ML111880954

Request for Additional Information, Adoption of TSTF-425, Rev. 3, Relocate Surveillance Frequencies to Licensee Control - Risk Informed Technical Specification Task Force (RITSTF) Initiative 5b (TAC ME6010-ME6012)

ML111880954
Person / Time
Site:	Palo Verde
Issue date:	07/07/2011
From:	Lauren Gibson Plant Licensing Branch IV
To:	Stroud R Arizona Public Service Co
Gibson, Lauren, NRR/DORL/LPL4, 415-1056
Shared Package
ML111880937	List: ML111880948 ML111880954
References
TAC ME6010, TAC ME6011, TAC ME6012
Download: ML111880954 (2)

Text

DRAFT REQUEST FOR ADDITIONAL INFORMATION LICENSE AMENDMENT REQUEST TO ADOPT TECHNICAL SPECIFICATIONS TASK FORCE TRAVELLER TSTF-425, REVISION 3, TO RELOCATE SPECIFIC SURVEILLANCE FREQUENCIES TO A LICENSEE CONTROLLED PROGRAM PALO VERDE NUCLEAR GENERATING STATION (PVNGS) UNITS 1, 2, AND 3 DOCKET NO. 50-528, 50-529, AND 50-530 ARIZONA PUBLIC SERVICE COMPANY By letter dated March 31, 2011 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML11103A053) Arizona Public Service Company (the licensee),

submitted a license amendment request (LAR) to relocate certain surveillance frequencies to a licensee-controlled program (the Surveillance Frequency Control Program, SFCP) in accordance with Technical Specification Task Force (TSTF) Traveler 425, Relocate Surveillance Frequencies to Licensee Control-- RITSTF (Risk Informed Technical Specification Task Force) Initiative 5b, Revision (Agencywide Documents Access and Management System (ADAMS) Accession No. ML090850642).

The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the information provided by the licensee and determined that the following additional information is needed to complete the review:

1. In Section 6 of Attachment 2 to the submittal it is stated that PVNGS will follow the Nuclear Energy Institute (NEI) 04-10 guidance to assess the fire and seismic risk associated with Surveillance Test Interval (STI) changes. However, the statement does not include other external events (e.g., high winds, external floods, transportation, nearby facility accidents) in the statement. Please clarify if Palo Verde Nuclear Generating Station (PVNGS) intends to follow NEI 04-10 guidance to assess risk associated with these types of other external events as well. If not, what methodology would be used?

2. The scope of risk assessments may need to include shutdown, using NEI 04-10 guidance for STI changes. What shutdown risk method would be used for the analyses?

3. As noted in the submittal, identifying plant changes that have been incorporated at the site, but are not yet in the PRA model and justifying why the changes do not impact the PRA results used to support the amendment request is one aspect of the technical adequacy of the PVNGS PRA model used to support risk-informed applications. Please discuss PVNGSs approach to assessing plant changes not yet incorporated into the PRA model for this application.

Enclosure

4. The peer review found that the Category II requirement for SY-A4, given in Table 2, RG 1.200 Category II Supporting Requirements Not Met Evaluation, was not met since walkdowns and interviews either were not conducted or not documented. It is not clear that walkdowns have been performed to confirm that the systems analysis correctly reflects the as-built, as-operated plant. As a specific example, the peer review observation in Table 1, Open CEOG Internal Event PRA Peer Review F&Os, for SY-03, sub-element SY-3, discusses observations from a walkdown performed for the Auxiliary Feedwater System, for which no specific evaluation is provided. More generally, the evaluation for the SY-A4 peer review finding does not explicitly mention that walkdowns were performed.

Please clarify if walkdowns have been conducted but not yet documented. If this is not the case, please provide justification as to why walkdowns are not necessary for this application or how the intent of the Supporting Requirement is met for this application.

Also, specifically, please evaluate the importance of the peer review observations for SY-03, sub-element SY-3 for this application.

5. The peer review also noted for SY-C1 in Table 2 that system studies have not been updated for several revisions of the model. The PVNGS evaluation of the peer review finding for SY-C1 Category II requirement apparently does not rely on the documentation of theses system studies. While this is a documentation-related finding, it is not clear what impact out-of-date system studies have on the PRA model. Please assess the impact of the out-of-date system studies on the PRA model.

6. Do the failure probabilities of structures, systems, and components that are in standby mode for extended periods, as modeled in the PVNGS PRA, include a standby time-related contribution and a cyclic demand-related contribution? Please describe how you address the standby time-related contribution for extended surveillances.