ML20080R443
| ML20080R443 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 10/07/1983 |
| From: | Rybak B COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.K.3.22, TASK-TM 7434N, NUDOCS 8310170545 | |
| Download: ML20080R443 (1) | |
Text
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Commonwealth Edison one First National Plaza Chicago, Illinoys 2
} Address Reply to Post Office Box 767 s.-
,e Chicago, Illinois 60690 October 7, 1983 Mr. Harold R.
Denton, Director Of fice of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555 i
Subject:
Quad Cities Station Units 1 and 2 NUREG 0737 Item II.K.3.22 Additional Information Concerning the use of HPCI Level Switches NRC Docket Nos. 50-254 and 50-265 Mr. Denton:
The NRC has expressed concern with the method used to implement RCIC suction switchover as required by NUREG 0737 item II.K.3.22.
Commonwealth Edison believes the following information justifies the use of the HPCI logic for RCIC suction switchover.
The CCST low level signal is provided by four level switches in one out of four logic scheme.
The probability of all four switches failing is considered extremely remote.
High suppression pool level is provided by two level switches in a one out of two once logic scheme.
The HPCI and RCIC logic is isolated by a safety grade relay.
Any postulated failure will not prevent manual suction switchover.
The RCIC system is not safety related and le not intended as a backup to the HPCI system.
This work was completed in 1981.
Installing a new set of diverse level switches is estimated to cost an additional $250,000 for both units.
The high reliability of the existing logic scheme and the cost of installing diverse level switches justifies the use of utilizing the existing CCST and suppression pool level switches to implement RCIC suction switchover.
One signed original and forty (40) copies of this letter is provided for your use.
Very truly yours, p
/
B.
yb'a Nuclear Licens Administrator Ak 1*
kO cc:
NRC Resident Inspector - Quad Cities g p 8310170545 831007 PDR ADOCK 05000254 7434N p
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