ML17299A431
| ML17299A431 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 07/12/1985 |
| From: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | Knighton G Office of Nuclear Reactor Regulation |
| References | |
| ANPP-33006-EEVB, NUDOCS 8507160474 | |
| Download: ML17299A431 (6) | |
Text
REGULAT FORMATION DISTRIBUTION M (RIDS)
ACCESSION NBR; 8507160474 DOC ~ DATE: 85/07/12 NOTARIZED:
NO FACIL;STN 50 528 Palo Verde Nuclear Station~
Unit li Arizona Publ,i STN-50-529 Palo 'Verde Nuclear Stationi Unit 2g Arizona Publi STN-50-530 Palo Verde Nuclear Station~
Unit 3i Arizona Publi AUTH BYNAME AUTHOR AFFILIATION VAN BRUNTiE,E, Arizona Public Ser vice Co.
RECIP ~ NAME RECIPIENT AFFILIATION KNIGHTONiG ~ H ~
Licensing Branch 3
SUBJECT:
Discusses potential nonconservatism in element of C"Ei large break LOCA evaluation model AC-E evaluation model used for large break LOCA analyses unacceptable for demonstrating compliance w/10CFRSO,Addi info expected by 850830, DISTRIBUTI N CODE:
B001D COPIES RECEIVED:LTR ENCL SIZE:
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O TITLE: Licensing Submittal:
PSAR/FSAR Amdts L Related Correspondence DOCKET i'5000528 05000529 05000530 NOTES:Standardized plant-.
05000528 OL: 12/31/84 Standardized plant ~
05000529 Standardized plant ~
05000530 RECIPIENT ID CODE/NAME NRR/DL/ADL NRR LB3 LA INTERNAL: ACRS
<l1 ELD/HDS3 IE/DEPER/EPB 36 NRR ROEiM ~ L NRR/DE/CEB 11 NRR/DE/EQB 13 NRR/DE/MEB 18 NRR/DE/SAB 2Q NRR/DHFS/HFEBIlO NRR/DHFS/PSRB NRR/DS I/AEB 26 NRR/DSI/CPB 10 NRR/DSI/ICSB 16 NRR/DSI/PSB 19 NRR/DSI/RSB 23 RGNS EXTERNAL: 24X DMB/DSS (AMDTS)
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Arizona Nuclear Power Project P.o. BOX 52034 4
PHOENIX, ARIZONA85072-2034 Director of Nuclear Reactor Regulation Attention:
Mr. George V. Knighton, Chief Licensing Branch No.
3 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555 July 12, 1985 ANPP-33006-EEVB/KLM
Subject:
Palo Verde Nuclear Generating Station (PVNGS)
Units 1, 2, and 3
Docket Nos.
STN 50-528 (License No. NPF-41)/529/530 Potential LOCA Analysis Non-Conservatism File:
85-056-026 G.l.01.10
References:
(A)
C-E letter, LD-85-031, A.E. Scherer to G.
M. Knighton, dated July 2, 1985 (B)
C-E letter,.LD-81-096, A.E. Scherer to R.L. Tedesco, dated December 21, 1981
Dear Mr. Knighton:
On July 2, 1985, Combustion Engineering (C-E) notified the Nuclear Regulatory Commission of a potential non-conservatism in one element of C-E's large break loss-of-coolant accident (LOCA) evaluation model (Reference (A)).
The particular element in question was the treatment of axial power distribution and peaking factor.
C-E stated that this potential non-conservatism applied to all plants for which they had performed ECCS performance evaluations using this large break LOCA model.
At a meeting with the NRC staff on July 10,
- 1985, C-E provided more detailed information on this subject as well as a summary of the status of those plants for which C-E currently provides the large. break LOCA evaluations.
PVNGS Units 1, 2, and 3 were included in that summary.
As reported in that meeting, C-E's estimate of the increase in peak clad temperature (PCT),, resulting 'from a more adverse axial power distribution and peaking factor is 34'F.
This is based on a preliminary evaluation of the CESSAR worst-case large break LOCA analyses.
ANPP currently references the CESSAR LOCA analyses.
The current maximum PCT presented in CESSAR and at the July 10, 1985 meeting for PVNGS Units 1, 2, and 3 is 2169 F.
Additional information, however, reveals that this value does not reflect the most recent large-break LOCA evaluation.
To address an earlier NRC concern involving cladding ballooning and flow blockage
- models, documented in NUREG-0630, C-E submitted a supplemental large break LOCA analysis on the CESSAR docket (Reference (B)).
This supplemental analysis was reviewed by the staff and was approved in the CESSAR Safety, Evaluation Report (NUREG-0852) Supplement 1.
The PCT reported in this"supplemental analysis was 2152'F which provides a margin of 48'F to the acceptance criteria for PCT stated in 10CFR50.46.
Incorporation of the more adverse axial.power distribution is not expected to increase PCT to the regulating limit of,2200'F.
ANPP believes, therefore, that ECCS performance continues to be in compliance with the acceptance criteria of 10CFR50.46.
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. P>-V-. Knighton Potential LOCA Analysis on-Conservatism ANPP-33006 Page 2
The staff indicated in the July 10, 1985 meeting that the current C-E evaluation model used for large break LOCA analyses is not deemed to be an acceptable tool for demonstrating compliance to 10CFR50.46.
As a result of this position, ANPP will be pursuing this issue further with C-E and; if necessary, a new analysis will be provided.
Ve expect to provide additional information, including any schedular commitments, by August 30, 1985.
If you have any additional questions or comments on this issue please contact Mr. W. F. Quinn of my staff.
Very truly yours, E. E.
Van Brunt, Jr.
Executive Vice President Project Director EEVB/KLM/slh cc:
E.
A. Licitra R. P.
Zimmerman A. C. Gehr
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