ML20211H028
| ML20211H028 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 09/30/1997 |
| From: | Cruse C BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC |
| References | |
| RTR-NUREG-1602, TASK-*****, TASK-RE NUDOCS 9710060160 | |
| Download: ML20211H028 (11) | |
Text
'
Curnt.r.s 11. Cav:t Baltimore Ons and Electric Company Vice President Calvert Ciffs Nuclear Power Plant Nuclear Energy 1650 Calvert Cliffs Parkway Lusby, Maryland 40657 410 495-4455 l
September 30,1997 U. S. Nuclear Regulatory Commission Washington,DC 20555 ATTENTION:
Chief, Rules and Directives Branch
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50 317 & 50-318 Comments on Draft NUREG 1602, Draft Regulatory Guides DG 1061, DG-1062, DG-1065, and Draft Standard Review Plan Chapters 3.9.7,16.1, and
- 19. Addressing Use of ProbabilLtic Risk Analysis in the Reculatory Process
REFERENCE:
(a)
Federal Register Notice, dated June 25, 1997, Use of PRA in Plant Specific Reactor Regulatory Activities: Proposed Regulatory Guides, Standard Review Plan Sections, and Supporting NUREG (62 FR 34321) i Baltimore Gas and Electric Company is a strong supporter of the effective use of Probabilistic Risk Analycis (PRA) to aid in the safe and cost effective operation of nuclear power plants. We, therefore, are pleased that the Nuclear Regulatory Commission (NRC) is pursuing risk-informed regulation and for the opportunity to provide comments.
However, we are concerned that without significant changes to the draft regulatory guidelines, risk-informed regulation is in jeopardy, it appears that these documents, as currently written, will not reduce the regulatory uncertainty in this emerging area. The associated uncertainty in effort and cost, and the limited allowable benefits will likely discourage future PRA applications. Discouraging applications is inconsistent with the Commission's PRA policy statement to increase the use of PRA technology in regulatory matters and to reduce unnecessary conservatism associated with regulatory requirements, /j Specifically, the requirement of an absolute numerical criterion, the need for uncertainty evaluations, thea lack of clarity associated with the quality required for the PRA, and the apparent inconsistency between
//S/
the requirements for the pilot applications and that stated in the draft documents are of concern.
It appears to us that a framework which encourages growth in both the application and quality of PRAs has not been achieved. Baltimore Gas and Electric Company's comments are, therefore, focused on issues that we believe will help to reconcile these concerns.
(+ 1,e b L 3 n
~mnp d
9710060160 970930 PDR ADOCK 05000317
\\\\\\,\\\\
E
- Chl:f, R' les and Directives Branch u
September 30,1997 Page 2 --
- We also believe, due to the magnitude and importance of the draft _ documents, that adequate tima to perform an etYective review was not made available. 'Iherefore, the lack of comments in a speelfic area does not indicate agreement.-
Should you have questions regarding this matter, we will be pleased to discuss them with you.
- Very truly yours,-
CHC/SJR/bjd
/
Attachment:
(1) _ Comments on Draft NUREG 1602, Draft Regulatory Guides DG-1061. DG 1062,-
DG-1065, and Draft SRP Chapters 3.9.7,16.1, and 19,- Addressing Use of Probabilistic Risk Analysis in the Regulatory Process cc:
Document Control Desk, NRC H. J. Miller, NRC R. S. Fleishman, Esquire -
- Resident Inspector, NRC
' J. E. Silberg, Esquire
' R.1. McLean, DNR Director, Project Directorate 1 1, NRC J. H. Walter, PSC
. A. W. Dromerick, NRC -
I 4
,-e-
ATTACIIMENT (1)-
1 1
i i
Comments on Draft NUREG-1602, Draft Regulatory Guides DG-1061, i.
DG-1062, DG-1065, and Draft Standard Review Plan Chapters 3.9.7, 16.1, and 19, Addressing Use of Probabilistic Risk Analysis I
in the Regulatory Process
)
i 1-i E
r i
l 4
Baltimore Gas and Electric Company Calvert Cliffs Nuclear Power Plant, Units 1 and 2 September 30,1997
ATTACHMENT f1)
COMMENTS ON DRAFT NUREG-1602, DRAFT REGULATORY GUIDES
-DG-1061, DG 1062. DG-1065, AND DRAFT STANDARD REVIEW PLAN CilAPTERS 3.9.7, 16.1, AND 19, ADDRESSING USE OF PROBABILISTIC RISK ANALYSIS a
IN THE REGULATORY PROCESS NUMERICAL ACCEPTANCE GUIDELINES The following comments are in reference to DG-1961, Section 2.4.2.1, page 14.
'Ihe current industry Probabilistic Risk Analyses (PRAs) do not support an upper level absolute acceptance guideline (a mean core damage frequency at or about IE-4 or a mean large early release frequency [LERF) at or about IE-5). Completeness, conservatism and non-conservatism, and the resulting inconsistencies between PRAs are issues that will take time to resolve. In addition, the complexity and dynamic nature (due to data, procedure changes, plant modifications, external hazard variations, etc.) make the dependency on an absolute number unmanageable. Not only will such an approach be difficult to manage and regulate, it will shift the industry's' focus from discovering risk insights to achieving low calculated core damage frequencies (CDFs). It will also result in penalizing those plants with high calculated CDFs, even if the high CDF is solely due to performing a quality PRA.
- In addition, there is also a configuration issue associated with the potential that plant changes made outside the risk informed regulation framework that meet current licensing practices could result in uncalculated risk increases. These risk increases could change previously-approved submittals and result in a complex configuration control system. We, therefore, believe the only numerical guidelines should be based on the change in risk. A general acceptance guideline of IE-6 is recommended.
Baltimore Gas and Electric Company (BGE) also believes that it is appropriate to pursue a long-term objective of conforming PRAs to standards that result in the ability to compare the risk between plants with confidence that the calculated differences reflect real risk dif1'erences. Such an objective should be clearly stated and an appropriate means and target date developed (i.e.,2005),
In addition, since comparing the risks of all plants obviously cannot be achieved without considereble cost, the improved benefit of achieving this objective needs to be defined. The defined benefits should include an effective risk informed means to achieve relief from low risk significant regulatory compliance issues. By allowing real near term operating issues to be addressed, the value of having a quality PRA will not be in question.
If a framework that is not dependent on an absolute CDF and LERF number is not a viable option, then the guideline should be dependent on the quantitative health objectives and not the surrogate values of CDF: lE-4 and LERF: IE-5. Please note however, that we believe such a choice will be adverse to achieving quality industry PRAs and adverse to promoting PRA applications.
QUALrrY ASSURANCE 1.
In reference to DG-1061, Section 2.7, page 22, the following five bullets are listed identifying the quality requirements for a PRA application.
Utill:e personnel quah)edfor the analysis.
It was stated at the workshop that qualified personnel referred more to the use of experienced staff, as opposed to the establishment of a formal qualification program. Ba'ltimore Gas and Electric Company believes that a formal program should be expected. Clarification of the expectation for qualified staff should be included in DG 1061.
I
A*lTACHMENT in COMMENTS ON DRAFT NUREG 1602, DRAFT REGULATORY GUIDES DG-1061. DG-1062, DG-1065, AND DRAFT STANDARD REVIEW PLAN CHAPTERS 3.9.7, 16.1, AND 19, ADDRESSING USE OF PROBABILISTIC RISK ANALYSIS IN TIIE REGULATORYPROCESS Utilize procedures that ensure control ofdocumentation, including revi> Ions, andprovidefor the independent review, vertfication or checking ofcalculations andlitformation used in the analysis (an independentpeer can be used as an important element in this process).
The parenthetical implies a peer review may,atisfy, at least in part, the independent review requirement, is it the intent to say that the peer review satisfies this requirement only if such a review performs detailed checking of calculations in the analysis? He guidance should be revised to clarify the NRC's position prior to fmal issuance.
Provide documentation and maintain records in accordance with the guidelines in Section 3 of this guide.
The documentation required in Section 3 appears to be inconsistent with that required in the pilot applications. An application like emergency diesel generator allowed outage time extension requires nearly all aspects of a PRA in order to assess the risk. Herefore, the documentation requirements listed on page 25 would result in a submittal far greater than that of the Individual Plant Examination requiring newly all the tier two PRA documents. At Calvert Cliffs Nuclear Power Plant, this submittal would be well over 50 volumes.
If the intent of this section is to " illustrate the scope and quality of the engineering analysis,"
then the information requested should be stated as being summary in nature to the extent necessary to provide confidence in the application.
Baltimore Gas and Electric Company recommends the following approach: In lieu of providing the large amount of data requested, the application should include a summary of the difreences of the utilities' PRA from that of NUREG-1602. This summary should also include a discussion of why each difference is acceptable for the application being pursued. Such an approach will result in a self assessmat of the quality of the PRA by the licensee prior to the submittal of an application. As such, the regulator is provided a means to cost effectively assess the quality of the PRA used for each application and the licensee is protected from future enforcement that could result from unclear quality expectations. His simple and cost effective approach removes considerable regulatory uncertainty. It also requires the role of NUREG-1602 to change from dePming a state-of the-art PRA to defining the quality of a PRA necessary to meet the regulator's expectations. Note that this change also increases the importance of NUREG-1602 and necessitates the removal of some unreasonable expectations. See NUREG-1602 comments.
Finaiiy, it is recommended that this bullet be reworded to " maintain records in accordance with the guidelines in Section 3 of this guide" since providing documentation is a reporting requirement, not a quality requirement, Providefor an independent auditfunction to verify quality (an independent peer review can be o
usedfor thispurpose).
It is assumed that the quality audit function described here is an audit of the PBA program and not each application. The guidance should be revised to clarify the NRC's posl tion prior to final issuance.
2
ATTACHMENT H)
COMMENTS ON DRAW NUREG-1602, DRAFT REGULATORY GUIDES-DG-1061, DG-1062, DG-1065, AND DRAW STANDARD REVIEW PLAN CHAPTERS 3.9.7, 16.1, AND 19, ADDRESSING USE OF PROBABILISTIC RISK ANALYSIS IN TIIE REGULATORY PROCESS-In addition, the peer review objectives and scope described in NUREG-1602 appear to be very onerous. Since there is no other peer review description provided, please clarify the scope of the peer review expected to satisfy DG 1061. If an independent review is performed in accordance with Bullet 2, then can it be assumed that the peer review that would satisfy this requiretc.ent is a high level check of assumptions, methodology, and conclusions?
Utill:e procedures that ensure appropriate attention and corrective actions are taken if analysis e
- or irtformation used in previous decision making is determined to be in error.
Due to the dynamic nature of PRAs (periodic updates due to data, plant configuration, analysis changes), it is unclear as to what degree of change in the PRA results would warrant a re-submittal of previously approved applications. Since this liability grows with each submittal made, it is imponant to understand when a small change is not considered significant. Baltimore Gas and Electric Company recommends that such an update would only occur when there is a significant error that invalidates the conclusions of a previous submittal. The guidance should be revised to clarify the NRC's position prior to final issuance.
4 2.
It is BGE's understanding that the PRA quality requirements for the risk-informed Technical Specification change were satisfied through the use of a cross comparison of key issues and results of several PRAs associated with the pilot application. It is unclear on review of DG-1061 as to whether this practice would be acceptable in the future, and if not, then the pilot application did not meet the quality expectations. The guidance should be revised to clarify the NRC's position prior to final issuance.
THE ROLE OF NUREG-1602 In reference to page xii, last paragraph, it appears that NUREG-1602 is not adequate for the role that is needed. It is stated that the most demanding applications define the level of technical detail contained in the NUREG. It was also stated at the August 1997 workshop that the definition of the minimal requirements for a particular application was going to be identified through the application approval-process. This approach leaves considerable regulation uncertainty, It feits to provide enough up-front
_ guidance to allow any degree of confidence that pursuing a risk-informed application can be done in a cost effective manner. It also adds an enonm is regulatory risk factor in that a risk-informed application that was done in good faith could be later inspected to the only PRA quality guidance available (the technical requirements for the most demnding applications). Such an inspection would likely be frustrating and costly.
The fix is to design NUREG-1602 as a document that defines the quality of a PRA necessary to meet the regulator's expectations for a good PRA. As stated in the discussion of quality above, NUREG 1602 should be used as a benchmark document where differences are summarized in each submittal. This fix implies that NUREG 1602 should be reasonable in its expectations and consistent with current good practices. State-of-tne-art or best practices could still be included, but they should be clearly identified.
The below comments are made with this position in mind and attempt to identify the major issues in addition to unclear statements.
l 3
A*ITACHMENT (1)
COMMENTS ON DRAFT NUREG-1602, DRAFT REGULATORY GUIDES DG-1061, DG-1962, DG-1065, AND DRAFT STANDARD REVIEW PLAN CHAPTERS 3.9.7, 16.1, ann 19, ADDRESSING USE OF PROBABILISTIC RISK ANALYSIS IN THE REGULATORYPROCESS Initiating Events (Section 2.1.1) 1.'
In Section 2.1.1.1, page 2-3, the inclusion of" unplanned controlled shutdown" events appears to be
- inappropriate. Such events will not challenge the Reactor Protective System, will have considerably longer human action responses for many actions, and are likely to have different system success criteria due to lower decay heat. Baltimore Gas r.nd Electric Company recommends that this initiator type be removed.
2.
It is unclear as to what is meant by an initiating event that has occurred during shutdown conditions.
- lhis reference should be clarified or removed.
Data Analysis (Section 2.1.4) 1.
In Section 2.1.4.1, pege 2-21, Equipment Reliability, it is stated: "For test surveillance or other demands for which actual run times are distinctly less than the length of the mission time modeled in the PRA, it should be determined whether the failure rate derived for the truncated tests or demands is applicable over the mission time." While we agree that the obvious differences between test and actual demands need to be addressed, exclusion of routine surveillance test in reliability calculations appears inappropriate. If such an approach is used, there will be little plant-specific data included in the reliability calculations for standby equipment.
- 2. In Section 2.1.4.1, page 2-22, Common Cause Failures, it is stated: "Since there is generally insufficient data to derive plant-specific estimates of the common cause failure parameters, generic data should be used." This statement is too simple and could be misleading. As stated in Electric Power Research Institute document TR-100382, A Database of Common Cause Events for Kisk and Reliability Applications, it is " essential to reinterpret the (generic) event in light of the specific characteristics of the system under consideration." Electric Power Research Institute document TR-1002747, Common-Cause Data Analysis Tool (CCDAT) User's Manual, provides a tool to help in the development c# plant specific, common-cause failure frequency parameters. In addition, it is BGE's opinion that it is also valuabic to n,xiate generic data with plant-specific data. This statement should be rewritten to state: "Since there is generally insufficient data to derive plant-specific estimates of the common cause failure parameters, generic data can be used as long as it is appropriately mapped to the specific characteristics of the system under consideration."
Human Actions (Section 2.1.5) 1.
In Section 2.1.5.1, page 2-24, of NUREG-1602 states: "... credit for recovery actions may not be given unless at least some procedural guidance is provided or operators receive frequent training that would lead them to perform the required actions." Although most credited human actions do have procedural guidance, some of the actions rely on the operators' expertise and their overall knowledge of the plant. In Calvert Cliffs' Human Action Methodology, such actions are classified as either knowledge or skill based. This human action methodology appropriately degrades thr failure probability given that procedural guidance and/or training is limited or does not exist fer -
particular action. It is, therefore, too conservative to restrict human actions when the degree on procedure guidance and tmining man Iw addressed by available methodologies. It'is recommended that this statement be modified to indicate the need for the assessment of the degree of procedure guidance and training available.
4 i
ATTACHMENT (1)
COMMENTS ON DRAFT NUREG-1602, DRAFT REGULATORY GUIDES DG-1061 DG-1062, DG-1065, AND DRAFT STANDARD REVIEW PLAN CHAPTERS 3.9.7,
{
16.1, AND 19, ADDRESSING USE OF PROBABILISTIC RISK ANALYSIS IN THE REGULATORYPROCESS
-2.
In Section 2.1.5.1, page 2-24, of NUREG 1602 states: "At a minimum, plant walk throughs, interviews with plant personnel (e.g. training, maintenance, operators, shift supervisor, shift technical advisors), and procedure reviews are performed in identifying and selecting the human events for a PRA." It also adds that, " Observations of simulator exercises and maintenance crew performance can be used to provide additional information..." These stipulations, if meant to be a set of minimum requirements, are both impractical and unrealistic. With the number of human actions currently being used in PRAs (over 100 in Calvert Cliffs' PRA), the additional time and resources required just to interview the recommended personnel is impractical, Interviews with knowledgeable operators using well-defined action descriptions and table top walk throughs are believed to be very effective, ne above statement should be modified as such.
3.
In Section 2.1.5.1, page 2-25, Screening / Excluding Human Events, states: "A screening analysis can be performed to identify and exclude these (non critical) events from detailed evaluation.
However, the screened human events should be reconsidered for every risk informed regulatory application of the PRA to ensure that all of the risk contributing actions are included in the application analysis." The intent of this statement is unclear. Is this statement focused on pre-initiator human errors? Is a documented assessment expected for each application?
4.
In Section 2.1.5.1, page 2-25, Screening / Excluding Human Events, states: " Human events, such as all pre-initiators, generally cannot be excluded from consideration based on the argument that these events are included in the components hardware data. Many human events (such as miscalibration) occur rarely and are not necessarily reflected in the random failure data. Further, their effects can be subtle in that they impact multiple systems and, thus, can play a key factor in contributing to core damage." While we agree that pre-initiator human errors that impact multiple channels or trains should be addressed since they represent a potential common mode failure, it appears urJeasonable to include this impact as a separate contributor to the failure rate of a single basis event. In addition, we b;lieve that most, if not all, significant maintenance (including miscalibration) errors are captured in the hardware data. Since it is stated that many human error events are rare, this statement indicates that even if they are not captured in the failure rate data, they would likely be an insignificant contribution. Therefore, be,and the impact of multiple channels or systems, it does not appear that the level of effort to include these e. cars at a basic event level is warranted.
- 5. - In Section 2.1.5.1, page 2-26 NUREG-1602 states: "The available time is accident specific and determined from engineering analyses which include actual time measurements derived from walk-throughs and simulator observation." This statement is apparently confusing the available time with the actual time. The available time should be based on engineering analyses or model structure that establishes the constraint for an action. The actual time is determined through the interview process that, at a minimum, should include a table top walk-through.
6.
In Section 2.1.5.1, page 2-27, NUREG-1602 states: "For post-initiators, the human event should be evaluated relative to the specific context of the accident progression. Therefore, for different
. accident sequences, the human event is evaluated for each sequence." Since a huntan action has the possibility of being utilized in multiple sequences, possibly thousands, analyzing each particular use would be impractical. The recommendation should be clarified to say: "Therefore, a human failure probability should be bounding for all accident sequences for which it is used." The boundaries both define the action being interviewed and establish the boundary for its use in the plant model.
5
ATTACHMENT (1)
COMMENTS ON DRAFT NUREG-1602, DRAFT REGULATORY GUIDES DG-1061, DG-1062, DG-1065, AND DRAIT STANDARD REVIEW PLAN CHAPTERS 3.9.7, 16.1, AND 19, ADDRESSING USE OF PROBABILISTIC RISK ANALYSIS IN THE REGULATORY PROCESS.
The bounding condition should also in.lude the key elecidcal and/or mechanical supports required by the operator to identify, diagnose, and perform the actk.
7.
In Section 2.1.5.1, page 2 27, NUREG 1602 states that errors made in performance by the original operator can be " recovered" by the same operator and by other plant personnel (e.g., shift technical advisor). Total credit for all such " recoveries" should not exceed a factor of ten (higher credits should be identified and justified). Baltimore Gas and Electric Company believes that this factor of ten seems too conservative for all such applications. It is suggested that, if a second redundant person (ca., shift technical advisor) whose sole purpose is to do certain safety function status checks on a set interval catches the initial error, then the factor of 10 can be exceeded. In fact, this second recovery action by the shift technical advisor should be able to be quantified as a separate individual action as long as attention is given to the preceding related unsuccessful action. Other actions, where a second alarm may come in given that the initial indication went unnoticed, should be interviewed in such a manner so that the initial mistake has a consequence on the recovery action. The outcome of such an analysis may or may not be bounded by the factor of ten.
Accident Sequsnee Ounntification (Section 21.61 In Section 2.1.6.1, page 2-30, Selecting Truncation Values states: "At least 95% of the total core damage frequency and 95% of the early and late release frequencies should be expressed in the model results. Also, it should be verified that lowering the truncation limit does not significantly increase the model estimation of the total core damage and release frequencies." Truncation is required in order to make large fault-trees and event trees solvable given the available computers and computer codes.
Daltimore Gas and Electric Company uses PLG, Inc.'s RISKMAN software. Cutoff frequencies speed the quantification of event trees, and make it possible to build very large trees, quantify the highest frequency sequences and bypass insignificant aequences, Cutoff frequencies can be set for each j
initiating event. RISKMAN calculates the frequency of sequences that fall below the cutoff frequency.
This frequency can be a large percentage of the calcuhted CDP. However, the portion of these unaccounted sequences that lead to core damage is unknown. Therefore, stating that "95% of the CDF should be expressed" is a target that cannot be verified unless all sequences are quantified (at which point truncation would not be an issue). Stating that a truncation value that is four orders of magnitude lower than the final CDF is sufficient, is believed to be non-conservative, Using this method would significantly decrease Calvert Cliffs Nuclear Power Plant's calculated CDF. Requiring truncation to be considered before and after operator recovery is also inappropriate for the large event tree methodology.
Human actions are included as either top events within the event tree or Ssic event within a fault tree that is used to calculate the top event. Removing these actions would prove to be extremely difficult and time consuming. However, BGE does agree with the statement: "Also, it should be verified that lowering the truncation limit does not significantly increase the model estimation of total core damage and release frequencies." To ensure greater consistency, a numerical value should be associated with "significantly increased." Determination of this value may require some sensitivity analysis.
Section 2.1.6.1, Estimating Uncertainties, page 2-31, addresses the use of mean values and guidance on estimating uncertainties. It is BGE's opinion that the use of point estimates, with sensitivity analysis on key parameters, would be just as valuable and more workable. Performing uncertainty analysis for each application appears to be an unwarranted cost and will likely inhibit risk-informed regulation.
6
O ATTACilMENT (1)
COMMENTS ON DRAIT NUREG-1602, DRAFT REGULATORY GUIDES DG-1061, DG 1062, DG-1865, AND DRAFI' STANDARD REVIEW PLAN CHAPTERS 3.9.7 16.1, AND 19, ADDRESSING USE OF PROBABILISTIC RISK ANALYSIS IN TIIE REGULATORY PROCESS Section 2.1.6.4, Doe.. mentation, page 2-33, provides a list of information regarding PRA quantification that should be documented. This list of bullets goes well beyond the information needed to ensure the quality of the quantification process, in addition, the bullets appear to be focused towards the CAFTA
[compurcr-aidedfault tree analysisJ software code quantification process, ne following changes are recommended:
Bullet 2: Remove "and accident classes."
Bullet 4: Delete. The documentation of human actions is addressed in Section 2.1.5.4. This bullet addresses the assessment of the results, which is better addressed when assessing the PRA for a particular application.
Bullet 6: Delete. See Section 2.1.6.1 uncertainty comment.
Bullet 7: Delete. This bullet is a post-process item. Its importance will vary in eccordance with each application, 4
Bullet 8: His bullet appears to be software specific and not applicab'e to a RISKMAN quantification.
Bullet 9: Maintaining a file of all sequences (currently greater than 100,000) appears reasonable.
Providing brief descriptions of these sequences is not. Therefore, delete the description requirement.
Bullet i1: Please define "non-recovery terms."
Bullet 12: Delete. This bullet appears to be software specific.
EEER REVIEW ll j
In NUREG-1602, Appendix B, PRA Peer Review, addresses the objectives and scope of a peer review.
This section implies that an extensive peer review should be performed with each application. This requirement is inconsisten' with DG-1061's quality audit requirement and with the risk informed Technical Specification pilot. The quality audit requirement implies an audit on the PRA process not the application. For the Technical Specification pilot application, cross comparisons w.ce performed in lieu
- of the detailed peer review outlined here.
it also appears that the line between idependent review and peer review is unclear. The peer review described is onerous and costly, and substantially overlaps the role of the independent reviewer, it is more appropriate to focus the peer review on the review of key assumptions, the methodology and the reasonableness of the conclusions.
Baltimore Gas and Electric Company recommends that NUREG-t602 be used as a tool for self-assessment performed by the licensee's PRA staff. We believe that high-level peer reviews peiformed by PRA experts to assess the key assumptions, the methodology, and the reasonableness of the conclusions coupled with independent document reviews is a cost etTective method to achieve a quality PRA.
Peer reviewers who are experienced PRA practitioners, but who are not necessarily knowledgeable with the plant, are believed to be acceptable, ne verification of the model to the plant is the responsibility of the independent reviewers. We also believe that a peer review for each application is unnecessary and appaars to exceed the 10 CFR Part 50, Appendix B requirements for safety-related work.
7
ATTACIIMENT (1)
COMMENTS ON DRAIT NUREG-1602, DRAIT REGULATORY GUIDES DG 1961 DG 1062, DG-1065, AND DRAFT STANDARD REVIEW PLAN CHAPTERS 3.9.7, 16.1, AND 19, ADDRESSING USE OF PROBABILISTIC RISK ANALYSIS IN THE REGULATORY PROCESS MAINTENANCE RULE Conspicuously absent from th'e framework of risk-informed regulation are guidelines for the most utilized PRA application: on line maintenance risk assessment. In response to a question at the workshop as to the quality of the PRA required for this analysis, it was stated that the absence of guidelines for on-line maintenance risk assessment is a problem for the industry to resolve. Since on line maintenance is a necessity for cost-effective operation, the design of a risk informed regulation without resolution of this issue appears to be a major weakness. 'Ihe silence in this area muddles the regulatory requirement for having a PRA and contributes to the considerable plant to-plant variation in the level of PRA resources. The development of a Configuration Risk Management Program for risk informed l
Technical Specifications appears to be an attempt to address this weakness. By placing this overhead only on risk informed Technical Specifications, it discourages the pursuit of these Technical l
Specifications since the cost of a quality Configuration Risk Management Program is high. A l
framework that does not address this issue will result in a division in the industry between PRA players and those that are not. Baltimore Gas and Electric Company recommends that guidance on this issue be clearly stated.
8 1
________ I