ML20084A972
| ML20084A972 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 11/07/1974 |
| From: | White L ROCHESTER GAS & ELECTRIC CORP. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML20084A958 | List: |
| References | |
| NUDOCS 8304060047 | |
| Download: ML20084A972 (1) | |
Text
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tion u wuait. JR inter o e uc t rae siot eer sera coot ns 5 4 b.2 700 November 7,1974 Mr. James P. O'Reilly 7
r Director U.S. Atomic Energy Commission
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b Directorate of Regulatory Operations
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Region I N
G31 Park Avenue l'ing of Prussia, Pennsylvania 19406 m
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Subject:
Unusual Event - R.E. Ginna Nuclear Power Plant Unit No.1 Docket No. 50-244 ek 7
Dear Mr. O'Reilly:
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Rochester Cas and Electric Corporatiori was informed at a meeting on October 8,1974 by Westinghouse Electric Co' peration that the Safety Injection r
h System delivery curve employed for the Steam LUu Preak Accident Analysia (SLilA Analysis) was inconsistent with that used for recent Loss of. Coolant
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y Accident Analyses. The delivery curve had been revised subsequent to the most recent SLBA Analycis, rcrferr'od by Westinghousc in I cbrusrv 1971 to cccount for the as-built piping configuration and operatio +] characteristics and to p_
include a provision for system degradation over'the life of the plant. Those revisions resulted in a lowrsing of the delivery curve.
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Preliminary analyses performed by Westinghouse with conservativo reactivity 3
a pLrameters demonstrate that a shutdown margin of 2.45%Ak/k will insure that all f
design criteria are met. The calculated shutdown margin for the present fuci a
cycle, Cycle 4, which includes provision for the most reactive contrei rod being stuck out of the core and includas a 10% design allowance,'2s 2.48%$k/k at E
the end of the cycle ( 0 ppta boron) with equilibrium ::enon and is 0.25G Ak/k
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ilt the haginning of the cycle with equilibrium xenon. The shutdown m:rgir 7
required by the Technical Snecifications is 1.9% Ak/k at the end of the cycle.
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Roc 60 ster Gat and Electric CorporMioil has asked Westinghouse to perform' h
g additional analyses in order to minimize the shutdown margin required to meet L
all design objectives. In the interim, P.G&E will maiittain a chutdown marcin E
at least 2.45% Ah/k.
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Very truly youri,
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