[Federal Register Volume 62, Number 122 (Wednesday, June 25, 1997)]
[Notices]
[Pages 34321-34326]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-16072]


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NUCLEAR REGULATORY COMMISSION


Use of PRA in Plant Specific Reactor Regulatory Activities: 
Proposed Regulatory Guides, Standard Review Plan Sections, and 
Supporting NUREG

AGENCY: Nuclear Regulatory Commission.

ACTION: Notice of availability.

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SUMMARY: The Nuclear Regulatory Commission has issued for public 
comment drafts of four regulatory guides, three Standard Review Plan 
Sections, and a NUREG document. These issuances follow Publication of 
the Commission's August 16, 1995 (60 FR 42622) Policy statement on the 
Use of PRA Methods in Nuclear Regulatory Activities. The NRC has 
developed draft guidance for power reactor licensees on acceptable 
methods for using probabilistic risk assessment (PRA) information and 
insights in support of plant-specific applications to change the 
current licensing basis (CLB). The use of such PRA information and 
guidance is voluntary. To facilitate comment, the Commission intends to 
conduct a workshop during the comment period to explain the draft 
documents and answer questions. The exact time, location and agenda 
will be announced in a future issue of the Federal Register. Section VI 
of this notice provides additional information on the scope, purpose 
and topics for discussion at the workshop.

DATES: Comment period expires September 23, 1997. Comments received 
after this date will be considered if it is practical to do so, but the 
Commission is able to assure consideration only for comments received 
on or before this date.

ADDRESSES: Mail written comments to: David L. Meyer, Chief, Rules and 
Directives Branch, Office of Administration, Mail Stop T-6D59, U.S. 
Nuclear Regulatory Commission, Washington, DC 20555-0001.
    In addition to written comments, please (1) attach a diskette 
containing your comments, in either ASCII text or Wordperfect format 
(Version 5.1 or 6.1), or (2) submit your comments electronically via 
the NRC Electronic Bulletin Board on FedWorld or the NRC's Interactive 
Rulemaking Website.

[[Page 34322]]

    Deliver comments to 11545 Rockville Pike, Rockville, Maryland, 
between 7:30am and 4:15pm, Federal workdays.
    Copies of the draft regulatory guides, standard review plan 
sections and NUREG are available for inspection and copying for a fee 
at the NRC Public Document Room, 2120 L Street NW. (Lower Level), 
Washington, DC 20555-0001. A free single copy of these draft documents 
to the extent of supply, may be requested by writing to Distribution 
Services, Printing, Graphics and Distribution Branch, U.S. Nuclear 
Regulatory Commission, Washington, DC 20555-0001, or by Fax to (301) 
415-5272. Electronic copies of the draft document are also accessible 
on the NRC's Interactive Rulemaking Website through the NRC home page 
(http://www.nrc.gov). This site provides the same access as the 
FedWorld bulletin board, including the facility to upload comments as 
files (any format), if your web browser supports the function.
    For more information on the NRC bulletin boards call Mr. Arthur 
Davis, Systems Integration and Development Branch, NRC, Washington, DC 
20555-0001, telephone (301) 415-5780; e-mail AXD[email protected]. For 
information about the Interactive Rulemaking Website, contact Ms. Carol 
Gallagher, (301) 415-5905; e-mail [email protected].
    The NRC subsystems on FedWorld can be accessed directly by dialing 
the toll free number: 1-800-303-9672. Communication software parameters 
should be set as follows: parity to none, data bits to 8, and stop bits 
to 1 (N,8,1). Using ANSI or VT-100 terminal emulation, the NRC NUREGs 
and Reg Guides for Comment subsystem can then be accessed by selecting 
the ``Rule Menu'' option from the ``NRC Main Menu.'' For further 
information about options available for NRC at FedWorld, consult the 
``Help/Information Center'' from the ``NRC Main Menu.'' Users will find 
the FedWorld online User's Guides'' particularly helpful. Many NRC 
subsystems and databases also have a ``Help/Information Center'' option 
that is tailored to the particular subsystem.
    The NRC subsystem on FedWorld can also be accessed by a direct dial 
phone number for the main FedWorld BBS, 703-321-3339, or by using 
Telnet via Internet, fedworld.gov. If using 703-321-3339 to contact 
FedWorld, the NRC subsystem will be accessed from the main Fedworld 
menu by selecting the ``Regulatory, Government Administration and State 
Systems,'' then selecting ``Regulatory, Information Mall.'' At that 
point, a menu will be displayed that has an option ``U.S. Nuclear 
Regulatory Commission'' that will take you to the NRC Online main menu. 
The NRC Online area also can be accessed directly by typing ``/go nrc'' 
at a FedWorld command line. If you access NRC from FedWorld's main 
menu, you may return to FedWorld by selecting the ``Return to 
FedWorld'' option from the NRC Online Main Menu. However, if you access 
NRC at FedWorld by using NRC's toll-free number, you will have full 
access to all NRC systems but you will not have access to the main 
Fedworld system.
    If you contact FedWorld using Telnet, you will see the NRC area and 
menus, including the Rules menu. Although you will be able to download 
documents and leave messages, you will not be able to write comments or 
upload files (comments). If you contact FedWorld using FTP, all files 
can be accessed and downloaded but uploads are not allowed; all you 
will see is a list of files without descriptions (normal Gopher look). 
An index file listing all files within a subdirectory, with 
descriptions, is included. there is a 15-minute time limit for FTP 
access.
    Although Fedworld can be accessed through the World Wide Web, like 
FTP that mode only provides access for downloading files and does not 
display the NRC Rules menu.

FOR FURTHER INFORMATION CONTACT: Mark Cunningham, Office of Nuclear 
Regulatory Research, MS: T10-E50, U.S. Nuclear Regulatory Commission, 
Washington, DC 20555-0001, (301) 415-6189.

SUPPLEMENTARY INFORMATION:

I. Background

    On August 16, 1995, (60 FR 42622) the Commission published in the 
Federal Register a final policy statement on the Use of Probabilistic 
Risk Assessment Methods in Nuclear Regulatory Activities. The policy 
statement included the following policy regarding expanded NRC use of 
PRA:
    1. The use of PRA technology should be increased in all regulatory 
matters to the extent supported by the state-of-the-art in PRA methods 
and data and in a manner that complements the NRC's deterministic 
approach and supports the NRC's traditional defense-in-depth 
philosophy.
    2. PRA and associated analyses (e.g., sensitivity studies, 
uncertainty analyses, and importance measures) should be used in 
regulatory matters, where practical within the bounds of the state-of-
the-art, to reduce unnecessary conservatism associated with current 
regulatory requirements, regulatory guides, license commitments, and 
staff practices. Where appropriate, PRA should be used to support 
proposals for additional regulatory requirements in accordance with 10 
CFR 50.109 (Backfit Rule). Appropriate procedures for including PRA in 
the process for changing regulatory requirements should be developed 
and followed. It is, of course, understood that the intent of this 
policy is that existing rules and regulations shall be complied with 
unless these rules and regulations are revised.
    3. PRA evaluations in support of regulatory decisions should be as 
realistic as practicable and appropriate supporting data should be 
publicly available for review.
    4. The Commission's safety goals for nuclear power plants and 
subsidiary numerical objectives are to be used with appropriate 
consideration of uncertainties in making regulatory judgments on the 
need for proposing and backfitting new generic requirements on nuclear 
power plant licensees.
    It was the Commission's intent that implementation of this policy 
statement would improve the regulatory process in three areas:
    1. Enhancement of safety decision making by the use of PRA 
insights,
    2. More efficient use of agency resources, and
    3. Reduction in unnecessary burdens on licensees.
    In parallel with the development of Commission policy on uses of 
risk assessment methods, the NRC developed an agency-wide 
implementation plan for application of probabilistic risk assessment 
insights within the regulatory process (SECY-95-079). This 
implementation plan included tasks to develop Regulatory Guides (RG) 
and Standard Review Plans (SRP) in the areas of:

--General guidance,
--Inservice inspection (ISI),
--Inservice testing (IST),
--Technical specification (TS), and
--Graded quality assurance (GQA).

    These RGs and SRPs are intended to help implement the Commission's 
August 1995 policy on the use of risk information in the regulatory 
process and to provide an acceptable approach for power reactor 
licensees to prepare and submit and NRC staff to review applications 
for proposed plant-specific changes to the current licensing basis that 
utilize risk information. Currently, draft RGs/SRPs have been developed 
and are ready for comment in the areas of general guidance, IST and TS. 
A draft RG for GQA has also been developed and is ready for comment. No 
SRP has been developed for GQA, since the NRC staff will utilize its 
inspection process

[[Page 34323]]

in the GQA area. In addition, the NRC has prepared draft NUREG-1602, 
``Use of PRA in Risk-Informed Applications,'' to provide reference 
information for licensees and NRC staff and it is also ready for public 
comment. Each of these documents is discussed in more detail below.

II. An Overview of Draft RGs, SRPs, and NUREG-1602

    The specific documents available for comment are:
     Draft regulatory guide DG 1061, ``An Approach for Using 
Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-
Specific Changes to the Current Licensing Basis,'' and its companion 
SRP, Chapter 19,
     Draft regulatory guide DG-1062 ``An Approach for Plant-
Specific, Risk-Informed, Decision Making: Inservice Testing'' and its 
companion SRP, Chapter 3.9.7,
     Draft regulatory guide DG-1064, ``An Approach for Plant-
Specific, Risk-Informed Decision Making: Graded Quality Assurance,''
     Draft regulatory guide DG-1065, ``An Approach for Plant-
Specific, Risk-Informed Decision Making: Technical Specifications'' and 
its companion SRP, Chapter 16.1, and
     Draft NUREG-1602, ``Use of PRA in Risk-Informed 
Applications.''
    The purpose of the RGs and SRPs is to provide guidance to power 
reactor licensees and NRC staff reviewers on an acceptable approach for 
utilizing risk information to support requests for changes in a plant's 
CLB. The purpose of NUREG-1602 is to provide reference information 
useful in making decisions on the scope and attributes of PRA. The RGs 
describe an alternate means by which licensees can propose plant-
specific CLB changes under 10 CFR Part 50. Adopting the approach of 
these RGs is voluntary. Licensees submitting applications for changes 
to their CLB may use this approach or an alternative equivalent 
approach. To encourage the use of risk information in such 
applications, the staff intends to give priority to applications for 
burden reduction that use risk information as a supplement to 
traditional engineering analyses, consistent with the intent of the 
Commission's policy. All applications that improve safety will continue 
to receive high priority.
    The general RG/SRP have been developed to provide an overall 
framework and guidance that is applicable to any proposed CLB change 
where risk insights are used to support the change. The application-
specific RGs/SRPs (i.e., IST, TS, GQA) build upon and supplement the 
general guidance for proposed CLB changes in their respective technical 
areas. Each application-specific RG/SRP references the general RG/SRP, 
states that the general guidance is applicable and provides additional 
guidance specific to the technical area being addressed.
    The guidance provided in these documents is designed to encourage 
licensees to use risk information by defining an acceptable framework 
for the use of risk information on a plant-specific basis, and by 
promoting consistency in PRA applications. It is expected that the 
long-term use of risk information in plant-specific licensing actions 
will result in improved safety by focusing attention on the more risk 
significant aspects of plant design and operation. The draft guidance 
provides flexibility to licensees by allowing them to define the scope 
of the analysis required to support their proposed change and to 
perform appropriate analysis to justify proposed changes to the plant's 
CLB.
    In conjunction with developing these RGs and SRPs, the staff has 
also been working with several licensees on pilot applications of risk 
informed regulation in the technical areas listed above. The knowledge 
gained to date in interacting with licensees on these pilot 
applications has been used to help define the content and guidance 
contained in these RGs/SRPs. Additional interactions are expected over 
the next several months as work on these pilot applications continues 
and licensees and other interested persons have an opportunity to 
review the draft RGs/SRPs. The results of these additional interactions 
will be factored into the final RGs/SRPs.

III. Policy Issues

    On May 15, 1996, the Commission requested the staff to identify and 
recommend resolution of the following four policy issues associated 
with risk-informed changes to a plant's CLB:
     The role of performance-based regulation,
     Plant-specific application of safety goals,
     Risk neutral vs. increases in risk,
     implementation of changes to risk-informed IST and ISI 
requirements.
    On January 22, 1997, the Commission provided the following guidance 
on these issues:

A. The Role of Performance-Based Regulation in the PRA Implementation 
Plan

    The Commission instructed the staff to include, where practical, 
performance-based strategies in the implementation of the risk-informed 
regulatory process. Furthermore, the Commission indicated that 
application of performance-based approaches should not be limited to 
risk-informed initiatives and that performance-based initiatives that 
do not explicitly reference criteria derived from PRA insights should 
not be excluded from consideration. The Commission also instructed the 
staff to include in the PRA Implementation Plan, or in a separate plan, 
how these performance-based initiatives will be phased into the overall 
regulatory improvement and oversight program and to solicit input from 
industry on (or develop on its own) additional performance-based 
objectives which are not amenable to probabilistic risk analysis but 
could be ranked according to, for example, a relative hazards analysis, 
and phase in these initiatives.

B. Plant-Specific Application of Safety Goals

    The Safety Goals policy statement, issued by the Commission in 
1986, established two qualitative safety goals to help ensure that 
nuclear power plant operations do not significantly increase risk to 
individuals or to the society. The policy statement also defined two 
Quantitative Health Objectives (QHO) for use ``in determining 
achievement of the qualitative goals.'' Subsequently, the Commission 
approved for use two subsidiary objectives derived from the Safety Goal 
QHOs, one on core-damage frequency and one on containment performance, 
for use in assessing reactor designs for generic actions. The 
Commission approved the Safety Goals for use in generic actions with 
the intent that they would define ``how safe is safe enough'' in 
deciding how far to go when proposing safety enhancements.
    The staff has considered the need for risk guidelines to support 
regulatory decision-making in plant-specific circumstances, recognizing 
that the use of risk information remains complementary to traditional 
engineering analysis and judgment. Specifically, the staff recommended 
the development of guidelines for plant-specific applications, derived 
from the Commission's current Safety Goals and/or subsidiary objectives 
and requested Commission approval.
    The Commission tentatively approved the plant-specific application 
of safety goals and/or their subsidiary objectives.

C. Risk Neutral vs. Increases in Risk

    This policy issue is related to whether to allow small increases in 
calculated plant risk in approving a change to the CLB.

[[Page 34324]]

    The Commission approved small increases in risk under certain 
conditions, for proposed changes to a plant's CLB. In giving this 
approval the Commission noted that the terms ``small'' and ``under 
certain conditions'' require more precise definition. The staff was 
requested to provide a sound rationale for judging small increases and 
provide for explicit consideration of uncertainties. Criteria for 
judging small increases in risk should be considered in the context of 
maintaining reasonable assurance that there is no undue risk to public 
health and safety.
    Moreover, the Commission asked the staff that, in its development 
of risk-informed guidance and review of applications regarding risk-
informed initiatives, to evaluate all safety impacts of proposed 
changes in an integrated manner including the use of risk insights to 
identify areas where requirements should be increased or improvements 
could/should be implemented.

D. Implementation of Changes to Risk-Informed IST and ISI Requirements

    This policy issue is related to identifying a means for 
implementing risk-informed inservice inspection and testing programs 
until rulemaking is complete. The alternatives are to treat proposed 
changes as exceptions to 10 CFR 50.55(a) or to treat them as authorized 
alternatives under the current rule. The Commission approved risk 
informed ISI and IST changes as authorized alternatives under 10 CFR 
50.55a(a)(3)(i) to approve the pilot plant applications, provided 
appropriate findings can be made. In addition, the Commission 
instructed the staff that in cases where the findings necessary to 
approve the alternative cannot be made, then the use of exemptions 
should be considered.

IV. Structure, Guidelines and Rationale for RGs/SRPs

    The approach described in each of the RGs/SRPs has four basic 
steps. These are:

--Define the proposed change;
--Perform an integrated engineering analysis (which includes both 
traditional engineering and risk analysis) and use of an integrated 
decision process;
--Monitoring and feedback to verify assumptions and analysis; and
--Document and submit proposed change.

    Five fundamental safety principles are described which should be 
met in each application for a change in the CLB. These principles are:

--The proposed change meets the current regulation. This principle 
applies unless the proposed change is explicitly related to a requested 
exemption or rule change (i.e., a 50.12 ``specific exemption'' or a 
2.802 ``petition for rulemaking'');
--Defense-in-depth is maintained;
--Sufficient safety margins are maintained;
--Proposed increases in risk, and their cumulative effect, are small 
and do not cause the NRC Safety Goals to be exceeded;
--Performance-based implementation and monitoring strategies are 
proposed that address uncertainties in analysis models and data and 
provide for timely feedback and corrective action.

    These principles represent fundamental safety practices that the 
staff believes must be retained in any change to a plant's CLB to 
maintain reasonable assurance that there is no undue risk to public 
health and safety. Each of these principles is to be considered in the 
integrated engineering analysis and decision-making process.
    The guidelines for assessing risk proposed in the RGs/SRPs are 
derived from the Commission's Safety Goal Quantitative Health 
Objectives (QHOs). Specifically, the subsidiary objectives of Core 
Damage Frequency (CDF) and Large Early Release Frequency (LERF) are 
used as the measures of risk against which changes in the CLB will be 
assessed, in lieu of the QHOs themselves, which require level 3 PRA 
information (offsite health effects). These were chosen to simplify the 
scope of PRA analysis needed, to avoid the large uncertainties 
associated with level 3 PRA analysis, and to be consistent with 
previous Commission direction to decouple siting from plant design.
    The values used in the RGs/SRPs as guidelines for CDF and LERF were 
selected to be consistent with the Safety Goal QHOs and previous 
Commission guidance. Specifically, a CDF value of 10-4/RY is 
proposed as the guideline where further increases in CDF would not be 
acceptable (i.e., plants with CDF 10-4/RY would 
be expected to propose changes that result in CDF decreases or are 
neutral). The CDF value of 10-4/RY is the value endorsed by 
the Commission in a Staff Requirements Memorandum dated June 15, 1990, 
as a benchmark objective for accident prevention. For plants with CDFs 
<10-4/RY, guidelines are proposed on changes in CDF 
(CDF) that ensure increases in risk from CLB changes are made 
in small steps and that increased NRC management attention is provided 
for proposed changes that approach the guidelines (i.e., CDFs in the 
range 10-5/RY-10-4/RY and 
CDF>10-6/RY). The use of small steps is consistent 
with a measured approach (allowing time for monitoring, feedback and 
corrective action) and the values chosen for CDF are 
consistent with the Commission's Regulatory Analysis Guidelines (NUREG/
BR-0058, Rev. 2).
    The guidelines on LERF are derived from the Commission's Safety 
Goal QHO for early fatality risk. A LERF value of 10-5/RY is 
proposed as the guideline where further increases in LERF would not be 
acceptable (i.e., plants with a LERF 10-5/RY 
would be expected to propose changes that result in LERF decreases or 
are neutral). Similar to CDF, a range is proposed where increased NRC 
management attention is required if LERF approaches the guideline 
(i.e., LERF in the range of 10-6/RY to 10-5/RY). 
The value of 10-5/RY for the LERF guideline corresponds to 
that value, estimated from existing PRA results, necessary to ensure 
that the early-fatality QHO would be met without undue conservatism. In 
effect, the guideline value for LERF is a surrogate for the 
Commission's QHO on early fatality risk. Guidelines for changes in LERF 
(LERF) are used that limit increases in risk to small values 
(i.e., LERF <10-6/RY) to ensure that increases are 
made in small increments, are consistent with the Regulatory Analysis 
Guidelines and, similar to CDF, require increased management 
attention when they approach the guideline value (i.e., LERF 
in the range of 10-7/RY to 10-6/RY).
    The CDF/CDF and LERF/LERF guidelines are intended 
for comparison with a full-scope PRA (i.e., full power, low power and 
shutdown conditions and internal and external events). It is expected 
that the cumulative impact of previous CLB changes will also be 
reflected in the PRA. However, it is recognized that less than full-
scope PRA analysis will likely be acceptable for many proposed CLB 
changes and the RG/SRP guidance is intended to allow licensees 
flexibility to do analyses appropriate for their proposed change and to 
allow the use of qualitative factors in the decision process. In 
addition, mean values of CDF and LERF are to be compared against the 
guidelines. However, when a proposed change is closer to the 
guidelines, a more comprehensive uncertainty and sensitivity analysis 
is expected that includes the consideration of qualitative factors. 
Only general guidelines on uncertainty/sensitivity analyses are 
included in the RGs/SRPs to allow

[[Page 34325]]

licensees flexibility to provide analyses appropriate for their 
specific application.
    Monitoring and feedback strategies are to be utilized in 
implementing the proposed CLB change to help verify assumptions and 
analysis and to allow for corrective action should performance be less 
than assumed in the analysis. In addition, NRC expects licensees to 
identify how and where their proposed changes will be documented as 
part of the plant's CLB. This should include documentation that clearly 
establishes the basis for the change, ensures that commitments are 
known and provides sufficient documentation to allow inspection and 
enforcement, if appropriate. Related to the above, since these RGs/SRPs 
allow the use of risk information and monitoring programs to support 
CLB changes associated with safety related systems, structures and 
components (SSCs), it is reasonable to expect that the quality of these 
analyses and monitoring programs should be consistent with the quality 
of other analyses and activities associated with safety related SSCs 
(i.e., 10 CFR part 50, Appendix B, ``Quality Assurance Criteria for 
Nuclear Power Plants and Fuel Reprocessing Plants''). Accordingly, DG-
1061 includes guidance regarding quality assurance, including that 
associated with the PRA,that ensures the pertinent requirements of 10 
CFR part 50, Appendix B are met. In addition, the draft RGs/SRPs use 
the definition of CLB that is currently in 10 CFR part 54 ``License 
Renewal.'' Although not officially incorporated in 10 CFR part 50, this 
definition is considered appropriate for use in these RGs/SRPs.
    As mentioned above, the draft guidance encourages licensees to 
utilize risk insights to improve safety, as well as to propose 
reductions of unnecessary burdens. The Commission's Safety Goals, their 
subsidiary objectives and Regulatory Analysis Guidelines have been used 
to derive guidelines for judging the acceptability of any calculated 
risk increases associated with the proposed CLB change. In this regard, 
a measured approach to reviewing and accepting changes to CLBs that 
increase risk has been taken. Specifically, the guidelines used 
correspond to small calculated increases in risk. In theory, one could 
construct an even more generous regulatory framework for consideration 
of those risk-informed changes which may have the effect of increasing 
risk to the public. Such a framework would include, of course, 
assurance of continued adequate protection (that level of protection of 
the public health and safety which must be reasonably assured 
regardless of economic cost), but it could also include provision for 
possible elimination of all measures not needed for adequate protection 
which either do not contribute to a substantial reduction in overall 
risk or result in continuing costs which are not justified by the 
safety benefits. However, a more restrictive practice has been used 
which would permit only small increases in risk, and then only when it 
is reasonably assured, among other things, that sufficient defense in 
depth and safety margins are maintained. This practice is used because 
of the uncertainties in PRA and to account for the fact that safety 
issues continue to emerge regarding design, construction, and 
operational matters notwithstanding the maturity of the nuclear power 
industry. In addition, limiting risk increases to small values is 
considered prudent until such time as experience is obtained with the 
methods and applications discussed in the RGs/SRPs.

V. Comments

    The staff is soliciting comments related to the guidance described 
in the draft RGs, SRPs and NUREG-1602. Comments submitted by the 
readers of this FRN will help ensure that these draft documents have 
appropriate scope, depth, quality, and effectiveness. Alternative 
views, concerns, clarifications, and corrections expressed in public 
comments will be considered in developing the final documents.

VI. Workshop

    The Commission intends to conduct a workshop to discuss and explain 
the material contained in the draft guides, SRPs and NUREG-1602, and to 
answer questions and receive comments and feedback on the proposed 
documents. The purpose of the workshop is to facilitate the comment 
process. In the workshop the staff will describe each document, its 
basis and solicit comment and feedback on their completeness, 
correctness and usefulness. Since these documents cover a wide range of 
technical areas, many topics will be discussed. Listed below are topics 
on which discussion and feedback are sought at the workshop:

(1) Overall Approach

    (A) Is it appropriate to apply the Commission's Safety Goals and 
their subsidiary objectives on a plant specific basis?
    (B) Is it appropriate to allow, under certain conditions, changes 
to a plant's CLB that increase CDF and/or LERF?
    (C) Is the level of detail in the guidance contained in the 
proposed Regulatory Guides and SRPs clear and sufficient, or is more 
detailed guidance necessary? What level of detail is needed?
    (D) Are the four elements of the risk-informed process described in 
the Reg Guides and SRPs clear and sufficient?
    (E) Is the guidance on the treatment of uncertainties clear and 
sufficient, or is additional guidance necessary? What additional 
guidance is needed?
    (F) Is guidance on the acceptability and treatment of temporary 
changes in the CLB (i.e., temporary changes in risk) needed? If so, 
what guidance and acceptance guidelines should be included? Should the 
guidance be different for full-power operation vs a shutdown condition?
    (G) Is it appropriate to use the definition of ``current licensing 
basis'' included in 10 CFR 54 ``License Renewal,'' in these RGs/SRPs? 
What other definition would be more appropriate?
    (H) Should licensees be required to submit risk information in 
support of proposed changes to their CLB?
    (I) Are the guidelines for quality described in DG-1061 sufficient 
to ensure appropriate quality in those activities that support proposed 
changes to the CLB for safety related systems, structures and 
components? Are the appropriate provisions from 10 CFR 50, Appendix B, 
``Quality Assurance Criteria for Nuclear Power Plants and Fuel 
Reprocessing Plants'' applied to the PRA?
    (J) Should a licensee's PRA be required to be included in the NRC's 
docket file and updated as necessary to reflect previous changes and 
recent operating experience?
    (K) What other areas, besides graded QA, Tech Specs, IST and ISI 
could this process and these guidelines be applied to?

(2) Engineering Evaluation

    (A) Are the proposed safety principles clear and sufficient? What 
should be clarified and/or added?
    (B) Is sufficient guidance provided regarding the intent, scope, 
and level of detail requested in the submittal with respect to the 
evaluation of the safety principles? What should be added? For example:
    1. Should there be different guidance on defense-in-depth for those 
items analyzed in the PRA versus those not analyzed? What should the 
differences be?
    2. Should there be quantitative guidelines for determining the 
sufficiency of defense-in-depth and safety margins?

[[Page 34326]]

    (C) Is the guidance associated with the probabilistic analysis 
sufficient? For example:
    1. Is additional guidance on the use of qualitative risk 
evaluations necessary? What additional guidance would be appropriate?
    2. Are the proposed acceptance guidelines for CDF and LERF and 
changes in CDF and LERF appropriate? Are they too restrictive or too 
liberal? What guidelines would be more appropriate?
    3. Is more specific or less detailed guidance needed on comparison 
of PRA results with the CDF and LERF and the CDF and 
LERF guidelines?
    4. Should there be additional guidance on the number of proposed 
risk increases which can be submitted in any given year?
    5. Should there be separate LERF guidelines for PWRs and BWRs? What 
should they be?
    6. Should there be separate LERF guidelines for shutdown 
conditions/external events? What should they be?
    7. Should there be a guideline on long term release frequency to 
supplement LERF? What should it be based upon?
    8. Is the guidance in Appendix B of DG-1061 for estimating LERF 
sufficient? What else is needed? (It should be noted that the staff 
intends to expand this guidance to cover shutdown conditions and 
external events).
    9. Should there be acceptance guidelines for the use of PRA level 3 
(segment of PRA that includes estimation of consequences/health effects 
and risk to the public) information? What guidelines would be 
appropriate?
    10. Should the acceptance guidelines specify a confidence level 
that the PRA results should meet when being compared to the risk 
guidelines? What is an appropriate confidence level?
    11. Should a confidence level or uncertainty level be used to 
define the ``management attention'' region in, lieu of a CDF and LERF 
range?

(3) Performance Monitoring and Feedback

    (A) Should the use of performance monitoring be more widely applied 
in regulation and regulatory practice, or is it sufficient to implement 
it through the elements described in the proposed Regulatory Guides?
    (B) Is performance monitoring and feedback an appropriate element 
of the risk-informed process? Should it be used to a greater or lesser 
degree?
    (C) Is the guidance on performance monitoring and feedback clear 
and sufficient? What should be improved?

(4) Graded Quality Assurance Regulatory Guide (DG-1064)

    (A) Is the approach for determining the safety-significance of 
plant SSCs appropriate? Is it sufficient to identify high and low 
safety significant categories? Is the amount of risk analysis overly 
burdensome relative to the potential benefits?
    (B) Is the guidance in the proposed regulatory guide regarding the 
content of QA programs for low safety significant SSCs appropriate? 
What additional guidelines are needed, and/or what portions of the 
proposed guidelines should be deleted?
    (C) Are there any quantitative data that can be used to assess the 
risk impact (i.e., CDF or LERF) of reducing QA controls on equipment 
performance?
    (D) Is the proposed scope of graded QA, that includes safety-
related and other important plant equipment as covered by the 
Maintenance Rule, appropriate?
    (E) Is the guidance on equipment-performance-monitoring strategies 
sufficient?
    (F) Is the guidance sufficient regarding the QA controls for 
safety-significant, but non-safety-related, equipment that should be 
included in the licensee's QA program? What guidance should be 
included?
    (G) Should the guidance allow for further removal of QA 
requirements? In what areas should this be done and what guidance would 
be appropriate? For example, is it appropriate for a graded QA program 
to eliminate all requirements associated with some of the 18 criteria 
specified in 10 CFR part 50, Appendix B?

(5) Technical Specifications Regulatory Guide (DG-1065) and SRP

    (A) Are the proposed acceptance guidelines on incremental 
conditional core damage probability and incremental conditional large 
early release probability from a single AOT change (5E-07 and 5E-08, 
respectively) appropriate?
    (B) Should there be a guideline on maximum conditional CDF/LERF 
during an AOT? What should it be?

(6) Inservice Testing Regulatory Guide (DG-1062) and SRP

    (A) PRA models of component unavailability typically use a 
parameter lambda () to characterize the component's failure 
rate, and this parameter is often considered to be a constant value. Is 
the assumption of constant value for  realistic? What 
different values might be more realistic and what evidence (data) 
supports the alternate values?
    (B) Is it appropriate, as part of a risk-informed program, to 
require licensees to look outside the ASME code boundary and identify 
candidate components for testing and then apply ASME criteria to the 
conduct of those tests? What is a reasonable way to deal with 
relatively high-risk components that are not part of a currently 
prescribed IST program?
    (C) Is it appropriate to use the ``other acceptable methods'' 
provision of 10 CFR 50.55a to implement changes to the CLB?

(7) NUREG-1602

    (A) Draft NUREG-1602 provides reference material on the scope and 
quality of a PRA. Is the information in draft NUREG-1602 complete and 
correct? Is it useful as reference material in making assessments on an 
application specific basis on the scope and quality of the risk 
assessment to support that particular application? How could it be 
improved? For example, should it specify acceptable PRA methods?
    (B) Would draft NUREG-1602 be useful as a starting point to develop 
a national consensus standard on PRA? What would be needed?
    (C) Is a national consensus standard on PRA needed or desirable?

VII. Paperwork Reduction Act Statement

    These draft regulatory guides contain information collections that 
are subject to the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et 
seq.). These regulatory guides will be submitted to the Office of 
Management and Budget for review and approval of the information 
collections before the final guides are published.

VIII. Public Protection Notification

    The NRC may not conduct or sponsor, and a person is not required to 
respond to, an information collection unless it displays a currently 
valid OMB control number.

    Dated at Rockville, Maryland, this 13th day of June, 1997.

    For the Nuclear Regulatory Commission.
John C. Hoyle,
Secretary of the Commission.
[FR Doc. 97-16072 Filed 6-18-97; 8:45 am]
BILLING CODE 7590-01-P