ML083400366

Extended Power Uprate Acceptance Review Questions on Probabilistic Risk Assessment Issues

ML083400366
Person / Time
Site:	Monticello
Issue date:	12/02/2008
From:	Tam P Plant Licensing Branch III
To:	Blake T, Loeffler R, Salamon G, Weinkam E Xcel Energy
Tam P
References
TAC MD9990
Download: ML083400366 (3)

Text

Accession No. ML083400366 From: Peter Tam Sent: Tuesday, December 02, 2008 8:45 AM To: Salamon, Gabor; Ed Weinkam (edward.weinkam@xenuclear.com); Loeffler, Richard A.; Blake, Tim M.

Cc: Andrew Howe

Subject:

Monticello - Acceptance review questions by the PRA Branch Gabe:

This is regarding your 11/5/08 application for extended power uprate. Our PRA Branch is identifying information required by RS-001 (which NSPM states its submittal is conforming to) which our reviewer, Andrew Howe, cannot locate in the 11/5/08 submittal. We hope that the information is in fact in the submittal and your people can quickly identify its location. If not, then you should follow LIC-109 and promptly submit the missing information:

1. RS-001, Attachment 1 to Matrix 13, Section 3.1, requires the licensee to address the impacts of extended power uprate (EPU) on component and system reliability and response times. Enclosure 15 Section 4.1.5 of the license amendment request (LAR) addresses the reliability impacts, but does not identify impacts on response times.

2. RS-001, Attachment 1 to Matrix 13, Section 3.1, requires the licensee to address the potential impacts of EPU on the probabilistic risk assessment (PRA) results from other areas that either are affected by the uprate or are being implemented in parallel with the uprate. Specifically, RS-001 identifies potential risk impacts from changes to maintenance practices or approaches, turbine trip setpoints, condensate/feedwater modifications or operational changes, main transformer modifications, and increased fuel burnup. Enclosure 8 of the LAR identified main transformer replacement, and Enclosure 4 identified increased fuel burnup, as being implemented in parallel with EPU. Enclosure 15 identifies potential changes in some turbine trip setpoint parameters, and increased feedwater flow. However, the LAR does not address potential risk impacts from these and the other identified changes.

3. RS-001, Attachment 1 to Matrix 13, Section 3.1, requires the licensee to justify the applicability of the generic and/or plant-specific data used to derive initiating event frequencies. Enclosure 15 states that there is no direct significant impact for general transients without any justification.

4. RS-001, Attachment 1 to Matrix 13, Section 3.1, requires the licensee to describe how they ensure that the PRA adequately models the as-built, as-operated plant, and that the analyses supporting the EPU adequately reflects how the plant will be operated and configured for EPU conditions. Enclosure 15, Section 1.4 of the LAR identifies an assumption that the plant and procedure changes identified represent the as-built, as-operated post-EPU plant, but there is no discussion of how this is assured in the PRA model. Appendix C further states that the PRA is routinely updated, but does not confirm that the current model (identified as a 2005 version) used to support the analyses of this LAR is up-to-date and adequately reflects the planned configuration of the plant post-EPU.

5. RS-001, Attachment 1 to Matrix 13, Section 3.1, requires the licensee to specifically address vulnerabilities, weaknesses, or review findings identified in the Individual Plant Examination (IPE), the staff or contractor evaluation reports on the IPE, and(or) and

independent/industry peer review findings, that could impact the PRA results and conclusions. It further requires the licensee to present the overall findings of the peer review (by element) and to discuss low rated elements, and any findings and observations that could potentially impact the licensees proposed EPU. Enclosure 15, Appendix C of the LAR discusses the peer review findings, but does not address the other IPE reviews, nor is the overall results of the peer review discussed as required. Further, subsequent recent assessments of the PRA model against the internal events standard are identified, but there is no discussion of the results of such assessments, or the disposition of any findings from those assessments.

6. RS-001, Attachment 1 to Matrix 13, Section 3.1, requires the licensee to address modifications or improvements credited in the IPE/PRA but not yet implemented by specifically indicating if the improvements have been implemented in accordance with the assumptions and conditions identified in the IPE/PRA. Enclosure 15 Section 2 of the LAR simply states that all IPE commitments have been resolved.

7. RS-001, Attachment 1 to Matrix 13, Section 3.1, requires the licensee to address plant modifications which are not completely finalized as to their potential risk impact. Enclosure 15 Section 3.3.1 of the LAR identifies that the AC distribution system modifications are not finalized, and that risk will be assessed as part of the modification process, which is inconsistent with the requirement to identify how the risk analyses of the LAR are bounding.

8. RS-001, Attachment 1 to Matrix 13, Section 3.2, requires the licensee to specifically address vulnerabilities, outliers, anomalies, or weaknesses, or review findings identified in the Individual Plant Examination of External Events (IPEEE), the staff or contractor evaluation reports on the IPEEE, and(or) and independent/industry peer review findings, that could impact the risk results and conclusions. This is not addressed in the submittal. A review of the staff review report of the IPEEE identified additional analyses and potential plant changes, identified by the licensee in its IPEEE submittal, which were under consideration but not yet implemented.

9. RS-001, Attachment 1 to Matrix 13, Section 3.3, requires the licensee to describe the plants shutdown risk management philosophies, processes, and controls relied upon to ensure that the risk impacts of EPU on shutdown operations is not significant. It also requires the licensee to address shutdown risk impacts of longer times to shutdown. Enclosure 15, Section 4.6 of the LAR does not provide this information.

I propose that we hold a conference call for your people to explain how we can access the above described information. Alternatively, if you can easily point to the information in the submittal, you are welcome to simply reply by e-mail. In either case, timely action on your part is crucial in order for the staff to complete its acceptance review within the schedule imposed by LIC-109. Thanks.

Peter S. Tam, Senior Project Manager (Project Manager for Duane Arnold, Kewaunee, and Monticello)

Plant Licensing Branch 3-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Tel. 301-415-1451

E-mail Properties Mail Envelope Properties ()

Subject:

Monticello - Acceptance review questions by the PRA Branch Sent Date: 12/02/2008 8:29:20 AM Received Date: 12/02/2008 8:44:00 AM From: Peter Tam Created By: Peter.Tam@nrc.gov Recipients:

Gabor.Salamon@xenuclear.com (Salamon, Gabor)

Tracking Status: None edward.weinkam@xenuclear.com (Ed Weinkam (edward.weinkam@xenuclear.com))

Tracking Status: None Richard.Loeffler@xenuclear.com (Loeffler, Richard A.)

Tracking Status: None Tim.Blake@xenuclear.com (Blake, Tim M.)

Tracking Status: None Andrew.Howe@nrc.gov (Andrew Howe)

Tracking Status: None Post Office:

Files Size Date & Time MESSAGE 22438 12/02/2008 Options Expiration Date:

Priority: olImportanceNormal ReplyRequested: False Return Notification: False Sensitivity: olNormal Recipients received: