ML17312A915

Informs of Delay of RAI Re risk-informed Inservice Testing Program Pilot

ML17312A915
Person / Time
Site:	Palo Verde
Issue date:	08/07/1996
From:	Stewart W ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
102-03752-WLS-A, 102-3752-WLS-A, NUDOCS 9608160127
Download: ML17312A915 (5)

Text

CATEGORY j.

REGULAT INFORMATION DISTR1BUTION ~ STEM (RIDS)

ACCESSXOti NBR:9608160127 DOC.DATE: 96/08/07 NOTARIZED: NO DOCKET I FACjL~STN-50-528 Palo Verde Nuclear Station, Unit 1, Arizona Publi 05000528 STN-50-529 Palo Verde Nuclear Station, Unit 2, Arizona Publi 05000529 STN-50-530 Palo Verde Nuclear Station, Unit 3, Arizona Publi 05000530 AUTH. NAME AUTHOR AFFILIATION STEWART,W.L. Arizona Public Service Co. (formerly Arizona Nuclear Power RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Informs of delay of RAI re risk-informed Inservice Testing Program Pilot. A DISTRIBUTION CODE: A047D COPIES RECEIVED:LTR ENCL SIZE: T TITLE: OR Submittal: Inservice/Testing/Relief from ASME Code GL-89-04 NOTES:STANDARDIZED PLANT 05000528 Standardized plant. 05000529 G Standardized plant. 05000530 0

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD4-2 LA PD4-2 PD CLIFFORD,J CLIFFORD,J.

INTERNAL AEOD/SPD/RAB ILE CEN ER 01 NRR/DE/ECGB NR NRR/DE/EMEB NUDOCS-ABSTRACT OGC/HDS2 RES/DET/EMMEB RES/DSIR/EIB D EXTERNAL: LITCO ANDERSON NOAC 0 NRC PDR N

NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTETH CONTACT THE DOCUMENT CONTROL DESK, ROOM OWFN SD-5(EXT. 415-2083) TO ELIMINATE YOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

TOTAL NUMBER OF COPIES REQUIRED: LTTR 17 ENCL

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Arizona Public Service PALO VERDE NUCLEAR GENERATING STATION P.O. BOX 52034 PHOENIX, ARIZONA 85072-2034 102-03752-WLS/A KK/GAM WILLIAML. STEWART EXECUTIVEVICE PRESIOENT August 7, 1996 NUCLEAR U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Station P1-37 Washington, DC 20555-0001

References:

1. Letter dated March 15, 1996, from C. R. Thomas, USNRC, to W L. Stewart, APS "Request for Additional Information (RAI) on Risk- Informed Inservice Testing (Rl-IST) Pilot Plant - Palo Verde Nuclear Generating Station Units 1, 2, and 3."

Letter No. 102-03714, dated June 7, 1996, from J. A. Bailey, APS to USNRC, "Response to NRC Request for Additional information on Risk-Informed Inservice Testing Program" B

Subject:

Palo Verde Nuclear Generating Station(PVNGS)

Units 1, 2, and 3 Docket Nos. STN 50-528/529/530 Delay of Additional Information Related to the Risk-Informed Inservice Testing Program Pilot In Reference 1, the NRC Staff provided to Arizona Public Service Company (APS) a request for additional information (RAI) related to the APS request to utilize a risk-informed inservice testing (RI-IST) program to determine inservice test frequencies for

'ST components. In the response provided in Reference 2, APS committed to provide additional information for some of the RAI questions unavailable at the time the response was prepared. Due to unforeseen circumstances related to the PVNGS Probabilistic Risk Assessment (PRA) software described below, the additional information will not be available for submittal in accordance with the dates identified in Reference 2. This delay was discussed during a phone call on July 31, 1996, between APS Staff and Mr. Jim Clifford of the NRC Staff along with other NRC Staff members.

One of the sensitivity studies needed for the Rl-IST project is an evaluation of the effect of solution truncation level on the risk ranking results for the IST components. APS has determined it is not possible to achieve solutions below the 1.0E-09 truncation level with the software currently used at PVNGS. Thus the truncation sensitivity cannot be done with this software. This is considered an important study to perform and thus APS 9608160i27 960807 PDR, ADQCK G>>,i ', 05000528 PDR

has identified an alternate means to conduct this study. APS intends to perform the study using the IRRAS code package for the solution. This is possible due to the recent conversion of the PVNGS PRA model to the IRRAS format. Training on the use of the code will be conducted for APS personnel. However, the additional time required to perform the study cannot currently be estimated. The sensitivity studies are not expected to be completed by the August 1, 1996, date provided in Reference 2. The completion of re-ranking IST components is also expected to be delayed beyond the date of September 30, 1996, provided in Reference 2. Development of decision criteria for deterministic considerations (areas not quantified from a PRA perspective) is continuing, as well as the effort to define plans for implementation of the risk informed program.

APS will evaluate the impact of the PRA software changes and provide the NRC with a revised schedule for submitting the additional information identified in Reference 2 by September 15, 1996.

Should you have any questions, please contact Scott Bauer at (602) 393-5978.

Sincerely, WLS/AKK/GAM/rv cc: L. J. Callan K. E. Johnston C. W. Clifford K. E. Perkins D. C. Fischer

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