ML17306A326
| ML17306A326 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 12/16/1991 |
| From: | Conway W ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 161-04341-WFC-G, 161-4341-WFC-G, NUDOCS 9112190189 | |
| Download: ML17306A326 (4) | |
Text
g,A REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS )
ACCESSION NBR:9112190189 DOC.DATE: 91/12/16 NOTARIZED: NO DOCKET FACIL:STN-50-529 Palo Verde Nuclear Station, Unit 2, Arizona Publi 05000529 AUTH.NAME AUTHOR AFFILIATION CONWAY,W.F.
Arizona Public Service Co.
(formerly Arizona Nuclear Power RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Advises that Cycle 4 nuclear design analysis not performed exactly in same manner as previous nuclear design analyses.
Increased accuracy of improved design codes not credited in Cycle 4 safety analysis.
DISTRIBUTION CODE:
ROOID COPIES RECEIVED:LTR
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ENCL P
SIZE:
TITLE: OR Submittal:
General Distribution NOTES:Standardized plant.
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05000529 A
RECIPIENT ID CODE/NAME PD5 LA TRAMMELL,C INTERNAL: ACRS NRR/DET/ESGB NRR/DST 8E2 NRR/DST/SICB8H7 NUDOCS-ABSTRACT OGC/HDS1 RES/DSIR/EIB EXTERNAL: NRC PDR NOTES:
COPIES LTTR ENCL RECIPIENT ID CODE/NAME PD5 PD THOMPSON,M NRR/DET/ECMB 7D NRR/DOEA/OTSB1 1 NRR/DST/SELB 7E NRR/DST/SRXB 8E OC/LFMB EG~M'-
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NOTE TO ALL"RIDS" RECIPIENTS:
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PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM PI-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!
TOTAL NUMBER OF COPIES REQUIRED:
LTTR 27 ENCL
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Arizona Public Service Company P.O. BOX 53999
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PHOENIX, ARIZONA 85072<999 WILLIAMF. CONWAY EXECUTIVEVICEPRESIDENT NUCLEAR 161-04341-WFC/GAM December 16, 1991 Docket No.
STN 50-529 U.
S. Nuclear Regulatory Commission Attn:
Document Control Desk Mail Station Pl-37 Washington, D.C.
20555
Dear Sirs:
Subj ect:
Palo Verde Nuclear Generating Station (PVNGS)
Unit 2 Unit 2, Cycle 4 Nuclear Design Analysis File: 91-056-026; 91-005-419 '
Arizona Public Service Company (APS) has recently determined that the Unit 2, Cycle 4 nuclear design analysis was not performed in exactly the same manner as previous PVNGS nuclear design analyses, as previously reported to the NRC in the Monthly Operating Report.
The Unit 2, Cycle 4 nuclear design analysis was performed by ABB Combustion Engineering using the DIT, ROCS and MC computer codes described in Topical Report CENPD-266-P-A, as were previous PVNGS nuclear design
- analyses, but with improvements in anisotropic scattering, higher order interface currents, nodal expansion method and assembly discontinuity factors.
The increased accuracy of the improved design codes were not credited in the Unit 2, Cycle 4 safety
- analysis, as the larger of the uncertainties associated with either the previous or the improved code versions was used.
This approach yielded the most conservative results.
The Unit 2, Cycle 4 reload is. otherwise typical of other PVNGS cycles.
APS has reviewed the reload pursuant to the requirements of 10 CFR 50 '9, and has determined that an unreviewed safety question does not exist and no changes to the Technical Specifications are required.
If you should have any questions, please contact Michael E. Powell of my staff at (602) 340-4981.
Sincerely, WFC/GAM/gam cc:
J.
B. Martin D. H.
Coe A.
C. Gehr A. H. Gutterman C.
M. Trammell 91121901S9 911216 PDR
, ADGCK 05000529 PDR
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