ML19324B818
| ML19324B818 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 10/24/1989 |
| From: | William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TXX-89765, NUDOCS 8911080310 | |
| Download: ML19324B818 (2) | |
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Ref. # 10CFR50 nlELECTRIC October 24, 1989
?Ok'r?}l,:a U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C.
20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NOS. 50 445 AND 50-446 ADDITIONAL INFORMATION IN SUPPORT OF PRESSURIZER SURGE LINE THERMAL STRATIFICATION AND LEAK-BEFORE-BREAK EVALUATION REF:
- 1) TV Electric letter (TXX-89223) from W. J. Cahill, Jr. to NRC dated May 1, 1909
Gentlemen:
On May 1,1989, TU Ehetric submitted, by reference 1, a plant specific l
analyses of the effects of thermal stratification on the Comanche Peak Unit 1 Fres3urizer Surge Line (Surge Line) and the ability to satisfy leak before-break criteria. TU Electric subsequently provided, by reference 2, responses to NRC questions snd c1r.rifying information on the plant specific analyses.
References 1 and 2 justified the use of 2450F as the maximum Surge Line pipe delta T daring a forced c'vidown with a postulated crack in the Surge Line. This letter is being submitted to respond to an additional concern raised by the NRC staff in a conversation with M. Fields on September 22, 1989.
The 2450F delta T is based on the expeditious depressurization of the Reactor Coolant System (RCS) in such an event. Technical Specifications require shutdown for unidentified RCS leakage exceeding 1 gpm. CPSES procedures for unidentified RCS leakage during operation would result in determining the location of the leak while the plant is in Mode 3.
Upon discovery that the source is an unisolable RCS pressure boundary leak in the Surge Line, the operator's first priority would be to depressurize expeditiously. To provide further assurance of expeditious depressurization, the appropriate procedure is being revised to provide increased emphasis on the need for prompt depressurization in the event of a unisolable leak in the Surge Line.
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TXX 89765 October 24, 1989 Page 2 of 2 t
This change has been discussed with S. Lee and M. Fields of your staff and we understand that it resolves the NRC staff question regarding the operational procedure used during a forced cooldown with a postulated 1 gpm crack in the Surge Line.
If you have any questions, please contact H. A. Marvray at (214) 812 8296.
Sincerely, William J. Cahill, Jr.
HAM /sipp c - Mr. R. D. Martin, Region IV Resident Irispectors, CPSES (3) t i
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