ML18223A005

Updated Proposed License Condition Regarding License Amendment Request to Adopt 10 CFR 50.69 Risk-Informed Categorization and Treatment of Structures, Systems, and Components

ML18223A005
Person / Time
Site:	Palo Verde
Issue date:	08/10/2018
From:	Lacal M Arizona Public Service Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
102-07765-MLL/MDD
Download: ML18223A005 (4)

Text

10 CFR 50.69 10 CFR 50.90 MARIA L. LACAL Senior Vice President Nuclear Regulatory and Oversight Palo Verde Nuclear Generating Station P.O. Box 52034 102-07765-MLL/MDD Phoenix, AZ 85072 August 10, 2018 Mail Station 7605 Tel 623.393.6491 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Reference:

Arizona Public Service Company (APS) Letter 102-07690, APS Response to Request for Additional Information for License Amendment Request to Adopt 10 CFR 50.69 Risk-Informed Categorization and Treatment of Structures, Systems, and Components, dated May 9, 2018, ADAMS No. ML18129A448

Subject:

Palo Verde Nuclear Generating Station Units 1, 2, and 3 Docket Nos. STN 50-528, 50-529, and 50-530 Updated Proposed License Condition Regarding License Amendment Request to Adopt 10 CFR 50.69 Risk-Informed Categorization and Treatment of Structures, Systems, and Components On July 19, 2017, APS submitted a license amendment request (LAR) to adopt Title 10 of the Code of Federal Regulations (10 CFR) Section 50.69, Risk-Informed Categorization and Treatment Of Structures, Systems, and Components for Nuclear Power Reactors. During the week of February 20, 2018, the NRC staff conducted an audit at the Palo Verde Nuclear Generating Station (PVNGS) to gain an understanding of the risk-informed categorization process and to review the probabilistic risk assessment models that will be used by APS for this risk-informed LAR. The NRC staff determined that additional information was required to complete their review. The APS response to the Request for Additional Information (RAI) was provided by the referenced letter.

Subsequently, the NRC staff requested a clarification call with APS that was held on August 8, 2018. During the call, the NRC noted that it would be appropriate for APS to provide an update to the proposed license condition. Specifically, the license condition should itemize, in greater detail, the probabilistic risk assessment models used to perform 10 CFR 50.69 evaluations. The enclosure to this letter includes the entire license condition that supports the license amendment request.

APS has reviewed the information supporting a finding of no significant hazards consideration that was provided to the NRC. The information provided in this letter does not affect the basis for concluding that the proposed license amendment does not involve a significant hazards consideration under the standards set forth in 10 CFR 50.92.

A member of the STARS Alliance Callaway Diablo Canyon Palo Verde Wolf Creek

Enclosure Updated Proposed License Condition

Enclosure Additional Condition Operating License No. NPF-41, NPF-51, and NPF-74 APS proposes the following license condition be added to Appendix D of the PVNGS Units 1, 2, & 3 Renewed Operating Licenses:

Amendment Additional Condition Implementation Number Date APS is approved to implement 10 CFR 50.69 using the processes for categorization of Risk-Informed Safety Class (RISC)-1, RISC-2, RISC-3, and RISC-4 structures, systems, and components (SSCs) using: Probabilistic Risk Assessment (PRA) models to evaluate risk associated with internal events, internal flooding, internal fire, and seismic; the shutdown safety assessment process to assess shutdown risk; the Arkansas Nuclear One, Unit 2 (ANO-2) passive categorization method to assess passive component risk for Class 2 and Class 3 SSCs and their associated supports; and the results of non-PRA evaluations that are based on a screening of other external hazards using the external hazard screening significance process identified in ASME/ANS PRA Standard RA-Sa-2009; as specified in license amendment [NUMBER] dated

[DATE].

Prior NRC approval, under 10 CFR 50.90, is required for a change to the categorization process specified above (e.g.,

change from a seismic margins approach to a seismic probabilistic risk assessment approach).

[NUMBER] APS will complete the implementation items listed in the Prior to implementation of Enclosure of APS letter 102-07546, dated July 19, 2017, to 10 CFR 50.69.

the NRC and in Attachment 1, Table 1-1 of APS letter 102-07690, dated May 8, 2018, prior to implementation of 10 CFR 50.69. All issues identified in the enclosure will be addressed and any associated changes will be made, focused scope peer reviews will be performed on changes that are PRA upgrades as defined in the PRA standard (ASME/ANS RA-Sa-2009, as endorsed by RG 1.200, Revision 2), and any findings will be resolved and reflected in the PRA of record prior to implementation of the 10 CFR 50.69 categorization process.