ML17299A639
| ML17299A639 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 09/30/1985 |
| From: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | Knighton G Office of Nuclear Reactor Regulation |
| References | |
| ANPP-33609-EEVB, NUDOCS 8510020380 | |
| Download: ML17299A639 (6) | |
Text
REGULATO INFORMATION DISTRIBUTION STEM (RIDS)
ACCESS3;ON NBR:8510020380 DOC ~ DATE'5/09/30 NOTARIZED:
NO DOCKET FACIL:STN 50 528 Palo Verde Nuclear Stationi Uni,t li Arizona= Publi 05000528 STN 50-529 Palo Verde Nuclear Stationi Unit 2< Ar)zona Publi 05000529 STN-50-530 Palo Verde Nuclear Station~
Unit 3~ Arizona Publi 05000530 AUTH,NAME AUTHOR AFFILIATION VAN BRUNTiE,E, Arizona Nuclear Power Project (formerly Arizona Public Serv RECIP ~ NAME, RECIPIENT AFFILIATION KNIGHTON G, W, Licensing Branch 3
SUBJECT:
Provides addi info confirming that facility small break LOCA spectrum conf'orms to cr'iter ia of 10CFR50.46 8 bounded by limiting, large: break LOCA ~
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Arizona Nuclear Power Project P.o. BOX 52034 O
PHOENIX, ARIZONA85072-2034 Director of Nuclear Reactor Regulation Attention:
Mr. George W. Knighton, Chief Licensing Branch No.
3 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555 September 30, 1985 ANPP-33609-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 Limiting Small Break LOCA Analysis-Additional Information File: 85-056-026 G.l.01.10
References:
(A) Letter to G. N. Knighton, NRC, from E. E.
Van Brunt, Jr.,
ANPP, dated April 15, 1985 (ANPP-32401);
Subject:
Revised Chapter 15 Analyses (B) Letter to G.
tIt. Knighton, NRC, from E. E.
Van Brunt, Jr.,
ANPP, dated December 19, 1984 (ANPP-31535);
Subject:
Post-FDA Proposed CESSAR Changes
Dear Mr. Knighton:
This letter provides additional information confirming that the PVNGS small break LOCA spectrum conforms to the criteria of 10CFR 50.46 and is bounded by the limiting large break LOCA.
This information supplements the evaluation provided in the Reference (A) wh'ich addressed the Staff's concerns stated in PVNGS Operating License NPF-34 Condition 2.C.(21) and was discussed with members of your staff in a meeting held on August 29, 1985.
The limiting small break analyzed in the spectrum presented in CESSAR is a 0.05ft break in the Reactor Coolant Pump (RCP) discharge leg.
This break was reanalyzed to evaluate the results of PVNGS plant specific changes.
The results of this reanalysis yielded a Peak Cladding Temperature (PCT) of 1630' which was presented in Reference (B).
Discussion was provided in Reference (A) to demonstrate that this 0.05ft break would remain the most limiting break analyzed in the small break spectrum.
To resolve a
NRC concern that another break size, not currently analyzed, could yield more adverse results than currently presented, further evaluation was con-ducted.
As stated in Reference (A), the most limiting small break LOCA would be the size which results in the maximum RCS depressurization possible without the Safety Injection Tanks (SITs) acting to mitigate the PCT.
An engineering calculation indicated that a break size.of 0.07ft would provide this performance.
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Hr. George M. Knighton Limiting Small Break LOCA Analysis ANPP 33<09 Page 2
This break size was then analyzed using the NRC approved small break LOCA evalua-tion model.
The results yielded a PCT of 1230'F.
This was lower than the 0.05ft result because of beneficial effects of an additional loop seal blowing out, re-sulting in redistribution of water
$o the reactor vessel.
As predicted,
- however, RCS depressurization for the 0.07ft break was such that the maximum PCT was achieved just b'efore SIT actuation.
To conservatively define an upper limit on PCT for small break LOCA, core uncovery and depressurization
'were estimate/
using a hand calculation which assumed the same loop seal behavior as the 0.05ft case.
This calculation resulted in a PCT of approximately 1870'F occurring at 1365 seconds into the transient.
SIT actuation was estimated to occur coincident with the maximum PCT.
These results indicate that the post limiting analyzed break in the small br~ak LOCA spectrum remains the 0.05ft case.
Although a break larger than 0.05ft should exist which results in a higher PCT than the 0.05ft
- case, an engineering evaluation has confirmed 'that the large break LOCA results bound the small break LOCAs. The PVNGS changes which resulted in Unit l,license NPF-34 condition 2.C.(21) have, therefore, been demonstrated'to result in consequences which preserve the licensing conclusions presented by the NRC in the PVNGS Safety Evaluation Report.
Please contact Hr. M. F. Quinn','of my staff, if you have any questions concerning this matter.
Very truly your CU< )
E. E.
Van Brunt, Jr.
Executive Vice President project Director EEVB/KLH/bg cc:
E. A. Licitra R. P.
Zimmerman A. C. Gehr