur regularly.

The Commission also proposes to eliminate certain terms in part 60

that are undefined and may be subject to differing interpretations--

specifically, the terms ``normal conditions,'' ``anticipated

operational occurrences,'' and ``accidents.'' These terms would be

supplanted by the new term ``design basis events.'' Besides enhancing

clarity of expression, the new language better reflects the regulatory

framework articulated above. Lastly, where the term ``controlled area''

appears in the language of this section, it would be

[[Page 15185]] changed to ``postclosure controlled area.''

Section 60.43 License Specification

The term ``controlled area'' would be changed to ``postclosure

controlled area.''

Section 60.46 Particular Activities Requiring License Amendment

The term ``controlled area'' would be changed to ``postclosure

controlled area.''

Section 60.51 License Amendment for Permanent Closure

The term ``controlled area'' would be changed to ``postclosure

controlled area.''

Section 60.102 Concepts

The term ``controlled area'' would be changed to ``postclosure

controlled area.''

Section 60.111 Performance of the Geologic Repository Operations Area

Through Permanent Closure

Consistent with the petitioner's proposal, the Commission would

delete the phrase ``at all times'' from the performance objective of

Sec. 60.111(a). This change would clarify that this requirement does

not apply to radiation exposures, levels, and releases from Category 2

design basis events.

Section 60.121 Requirements for Ownership and Control of Interests in

Land

The term ``controlled area'' would be changed to ``postclosure

controlled area.''

Section 60.122 Siting Criteria

The term ``controlled area'' would be changed to ``postclosure

controlled area.''

Section 60.130 Scope of Design Criteria for the Geologic Repository

Operations Area

The Commission proposes to modify the title of this section to the

term ``General Considerations'' and add clarifying language, to the

existing discussion, to indicate that Secs. 60.131 through 60.134

specify the minimum criteria for the design of those structures,

systems, and components important to safety, or important to waste

isolation. These changes are necessary to provide consistency with the

modified definition of ``important to safety'' (10 CFR 60.2) as well as

to clarify the purpose of these criteria. These changes will also

provide consistency with the corresponding ``minimum'' design criteria,

for an MRS, in 10 CFR part 72.

Section 60.131 General Design Criteria for the Geologic Repository

Operations Area

Consistent with the modifications to Sec. 60.130, as described

above, the Commission would delete the reference to ``Structures,

systems, and components important to safety,'' in the title of

Sec. 60.131(b), and re-letter or re-number the current criteria in

Secs. 60.131(b)(1) through 60.131(b)(10), as appropriate. This change

would eliminate the confusion in the existing rule related to the

identification of only the criteria in Sec. 60.131(b) as ``important to

safety.'' It would also resolve the present incongruity with

Sec. 60.131(b)(7), ``Criticality control,'' regarding the reference to

waste ``isolation'' (a postclosure term) in the requirement.

The current rule employs the term ``normal and accident

conditions,'' or similar expression, in several places. However, the

conditions that must be addressed under this language are not well-

defined. The Commission proposes to remedy this situation by replacing

current terminology with references to ``design basis events,'' thereby

ensuring that the design appropriately takes into account the

consequences of all design basis events (i.e., as discussed in this

document, Category 1 and 2 design basis events). Accordingly,

modification of paragraphs (b)(5)(i), (b)(7), and (b)(8) is being

proposed for this section. The Commission would also revise the

language in 10 CFR 60.131(b)(1), which refers to ``anticipated''

natural phenomena and environmental conditions, so as to encompass all

design basis events. The ``necessary safety functions'' that must be

accommodated in the design, pursuant to that paragraph, include

whatever is necessary to meet the quantitative limits set out in the

Commission's rules (i.e., in 10 CFR 60.111(a) and 10 CFR 60.136).

Section 60.132 Additional Design Criteria for Surface Facilities in

the Geologic Repository Operations Area

Section 60.132(c)(1) requires that the surface facilities must be

``* * * designed to control the release of radioactive materials in

effluents during normal operations so as to meet the performance

objectives of Sec. 60.111(a).'' As indicated previously, the design

should ordinarily be sufficiently conservative so as to provide

reasonable assurance of meeting part 20 not only during normal

operations, but even for events that are likely to occur moderately

frequently or one or more times before permanent closure of the

geologic repository (i.e., all Category 1 design basis events).

Deleting the phrase ``during normal operations,'' as proposed, will

broaden the scope of this provision to reflect the Commission's intent

more accurately.

Section 60.133 Additional Design Criteria for the Underground Facility

As in the case of the changes proposed to 10 CFR 60.131, a

reference to design basis events would be substituted for the less

precise ``normal operations and * * * accident conditions.''

Section 60.136 Preclosure Controlled Area.

The proposed rule would adopt the petitioner's concept of a

preclosure control area under the name ``preclosure controlled area.''

The term would delimit an area over which the licensee exercises

control of activities to meet regulatory requirements. Control would

include the power to exclude members of the public, if necessary. The

zone, and related dose limits, would also be used to analyze and

identify structures, systems, and components that are important to

safety under unusual conditions that have heretofore been characterized

as Category 2 design basis events--credible, yet not likely to occur

during the period of operations. The issue that is presented concerns

the dose limits on or beyond the preclosure controlled area boundary

that are appropriate to ensure that the occurrence of any such events

presents no unreasonable risk to the health and safety of the public.

(Releases resulting from Category 1 design basis events would not be

permitted to cause doses exceeding the limits of part 20.) The

Commission proposes to adopt the basic provisions of part 72--namely, a

0.05-Sv (5-rem) dose limit, on or beyond the preclosure controlled area

boundary--as modified to reflect the part 20 system of dose limits (see

Sec. 20.1201(a)). In addition to providing for separate dose limits for

individual organs and tissue, the lens of the eye, and the skin, the

use of ``total effective dose equivalent'' (TEDE) in part 20 explicitly

accounts for exposures via the ingestion and inhalation dose pathways.

Modification of the 0.05-Sv (5-rem) dose limit, to reflect the part

20 system of dose limits, results in a family of dose limits: a TEDE of

0.05 Sv (5 rem); or the sum of the deep-dose equivalent and the

committed dose equivalent to any individual organ or tissue (other than

the lens of the eye) of 0.5 Sv (50 rem); an eye dose equivalent of 0.15

Sv (15 rem); and a shallow dose equivalent, to [[Page 15186]] skin, of

0.5 Sv (50 rem).1 The eye and skin dose limits are adequate to

ensure that no observable effects (e.g., induction of cataracts in the

lens of the eye) will occur as a result of any accidental radiation

exposure. In implementing this provision, dose calculations should be

made solely with reference to the consequence of the specific Category

2 design basis event, and not cumulatively with other design basis

events. To clarify this matter further, the analysis of a specific

Category 2 design basis event would require an analysis of an event

sequence or scenario which includes an initiating event (e.g., an

earthquake) and the associated combinations of repository system or

component failures that can potentially lead to exposure of the public

to radiation. An example sequence is a postulated earthquake (the

initiating event) which results in the failure of a crane lifting a

spent fuel waste package inside a waste handling building, the drop and

breach of the waste package, damage to the spent fuel and partitioning

of a fraction of the radionuclide inventory to the building atmosphere,

failure of the building filtration system, and public exposure to the

released radioactive material.

\1\Radiation exposure terminology is as used in part 20 (56 FR

23360; May 21, 1991).

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

The only other noteworthy deviation from part 72 (specifically 10

CFR 72.106) would be to refer to doses attributable to any ``design

basis event'' instead of any ``design basis accident.'' The term

``design basis event'' is used because it is a defined term in part 60.

The change in terminology is not intended to be one of substance as a

design basis accident is the consequence of some design basis event.

As discussed above, the 0.05 Sv (5 rem) dose limit is being

proposed by the Commission as the appropriate design basis for

protection of public health and safety from Category 2 design basis

events at a GROA and will harmonize part 60 with part 72. In this

regard, the Commission notes that part 72 applies to those facilities

(MRS installations) most similar to the surface facilities of a

repository and for which the kinds of design basis events are also

expected to be similar. Further, the proposed dose limit is consistent

with dose values (0.06 Sv [6 rem] to the whole body) established as

guidance for both fuel-handling accidents and spent-fuel cask-drop

accidents at nuclear power plants.2 Moreover, the proposed dose

limit is consistent with the accident-dose value (0.05 Sv [5 rem]

effective dose equivalent) proposed by DOE in its PRM.

\2\NUREG-0800, ``Standard Review Plan for the Review of Safety

Analysis Reports for Nuclear Power Plants,'' June 1987.

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

However, while consistency between the proposed 0.05 Sv (5 rem)

dose limit for part 60 and other Commission rules or guidance documents

is important, consistency alone does not necessarily ensure that there

would be no unreasonable risk to the health and safety of the public

associated with the proposed limit. As such, a perspective is provided

on the risks associated with an operational repository and the

appropriateness of the proposed 0.05 Sv (5 rem) dose limit as the

design basis for protection of public health and safety from Category 2

design basis events.

Based on estimates provided by the National Council on Radiation

Protection and Measurements (NCRP)3 the lifetime risk to

individuals in the general population is 0.05 fatal cancers per Seivert

(Sv) of exposure. Therefore, the lifetime risk of fatal cancer from an

assumed 0.05 Sv (5 rem) exposure resulting from a postulated Category 2

design basis event is 0.0025 (i.e., 2.5 x 10-3) per individual

exposed. While this assessment provides perspective on the risk

associated with a hypothetical exposure of a 0.05 Sv (5 rem) dose, it

does not provide perspective on the estimated actual risk associated

with the spectrum of possible Category 2 design basis events at a

repository during its operational lifetime (estimated to be about 100

years).

\3\National Council on Radiation Protection and Measurements,

``Risk Estimates for Radiation Protection,'' NCRP Report No. 115,

December 31, 1993.

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

Perspective on actual risk must include consideration of the

frequencies (i.e., probabilities) of occurrence of these events, as

well as their consequences, as ``risk'' is defined as the probability

of an event times its consequences. With respect to the range of

probabilities of Category 2 design basis events, the upper bound is

roughly 1 x 10-2 per year (i.e., event scenarios with

probabilities of occurrence greater than 1 x 10-2 per year would

generally be considered to be Category 1 events) and the lower bound is

considered to be on the order of 1 x 10-9 per year (i.e., event

scenarios with probabilities of occurrence less than 1 x 10-9

per year would generally be screened from further consideration due to

their negligible contribution to overall risk). Accordingly, assuming

event consequences equivalent to the proposed 0.05 Sv (5 rem) dose

limit for part 60, the hypothetical upper bound on individual risk is

2.5 x 10-5 fatal cancers per year. To put this risk in

perspective, the International Commission on Radiological

Protection4 notes that, based on a review of information related

to risks regularly accepted in everyday life for stochastic phenomena,

a fatal cancer risk in the range of 1 x 10-6 to 1 x 10-5

per year from exposure to radiation would likely be acceptable to

individual members of the public. Thus, while the risk associated with

repository event consequences at the proposed dose limit and bounding

probability of occurrence exceeds this range by a small factor, and is

at a level that the Commission considers safe for occupational

exposures, the Commission believes this result significantly

overestimates the actual risk of an operating repository.

\4\Recommendations of the International Commission on

Radiological Protection. ICRP Publication 26, January 1977.

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

Perspective on actual repository risk can be obtained by developing

an understanding of the spectrum of potential Category 2 design basis

events and estimating the consequences of these events as well as their

probabilities of occurrence. In this regard, the Commission recognizes

that there is no high-level waste repository operating experience and

that only conceptual designs have been developed for these facilities.

Nonetheless, some perspective can be gained from the preliminary risk

assessment by DOE5 of a conceptual design for a repository at

Yucca Mountain, Nevada, as well as from consideration of risk

assessments of selected U.S. nuclear power plants.6

\5\U.S. Department of Energy, ``Site Characterization Plan,

Yucca Mountain Site, Nevada Research and Development Area, Nevada,''

DOE/RW-0199, December 1988.

\6\NUREG-1150, ``Severe Accident Risks: An Assessment for Five

U.S. Nuclear Power Plants,'' December 1990.

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

Consistent with risk assessments for nuclear power plants, the

spectrum of possible repository design basis events includes both

internally and externally initiated events. Internally initiated events

would include waste transporter collisions, crane failures or other

types of fuel assembly, waste package or cask drop events, building or

facility exhaust filter fires, and exhaust filter bypass or failure.

Externally initiated events would include those resulting from

earthquakes, tornados, and flooding. Regardless of the type or nature

of the initiating event, the Commission believes that, for several

reasons, both the variety of credible event sequences and the resulting

potential consequences to members of the public will be somewhat

limited at repository facilities. First, in comparison with a

[[Page 15187]] nuclear power plant, an operating repository is a

relatively simple facility in which the primary activities are in

relation to waste receipt, handling, storage, and emplacement. A

repository does not require the variety and complexity of systems

necessary to support an operating nuclear power plant. Further, the

conditions are not present at a repository to generate a radioactive

source term of a magnitude that, however unlikely, is potentially

capable at a nuclear power plant (e.g., from a postulated loss of

coolant event). As such, the estimated consequences resulting from

limited source term generation at a repository would be correspondingly

limited. This conclusion is consistent with the results of the

aforementioned preliminary risk assessment by DOE of a conceptual

repository design at Yucca Mountain, Nevada. In that assessment, the

DOE considered 149 scenarios for a variety of internally and externally

initiated events. Of the 149 scenarios, only 7 resulted in offsite

doses in excess of 0.005 Sv (0.5 rem) to the critical organs of a

maximally exposed individual and also had associated probabilities of

occurrence greater than 1 x 10-9 per year. The highest estimated

offsite dose from the DOE risk assessment was 0.021 Sv (2.1 rem) with

an associated probability of occurrence of 5 x 10-7 per year.

The dose estimates of the DOE risk assessment are only reflective

of a conceptual design for a repository at Yucca Mountain, Nevada.

Nonetheless, the Commission believes they provide perspective on the

magnitude of the estimated consequences to members of the public from

postulated Category 2 design basis events and that variations in

repository design or site selection would not likely vary these

estimates by more than order of magnitude. The results of the DOE risk

assessment also provide some perspective on the estimated probabilities

of occurrence of the postulated repository design basis events and, as

such, perspective on actual risk from an operating repository.

In general, the Commission would expect the potential higher

consequence events to have correspondingly lower probabilities of

occurrence. This expectation is consistent with the results of the DOE

risk assessment as the estimated probabilities of occurrence for the 7

scenarios which resulted in offsite doses in excess of 0.005 Sv (0.5

rem) vary from 1 x 10-9 to 5 x 10-6 per year. The

corollary to the above is the expectation that higher frequency events

would have correspondingly lower offsite consequences and perspective

on actual risk from an operating repository necessitates consideration

of these events as well as lower frequency events. Review of the DOE

risk assessment indicates that some higher frequency, but lower

consequence, events are just as important to actual risk as the lower

frequency, but higher consequence, events. With respect to actual risk

from the broad spectrum of all events considered in the DOE risk

assessment, the estimated actual risk of an operating repository is

roughly two to three orders of magnitude lower than the range of fatal

cancer risks that would likely be acceptable to members of the public

(i.e., a fatal cancer risk of 1 x 10-6 to 1 x 10-5 per

year as noted in ICRP Publication 26).

With respect to the appropriateness of the proposed 0.05 Sv (5 rem)

dose limit for part 60 as the design basis for protection of public

health and safety from Category 2 design basis events, the DOE risk

assessment indicates the potential for events with offsite consequences

on the order of several hundredths to several tenths of Sv (several rem

to several tens of rem), depending on design and siting factors. The

event consequences in this range, coupled with the estimated event

probabilities of occurrence, result in estimated risks that would

likely be acceptable to members of the public. However, given the lack

of repository design, siting and operating experience and the

supporting data base for probabilistic risk assessment, the Commission

believes there is considerable uncertainty in the estimates of both the

consequences and the probabilities of occurrence of postulated Category

2 design basis events. As such, the Commission believes that

establishing a dose limit in part 60 to the proposed 0.05 Sv (5 rem)

value would provide an adequate margin of safety and an appropriate

design basis for protection of members of the public from unlikely, but

credible events. Further, the Commission believes that a singular dose

limit is appropriate for the broad range of possible event frequencies,

given the limited potential for offsite consequences at repository

facilities and the significant uncertainties in repository risk

assessment. Stated differently, the level of sophistication in

repository risk assessment does not presently exist to warrant a more

complex set of requirements in part 60 for protection of public health

and safety from postulated Category 2 design basis events.

Notwithstanding these views and the Commission's parallel interest in

harmonizing part 60 and part 72, the Commission specifically seeks

public comment on (1) the appropriateness of the proposed 0.05 Sv (5

rem) dose limit in Section 60.136 as the design basis for protection of

public health and safety, and (2) the rationale, as discussed herein,

supporting the proposed 0.05 Sv (5 rem) dose limit.

Section 60.183 Criminal Penalties

A conforming change has been made to this section, to include

Sec. 60.136 (pertaining to the preclosure controlled area) among the

regulations that are not issued under Sections 161b, 161i, or 161o of

the Atomic Energy Act, for purposes of section 223 of the Act.

Environmental Impact: Categorical Exclusion

NRC has determined that this proposed regulation is the type of

action described in 10 CFR 51.22 (c)(2), pertaining to the promulgation

of technical requirements and criteria that the Commission will apply

in approving or disapproving applications under part 60. Therefore,

neither an environmental impact statement nor an environmental

assessment has been prepared for this proposed regulation.

Paperwork Reduction Act Statement

This proposed rule does not contain a new or amended information

collection requirement subject to the Paperwork Reduction Act of 1980

(44 U.S.C. 3501, et seq.). Existing requirements were approved by the

Office of Management and Budget, approval number 3150-0127.

Regulatory Analysis

The Commission has prepared a draft regulatory analysis on this

proposed regulation. The analysis examines the costs and benefits of

the alternatives considered by the Commission. The draft analysis is

available for inspection in the NRC Public Document Room, 2120 L Street

NW. (Lower Level), Washington, DC. Single copies of the draft analysis

may be obtained from Dr. Richard A. Weller, U.S. Nuclear Regulatory

Commission, Office of Nuclear Material Safety and Safeguards, Division

of Waste Management, Washington, DC 20555, Telephone (301) 415-7287.

Regulatory Flexibility Certification

As required by the Regulatory Flexibility Act of 1980, 5 U.S.C.

605(b), the Commission certifies that this rule, if adopted, will not

have a significant economic impact on a substantial number of small

entities. The only entity subject to regulation under this rule is

DOE. [[Page 15188]]

Backfit Analysis

NRC has determined that the backfit rule, 10 CFR 50.109, does not

apply to this proposed rule and, therefore, that a backfit analysis is

not required for this proposed rule, because these amendments do not

involve any provisions that would impose backfits as defined in 10 CFR

50.109(a)(1).

List of Subjects in 10 CFR Part 60

Criminal penalties, High-level waste, Nuclear power plants and

reactors, Nuclear materials, Reporting and recordkeeping requirements,

and Waste treatment and disposal.

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, the Nuclear Waste Policy Act of 1982, as

amended, and 5 U.S.C. 553, NRC is proposing to adopt the following

amendments to 10 CFR part 60.

PART 60--DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN GEOLOGIC

REPOSITORIES

1. The authority citation for part 60 continues to read as follows:

Authority: Secs. 51, 53, 62, 63, 65, 81, 161, 182, 183, 68 Stat.

929, 930, 932, 933, 935, 948, 953, 954, as amended (42 U.S.C. 2071,

2073, 2092, 2093, 2095, 2111, 2201, 2232, 2233); secs. 202, 206, 88

Stat. 1244, 1246 (42 U.S.C. 5842, 5846); secs. 10 and 14, Pub. L.

95-601, 92 Stat. 2951 (42 U.S.C. 2021a and 5851); Sec. 102, Pub. L.

91-190, 83 Stat. 853 (42 U.S.C. 4332); Secs. 114, 121, Pub. L. 97-

425, 96 Stat. 2213g, 2228, as amended (42 U.S.C. 10134, 10141).

2. Section 60.2 is amended by adding definitions of ``Design

bases,'' ``Design basis events,'' and ``Preclosure controlled area,''

revising the definitions of ``Accessible environment,'' ``Disturbed

zone,'' ``Important to safety,'' and ``Site,'' renaming the defined

term ``Controlled area'' to ``Postclosure controlled area,'' and

alphabetizing the definitions to read as follows:

Sec. 60.2 Definitions.

* * * * *

Accessible environment means: (1) The atmosphere, (2) the land

surface, (3) surface water, (4) oceans, and (5) the portion of the

lithosphere that is outside the postclosure controlled area.

* * * * *

Design bases means that information that identifies the specific

functions to be performed by a structure, system, or component of a

facility and the specific values or ranges of values chosen for

controlling parameters as reference bounds for design. These values may

be restraints derived from generally accepted ``state-of-the-art''

practices for achieving functional goals or requirements derived from

analysis (based on calculation or experiments) of the effects of a

postulated event under which a structure, system, or component must

meet its functional goals. The values for controlling parameters for

external events include:

(1) estimates of severe natural events to be used for deriving

design bases that will be based on consideration of historical data on

the associated parameters, physical data, or analysis of upper limits

of the physical processes involved; and

(2) estimates of severe external man-induced events, to be used for

deriving design bases, that will be based on analysis of human activity

in the region, taking into account the site characteristics and the

risks associated with the event.

Design basis events means:

(1) those natural and human-induced events that are reasonably

likely to occur regularly, moderately frequently, or one or more times

before permanent closure of the geologic repository operations area;

and

(2) other natural and man-induced events that are considered

unlikely, but sufficiently credible to warrant consideration, taking

into account the potential for significant radiological impacts on

public health and safety.

The events described in paragraph (1) of this definition are

referred to as ``Category 1'' design basis events. The events described

in paragraph (2) of this definition are referred to as ``Category 2''

design basis events.

* * * * *

Disturbed zone means that portion of the postclosure controlled

area the physical or chemical properties of which have changed as a

result of underground facility construction or as a result of heat

generated by the emplaced radioactive wastes such that the resultant

change of properties may have a significant effect on the performance

of the geologic repository.

* * * * *

Important to safety, with reference to structures, systems, and

components, means those features of the repository whose function is:

(1) to provide reasonable assurance that high-level waste can be

received, handled, packaged, stored, emplaced, and retrieved without

exceeding the requirements of Sec. 60.111(a) for Category 1 design

basis events; or

(2) to prevent or mitigate Category 2 design basis events that

could result in doses equal to or greater than the values specified in

Sec. 60.136 to any individual located on or beyond the nearest boundary

of the preclosure controlled area.

* * * * *

Postclosure controlled area means a surface location, to be marked

by suitable monuments, extending horizontally no more than 10

kilometers in any direction from the outer boundary of the underground

facility, and the underlying subsurface, which area has been committed

to use as a geologic repository and from which incompatible activities

would be restricted following permanent closure.

* * * * *

Preclosure controlled area means that surface area immediately

surrounding the geologic repository operations area for which the

licensee exercises authority over its use, in accordance with the

provisions of this part, until permanent closure has been completed.

* * * * *

Site means the location of the postclosure controlled area.

3. Section 60.8 is revised to read as follows:

Sec. 60.8 Information collection requirements: OMB approval.

(a) The Nuclear Regulatory Commission has submitted the information

collection requirements of general applicability contained in this part

to the Office of Management and Budget (OMB) for approval as required

by the Paperwork Reduction Act of 1980 (44 U.S.C. 3501, et seq.). OMB

has approved the information collection requirements contained in this

part under control number 3150-0127.

(b) The approved information collection requirements contained in

this part appear in Secs. 60.62, 60.63, and 60.65.

4. In Sec. 60.21, paragraphs (c)(1)(i), (c)(1)(ii)(B), (c)(3), and

(c)(8) are revised to read as follows:

Sec. 60.21. Content of application.

* * * * *

(c) * * *

(1) * * *

(i) The description of the site shall also include the following

information regarding subsurface conditions. This description shall, in

all cases, include such information with respect to the postclosure

controlled area. In addition, where subsurface conditions outside the

postclosure controlled area may affect isolation within the postclosure

controlled area, the description shall include such information with

respect to subsurface conditions outside the postclosure controlled

area to the extent such information is relevant and

[[Page 15189]] material. The detailed information referred to in this

paragraph shall include:

(A) the orientation, distribution, aperture in-filling and origin

of fractures, discontinuities, and heterogeneities;

(B) the presence and characteristics of other potential pathways

such as solution features, breccia pipes, or other potentially

permeable features;

(C) the geomechanical properties and conditions, including pore

pressure and ambient stress conditions;

(D) the hydrogeologic properties and conditions;

(E) the geochemical properties; and

(F) the anticipated response of the geomechanical, hydrogeologic,

and geochemical systems to the maximum design thermal loading, given

the pattern of fractures and other discontinuities and the heat

transfer properties of the rock mass and groundwater.

(ii) * * *

(B) Analyses to determine the degree to which each of the favorable

and potentially adverse conditions, if present, has been characterized,

and the extent to which it contributes to or detracts from isolation.

For the purpose of determining the presence of the potentially adverse

conditions, investigations shall extend from the surface to a depth

sufficient to determine critical pathways for radionuclide migration

from the underground facility to the accessible environment.

Potentially adverse conditions shall be investigated outside of the

postclosure controlled area if they affect isolation within the

postclosure controlled area.

* * * * *

(3) A description and analysis of the design and performance

requirements for structures, systems, and components of the geologic

repository that are important to safety. The analysis must include a

demonstration that--(i) the requirements of Sec. 60.111(a) will be met,

assuming occurrence of Category 1 design basis events; and (ii) the

requirements of Sec. 60.136 will be met, assuming occurrence of

Category 2 design basis events.

* * * * *

(8) A description of the controls that the applicant will apply to

restrict access and to regulate land use at the site and adjacent

areas, including a conceptual design of monuments which would be used

to identify the postclosure controlled area after permanent closure.

* * * * *

Sec. 60.43 [Amended]

5. In Sec. 60.43(b)(5), the term ``controlled area'' is revised to

read ``postclosure controlled area.''

Sec. 60.46 [Amended]

6. In Sec. 60.46(a)(3), the term ``controlled area'' is revised to

read ``postclosure controlled area wherever it appears.''

Sec. 60.51 [Amended]

7. In Sec. 60.51(a)(2)(i) and (a)(2)(ii), the term ``controlled

area'' is revised to read ``postclosure controlled area.''

Sec. 60.102 [Amended]

8. In Sec. 60.102(c), the term ``controlled area'' is revised to

read ``postclosure controlled area.''

9. In Sec. 60.111, paragraph (a) is revised to read as follows:

Sec. 60.111. Performance of the geologic repository operations area

through permanent closure.

(a) Protection against radiation exposures and releases of

radioactive material. The geologic repository operations area shall be

designed so that until permanent closure has been completed, radiation

exposures and radiation levels, and releases of radioactive materials

to unrestricted areas, will be maintained within the limits specified

in part 20 of this chapter and such generally applicable environmental

standards for radioactivity as may have been established by the

Environmental Protection Agency.

* * * * *

Sec. 60.121 [Amended]

10. In Sec. 60.121(a) and (b), the term ``controlled area'' is

revised to read ``postclosure controlled area.''

Sec. 60.122 [Amended]

11. In Sec. 60.122(b)(6) and (c) introductory text, the term

``controlled area'' is revised to read ``postclosure controlled area.''

12. Section 60.130 is revised to read as follows:

Sec. 60.130 General considerations.

Pursuant to the provisions of Sec. 60.21(c)(2)(i), an application

to receive, possess, store, and dispose of high-level radioactive waste

in the geologic repository operations area must include the principal

design criteria for a proposed facility. The principal design criteria

establish the necessary design, fabrication, construction, testing,

maintenance, and performance requirements for structures, systems, and

components important to safety and/or important to waste isolation.

Sections 60.131 through 60.134 specify minimum requirements for the

principal design criteria for the geologic repository operations area.

These design criteria are not intended to be exhaustive, however.

Omissions in Secs. 60.131 through 60.134 do not relieve DOE from any

obligation to provide such features in a specific facility needed to

achieve the performance objectives.

13. In Sec. 60.131, paragraph (b) is revised, and paragraphs (c)

through (k) are added to read as follows:

Sec. 60.131 General design criteria for the geologic repository

operations area.

* * * * *

(b) Protection against design basis events. The structures,

systems, and components important to safety shall be designed so that

they will perform their necessary safety functions, assuming occurrence

of design basis events.

(c) Protection against dynamic effects of equipment failure and

similar events. The structures, systems, and components important to

safety shall be designed to withstand dynamic effects such as missile

impacts, that could result from equipment failure, and similar events

and conditions that could lead to loss of their safety functions.

(d) Protection against fires and explosions. (1) The structures,

systems, and components important to safety shall be designed to

perform their safety functions during and after credible fires or

explosions in the geologic repository operations area.

(2) To the extent practicable, the geologic repository operations

area shall be designed to incorporate the use of noncombustible and

heat resistant materials.

(3) The geologic repository operations area shall be designed to

include explosion and fire detection alarm systems and appropriate

suppression systems with sufficient capacity and capability to reduce

the adverse effects of fires and explosions on structures, systems, and

components important to safety.

(4) The geologic repository operations area shall be designed to

include means to protect systems, structures, and components important

to safety against the adverse effects of either the operation or

failure of the fire suppression systems.

(e) Emergency capability. (1) The structures, systems, and

components important to safety shall be designed to maintain control of

radioactive waste and radioactive effluents, and permit prompt

termination of operations and evacuation of personnel during an

emergency. [[Page 15190]]

(2) The geologic repository operations area shall be designed to

include onsite facilities and services that ensure a safe and timely

response to emergency conditions and that facilitate the use of

available offsite services (such as fire, police, medical, and

ambulance service) that may aid in recovery from emergencies.

(f) Utility services. (1) Each utility service system that is

important to safety shall be designed so that essential safety

functions can be performed, assuming occurrence of the design basis

events.

(2) The utility services important to safety shall include

redundant systems to the extent necessary to maintain, with adequate

capacity, the ability to perform their safety functions.

(3) Provisions shall be made so that, if there is a loss of the

primary electric power source or circuit, reliable and timely emergency

power can be provided to instruments, utility service systems, and

operating systems, including alarm systems, important to safety.

(g) Inspection, testing, and maintenance. The structures, systems,

and components important to safety shall be designed to permit periodic

inspection, testing, and maintenance, as necessary, to ensure their

continued functioning and readiness.

(h) Criticality control. All systems for processing, transporting,

handling, storage, retrieval, emplacement, and isolation of radioactive

waste shall be designed to ensure that nuclear criticality is not

possible unless at least two unlikely, independent, and concurrent or

sequential changes have occurred in the conditions essential to nuclear

criticality safety. Each system must be designed for criticality safety

assuming occurrence of design basis events. The calculated effective

multiplication factor (keff) must be sufficiently below unity to show

at least a 5 percent margin, after allowance for the bias in the method

of calculation and the uncertainty in the experiments used to validate

the method of calculation.

(i) Instrumentation and control systems. The design shall include

provisions for instrumentation and control systems to monitor and

control the behavior of systems important to safety, assuming

occurrence of design basis events.

(j) Compliance with mining regulations. To the extent that DOE is

not subject to the Federal Mine Safety and Health Act of 1977, as to

the construction and operation of the geologic repository operations

area, the design of the geologic repository operations area shall

nevertheless include such provisions for worker protection as may be

necessary to provide reasonable assurance that all structures, systems,

and components important to safety can perform their intended

functions. Any deviation from relevant design requirements in 30 CFR,

Chapter I, Subchapters D, E, and N will give rise to a rebuttable

presumption that this requirement has not been met.

(k) Shaft conveyances used in radioactive waste handling. (1)

Hoists important to safety shall be designed to preclude cage free

fall.

(2) Hoists important to safety shall be designed with a reliable

cage location system.

(3) Loading and unloading systems for hoists important to safety

shall be designed with a reliable system of interlocks that will fail

safely upon malfunction.

(4) Hoists important to safety shall be designed to include two

independent indicators to indicate when waste packages are in place and

ready for transfer.

14. In Sec. 60.132, paragraph (c)(1) is revised to read as follows:

Sec. 60.132. Additional design criteria for surface facilities in the

geologic repository operations area.

* * * * *

(c) Radiation control and monitoring--(1) Effluent control. The

surface facilities shall be designed to control the release of

radioactive materials in effluents so as to meet the performance

objectives of Sec. 60.111(a).

* * * * *

15. In Sec. 60.133, the introductory text of paragraph (g) and

paragraph (g)(2) are revised to read as follows:

Sec. 60.133 Additional design criteria for the underground facility.

* * * * *

(g) Underground facility ventilation. The ventilation system shall

be designed to:

* * * * *

(2) Assure the ability to perform essential safety functions

assuming occurrence of design basis events; and

* * * * *

16. A new undesignated center heading and Sec. 60.136 are added to

read as follows:

Preclosure Controlled Area

Sec. 60.136 Preclosure controlled area.

(a) A preclosure controlled area must be established for the

geologic repository operations area.

(b) The geologic repository operations area shall be designed so

that, for Category 2 design basis events, no individual located on or

beyond the nearest boundary of the preclosure controlled area will

receive the more limiting of a total effective dose equivalent of 0.05

Sv (5 rem), or the sum of the deep-dose equivalent and the committed

dose equivalent to any individual organ or tissue (other than the lens

of the eye) of 0.5 Sv (50 rem). The eye dose equivalent may not exceed

0.15 Sv (15 rem), and the shallow dose equivalent to skin may not

exceed 0.5 Sv (50 rem). The minimum distance from the surface

facilities in the geologic repository operations area to the boundary

of the preclosure controlled area must be at least 100 meters.

(c) The preclosure controlled area may be traversed by a highway,

railroad, or waterway, so long as appropriate and effective

arrangements are made to control traffic and to protect public health

and safety.

17. In Sec. 60.183, paragraph (b) is revised to read as follows:

Sec. 60.183 Criminal penalties.

* * * * *

(b) The regulations in part 60 that are not issued under sections

161b, 161i, or 161o for the purposes of section 223 are as follows:

Secs. 60.1, 60.2, 60.3, 60.5, 60.6, 60.7, 60.8, 60.15, 60.16, 60.17,

60.18, 60.21, 60.22, 60.23, 60.24, 60.31, 60.32, 60.33, 60.41, 60.42,

60.43, 60.44, 60.45, 60.46, 60.51, 60.52, 60.61, 60.62, 60.63, 60.64,

60.65, 60.101, 60.102, 60.111, 60.112, 60.113, 60.121, 60.122, 60.130,

60.131, 60.132, 60.133, 60.134, 60.135, 60.136, 60.137, 60.140, 60.141,

60.142, 60.143, 60.150, 60.151, 60.152, 60.162, 60.181, and 60.183.

Dated in Rockville, Maryland, this 15th day of March, 1995.

For the Nuclear Regulatory Commission.

John C. Hoyle,

Secretary of the Commission.

[FR Doc. 95-6872 Filed 3-21-95; 8:45 am]

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