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American Nuclear Society Risk-Informed Standards Committee (RISC)

Meeting Minutes November 12, 2008

Reno, Nevada • Grand Sierra Resort & Casino Members present: Allen Camp (RISC Chair), Sandia National Lab; Robert Budnitz (RISC Vice Chair), Lawrence Berkeley National Lab; Paul Amico*, SAIC; Richard Black, US DOE; Biff Bradley*, NEI; Mary Drouin*, NRC; John Gaertner, EPRI; Dennis Henneke*, General Electric; Rick Hill*, ERIN; Gene Hughes, ETRANCO ; Ken Kiper, FPL; Greg Krueger, Exelon; Stanley Levinson*, AREVA; Patricia Schroeder, ANS; Bill Stillwell, STPNOC; Jonathan Young, Pacific Northwest National Lab; Don Wakefield, ABS Consulting Alternates present: Ching Guey, FPL; Gareth Parry, NRC; John Lehner (for Bob Bari), Brookhaven National Lab; Rupert Weston (for Dave Finnicum), Westinghouse Observers, liaisons, and guests present: William Burchill, ANS/Texas A&M University; Brian Carroll*, Duke Energy; Sarah Chisholm, Duke Energy; Rick Grantom, STPNOC; David Johnson, ABS Consulting; Jeff Julius*, Curtiss Wright; N. Prasad Kadambi, NRC; James Mallay, Individual; Kevin, O’Kula; WSMS; Doug Paul, Duke Energy; Leo Shanley, ERIN; Mary Beth Gardner, ANS; Grant Teagarden, ERIN; Earl Lynn Tipton, University of Missouri; Keith Woodward, ABS Consulting *participated by phone 1. Roll Call and Introduction of New Members Roll call was taken and introductions were made. 2. Approval of Agenda The agenda was approved as presented. 3. Meeting Key Issues and Objectives (Camp) – Attachment A RISC Chair Allen Camp stated that most of the agenda would focus on the reballot of the low power shutdown (LPSD) standard. After discussions, the committee would be asked to provide a path forward for the working group. Additionally, brief reports would be provided from the Level 2 & 3 working groups. 4. RISC Chair’s Report and NRMCC Activities (Camp/Budnitz) Summary of Standards Board Meeting – RISC Chair Report, Attachment B Allen Camp explained that RISC was one of four consensus committees under the management of the ANS Standards Board (SB). He reported that he discussed the LPSD reballot at the SB meeting the previous day. During the discussion, he was told that changing the scope of the standard would require a new PINS. Camp stated that the SB would heavily consider the opinion of the working group whether the scope needed to be changed. He made an offer for RISC to support risk-informed standards developed by the other consensus committees. Camp reminded the SB that the RISC was looking for grant funds to support development of Probabilistic Risk Assessment

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(PRA) standards. To support this effort, the ANS Washington Representative Craig Pierce had been requested to work on soliciting funds to aid development of ANS standards. Dick Black said that he felt DOE might have discretionary funds to be applied for ANS standards. He explained that the DOE’s mind set was that they should support NRC in its licensing activities and that this could be achieved through support of standards development. Camp noted that even a small amount to be used for travel expenses would be of benefit. Action Item 11/08-01: Dick Black to follow up with Allen Camp on the possibility of grant funds from DOE. Camp explained that an individual approached the SB with a new standard proposal on thermal hydraulic design codes. He noted that the proposal was fluid but that he was interested in the RISC ‘s being involved. Camp reported that the SB discussed project planning. The project plan would require a proposed schedule to expedite a standard with realistic commitments from experts and funding for retired working group members and consultants. Nuclear Risk Management Coordinating Committee (NRMCC) Activities Camp reported on the last NRMCC meeting held October 29, 2009, in Washington DC. He stated that it was attended by several RISC members. Camp reminded the committee that the NRMCC was run by ANS and ASME with members from industry, other SDOs (Notably IEEE), and regulatory agencies. Camp noted that the draft standard on non-LWR advanced reactors was issued for comment only to RISC and CNRM. He confirmed that the draft included Level 2, Level 3, and LPSD. Camp stated that Working Group Chair Karl Fleming used draft materials from these three projects which could present problems if approved before the LPSD, Level 2, and Level 3 standards are adopted. The current agreement with the NRMCC did not cover the standards project for non-LWR advanced reactors. The sentiment at the NRMCC meeting was that they wanted the non-LWR advanced reactor standard to have a scope that is inclusive of all other PRA standards. ASME currently planned for the standard to be balloted by CNRM with RISC comments to be accounted for. Mary Drouin added that the NRMCC co-chairs were working on a strategic plan that would look past Level 1, 2, and 3 standards. Mary Drouin asked for Camp to make a request for ASME to allow an additional two months for RISC members to review the non-LWR advanced reactors draft standard. Action Item 11/08-02: Allen Camp to make request to Rick Grantom (ASME CNRM chair) to allow a two-month extension on preliminary review of the advanced non-LWR reactor standard. Bob Budnitz informed the committee that he was involved in identifying standards for sodium fast reactors and was asking standards developing organizations to initiate new or to reinvigorate standards if an agreement was made. Dick Black stated that a meeting was to be held in January at NIST to discuss standards identified for sodium reactors. Black offered to provide Camp more information about the meeting.

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Action Item 11/08-03: Dick Black to provide Allen Camp specifics of meeting planned for January 16 at NIST. Camp questioned if the composition of the RISC should change if development of standards for advanced reactors were initiated. He suggested that a subcommittee be formed to look at advanced non-LWR standards. John Gaertner, Gene Hughes, and Jon Young volunteered to serve on the subcommittee. Mary Drouin volunteered to help where she could. Gaertner volunteered to lead the subcommittee. Action Item 11/08-04: John Gaertner to let RISC know how subcommittee to work and what input is needed from RISC members. Camp anticipated a conference call on this subject in the near future. CNRM Interactions & ASME/ANS RA-S-2008 Addendum Update Mary Drouin reported that Addendum A of the combined standard was approved and that ASME hoped to have ANSI approval before the end of the year. She stated that ASME/ANS RA-S-2008 was at the publisher. Stanley Levinson explained that a lot of changes were made with Addendum A which was why additional time was requested for RG 1.200. The changes included a new numbering system. Levinson informed the committee that Duncan Brewer of Duke Power changed jobs and stepped down as chair of ASME CNRM's Subcommittee on Technology. He was replaced by Kenneth Kiper of Seabrook Station. Levinson also stated that a new ASME CNRM Subcommittee on Inquiries had been formed with Barry Sloane of ERIN Engineering as chair. Allen Camp asked Bob Budnitz and Levinson, ANS RISC’s liaisons to ASME CNRM, for a statement confirming that they were satisfied that Addendum A had appropriately accounted for comments from ANS RISC. Action Item 11/08-05: Bob Budnitz and Stanley Levinson to provide Allen Camp with a statement to confirm satisfaction with Addendum A. 5. Update on Joint Committee – Presentation Attachment C Allen Camp stated that the presentation was provided as informational. Mary Drouin explained that the presentation was used at the last NRMCC meeting and included alternatives for a joint ASME-ANS committee with pros and cons. Drouin explained that the reorganization task team was led by Ted Meyer. Concepts were still being developed. Drouin noted that the task team underestimated the amount of time needed to thoroughly research the options. Additional time would be needed to implement. Six options had been identified. At present, option 5 (slide 20 of the presentation) was favored. Each option would be explained in detail. Camp expressed concern that additional groups would mean additional meetings that members had to attend. Drouin explained that committees were divided into subcommittees for efficiency. CNRM usually met for two and a half days as they felt it was more productive. Camp asked Drouin to determine the number of meetings necessary for the recommended options. Action Item 11/08-06: Mary Drouin to ask the reorganization subcommittee to provide information on the number of meeting days necessary for each option.

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Committee members were asked to provide comments on the reorganization options to Drouin. Action Item 11/08-07: RISC members to provide Mary Drouin comments on the reorganization options (via email). 6. Qualitative Standards Ad hoc Committee Report – Status Report Attachment D Rick Hill updated the committee on discussions he had with Bob Bari on qualitative standards. Hill distributed a status report of their discussions. The following charter was drafted:

Recommend a framework by which qualitative standards and quantitative methods can be addressed in future ASME and ANS PRA standards so that these standards can support risk-informed decision-making.

The provided report defined the terms probabilistic risk assessment (PRA), probabilistic safety assessment (PSA), risk-informed, and risk. Hill and Bari provided two roles for qualitative methods. The status report concluded that “qualitative was a special case of quantitative; a first step in any quantitative PRA that was done right. For a qualitative analysis to be the basis for risk-informing, it should be the best that one can reasonably do, in terms of likelihoods and consequences. It should recognize dependencies to the extent possible, and it should give a clear statement of uncertainties in both likelihoods and consequences, even if these are presented in terms of qualitative descriptors or linguistic variables (e.g. H, M, L).” Hill asked for the RISC to provide comments on the paper for consideration. Action Item 11/08-08: RISC members to provide comments on Qualitative vs. Quantitative PRA Methods paper. Gene Hughes stated that the “best one can reasonably do” captures the intent. Bob Budnitz suggested to change “best” to “adequate” and recommended to define what we mean by qualitative. Greg Krueger noted that the ANS November 2009 meeting would have an embedded topical on risk management that may be of interest. Action Item 11/08-09: Pat Schroeder to distribute information to RISC on the risk management embedded topical to be held during the ANS November 2009 meeting. 7. Status of Standards Writing Group Activities A. External Events Pilot Update (Gaertner) – See Attachment E John Gaertner reminded the committee that the last version of the external events standard received a few negatives because it had not been through a pilot. The standard was approved with the understanding that the pilot would be conducted. Lessons learned would then be integrated into the standard. The length of time required

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to perform the pilot was longer than hoped because of funding. The Japanese earthquake also delayed progress but provided good lessons. Gaertner explained that the goal of the pilot project was to provide further guidance on how to conform to Capability Category II. He stated that new seismic hazards had been conducted for new nuclear power plant sites. EPRI conducted new hazard estimates for existing nuclear power plants in the central and eastern United States that could be used for Capability Category II seismic PRA studies. Gaertner felt that the generic seismic hazard issue was less problematic now. Plant logic model was increased in size to improve accuracy, and the model was updated to reflect plant changes since the original IPEEE study. A new fragility analysis was being done. New component screenings had been conducted. Gaertner provided a pilot schedule for plant seismic logic model, seismic fragilities, and risk quantification with an anticipation completion by October 2009 for the final report. He said that Greg Hardy is working under an EPRI contract on this. He announced that EPRI planned to conduct an industry workshop after August 2009 to review final evaluations and insights on the seismic PRA application. Bob Budnitz requested a list of items that needed to be updated in the external events standard. Action Item 11/08-10: John Gaertner to request a list of items from Greg Hardy that need to be changed in the external events standard based on findings from the pilot. Action Item 11/08-11: Bob Budnitz to keep ASME apprised of EPRI’s External Events Pilot. B. Level 2 (Lehner for Leonard) – See Presentation, Attachment F John Lehner reported for ANS-58.24 Working Group Chair Mark Leonard. Lehner stated that the last meeting was held September 2008. Two rough drafts had been completed. The working group determined that the standard needed a glossary to define subjective terms. Allen Camp asked that the definitions be coordinated with the existing PRA standards. The working group was determining how quality assurance would be handled and if the Level 2 standard should encourage a full-linked Level 1 – 2 logic model. The goal was to finish an updated, complete draft by the end of the calendar year. Don Helton had been assigned to the Level 2 working group as the NRC representative. Lehner stated that the Advanced Safety Assessment Methodologies; Level 2 Probabilistic Safety Assessment (ASAMPSA2) group expressed interest in interacting with the ANS Level 2 Working Group. It was anticipated that the two groups would meet in about a year. Action Item 11/08-12: Mark Leonard to invite members of ASAMPSA2 to join the Level 2 Working Group. C. Level 3 (Woodard) – See Presentation, Attachment G Keith Woodard provided a report on the Level 3 project (ANS 58.25). He reported that membership had changed a little. Sarah Chisholm was added and possibly a member from the United Kingdom would be added. Woodard felt that all subject areas were covered, but assignments may be adjusted to accommodate new members. He

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estimated that a draft was 75% complete although most sections were primitive and needed a lot of work. In discussion about the format of the Level 3 standard, Woodard was directed to use Addendum A of the combined standard as a point of reference. Woodard stated that the schedule for completion was uncertain. Woodard explained that the group was still struggling with the capability category approach as applied to the Level 3 standard but that Stanley Levinson had been tasked to adapt capability categories for the Level 3 standard. Woodward explained that he might need help of others to write section on risk integration (aggregation). A question was raised as to whether risk integration warranted a separate standard. Allen Camp suggested that the section on risk integration be postponed for a revision if found too time consuming to write and would delay the standard. The committee was in agreement that the initial release of the Level 3 standard should be kept simple. B. LPSD PRA (Wakefield) – See Attachments H, I, J, K Allen Camp thanked the ANS-58.22 Working Group for their many years of effort to this project and asked that they not get discouraged. The following documents were provided to the committee 1) LPSD Presentation, Attachment H, 2) Teleconference Summary Minutes, Attachment I, 3) Background Information, Attachment J, and 4) a List of Substantive Comments, Attachment K. Don Wakefield reported that Jeff Mitman was officially added to the working group as NRC representative. Steve Hess withdrew from the working group, but Doug Hance would remain as the EPRI representative. Moving forward, Bryan Carroll would take a more active role. Wakefield explained that over 600 comments were received on the reballot of the low power shutdown (LPSD) draft. Two hundred comments were directed specifically at individual requirements. A few commenters said that they ran out of time to review the full draft. Wakefield expressed concern that the entire draft did not get reviewed and asked for members to submit any additional comments. Action Item 11/08-13: RISC members to submit any additional comments on the LPSD draft issued for reballot. The following past directives were reaffirmed:

Move Forward Now on Stand-Alone Standard (agreed) The RISC agreed that the working group should proceed and make their best attempt to expedite the completion of the individual (stand-alone) LPSD standard. Following its approval and publication, it would be incorporated into the ASME-ANS combined standard. Mary Drouin injected that maintenance of the “stand- alone” standard including responses to inquiries would be ceased once incorporated in the combined standard. She anticipated that the time between approval of the individual LPSD standard and incorporation into the combined standard would be only a few months. Rick Grantom added that ASME was putting together a special committee on interpretations that would be populated by members of CNRM and RISC to begin processing inquiries.

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QRLA & QRA to be Combined in One Standard (agreed) There was much discussion of the merits of going back to the Standards Board to ask for a separate standard on qualitative requirements. Working group members were polled for their thoughts. It was recognized that neither the working group nor RISC was unanimous in this decision but that the consensus was to move forward with developing the LPSD standard to include both qualitative and quantitative methods. The approved PINS was reviewed and found to be acceptable to proceed with inclusion of both qualitative and quantitative methods. Don Wakefield asked Bill Stillwell to question his end users on inclusion of both methods in the LPSD standard. Action Item 11/08-14: Bill Stillwell to question end users on combining LPSD quantitative and qualitative methods in one standard. Allen Camp summarized the committee’s reaffirmed decision to include qualitative and quantitative methods in one standard. Full External Events (i.e., Hazard Groups), Except Internal Fire (agreed) After a brief discussion, RISC members did not feel strongly that internal fires should be added. The committee agreed that the standard would include full external events, except internal fires.

SR’s to Reference Combined Standard, Addendum A (agreed) RISC agreed with the working group recommendation and voted without dissent to change directive to make the LPSD standard consistent with the Addendum A of the combined standard in both format and outline. The following motion was approved unanimously:

MOTION: The LPSD working group should proceed with referencing Addendum A of the combined standard but to stay cognizant of changes in Addendum B.

Neither a Guidance Document nor Pilot Application Required (agreed) The committee agreed that the LPSD standard should be issued without the requirement of a pilot or guidance document although either would be welcomed. Outage Specific Requirements to be Included (agreed) RISC agreed that outage specific requirements be included in the standard, but left it up to the working group to determine the placement. Members of the committee noted that placing outage specific requirements in an appendix might reduce its significance even if it was a mandatory appendix. Metrics Other than CDF/LERF are Permitted (agreed) The opinion was expressed that qualitative methods could and probably should be used to facilitate screening of POSs or to, in other ways, focus the quantitative efforts. Gene Hughes agreed to draft some thoughts on this issue (especially regarding an alternative end state “boiling”) for consideration by the LPSD working group.

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Action Item 11/08-15: Hughes to draft recommended practice for boiling end state to be included along with core damage in the standard.

Compatibility Issue with Combined Standard as Stand-Alone Standard The committee considered the proposed outline changes to be consistent with the combined standard. They requested a new LPSD standard outline be prepared that would be consistent with Addendum A of the combined standard and that it be submitted for approval by RISC within the next three to four months. The outline of the individual LPSD standard should be consistent with the format and outline of Addendum A of the combined standard though the section numbering would be sequential (i.e., no sections would be skipped in order to match the combined standard). The revised outline should address where to place outage specific requirements. Section numbering would be maintained as closely as possible to Addendum A so that the ANS LPSD standard could be “dropped in” into the ASME-ANS combined standard after changing the section numbers. The following motion was approved with one not approved:

MOTION: It is acceptable for the stand-alone LPSD standard to have its own numbering system provided the structure of the outline matches the Addendum A outline with the outline provided to the RISC for review.

Jon Young explained that he disagreed with the motion because he did not feel it was necessary to have the RISC review the outline. Path Forward Wakefield acknowledged that revising the draft to reference Addendum A was editorial but would be much work. He thought that an informed editor might be needed to modify existing requirements to the format. RISC agreed with this approach. Wakefield would attempt to find an appropriate editor. Rick Grantom felt that a CNRM member should be added to the LPSD working group. Wakefield stated that a few new working members to represent the combined standard, plant operations/outage planning, and young engineers would be beneficial. RISC agreed with this approach but did not offer any specific names at the meeting. Wakefield summarized the path forward to include:

1) Clarify comments with authors; 2) Initiate work on shared sections on the combined standard and LPSD; e.g.

definitions; 3) Face-to-face working group meeting to review technical comments (possibly to

be held in conjunction with February ‘s CNRM meeting); 4) Revised draft for third ballot/public review in November 2009.

RISC was satisfied with the approach and schedule. Wakefield noted that grant funds would help expedite the project by allowing additional travel and a technical editor. He added that separating some elements into separate ballots could also help expedite.

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Dick Black explained that he was looking for a way to package a line item for standards in the DOE budget and needed the right words. Allen Camp offered to help prepare a statement. Action Item 11/08-16: Allen Camp to draft a statement for Dick Black to encourage DOE to include a budget item for standards development. Significant Reballot Comments Wakefield summarized significant comments received on the reballot. The majority of the discussion focused on the definition of capability indices for QLRA. The committee did not feel strongly either way. In some sense the use of a single category gained favor with a competing view that this approach would imply an un-acceptance for a large number of existing QLRA models. It was also noted, however, that from the time that this standard would be approved at its earliest and endorsed by the NRC, there would still be two years before this would be confronted by the plants. The working group was asked to reconsider its position and make a new recommendation to RISC in the next three to four months. A suggestion was made to conduct a RISC vote if the working group recommended making a change from the current three-category approach. Action Item 11/08-17: Don Wakefield to discuss the number of capability categories for QLRA with the LPSD Working Group and report back to RISC. The working group was directed to retain the current definitions in the combined standard and if necessary to add new ones for LPSD. Wakefield suggested that a RISC teleconference may be beneficial in January to discuss progress of the LPSD Working Group. Action Item 11/08-18: Pat Schroeder to coordinate a RISC teleconference with Don Wakefield to discuss the progress of the LPSD Working Group. (Potentially to be held in January 2009) 9. Other Business Mary Drouin questioned if RISC planned to submit public comments on RG 1.200. Allen Camp responded that comments would be submitted as individuals. 10. Next RISC Meeting At present, the next RISC meeting was planned for June 17, 2009, during the ANS Annual Meeting in Atlanta, Georgia. 11. Adjourn The meeting was adjourned at 4:45pm.

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Meeting Objectivesand

RISC Chair’s Report

Allen Camp

November 12, 2008

Meeting Objectives

• Information to RISC members on anumber of issues

– Joint committee

– Advanced reactors

• Key Decisions and a path forward for theLPSD writing group

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Standard’s Board Meeting

• Discussed status of LPSD standard– Approval for RISC to determine approach for qualitative

portion of the standard, Board approval required for newstandard

• Board concurrence on approach for advancedreactors

• Offered support to SB in developing risk-informedstandards

• Status of grant and impact on Level 2/3 standards– Craig Piercy ANS DC representative

• Lloyd Wright – Utility POC for ANS• Uncertainty analysis standard for Design Codes –

RISC role?• Need for better project planning

NRMCC Activities• Meeting on October 29• Reported Status of ANS PRA Standards• Grantom report on status of CNRM Activities• Significant discussion on advanced reactors

– Hope to ballot in next few months– Report from Fleming– Expanded scope, e.g., all rad sources– Potential for preempting ongoing ANS activities– Discussion of roles/responsibilities

• Current NRMCC agreement doesn’t cover everything• Intent of NRMCC to support expansion of joint activities• ANS role reaffirmed for Level 2/3 activities• NO official agreement yet, but sense of those present was that both

ANS and ASME would ballot the advanced reactor standard

• Limited discussion of Joint Committee

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CNRM Interactions

Report from Bob Budnitz and Others

RISC Progress ReportNovember 2008

PublicationThe publication of ANSI/ASME/ANS-RA-S-2008, “Standard for Level 1/Large EarlyRelease Frequency Probabilistic Risk Assessment for Nuclear Power PlantApplications,” has been delayed until December 2008.

Action CompletedThe RISC was provided an opportunity to comment on four ASME ballots for the firstaddendum to ANSI/ASME/ANS-RA-S-2008, “Standard for Level 1/Large Early ReleaseFrequency Probabilistic Risk Assessment for Nuclear Power Plant Applications.” ANSIapproval of the first addendum is expected by the end of the year with publication thebeginning of 2009.

In RISC Ballot/Vote (or resolving comments)ANS-58.22-200x, “Low Power Shutdown PRA Methodology”

Writing group led by Don Wakefield Reballot issued due to substantive changes Reballot closed October 2008 with 674 committee comments and 116

public comments Significant comments will be discussed at the RISC meeting to provide the

working group direction in resolving and determining a path forward

Standards in ProgressANS-58.24-200x, “Severe Accident Progression and Radiological Release (Level 2)PRA Methodology to Support Nuclear Installation Applications”

Writing group led by Mark Leonard PINS approved Progress hampered by lack of grant funds Ballot date to be determined

ANS-58.25-200x, “Standard for Radiological Accident Offsite Consequence Analysis(Level 3 PRA) to Support Nuclear Installation Applications”

Writing group led by Keith Woodard PINS approved Progress hampered by lack of grant funds Ballot date to be determined

Other Issues Committee consensus on qualitative standards Status of NRC grant Coordination with NRMCC and CNRM Combining ANS RISC with ASME CNRM

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Status of Reorganization Activities

ANS Risk Informed Standards Committee MeetingNovember 12, 2008

Mary Drouin (for Ted Meyer)

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Agenda• Status of Reorganization Task Team efforts• Process to formally consider alternative

CNRM/RISC organization structures • Some alternatives that were considered but not

accepted by the Reorganization Task Team– A summary of the concerns for each alternative that

was not accepted• Two similar concepts that have been generally

accepted by the Reorganization Task Team– Some additional details are provided for these two

concepts

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Reorganization Task Team• Ted Meyer, Lead• Barbara Baron, Secretary• Mary Drouin• Greg Krueger• Stanley Levinson• Daniel McLaughlin• Pamela Nelson• Doug True• Rick Grantom• Allen Camp

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Status

• No specific reorganization recommendations have been made to CNRM or to RISC– Only concepts are being provided here today

• Goal is to develop a set of options

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5

Process to formally consider alternative CNRM/RISC organization structures

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Who are the Interested Parties?

• ASME BNCS (ASME Board)• ASME CNRM Main Committee• ASME CNRM Standards Planning

Subcommittee• ANS Standards Board • ANS RISC• NRMCC including its member SDO’s• Some other SDO’s in the future

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What do we need to consider?• The final ANS RISC/ASME CNRM organization

structure is likely to take more than one year to be finalized

• We should consider establishing an “Interim”ANS RISC/ASME CNRM integrated organization structure to better support our standards development and maintenance needs

• We need to define the process steps to define and establish a final ANS RISC/ASME CNRM organization structure

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Suggested Process Steps1. Organization Structure Team recommends an initial “Conceptual

Organization Structure” and alternatives that were considered to:– CNRM/RISC– BNCS and ANS Standards Board representatives to this activity

2. Obtain feedback from CNRM and RISC Main Committees3. Obtain feedback from BNCS and ANS Standards Board representatives4. Develop a revision that includes the above feedback

A. Initial identification and assessment of ASME and ANS implementation issues by ANS and ASME Staff

5. Recommend the revised organization structure to:– CNRM and RISC Main Committees– BNCS and ANS Standards Board representatives to this activity

6. Develop the first “Draft Organization Structure” considering the second round feedback from CNRM, RISC and Board Rep’s

7. Present the Draft Organization Structure to the BNCS and ANS Standards Board– Resolve concerns from BNCS and ANS Standards Board

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Suggested Process Steps -continued

8. Present Final Draft Organization Structure to the CNRM and RISC– Ballot the Draft Organization Structure by the CNRM and RISC– Resolve negative vote issues

9. Present the Final Organization Structure that has been balloted by the CNRM and RISC to the BNCS and ANS Standards Board– Ballot the Final Organization Structure by the BNCS and ANS

Standards Board– Resolve negative vote issues

10. If all CNRM, RISC, BNCS and ANS Standards Board negatives have been resolved then complete development of an implementation plan for the new CNRM/RISC Organization Structure

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Some alternatives that were considered but not accepted by the Reorganization Task Team

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Criteria Considered to Identify and Evaluate Concepts

• Better enable member support of standards activities from both CNRM and RISC including the Main Committee, Subcommittees and Working and Task Groups

• Identify and find homes for the various “functions” (e.g., identifying what standards are needed) that RISC and CNRM require as standards development organizations

• Enable CNRM and RISC meetings to occur at the same time and location

• Enable clarification of which SDO process is used to issue and maintain/update the standard

• Enable clarification of which SDO sponsors the committee, sub-committee, and working group meetings

• Encourage collaboration and discourage independent efforts relative to the development of risk management standards

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Concepts/Options1. Maintain ANS RISC and ASME CNRM as they currently exist.2. Maintain an independent RISC within ANS and an independent CNRM

within ASME but relate their activities through a “Joint CNRM/RISC Main Committee.”

3. Virtual Committee of Combined Standards Groups (CNRM and RISC). Add a “Combined RISC/CNRM Standards” committee to both groups for interaction.

4. Maintain separate RISC and CNRM Main Committees and add new Subcommittees, but matrix all of the subcommittees to a “Combined RISC/CNRM Subcommittee” for review and interaction on all standards actions.

5. Integrate all Subcommittees, Working Groups, Task Teams into one Risk Management Standards body with a Main Committee consisting of all RISC and CNRM Main Committee Members.

• Main Committee members maintain their identity to RISC or CNRM.6. Option 6 but the Main Committee do not maintain their identity to RISC or

CNRM.

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Evaluation of Concepts

Options

1

2

3

4

Membe

rship

Functi

ons

Working

Grou

ps

Meetin

gs

Proces

s

• Committee size not affected

• Balance of interest is not impacted

• Committee size not impacted

• Balance of interest not impacted

• Members on both still exists

• Committee size not impacted


• Members on both still exists

• Subcommittees remain as they currently exist in both CNRM and RISC

• One Joint Main Committee that maintain their ANS/ASME identig

• All subcommittees are maintain within original SDO

• A Joint ANS/CNRM Subcommittee is formed

• RISC and CNRM Main Committees still exist as separate bodies

• Single combined main committee meeting

• Could result in more travel for some members

• Separate Main Committee meetings

• Can add travel for those on both committees

• Single combined working groups

• Less time and travel

• Separate working groups

• Duplicative, working group maintained under each committee

• Main Committee size not impacted


• Members on both still exist

• Working Groups unaffected • Two Main

Committees

• Concerns about roles/responsibility

• Potential for overlap

• Single meeting

• Less travel for those on both committees

• Less time separate from meetings (only supporting one committee)


• Working Groups unaffected


• Five new Subcommittees are created and report to CNRM and matirx to RISC

• A Joint ANS/CNRM Subcommittee is formed

• RISC and CNRM Main Committees still exist as separate bodies

• Separate Main Committee meetings

• Can add travel for those on both committees

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Evaluation of Concepts

Options

5

6

Membe

rship

Functi

ons

Working

Grou

ps

Meetin

gs

Proces

s

• Committee is larger than what is typically allowed in ASME

• Balance of interest impacted (some members may not be included)

• Members on both Main Committees goes away

• Subcommittees organized by functions with both CNRM and RISC members

• One decision (Main) committee

• Main Committee members maintain their identity with ANS or ASME

• Two Supervisory bodies

• Single meeting


• Reduced member time separate from meetings (only supporting one committee)

• Single set of combined Subcommittees and working groups


• Committee is larger than what is typically allowed in ASME• Balance of interest impacted (some members may not be included)• Members on both Main Committees goes away

• Subcommittees organized by functions with both CNRM and RISC members

• Single set of combined Subcommittees and working groups


• One decision (Main) committee

• Main Committee members do not maintain their identity with ANS or ASME

• Two Supervisory bodies

• Single meeting


• Reduced member time separate from meetings (only supporting one committee)

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Joint CNRM/RISC Main Committee

CNRM RISC

Subcommittee

Technology

Subcommittee

Applications

Subcommittee

Standards Planning

Non-LWR Working Group

Advanced LWR

Working Group

Executive Committee

Fire PRA Working Group

External Event

Writing Team

Low Power & Shutdown Writing Team

Level 2/Level 3 Writing Team

A

A Configuration ControlProject Team

Organizational ReviewProject Team

BNCS Stnds Board

NRMCCConcept 2

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ANS RISCMain Committee

CNRM StandingSubcommittees/Working

Groups

Combined ASME-CNRM /ANS-RISC Standards

Group(Sub-committee in both

Standards Groups)

Option 3“Virtual” Committee of Combined

Standards Groups(4-29-08 Revision)

ANS

NRMCC

Combined ASME-CNRM Standards Subcommittee

Members include:1.) All RISC Main Committee members2.) All CNRM Main Committee members

Charter: The “Combined ASME-CNRM Standards Subcommittee provides a structure for discussion of issues and ballots of common interest to both the ASME CNRM and the ANS RISC. It is not a “Balloting” body.

Notes1.) Each Standards Group uses its parent Standards body process and procedures.

2.) Both Standards Committees meet as a “Virtual” Combined Standards Subcommittee

3. Additional Processes will need to be defined to support combined subcommittee operation

4.) This option precludes the need to create a complete set of new Standards rules and allows autonomy and collaboration for both Standards Groups

5.) All of the CNRM Main Committee members become RISC Main Committee membrs and vice versa. If the ballot is primarily in RISCthen RISC ballot. If the ballot is primarily in CNRM then CNRM ballots.

ASME BNCS

ASME CNRM Main Committee

RISC StandingWriting Teams

Concept 3

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Concept 4

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Two similar concepts that have been generally accepted by the

Reorganization Task Team

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Terminology

•Individual working groups or task teams comprised of members from either or both ASME and ANS but report to either ASME or ANS CNRM and RISC, respectively, depending on which SDO has lead responsibility for the standard. These groups/teams report to a subcommittee (Standard Maintenance).

SDO Maintenance Groups or Teams

•Individual writing working groups or task teams comprised of members from both ASME and ANS but report to either ASME or ANS CNRM and RISC, respectively, depending on which SDO has lead responsibility for the standard. The writing teams report to a subcommittee (Standards Writing).

SDO Writing Groups or Teams

•Non-consensus bodies comprised of members from both ASME and ANS which report to the joint committee of ASME CNRM and ANS RISC consensus committees. These are “functional subcommittees” that have responsibility for interfacing, planning, developing and maintaining the PRA standards between the two SDO’s.

Joint SDO Subcommittees

•A single committee comprised of selected members from both ASME and ANS. This committee will consider the needs of the SDO’s and make recommendations to the SDO Consensus Committee.

Joint SDO Consensus Executive Committee

•A joint committee of ASME CNRM and ANS RISC consensus committees, comprised of members from both committees, each reporting to its respective boards. Each will ballot and govern the process for that standard where the SDO has the lead.

Joint SDO Consensus Committees

•ASME and ANS respective boards, each board will govern the process for that standard where the SDO (Standards Development Organization) has the lead, i.e., development and maintenance of the standard.

SDO Boards

•Coordinating committee among SDO’s and other stakeholders (ASME, ANS, IEEE, NRC, DOE, NEI). This Committee does not develop or ballot Standards. This committee includes senior level representation from various SDO’s and industry groups and provides an industry forum to coordinate industry efforts to develop risk management standards for the nuclear industry.

NRMCC

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ASME CNRM(Consensus Group)

ANS RISC Committee(Consensus Group)

Nuclear Risk Management Coordinating Committee

Standards Interface Subcommittee

Standards Planning Subcommittee

Standards Development

Subcommittee *

Executive Committee

ANS Risk-Informed Standards

Consensus (RISC) Committee

ASME Committee on Nuclear Risk

Management (CNRM)

Joint ANS RISC Committee/

ASME CNRM

For a standard consensus group, the box color indicates the SDO that will ballot and govern the balloting process.For other groups, the box color indicates the SDO that will govern the group’s process.SDO = Standard Development Organization

CONCEPT 5 CNRM ORGANIZATION STRUCTURE:September 24, 2008

Indicates a non-consensus body comprised of both ANS RISC and ASME CNRM members.

* Includes ability to vote on recommendations to

be made to the main Consensus committees.

ASME Board on Nuclear Codes and Standards

ANS Standards Board

Standards Maintenance

Subcommittee *

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ASME CNRM and ANS RISC Committee Members(Consensus Group)





Subcommittee *

Executive Committee




Management (CNRM)


ASME CNRM







ANS Standards Board


Subcommittee *

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ASME CNRM(Consensus Group)

ANS RISC Committee(Consensus Group)





Subcommittee *

Executive Committee




Management (CNRM)


ASME CNRM







ANS Standards Board

Advanced Non-LWR

Writing Group

Advanced LWR

Writing Group

Level 2 Writing Group


LPSD Writing Group


Subcommittee *

“Future”Working Group

Combined Standard Working Group


External Events

Working Group

Inquiries Process Working Group

“Future”Writing Group

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Charter/Purpose:

This S/C will provide an active interface with other Standards groups that are developing or implementing risk-informed or risk related standards.

Supporting Information:

A representative from each interfacing Standards group will be a member of this S/C. The intent is that this identical S/C will be part of the organization structure of ASME XI, ASME III and possibly other Standards groups.

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Charter/Purpose:

To identify, consider and make recommendations to the CNRM regarding the need for new risk management standards or modifications to existing standards and to develop and manage the CNRM Strategic Plan.


The Chairmen of the other CNRM S/C’s will be members of this S/C along with other members whose expertise is required to support the Standards Planning S/C charter. This committee will include both ASME CNRM and ANS RISC members.

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Standards Development Subcommittee

Advanced Non-LWR Writing

Group

Advanced LWR Writing

Group



LPSD Writing Group

Charter/Purpose:

This S/C is responsible for developing new Risk Management Standards that are deemed necessary to support nuclear industry needs.


Standards “Writing Groups” will be added to this S/C as required to provide the technical expertise required to develop new Standards. Once revision 0 of a Standard has been issued, the Writing Group will move to the Maintenance S/C and become a Working Group.

“Future”Writing Group

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Charter/Purpose:

This S/C has responsibility for maintaining existing standards, e.g., the initial “Combined” PRA Standard, and making recommendations to the Main Committee regarding inquiries and interpretations.


The standards maintenance Working Groups will report to this S/C. Additional Working Groups will be added as new Standards are developed in the future.

Standards Maintenance Subcommittee *

“Future”Standards

Working Group

Combined Standard

Working Group


External Events Working Group

Inquiries Process Working Group

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How do the functions of the current CNRM structure translate to the concept 1 structure?• The functions of Subcommittees, Working Groups, Writing Groups

and Task Teams– That relate to the development of new standards would become

part of the “Standards Development” S/C.• WG on Advanced LWR (CNRM)• WG on Non-LWR Plants (CNRM)• Level 2 Writing Group (RISC)• Level 3 Writing Group ((RISC)• LPSD Writing Group (RISC)

– That relate to the maintenance of existing standards including inquiries would become part of the “Standards Maintenance”S/C.

• S/C on Applications (CNRM)• S/C on Technology (CNRM) [except those functions that

relate to working on new standards]

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How do the functions of the current CNRM structure translate to the concept 1 structure?

continued• The functions of all Subcommittees, Working Groups, Writing

Groups, Task Teams that relate to the planning of activities for new standards or changes to existing Standards would become part of the “Standards Planning” S/C.

• S/C on Standards Planning (CNRM) [except those functions that relate to working on new Standards]

• The function of the existing “CNRM Executive Committee” will expand to include making recommendations pertinent to the ANS RISC

• The proposed “Standards Interface Committee” is a new function

Status Report on Working Group for Qualitative vs. Quantitative PRA Methods

Charter:Recommend a framework by which qualitative standards and quantitative methods can beaddressed in future ASME and ANS PRA standards so that these standards can supportrisk informed decision making.

Definitions:PRA The ANS Glossary is being revised and the proposed definition for PRA (there was

not one in the past) is, “Probabilistic risk assessment (PRA) technology provides aquantitative assessment of nuclear power plant accident risk. Models delineate the[note that some words are missing here in the text of the draft glossary, possibly theword “operation”] of systems and operators response to accident initiatingevents. Additional models identify component failure modes required to cause theaccident mitigating systems failure. Nuclear power plant PRA data analysis estimatesthe parameters used to determine the frequencies and probabilities of the variousevents modeled in PRA. (ANSI/ANS 53.1-200x Draft)” This definition expresses theopinion that the results need to be quantitative but does not exclude qualitativemethods to arrive at the quantitative result. As a personal note, I am not real happywith the reference to ANS-53.1, but that is another story.

The IAEA glossary defines PSA asprobabilistic safety assessment (PSA): A comprehensive, structured approach toidentifying failure scenarios, constituting a conceptual and mathematical tool forderiving numerical estimates of risk.

IAEA Requirements document Safety of Nuclear Power Plants: Design, NS-R-1, is thebase design document for nuclear power plants sort of like ANS-51.1 is for PWRs,ANS-52.1 is for BWRs, and ANS-53.1 is for HTGRs. This IAEA document in section5.73 identifies a mixed bag of elements for probabilistic safety analysis (PSA andwhat we call PRA) to be carried out in order:1. to provide a systematic analysis to give confidence that the design will comply

with the general safety objectives;2. to demonstrate that a balanced design has been achieved such that no particular

feature or postulated initiating event (PIE) makes a disproportionately large orsignificantly uncertain contribution to the overall risk, and that the first two levelsof defense in depth bear the primary burden of ensuring nuclear safety;

3. to provide confidence that small deviations in plant parameters that could giverise to severely abnormal plant behavior (‘cliff edge effects’) will be prevented

4. to provide assessments of the probabilities of occurrence of severe core damagestates and assessments of the risks of major off-site releases necessitating a shortterm off-site response, particularly for releases associated with early containmentfailure;

5. to provide assessments of the probabilities of occurrence and the consequences ofexternal hazards, in particular those unique to the plant site;

6. to identify systems for which design improvements or modifications tooperational procedures could reduce the probabilities of severe accidents ormitigate their consequences;

7. to assess the adequacy of plant emergency procedures; and8. to verify compliance with probabilistic targets, if set.

ASME standardprobabilistic risk assessment (PRA): a qualitative and quantitative assessment ofthe risk associated with plant operation and maintenance that is measured in termsof frequency of occurrence of risk metrics, such as core damage or a radioactivematerial release and its effects on the health of the public (also referred to as aprobabilistic safety assessment, PSA).

RiskRisk is generally accepted as a formulation of the product of likelihood (probability) andconsequences.

Risk InformedI have found no clear definition of “risk informed.” The NRC in Regulatory Guide 1.174states that PRA quality needs to be “commensurate with the application for which it isintended and the role the PRA results play in the integrated decision process.” Itappears that to the NRC, the key to understanding what is sufficient in terms ofqualitative vs. quantitative PRA technology lies in the nature of the application. Inaddition, conventional language would suggest that “risk informed” would be anydecision where the conclusion of the decision is “informed” not necessarily “basedentirely” on information that comes from a “risk” study. Thus “risk informed can befrom qualitative or quantitative sources and the NRC has allows both.

Status of Qualitative Methods in Standards:If I understand the situation correctly, here is the score on quantitative and qualitativestandards to date: Full Power Internal Events: ASME is a quantitative standard and more qualitative

methods e.g., IPE, are not recognized in the standard or used by the industry. External Events: The standard deals with all external events, but the focus in on

seismic. SMA takes a prominent role in the standard but there is a caveat that requiresenhancements (provided in Appendix D) to allow SMA to play that role.

Fire: The standard contains a non-mandatory appendix discussion on FIVE but doesnot recognize its use.

LP/SD: This standard is in draft; however, the decision was made by ANS RISC toallow the use of qualitative methods in the standard as a screening method todetermine if further quantitative analysis is needed. This decision will not be revisitedas part of this Working Group effort.

Potential Roles for Qualitative Methods:1. Use qualitative methods as analysis tools equivalent with quantitative methods when

the need for technical adequacy of quantitative methods is not required or supported

by data. The NRC Policy Statement of 1995 on uses of PRA states, “The use of PRAtechnology should be increased in all regulatory matters to the extent supported bythe state-of-the-art in PRA methods and data and in a manner that complements theNRC's deterministic approach and supports the NRC's traditional defense-in-depthphilosophy.”

An example of this approach is found in ANS-58.21, Section 3.1 which states,“Although both seismic PRA and SMA are intended to support risk-informedapplications, the distinction between them regarding their applicability to develop riskinsights needs to be clearly understood. The SMA is a deterministic methodology,and in this context, a well executed SMA can provide qualitative, and limited, riskinsights that could be used to support an intended application. However, for situationswhere detailed quantitative risk insights are necessary, a seismic PRA is needed. Thestandard in the same section recognizes that, “The scope of a seismic marginassessment (SMA) covered by this standard is limited to analyzing nuclear powerplant seismic capacities according to either the so-called Electric Power ResearchInstitute (EPRI) Method (“EPRI Method”) or the so-called U.S. Nuclear RegulatoryCommission (NRC) Method (“NRC Method”).” This is justified when the riskcontributor (seismic in this case) is judged to be low for the existing design and site.

2. Use qualitative methods as screening tools to judge if risk is significant enough torequire further evaluation with more quantitative means. This approach is anextension of screening techniques already employed in quantitative risk assessments.

The difference between 1 and 2 is that role 1 means that you already have a judgment thatrisk is low and the qualitative tool is sufficient to gain risk insights. Role 2 is employedwhen the qualitative tool can do an adequate job of screening risk at a low enough levelthat quantitative means are not needed. Also quantitative approaches may be difficultwhere uncertainties a large and difficult to quantify.

Notice that fire qualitative methods do not qualify for either of these roles. There is noengineering judgment that says fire risk is sufficiently low for a design or a site that it canbe treated qualitatively. Also the FIVE tool can not be raised to the adequacy of the morequantitative tool (let me withhold my own judgment on the quantitative tool’sinadequacies). The industry (with some pressure from the NRC and NFP-805) has prettymuch concluded that fire PRAs are needed as testified to by the wave (tsunami?) of thembeing done.

Conclusions:The Use of Qualitative Tools in the Combined StandardThe purpose of the combined standard is to combine the existing standards withoutchanging any technical elements or judgments. Thus, the combined standard needs toincorporate the qualitative methods already in the individual standards into its text.

The Use of Qualitative Tools in the Future Integrated Standard

Roles 1 and 2 appear to be appropriate for incorporation of qualitative tools in to PRAstandards. At some time in the future, having gained experience with the combinedstandard and resolved some technical integration problems, an integrated standard will beproduced. This standard may include other risk contributes such as fires duringshutdown. It is my judgment that the two roles identified above will be just as valid inthe future as they are today. For role 1, there is no need to expend needless resourcesusing a more demanding tool if the lesser tool gives an adequate assessment for thechallenge. For role 2, there is no need to automatically conduct extensive analysis whena screening assessment excludes a challenge as being a significant contributor to risk.

Thus qualitative is a special case of quantitative; a first step in any quantitative PRA thatis done right. For a qualitative analysis to be the basis for risk-informing, it should be thebest that one can reasonably do, in term of likelihoods and consequences. It shouldrecognized dependencies to the extent possible and it should give a clear statement ofuncertainties in both likelihoods and consequences, even if these are presented in terms ofqualitative descriptors or linguistic variables (e.g. H, M, L).

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ANS RISC Committee

November, 2008

John Gaertner

G. S. Hardy

ANS SPRA Standard

Pilot Application at Surry

2© 2008 Electric Power Research Institute, Inc. All rights reserved.

Pilot Project of ANS Seismic PRA Standard

• Original Industry Concerns with Standard vs CurrentPilot Project Tasks

– Overall Seismic PRA (SPRA)

• Effort and concurrence onCapability Cat 2 requirements

– Seismic Hazard Requirementsand Review

– Plant Logic ModelDevelopment

– Seismic Fragility Derivation

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Overall SPRA Approach Per ANS Standard

• Original Comments on Overall ANS Standard Approach fromIndustry

– The Standard is written with some ambiguity so that conformance witheach capability category is uncertain

• One goal of the Pilot project is to provide further guidance onhow to conform to the capability category II

– Cost of robust SPRA (per Standard) may not be reasonable

• At the completion of the pilot, betterinsights on the required costswill be available

Condenser Expansion Joints


Seismic Hazard Use in SPRA

• Original Seismic Hazard Issue from Industry

– NRC and Standard pushing toward requiringdevelopment of new seismic hazard forUS NPPs unless clear case can be made that existing hazard isaccurate or conservative

– Conservative extrapolation of hazard curves at high g levels

– Seismic hazard still in research mode

• Four different interpretations for the Charleston Seismic SourceZone were presented at the 2006 USGS CEUS workshop

• Current Pilot Plant Status on Seismic Hazard

– New seismic hazards have been conducted for New NPP sites

– EPRI has conducted new hazard estimates for CEUS existingNPP locations that can be used for Capability Category II SPRAstudies (such as the Pilot for Surry)

– This generic seismic hazard issue is less problematic now

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Plant Logic Model

• Existing Surry SPRA Plant Logic Model

– Very small number of components in existing model due toscreening of components (surrogate elements utilized)

• Surry Pilot Review

– Plant logic model being increased to improve accurace and sinceformer screening criteria not valid due to increased seismichazard

– Updating model to reflect plant changes since original IPEEEstudy


Seismic Fragility Challenges for Pilot Plant

• Non-conservative screening criteria (due to lower hazard) usedfor existing SPRA

– New component screening have been conducted

• Existing seismic response no longer valid for new hazard

– New probabilistic response being conducted for 2 buildings andscaling of response being conducted for remaining buildings

– Significant costs in this area, scaling accuracybeing studied as part of this Pilot

• Full relay chatter evaluations not conducted forexisting SPRA

– Pilot project reviewing options tocost-effectively include relays into theSPRA (systems and fragility screening)

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Pilot Seismic PRA by ANS Standard Tasks

• Task 1 - Review of Current Surry PRA and Comparisonto ANS Standard Capability Category II Criteria-- Completed

• Task 2 – Seismic Hazard Development, Plant LogicDevelopment and Seismic Fragility Development– Seismic Hazard and Site Response Completed

– Probabilistic Structural Response – Aux Bldg Completed

– Surry Site Walk down Completed

• Task 3 – Integration of Seismic Hazard and SeismicFragility and Generation of Final Project Report


Surry ANS SPRA Pilot Schedule

Task Description Completion DatePlant Seismic Logic Model Update SSEL – October 2008

Finalize Plant Logic Model – February 2009

Seismic Fragilities Seismic Response Aux Building – July 2008Seismic Response Control / ServiceBuilding – September 2008Scaling for Other Buildings – Dec 2009Seismic Fragilities – May 2009

Risk Quantification, FinalReport

Quantification – August 2009Final Report – October 2009

EPRI plans to conduct an industry workshop afterAugust 2009 to review final evaluation and

insights on SPRA Standard application

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Project Responsibilities

ANS Std. PilotPlant Task

EPRI Task Dominion Task

Review Surry Material X Provide Material (being done)

Comparison to ANS Std. CCII

X Review

Seismic Hazard X Review

In-Structure Spectra X Review

Seismic Fragilities Secondary Primary

Plant Logic Development X X

Quantification Review X

Final Project Report X Input to Report, Review

Status of Level 2 StandardWriting Group Activities

John Lehner for Mark Leonard

Nov. 12, 2008

Status

• This update is mainly based on notes fromthe WG meeting in Knoxville, TN ofSeptember 8, 2008– Attended by Mark Leonard and three other

WG members

• The WG members reviewed the seconddraft of the Standard. Severalobservations were made and questionswere raised for WG consideration

Observations

• Standard needs a glossary to definesubjective terms, such as “accurate,”“precise,” “validated,” “realistic,” etc.

• Supporting requirements in several sectionsare too vague.– Often appears to be a result of trying to

accommodate (or not show a preference for)different analysis tools or styles.

– Approach should be to write the requirements inan “if-then-else” style and be more specific aboutwhat is expected.

Observations

• The Standard should include requirementsfor the proper treatment of uncertainties ina Level 2 PSA.

– Subsequent discussion

• Compatibility with NUREG -1855, will try toincorporate similar guidance into the Level 2Standard.

• This will be a principal topic for the WG to reviewand debate in the next draft.

Questions for WGConsideration

• How should general QA be handled?– Section 4.2 of the ASME Standard appears to provide

only vague guidance.– No other requirements for QA appear to be offered.– Mark Leonard will discuss this question with members

of past Standard writing committees to understandhow QA requirements have been addressed in otherStandards.

• Should the Level 2 Standard encourage a fully-linked Level 1 – 2 logic model?– For example, should an event logic model (CET,

APET, etc.) require direct accounting ofdependencies (e.g., via linked fault trees) for Cap.Category III.

– This has implications for the Level 1-2 interface

Priority areas for next draft

• Section on deterministic analysis (accidentprogression and source term analysis)remains empty

• Section on Containment performance isstill in outline form

• Section on source term and releasecategory development retains old structurefrom previous draft and needs to beupdated

Next Steps

• The goal is to generate an updated complete draftby the end of the calendar year.

• When DRAFT-3 is distributed, all WG memberswill be free to edit and add to the entire Standard.– Individual mark-ups of the entire Standard will be then

be collected and distributed to the entire WG.– A WG meeting will then be scheduled to collect all

mark-ups and discuss their resolution as a group.• This meeting will be extremely important as it will be the first

time the WG can discuss the entire draft Standard together.

– Mark Leonard will notify the WG when and where areview meeting can be arranged.

Other Issues

NRC participation:

• Don Helton (RES/DRA/PRAB) has beenassigned to the Level 2 WG.– He is aware of the Level 2 status and he has

reviewed the current (Knoxville) draft.

– He recently (October 28-29, 2008) attended ameeting of an EU group in the very earlystages of putting together Level 2 BestPractice Guidelines, and provided a tripreport.

Report on ASAMPSA2

• Advanced Safety Assessment Methodologies:Level 2 Probabilistic Safety Assessment(ASAMPSA2) End User Workshop, Hamburg,Germany, October 28-29, 2008

• Primarily EU member countries but reached outinternationally via OECD WGRISK

• Group sent out extensive questionnaire (40 pages)– NRC did not answer questionnaire, but indicated

interest in group’s activities

• Workshop attended by 28 individuals from 20organizations

Report on ASAMPSA2

• The workshop organizers expressedinterest in interacting with those involvedin the ANS Level 2 Standard WorkingGroup. The organizers see a great deal ofoverlap between their activity and theStandard development activity.Specifically, it was suggested thatrepresentatives from the two groups meetin approximately one year’s time tocompare developments.

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MEETINGS

• 2nd Full Meeting held at MIT during Boston ANS June 2007

• 3rd Full Meeting Held During ANS Winter Meeting In Washington DC

• 4th Full Meeting Held in Anaheim During ANS Annual Meeting June 11, 2008

• 5th Partial Attendance Meeting Scheduled for Reno Winter ANS Meeting November 12th, 2008

MEMBERSHIP

• All Subject Areas in the Consequence Standard are Well Represented

• Well Rounded Group—Having Trouble Completing Draft Writing Assignments

• More than Half Have Expressed Concern about Funding to Attend Meetings

• About 40% of Group Will Attend Meeting in Reno 2008

• Lost One Member and Added Two More Including Mr. Bexon from UK and Sarah Chisholm from Duke Power

pschroeder

Text Box

ANS-58.25, Level 3 PRA Standard Presentation

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WORKING GROUP ASSIGNMENTS

• Overview---(Woodard*, O’Kula, Levinson, Mitchell)• Level 1/2 Interface--- (Paul/Chisholm*, Leaver)• Probabilistic Framework/Uncertainty ---(Johnson*,

Brewer, Levinson)• Site/Plant Input Data---(Teagarden)• Dispersion---(Woodard)• Dosimetry---(O’Kula)• Health Effects---(Mubayi)• Economic Factors (Mubayi)• Reporting of Results, Quantification (Teagarden)• Models (Codes), Example Cases----(Bixler*,Teagarden,

Mitchell)* Indicates Lead Author

EXPENSE COMPENSATION ISSUES• We Are Continuing to Have About 50%

Representation Meetings. There Have Been Conflicts With Other ANS Meetings on Wednesdays. Continue to think Wednesdays are Best

• Some Employers Have Agreed to Fund WG Members’Participation. We Have Been Able to Justify Attendance by Scheduling During ANS Meetings

• If We Had Travel Expense Allowances Meetings Could be Scheduled at Different Times & Venues Without Distraction of ANS Activities

• Had Planned to Have 4 Day Meeting at ANS Headquarters But Scrubbed Due to Expense Funding Issues

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PROGRESS• Our 4th Meeting in Anaheim was Helpful. Those in

Attendance Contributed in All Areas and Some were able to Participate via Conference Call.

• We are Still Struggling With Use of the “Capability Category” Approach as Applied to the Level 3 Standard

• Outlines Assigned Are Still About 75% Complete—But Most are Primitive and Need a Lot of Work

• Meeting Our Draft Writing Assignment Deadlines Needs Improvement!

• Additional Drafts of Deficient Sections Are Due Before the 5th Meeting in Reno. Little Progress has Been Made Since Anaheim

SCHEDULE

• It is Unlikely that we Will Have a Properly Formatted First Draft Complete by June 2009 as I Had Targeted at the Last RISC Meeting in Anaheim

• We Hope to Have a Reasonable Draft After a 4-Day Session at ANS Headquarters. This Will Most Likely Not Take Place Until We Have Funding.

• At this Point the Schedule Will Have to Remain Uncertain

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LPSD PRA Standard Status Report SLIDE 1KLK 11/5/2008

Low Power & Shutdown PRA Methodology Standard

Writing Group ANS-58.22

STATUS REPORTRISC Meeting – Reno, Nevada

November 12, 2008


LPSD WRITING GROUP

Current Membership– Don Wakefield – chair – Dennis Bley, Bob Budnitz, Bill Burchill, Jeff Julius,

Yehia Khalil, Bill Stillwell, Rupert Weston (Ken Kiper)

– Augmented WG for Qualitative Standard: Steve Hess, Leo Shanley, Bryan Carroll, Doug Hance

– Jeff Mitman now Officially NRC Representative.

pschroeder

Text Box

ANS-58.22 LPSD Presentation

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STATUS

Comments Received on 2008 Re-ballotBallot Status

» 7 APPROVED (including 3 with comments)» 9 NOT APPROVED» 2 Other (not returned)

RISC / Public Comments» More than 600 Comments Received» >200 Directed Specifically at Individual Requirements» Ballotters identified 45 Significant Comments for

Discussion» Additional Comments by RISC?


Need to Affirm Past RISC Directives

That RISC Desires to Move Forward NowMove Forward Now with Stand Alone LPSD StandardQLRA&QRA to be Combined in One StandardFull External Events, except Internal FiresSR’s to Reference ASME Standard for Internal Events and ANS for External EventsNeither a Guidance Document nor Pilot Application are required before standard issuanceOutage specific Requirements to be includedMetrics Other than CDF/LERF Should be Permitted for Both QRA/QLRA

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LPSD WG Recommendations on RISC Directives

Move Forward Now on Stand Alone Standard (agreed) This is a key!This is a key!QLRA & QRA to be Combined in One Standard (agreed)Full External Events (i.e. Hazard Groups), except Internal Fires(agreed)SR’s to Reference Combined Standard, Addendum ANeither a Guidance Document nor Pilot Application are Required (agreed, but a pilot would be welcome)Outage specific Requirements to be Included as Appendix (agreed)Metrics Other than CDF/LERF Are Permitted but User Must Formulate Applicable Requirements (agreed)


Compatibility Issues with Combined Standard as Stand-Alone LPSD Standard

While primarily editorial, involves a lot of work!Should LPSD Standard Repeat Introductory Sections for Stand alone LPSD Document?Where Place POS Requirements?Where Place Outage Specific RequirementsWhere Place QLRA sections and What Operating Modes Covered?Permission to Copy Combined Standard Text?

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Draft Outline for Revised LPSD Standard (I)


Draft Outline for Revised LPSD Standard (II)

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Draft Outline for Revised LPSD Standard (III)


Path Forward (LPSD Base Recommendation)

Task an Informed Editor to Modify Existing Requirements into Combined Standard Format and NumberingEnhance WG Participants:

(Combined Standard Representative, Plant Operations/ Outage Planning, Young engineer)Clarify Comments With AuthorsInitiate Work on Shared Sections of Combined Standard and LPSD; e.g. Definitions.Face-to-Face WG Meeting Needed for Technical Comment Resolution (February, 2009)Expected Revision for Ballot - November 2009

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Path Forward - Options

Faster Track Schedule:– Fund the activity, Initially for Technical Editor– Separate Some Elements into Separate Ballots

» External Events» QLRA

Defer Revision Until Pilot or Guidance Document Available


Sampling Of Other Significant Comments

Need for SR’s for Human-Induced InitiatorsIncorporation of Maintenance Conditions in POS definitionsRedefinition of Capability Categories for QLRARequirements for Evaluation of Future Shutdown ConfigurationsPolicy Regarding Requirements and Feasibility of Methods Weakly TestedBetter Focus Introduction Section

Notes from LPSD Writing Group Conference Call, October 16, 2008

WG members and guests participating in conference calli. Don Wakefield

ii. Bob Budnitziii. Bill Stillwelliv. Leo Shanleyv. Jeff Mitman

vi. Rupert Westonvii. Bill Stillwell

viii. Ken Kiper

1. The purpose of this call was to prepare for the next RISC meeting, to be held in Renoon November 12, 2008, by discussing the current status of the LPSD standard alongwith plans for going forward.

2. It was the sense of the writing group that we should ask RISC to reaffirm several ofthe WG working assumptions and directives previously approved in light of the mostrecent LPSD standard ballot comments and negative results. Many of the commentsreceived directly challenged the directives previously agreed to. Among these are:a. That the qualitative portion of the standard (QLRA) does represent a PRA and

should be combined with the quantitative requirements (QRA) in one standard.b. That the standard should include a full treatment of external events excepting that

for internal fires. The fire PRA standard is now much further along. RISC maynow wish to consider inclusion of requirements for internal fires in the LPSDstandard.

c. That the LPSD supporting requirements should reference (rather than includeverbatim) the existing ASME standard for internal events and the ANS standardfor external events as appropriate.

d. That a LPSD guidance document is useful and encouraged but not a prerequisitefor issuance of the LPSD standard, and not a commitment by ANS to develop one.

e. That an outage specific (as opposed to time-averaged risk assessment) set of QRArequirements be included within the standard.

f. That a pilot application of a draft version of the standard was not a prerequisitebefore issuance of the initial LPSD standard. It was noted that initial issuance wasno guarantee of NRC acceptance and that regarding the clock start time on therequirements for a LPSD PRA within one year after the availability of anapproved standard, it does not really begin until endorsement of the standard bythe NRC. The opinion was expressed that a pilot could be performed after ballotapproval and that results from the pilot then could be fed back in to a first revision.

g. That metrics other than CDF and LERF be permitted (e.g. time to boiling) but tonote that the user may have to develop and justify equivalent supporting

requirements as appropriate. It is assumed that this directive applies to both QRAand QLRA approaches.

3. It was the sense of the WG that going forward the correct thing to do was to revise theLPSD standard as a “drop-in” to the most recent RISC/CNRM combined standard,addendum A. Changes reflected in future versions of the combined standard wouldonly be accommodated in the second version of the LPSD standard. It wasrecognized that the combined standard, addendum A was not yet available and is stillundergoing revisions. RISC needs to help make this product available to the WG.Such an approach requires that issues related to the combined standard outline andcommon or shared sections between at-power and LPSD be worked out. Some of theissues identified are:a. Should the LPSD standard repeat the shared introductory sections (e.g. definitions,

application process) of the combined standard except as needed to be marked upfor applicability to LPSD? Should material not germane to LPSD be deletedbecause the initial LPSD standard will be a stand alone document?

b. Place for POS requirements (section 4.4) in the combined standard outline?c. Place for outage specific configuration requirements (3.7) in the combined

standard outline?d. Place for QLRA in the combined standard outline?e. The Shutdown Standard refers to the internal events standard a lot more than the

fire standard. There should be a consistent and agreed upon format for referring tosupporting requirements (SRs) as opposed to repeating them word for word, aswell as modifying SRs.

f. Does ANS have permission from ASME to repeat words from the combinedstandard in the initial ANS LPSD standard?

4. To begin revising the LPSD standard it was believed that first an informed editorshould be tasked to modify the existing standard requirements, just balloted, into theformat and numbering consistent with the combined standard, addendum A. Asappropriate the members of the LPSD WG would be consulted to respond toquestions when this process is not straightforward. In parallel to this effort, the WGwould work on the common sections of the combined standard to adopt them for usewith the LPSD standard. The intention would be to complete these two tasks byFebruary, 2009; i.e. prior to a face-to-face meeting of the LPSD WG. The LPSD WGchairman believes that at least one face-to face meeting of the WG is needed to jumpstart resolution of the technical comments. Funding for expenses of such a meeting isrequired.

5. Need for coordination with combined standard WG representative knowledgeable inintegration issues for at least the shared sections of the LPSD standard. Due to issuesidentified above, these may not all be straight-forward. At the same time, the WG

chairman plans to reassign the LPSD QRA sections so that each section has a primaryauthor and a second for review and technical concurrence.

6. LPSD WG members questioned the desire of a consensus of RISC members tocomplete the LPSD standard at this time. Partly this was based on opinions expressedvia balloter comments that portions of the LPSD PRA methodology are not mature,that some of the supporting requirements are not feasible, or that they are open-ended.The believed concern is that this would leave analysts in a situation similar to thatnow found in performing fire PRAs. Identifying currently available LPSD PRAS forcomparison against the draft standards was suggested as one way to ameliorate theseconcerns. It was judged that waiting for a LPSD PRA guidance document to beapproved would likely add another two years to the current goal for issuance of theLPSD standard; i.e. by December 2009.

7. This point was not discussed at length, but is offered by the chair as an issue commonto requirements for which many difficult to resolve comments were received. Theissue of methodology advancements, feasibility, or open-endedness of a requirementis not explicitly addressed in the ASME combined standard. Rather, capabilitycategories are defined and graded requirements are offered for different attributes of:1) scope of level of detail, 2) plant-specificity, and 3) realism. Of these only the thirdattribute (realism) appears to be relevant. The distinction between capabilitycategories I, II, and III is determined by whether the departures from realism have amoderate, small, or negligible effect on the conclusions and risk insights. Thisapproach allows much judgment by the author of the requirements and is possiblymuch of the basis for concern by a number of balloters when the requirement mayentail substantial resources. It would be useful to have a policy regardingrequirements which while feasible and more rigorous than existing methods, mightnot meet the criteria for impacting conclusions and risk insights for the capabilitycategories assigned. One such policy might be:. “All requirements must be "feasible"as determined by the WG. Only those analyses routinely performed in past studies orfound to be important by plant experience events should be resolved by requirementsin cat. II. Those requirements judged to be desired but not tested in previous studiesand not demonstrated to be significant by plant experience events should only beconsidered as CAT. III.” The policy should address how the author of therequirements should address the assessment of impact on the conclusions and riskinsights when assigning the requirements for each category..

8. There was some discussion of the current and anticipated regulatory requirements forLPSD PRA as drivers for the development of the LPSD PRA standard. Several pointswere raised. Jeff Mitman agreed to summarize these items for review by the WG andRISC. Among the possible applications for LPSD PRAs are for new plant licensing,significant determination process, LCOs, maintenance rule, and other risk-informedapplications.

9. Previously RISC voted to combine the QLRA and QRA requirements into a singlestandard. The consensus was that this issue should be revisited now that the ballot hasbeen completed. The LPSD WG offered the following thoughts:a. The QLRA and QRA sections will have to be separated for inclusion in the

combined standard. Question is whether it should be performed now or later.b. It is believed likely that approval for QRA and QLRA requirements by NRC

would be enhanced by separating them.c. RISC should consider whether (like seismic margins methodology), ASME wishes

to include QLRA in the combined standard.d. The QLRA is written for shutdown conditions. NRC notes that the methods are

also applicable to at-power conditions. RISC may wish to consider rewriting theQLRA requirements to make them applicable for all modes, including for at-power configuration management.

e. From the most recent ballot, the number of comments on the QLRA requirementswas noticeably less than for the QRA requirements. This suggests that byseparating the QLRA from the QRA requirements, it may eventually be approvedfaster than if combined with the QRA.

f. The availability of a guidance document for QLRA during shutdown conditionsmay help with a speedier approval.

g. On the other hand, it is noted that the QLRA sections did not get as thorough areview by the most impacted stakeholders (NRC and plant operations staffresponsible for outage planning), and so more comments might be expected in thenext ballot.

10. Actions:a. Don Wakefield is to prepare a summary of the conference call and distribute it to

the WG members. The intent is to capture a sense of the WG member’s views andto identify issues or considerations of a path forward for the LPSD standard inpreparation for the RISC meeting.

b. After some discussion by the group as a whole, Jeff Mitman agreed to summarizeexisting and anticipated regulatory requirements for a LPSD standard.

11. Schedule – The WG scheduled another conference call two weeks hence. A note willbe sent out confirming the call time, tentatively planned for October 30, 2008 at 3:30pm eastern time (12:30 pm west coast time).

Notes from LPSD Writing Group Conference Call, October 30, 2008

WG members and guests participating in the conference calli. Don Wakefield

ii. Bob Budnitziii. Leo Shanleyiv. Jeff Mitmanv. Rupert Weston

vi. Ken Kipervii. Doug Hance

viii. Jeff Julius

Absent were Dennis Bley, Yehia Khalil, Bill Stillwell, Bill Burchill.

1. The purpose of this call was to prepare for the next RISC meeting, to be held inReno on November 12, 2008, by discussing the current status of the LPSDstandard along with plans for going forward.

2. The WG participants spent most of this conference call discussing the draftslides to be presented to RISC next month in Reno. This was a usefulmechanism for focusing the discussion, because all of the key issues are on theslides. Key comments on the draft slides were as follows:a. We should remove as a WG suggestion that the QLRA be separated from the

QRA standard requirements for ballot. The rationale was that this wouldprovoke endless discussion at the RISC meeting. It was expressed that oneor the other of the QLRA or QRA might be held up by the other, laggingportion, if they continued to be balloted together. Another opinion was thatthey needed to be kept together for fear of the QLRA standard beingdropped. It seemed the consensus that the two should be developed inparallel anyway and that they could be separated for ballot at a later date ascircumstances dictate. One suggestion was to put the issue in a later slide, orto bring it up only if the RISC raised it.

b. There was general agreement that we should say we are targeting a newversion for ballot at the time of the RISC meeting in November 2009. TheLPSD WG would have cycled back to the commenters prior to this time.While our actual target could be as soon as June, there was generalagreement that this was optimistic as a commitment to RISC and theavailability of funding and other circumstances would impact the schedule.

c. One suggestion was to include a slide that would express the WG’ssuggestions for proceeding on a faster track. Suggestions offered were to

split the two parts focusing on QLRA or QRA, whichever could garnerfunding. A second suggestion was to drop external events, but this did notgather much support. A third suggestion was to fund a technical editor toget us started transferring to the combined standard, addendum A format.

d. A wording suggestion was made to change or add “hazard groups” towherever the phrase “external events” is used in the slides (in keeping withcombined standard terminology).

e. For metrics other than CDF/LERF we should rephrase the WG suggestion tosay additional metrics are permitted but would require applicablerequirements be formulated.

f. It was agreed that limiting the QLRA to modes 3-6 was not a RISC directiveand should be stricken from the slide 4.

g. We should reaffirm that the LPSD standard in its next balloted form is stillto be considered a stand alone document.

h. A suggestion was made that the group should meet with a subset of theprolific commenters to try and expedite the process. After some discussionit seemed the consensus was instead to try and do that by phone initially inadvance a of a face to face meeting to make sure the comments areunderstood and then again to contact them after consensus was arrived at bythe LPSD WG.

i. It was agreed that a face-face meeting of the LPSD WG in San Diegoadjacent to the February 25-27 ASME CNRM meeting (say, just before it)would be reasonable.

j. It seemed a consensus that the chairman should challenge the RISCmembers who said they had run out of steam commenting on the most recentdraft to provide any additional comments by the end of January, 2009.Particularly, any comments whose incorporation might otherwise changetheir next vote should be offered now.

k. The path forward should emphasize what we believe are the critical elementsfor our path forward strategy; i.e. NRC rep. and combined standard rep.

l. It was suggested that we line up the RISC affirmation points on the slideswith the LPSD WG suggestions for each point listed.

m. It was agreed that the phrasing for a pilot application or guidance documentwould be changed to say it is not required before issuance of the initialLPSD standard.

3. Selected key comments from the recent ballot were also discusseda. Human-induced initiators need more requirements – it was noted that the

HRA section covered both pre-initiator and post-initiator but not the cause ofthe initiator. The consensus seemed to be that for LPSD we should add ahigh level requirement for such an investigation even though the initiator

requirements also address this point. The treatment of dependencies betweenthe initiator and response actions was of concern by the commenters.

b. Maintenance conditions in POS definitions – There was some confusion asto whether the requirements insisted on maintenance conditions being a partof the POS definition or restricted them from not being so. The responsewas that they need not be but that nothing prevented them from being part ofthe definition. This approach allows users the flexibility to separate a POSinto two parts solely because the protected train changes, if desired.

c. Redefinition of capability categories as three capability indices – There wasconfusion among commenters on why these indices were introduced. TheWG subcommittee for QLRA maintains that they should be given a differentname because they are not exactly the same as capability categories; i.e. the3 attributes have been partially redefined and only one application isexpected from such shutdown models. It was conceded that a differentnumber of indices (than 3) may be warranted. Three capability indices wereapparently chosen to represent the different states of existing QLRA practiceand advancements expected in the future.

d. Some discussion was also made on the subject of whether QLRA for at-power conditions was warranted. Some believed that such methods werebeing used for a small number of plants, generally in a blended approachwith QRA evaluations.

4. Jeff Mitman completed his assignment regarding a summary of the regulatorydocuments driving the need for the LPSD standard. This was sent to all WGmembers.

5. A draft outline of the LPSD standard revised to be aligned to the outline of thecombine standard (addendum A) is provided as a table below. Tentativewriting group assignments are also identified. The outline will be added to thepresentation slides for RISC.

6. Actions:a. Don Wakefield is to revise the presentation for RISC in accordance with the

WG’s consensus points detailed above.b. All LPSD WG are encouraged to attend the RISC Reno meeting on

November 12th, 2008. Ken Kiper agreed to forward the call-in numbers forthose who cannot attend.

7. Schedule – The Chair will schedule the next conference call following the RISCReno meeting.

List of Writing Group Leads for LPSD Standard Sections

New section # Old Section # Title LEAD from Writing Group Second/ Backup

20.1 1 Introduction Don Wakefield Doug Hance

20.2 2 Acronyms & Definitions Ken Kiper Doug Hance

20.3 3 Application Process Bob Budnitz Don Wakefield

20.4 4.1 – 4.3 Technical Requirements Ken Kiper Bill Stillwell

21 4.4 POS Analysis Jeff Julius Ken Kiper

22.1 New Overview of Internal Events Don Wakefield “NRC Rep”

22.2.1 4.5.1 Initiating Event Don Wakefield “NRC Rep”

22.2.2 4.5.2 Accident Sequence Analysis Bill Stillwell Leo Shanley

22.2.3 4.5.3 Success Criteria Bill Stillwell “NRC Rep”

22.2.4 4.5.4. Systems Analysis Bill Stillwell Leo Shanley

22.2.5 4.5.5 HRA Dennis Bley Jeff Julius

22.2.6 4.5.6 Data Dennis Bley Bill Stillwell

Move to 23 4.5.7 Internal Flooding Yehia Khalil Bob Budnitz

22.2.7 4.5.8 Quantification Don Wakefield Jeff Julius

22.2.8 4.5.9 LERF Analysis Bob Budnitz Don Wakefield

23 Internal Flooding

24 Internal Fires

25 Seismic

26 Screening/

4.6 External Events Bob Budnitz “NRC Rep”

Conservative analysis

27 High Winds

28 External Flooding

29 Other Externals

Move to 1.5 5 LPSD Quantitative PRAConfiguration Control

Don Wakefield Ken Kiper

Move to 1.6, and withineach hazard group

6 LPSD Quantitative PRA PeerReview

Don Wakefield Ken Kiper

30 7 Shutdown Qualitative RiskAssessment

Leo Shanley/ Doug Hance “NRC Rep”

Move to each majorsection

8 References - -

App. A App. A POS Methodology for LPSDQuantitative PRA

Jeff Julius Doug Hance

App. B App. B Risk Metric CalculationMethodology

Don Wakefield Bill Stillwell

App. C App. C POS Analysis Methodology forShutdown QLRA

Doug Hance Jeff Julius

App. D App. D Technical Basis for ShutdownQLRA Methodology

Doug Hance Leo Shanley

App. E formerly 3.7 Requirements for Plant specificOutage Assessments

Don Wakefield Bob Budnitz

10-CFR-50.65 Requirements for monitoring the effectiveness ofmaintenance at nuclear power plants

The requirements of this section are applicable during all conditions of plant operation,including normal shutdown operations.

(4) Before performing maintenance activities (including but not limited to surveillance,post-maintenance testing, and corrective and preventive maintenance), the licensee shallassess and manage the increase in risk that may result from the proposed maintenanceactivities. The scope of the assessment may be limited to structures, systems, andcomponents that a risk-informed evaluation process has shown to be significant to publichealth and safety.

10-CFR-50.69 Risk-informed categorization and treatment of structures,systems and components for nuclear power reactors

(ii) A description of the measures taken to assure that the quality and level of detail of thesystematic processes that evaluate the plant for internal and external events during normaloperation, low power, and shutdown (including the plant-specific probabilistic riskassessment (PRA), margins-type approaches, or other systematic evaluation techniquesused to evaluate severe accident vulnerabilities) are adequate for the categorization ofSSCs.

10-CFR-50.71 - Maintenance of records, making of reports

(h)(1) No later than the scheduled date for initial loading of fuel, each holder of acombined license under subpart C (Subpart C—Combined Licenses) of 10 CFR part 52shall develop a level 1 and a level 2 probabilistic risk assessment (PRA). The PRA mustcover those initiating events and modes for which NRC-endorsed consensus standards onPRA exist one year prior to the scheduled date for initial loading of fuel.

(2) Each holder of a combined license shall maintain and upgrade the PRA required byparagraph (h)(1) of this section. The upgraded PRA must cover initiating events andmodes of operation contained in NRC-endorsed consensus standards on PRA in effectone year prior to each required upgrade. The PRA must be upgraded every four yearsuntil the permanent cessation of operations under § 52.110(a) of this chapter.

(3) Each holder of a combined license shall, no later than the date on which the licenseesubmits an application for a renewed license, upgrade the PRA required by paragraph(h)(1) of this section to cover all modes and all initiating events.

"Safety goals for the operations of nuclear power plants; PolicyStatement," Federal Register, Vol. 51, p. 30028 (51 FR 30028), August 4,1986

"Use of probabilistic risk assessment methods in nuclear activities: Finalpolicy statement," Federal Register, Vol. 60, p. 42622 (60 FR 42622), August16, 1995

SECY-04-0118, “Plan for the implementation of the commission’s phasedapproach to probabilistic risk assessment quality,” July 13, 2004.

The term PRA quality has been interpreted in different ways by different stakeholders,resulting in some confusion and misunderstanding. In this plan, PRA quality is defined asin Regulatory Guide (RG) 1.174 and RG 1.200 as having three aspects: the scope of riskcontributors addressed (full power, low power and shutdown modes of operation, internalinitiating events, and external initiating events), the level of detail, and the technicaladequacy of the model. Inherent in this definition is that a PRA of sufficient quality tosupport an application need only have the scope and level of detail sufficient to supportthat application, but it must always be technically adequate.

The plan covers the first three phases defined in the SRM, and identifies the activitiesrequired to support implementation. As directed by the SRM, the feasibility of the fourthphase will be assessed following achievement of Phase 3. The phases are achieved forspecific risk-informed activities when guidance documents are available to support thoseactivities, and in particular to address the issue of the quality of PRA necessary to supportthe activities. Phase 1 represents the current situation, where guidance on PRA quality isgeneral, and staff review of the base PRA supporting the activity is performed on a case-by-case basis. Phase 2 takes advantage of the work that has been performed to developPRA standards. Phase 2 occurs when there are PRA standards and the associatedregulatory guides in place to address those PRA scope items that are significant to thedecision. To be in Phase 2 for an application, the licensee's submittal is expected to be inconformance with the published standards. The PRA standards are being developed ondifferent schedules. As a result, the risk-informed activities will transition to Phase 2 ondifferent schedules according to which scope items are significant to the decision. Table3.3 of the plan provides the schedule for implementation of Phase 2 as a function of PRAscope. Phase 3 provides a regulatory framework for the development of a PRA that willbe of sufficient quality to support all current and anticipated applications. Phase 3 will becompleted by December 31, 2008.

SECY-01-0218, “Risk-informed regulation implementation plan,” SECY-00-0213, October 16, 2000; updated December 5, 2001

The Commission's 1995 PRA policy statement provides guidance on risk-informing itsregulatory activities. The Commission stated its vision that "the use of PRA technologyshould 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 deterministicapproach and supports the NRC's traditional defense-in-depth philosophy." The RIRIPdescribes the staff's plans to achieve that vision by applying criteria to select regulatoryrequirements and practices, risk-informing those requirements and practices, anddeveloping the necessary data, methods, guidance, and training. Thus, the RIRIP

integrates the agency's risk-informing activities. This plan is also intended to explain theagency's activities, philosophy, and approach to risk-informed regulatory policy tointernal and external stakeholders. The challenge in developing the RIRIP was to specifystaff activities that are both necessary and sufficient to implement the strategies describedin the NRC's strategic plan.

NUREG-0800, "Use of probabilistic risk assessment in plant-specific, risk-informed decisionmaking: General Guidance," Revision 1 of Chapter 19 ofthe Standard Review Plan, June 2002.

Regulatory Guide 1.174 - An approach for using probabilistic riskassessment in risk-informed decisions on plant-specific changes to thelicensing basis

The NRC continues to support ongoing initiatives to develop industry PRA standards andexpects to endorse PRA standards that are suitable for regulatory decisionmaking asdescribed in this regulatory guide. Other standards for external events (e.g., seismicevents) and low power and shutdown conditions are under development.5 In the interim,the NRC staff is continuing to evaluate PRAs submitted in support of specificapplications using the guidelines given in Section 2.2.3 and Section 2.5 of this regulatoryguide, Chapter 19 of the Standard Review Plan (Ref. 3), and the information in SECY-00-0162 (Ref. 10), which defines minimum technical attributes for a technicallyacceptable PRA. In addition, the references and bibliography

[There is additional extensive discussion of shutdown risk in this RG.]

Regulatory Guide 1.175, "An approach for plant-specific, risk-informeddecisionmaking: Inservice testing," August 1998.

Regulatory Guide 1.176, "An approach for plant-specific, risk-informeddecisionmaking: Graded quality assurance," August 1998.

Regulatory Guide 1.177,"An approach for plant-specific, risk-informeddecisionmaking: Technical specifications," August 1998.

For changes to TS requirements defined for the power operation mode, the scope ofanalysis should include internal fires and flooding if appropriate (e.g., when the subjectTS equipment is located in areas identified as vulnerable to fires or floods). Whenchanges to requirements for systems needed for decay heat removal are considered, anappropriate assessment of shutdown risk should also be considered. Examples of suchsystems are auxiliary feedwater, residual heat removal, emergency diesel generator, andservice water. Also, when AOTs are being modified to facilitate online maintenance (thatis, transferring scheduled preventive maintenance (PM) from shutdown to poweroperation), the impact on the shutdown modes should also be evaluated. When available,using both power operation and shutdown models, a comparative evaluation may be

presented to decide the appropriate condition for scheduling maintenance based on riskevaluations. In some cases, a semi-quantitative analysis of shutdown risk may beadequate (e.g., fault tree analysis or failure modes and effects analysis).

Regulatory Guide 1.178, "An Approach for plant-specific, risk-informeddecisionmaking: Inservice inspection of piping," September 1998.

2.2 Probabilistic Risk Assessment

In accordance with the Commission’s Policy Statement on PRA, the risk-informedapplication process is intended not only to support reduction in the number ofinspections, but also to identify areas where increased resources should be allocated toenhance safety. Therefore, an acceptable RI-ISI process should not focus exclusively onareas in which reduced inspection could be justified. This section addresses ISI-specificconsiderations in the PRA to support relaxation of inspections, enhancement ofinspections, and validation of component operability.

ASME has published a PRA standard that addresses a Level 1 and limited Level 2 PRAfor fullpower operation for internal events (excluding internal fire) (ASME RA-S-2002).Other standards for external events (i.e., seismic, wind and flood), low power andshutdown conditions and internal fires are under development by ANS.

The NRC staff is currently developing a regulatory guide to provide guidance to licenseeson determining the technical adequacy of a PRA used in a risk-informed integrateddecision making process, and to endorse standards and industry guidance (see DraftRegulatory Guide DG-1122). The NRC staff is continuing to evaluate PRAs submitted insupport of specific applications using the guidelines given in Section 2.2.3 and Section2.5 of Regulatory Guide 1.174 and in SRP Chapter 19 of the Standard Review Plan.

LPSD ReBallot Significant Comments

Mary Drouin

1) Some of the SRs, particularly in Section 4.5.9, have been revised with respectto the corresponding ASME/ANS joint standard SRs, for reasons that havenothing to do with LPSD specific features. It is not clear whether this changewas intentional or perhaps because the LPSD standard is referencing an earlierversion of the at-power standard. If intentional, there is no basis for the change.If unintentional, the joint standard is further justified to ensure thesediscrepancies do not occur. In either case, it has resulted in two different SRs forthe same issue.

2) Section 4.6, External Events, is written in such a way that it would beextremely difficult to use. There is no parallelism to the way in which externalevents are treated in the ASME/ANS joint standard. Some major differences are:

• A new set of technical elements has been defined. While there issome logic, they are different from the ones in the external eventspart of the at-power standard (or ANS 58.21-2007). Correspondingly,there are new high level requirements (HLRs) that differ from those inthe external events part of the at-power standard (or ANS 58.21).

• The way the requirements are linked back to the external event HLRsand corresponding supporting requirements (SRs) is convoluted andwould be difficult to use. For example, EXT-D2 contains “The relevantpart (emphasis added) of the Requirements under "HLR-ANA-C, SystemsAnalysis and Quantification" in Section 3.5.4 of the ANS Standard.Furthermore, the commentary states: “This includes both the relevantpart of the HLR labeled HLR-ANA-C and the relevant part of thetechnical SR ANA-C1.” In addition, there is not any guidance as towhat constitutes a “relevant part.”

• In light of the above, this part of the standard looks more like aplan for how to develop requirements than the requirements themselves.

• The index numbering is confusing, because HLR-EXT-A through Dalready exist in the joint standard (and in ANS 58.21) where they arerelated to Screening. Consequently, there are different HLRs and SRswith the same index number across the standards.

3) The risk from LPSD operation is significantly affected by human performance.The section of the standard addressing human reliability analysis is deficient inthat it does not address those human failures that take place during plantevolutions that may result in initiating events. Such human failure events,although are not addressed in the ASME/ANS joint standard for at-power

conditions, which addresses only pre-initiator and post-initiator human failureevents, need to be addressed in LPSD.

4) Section 1.2.2.3: The discussion on the evaluation of core damage frequency(CDF) by summing the contributions from individual plant operating states(POSs), Section 1.2.2.3, is incorrect. It does not take into account that asignificant contribution may come from the number of evolutions rather than thetime spent in a POS. The definitions of terms such as core damage frequency,conditional core damage frequency, conditional core damage probability, andinstantaneous core damage frequency in this subsection and appendix B areconfusing. This issue affects the whole standard. The core damage frequencyof a POS should be defined as the frequency that core damage occurs when theplant is in the POS, with the fraction of the year that the plant is in the POSincluded in the definition. This way, the CDFs of different POSs are additive, andthe discussions on adding conditional core damage probabilities becomeunnecessary. All the definitions should be included in section 2 and notscattered.

5) There is the need for a standard for configuration risk management duringshutdown conditions; that is, a qualitative risk assessment (QLRA). However,such a standard is not a standard for a PRA. The two have very differentobjectives. For the former, the objective is to provide requirements for how tocontrol and manage risk during LPSD. For the latter, the objective is to providerequirements for quantifying the potential risk of the plant during LPSD, that is,requirements for a PRA. By definition, a PRA is a probabilistic (i.e., quantitative)assessment of some defined risk. Since it is probabilistic, the assessment resultsin a numerical measure of the defined risk. It is not a qualitative assessment,since a qualitative assessment does not provide a probabilistic (or numerical)value of the risk. However, because a PRA is a probabilistic/quantitativeassessment, it does not preclude using qualitative screening to limit what isprobabilistically or quantitatively assessed (e.g., screening initiating events, plantdamage states, components). As stated in the objective of the Level 1 at-powerstandard, it is a standard that (1) sets forth the requirements for PRAs, and (2)prescribes a method for applying these PRA requirements for specificapplications, which is the same objective for the LPSD standard. However, theQLRA is outside the scope of that objective. It is a standard for configuration riskmanagement, which is very different than providing requirements for a LPSDPRA, or prescribing a method for applying the PRA requirements. While there isa need for a configuration risk management standard, it needs to be in aseparate standard, and not be confused with a standard for a PRA.

Dave Finnicum

1) Section 4.5: The references to the SRs in the combined standard do notprovide any indication of the breakdown of Capability Categories for the

referenced SRs. The lead-in in Section 4.5 needs to clearly state that theCapability Categories for each SR referencing an SR in the combined standardshall be based on the combined standard SR breakdowns.

2) Table 4.4-2 and Table 4.4-3: POS-A4 and POS-B5 require that the analystsreview “known” plans for Future outages. It is clearly stated that this is notapplicable to outage specific models so is only applicable to the average model.This basically requires prognostication which should not be part of any standard.The outage planning cycle begins as soon as the current outage is complete butwould only be complete to the point that the plan would be sufficiently developedto support these requirements about 6 months prior to the outage. This isequivalent to requiring that the LPSD PRA be performed during a specific timewindow. I recommend either deleting these two requirements or changing themto CC-III only requirements.

3) Section 1.3.2.4: The list of power operating states does not provide a goodclean differentiation between the states. It is particularly important to differentiatebetween full power and low power because the analyst would need to look at twodifferent standards to determine what has to be done. Also, the differentiationbetween hot standby and hot shutdown is somewhat nebulous. In fact, inreading the description of hot shutdown, it seems like there are two differentstates there, not one. It is very important to get a good definition of thedifferences between full power operation and low power operation because theat-power internal events standard and the LPSD standard are intended to covermutually exclusive but all encompassing operating states.

John Gaertner

1) Many elements of LPSD PRA drive the answer to be very conservative –many POSs vs one POS for at power PRA: grouping of POSs; use of non-mechanistic combinations; treatment of maintenance configurations; HRA withless training, procedures and experience than at power; huge number ofscenarios for flood, fire and external events, long times for recovery that aredifficult to credit. These problems will inevitably result in very large calculatedCDF and LERF frequencies. There must be some caution and control in theapplications section to prevent improper use of the quantified risk result and theendless use of resources to reduce the calculated risk result. Emphasis shouldbe on use of the PRA for choosing among planning options, for identifying HREs,and for risk management activities which do not rely directly on the calculatedvalue of the quantified risk.

2) Page 47, 4.5.1 and Table 4.5.1-4: Define what is meant by a “procedural ET”.Also, AS-A1 requires user to account for changing conditions within a POS; e.g.,RCIC becomes available. This is very confusing because I don’t understand howto change success criteria within a POS. Why isn’t that a new POS? This is one

of many situations in the standard where the lack of real applications or “howto” guidance on LPSD PRA leads to confusion.

3) Page 39, 4.4 and Table 4.4 - 4, POS C2: Use of the “highest frequency” ofsubsumed POSs doesn’t always make sense and isn’t always conservative. Ifthe POSs are mutually exclusive, then the requirement makes sense. It is betterto require that the analyst determine an “enveloping” frequency.

4) Page 33, 4.4 and Table 4.4-3, POS-B2: POS grouping requires combining allworst case conditions even if it is impossible to happen. Such unrealisticscenarios are not desirable in PRA and should not be required. It is better torequire a “worst case scenario” to represent the grouping. It is still conservative,but realistic insights can be gleaned, and there is some control over the level ofnon-realism and on the quantitative conservatism.

Dennis Henneke

1) The Shutdown Standard refers to the internal events standard a lot more thanthe fire standard, and there should be a consistent and agreed upon format forreferring to SRs, as well as modifying SRs. I made a number of commentsrelated to this, but a number of the comments would be addressed if RISCprovides some guidance on this, considering what has already occurred with theFire Section of the ASME standard.

2) Would be great to talk about "referenced SRs." For the Fire Standard,we had an issue at the Diablo Pilot with how to address and peer reviewreferenced SRs. We have had to spend a lot of time rewriting some of theSRs in order to make the process work, as well as modify NEI 07-12 towork with the standard.

Gene Hughes

1) Section 1.3.2.2 Defense in Depth and 1.3.2.3 Defense in Depth Metrics areshallow and inaccurate. The phrase "The concept of Defense in Depth providedthe safety margin and risk management capabilities successfully in those earlyyears, in the absence of technologies and capabilities to perform current state ofthe art risk modeling and simulation" is wrong. This section should be removedor rewritten. DID follows the Farmer suggestion that more frequent events havemore stringent criteria, a concept at the heart of safety analysis and licensingcriteria, and a concept not addressed yet by PRA that focuses only on CDF.PRA does a fine job of checking and measuring, for sure, but it is not asubstitute or a replacement for DID. The DID concept and implementationshould never be referred to in the past tense. Consider the importance oftransient criteria (DNBR), the necessity for air cleanup systems for routine

releases, and the significance of Equipment Qualification and QA in the defensein depth formulation for just a few. They are also important underpinnings of PRAas practiced today.

2) The quantitative analysis of LPSD risk follows a natural progression fromidentification of the possible initiators and sequences to the selection of the moreprobable and the more consequential. We use screening, pruning, subsuming,evaluation of precursor states like onset of boiling, and the like to shape ananalysis appropriately. The legitimate and necessary elimination of small ornegligible contributors from a fully quantitative PRA of LPSD is essential to theefficient analysis of this risk contributor. Literally hundreds of states at LPSD arepossible with little or no significance. The important contributors need thoroughanalysis.

This is not clear in the standard draft. For example, Table 4.5.1-2 says "Theinitiating event analysis shall provide a reasonably complete identification ofinitiating events for all identified POSs, internal events, and external events.(HLR-IE-A).” This needs to be restated to support screening and subsuming.

Likewise, POS-A1 should include the ability to prune non-contributorsat the outset.

Use of precurser end-sates to CDF should be endorsed to trim and focusthe analysis of LPSD CDF.

Ken Kiper

1) From Page 10, 1.1, last paragraph: This paragraph identifies “benchmarking ofqualitative methods against quantitative methods” as a Capability Index 3element. Benchmarking with quantitative shutdown PRA results is fundamental toestablishing adequate levels of defense in depth. Qualititative methods areeffective at judging relative risk, but this application requires absolute risk, i.e., isthe risk low enough to be acceptable. That can only be determined byquantitative PRA methods. Recommendation: establish three levels ofbenchmarking to align with the 3 indeces, as follows:

Index 1: provide benchmarking of qualitative results againstquantitative results from an appropriate generic shutdown model.

Index 2: provide benchmarking of qualitative results againstquantitative results from a plant specific shutdown model for thosePOSs with lowest thermal margin.

Index 3: provide benchmarking of qualitative results againstquantitative results from a plant specific shutdown model for allPOSs.

Stanley Levinson

1) The concept of introducing "Capability Indices" for the QLRA seemsunnecessary and confusing. The description of the Capability Index perfectlyparallels that of the Capability Category. Adding the new term (and concept?)does not seems to provide any benefit in understanding or the use of theStandard.

2) The juxtaposition of low power/shutdown issues with external events is atechnology area in which the industry has little or no experience. While thewriting group was following the dictates of the RISC, the work required forexternal events for each POS (see comment about increasing POSs orconservative POSs) become substantial (in cost and resources), possibly withoutthe necessary risk insights.

3) There is a general concern that it is possible to define many more POSs thanwould be warranted obtain risk insights from a LP/SD PRA model.

4) Many of the SRs discuss "changing plant configuration" within a plantoperating state (POS). Dealing with a changing configuration creates modelingcomplexities. A POS, by its definition, should not have changing configurations.This would mean splitting into more POSs. The amount of effort required foreach POS is already substantial, creating more POS adds that the burden,without necessarily resulting in any commensurate risk insights. POSs are alsoto be "constructed" with conservative "states" (even if they are physicallyimpossible) - this may lead to the combination of conservatisms that could havean impact on the realism (and usability) of the results, similar to what hasoccurred with the application of NUREG/CR-6850 for Fire PRAs.

5) Many of the SRs require the analyst to consider "future configurations." Thisis a requirement that can not be met, as this could require the identified of anunbounded set of configurations. The analysis (time-averaged) needs to beperformed based on the historical experience of the plant. If there are futureconfigurations that were not considered in the original analysis, thenthe PRA should be revised. These SRs are next-to-impossible to meet, whichwould also create an untenable burden on a peer reviewer. See, for example,POS-A4, POS- B5, POS-C1, POS-C4, and AS-B3. (This is not intended to be anexhaustivelist.)

6) The inclusion of requirements dealing with both time-average risk results andconfiguration specific risk results is confusing and seemingly at cross purposes.The Standard should be an application-neutral set of requirements that can beapplied when an application is identified. The attempt to identify configuration-specific SRs is an application-specific exercise. The configuration-specificrequirements do not parallel the approach used in an at-power PRA (where therecan be many different specific maintenance configurations). It seems thatperforming a peer review of the configuration-specific analysis would be difficult.

The Standard makes many references to the Maintenance Rule (10 CFR 50.69(a)(4)), which is also a specific application (e.g., second paragraph of Section1.1). See the discussion in Section 3.7.

Jon Young

1) Page 113, Table 7.4.4-2, ES-A6: There is no explicit risk related bases, eitherlikelihood or consequence related, provided for defining the integrated effects ofmultiple safety function end states.

2) There is no formal assessment and evaluation of the impact of potentialcommon cause failures, even though they may be identified in the systemsanalysis. There is no way to rank them in some order of significance relative toloss of safety function.

3) There needs to be a measure of relative likelihood introduced into thestandard. This could be based on a qualitative assessment of POS and HRElikelihood; and system unavailability using likelihood bins or similar approach oreven a likelihood assessment for each POS.

4) First and foremost, there is an absence of explicit or implied relative likelihoodof the HRE that challenge the plant and result in the various end state conditions.Without any information as to this likelihood, the end state definitions andsystem analysis do not contain sufficient information to result in a “risk” measure.Using a “criticality” measure, see Table 1.3.2.3-1, for safety function degradationsupported by qualitative descriptions of HRE and system unavailability, even withcalculations of time frames for system availability still does not provide a relativeor absolute assessment of risk because of the absence of a likelihood index ormeasure.

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