ML20235N481
| ML20235N481 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 02/13/1989 |
| From: | William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| REF-PT21-89 CP-89-39, TXX-89068, NUDOCS 8903010240 | |
| Download: ML20235N481 (2) | |
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Log. # TXX-89068 File # 10110 907.4 7UELECTRIC Ref. #
February 13, 1989 W. J. Calim Executive Vice President 4
U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C.
20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NOS. Ca-445 AND 50-446 RHR VALVE POSITION INDICATION SDAR: CP-88-39 (SUPPLEMENTAL REPORT)
Gentlemen:
On December 21, 1988, TV Electric notified the NRC via interim report logged TXX-88874, of a deficiency involving the position indication for the RHR heat exchanger outlet valve. A written report was due February 10, 1989.
- However, on this day, TV Electric requested and received a verbal extension from Mr. S. D. Bitter until February 15, 1989.
As described below, it was
' determined that this condition is not reportable under the provisions of 10CFR50.55(e).
As stated in TXX-88874 the monitor light box (MLB) window for each RHR heat exchanger outlet valve is wired to the valve's " closed" position switch such that it is possible for the RHR heat exchanger outlet valve position to be i
' indicated as proper (i.e., fully open) with a dark MLB, when the valve is l
actually )artially open. However, in addition to the status information provided )y the MLBs (fully closed or not fully closed), status information is
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also available in the Emergency Response Facility (ERF) computer.
The ERF computer status information is taken from the valve open position switch H
providing " full open" or "not full open" status to the operators.
The RHR heat exchanger outlet valves provide a passive safety function and the safety analysis is based on the assumption that the valves are fully open.
The valves are placed in the open position during plant start-up and, in accordance with technical specification requirements, are verified to be fully open at least once every thirty-one days. The valves are air operated and fail to the open position on loss of instrument air. The valves are opened and held open by a spring built into the valve actuator.
The fact that the control wiring is such that each of these valves would indicate a " dark" light box when it is not fully open does not affect the operation of the valve.
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TXX-89068 February 13, 1989 Page 2 of 2 Based on the above, we have concluded that no deficiency in design or construction exits and that the surveillance performed every thirty-one days, provides assurance that these passive valves are open.
This issue does not meet the criteria of 10CFR50.55(e)(1), and therefore, is not reportable.
From a " human factors" perspective, we have elected to modify this feature of the Westinghouse design at a future date, however this is considered a plant improvement not required for the safe operation of the RHR system.
Sincerely, WilliamJ.Mhill,J.
VPC/ddm c - Mr. R. D. Martin, Region IV Resident Inspectors, CPSES (3)
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