ML20235Z656
| ML20235Z656 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 10/09/1987 |
| From: | Johnson I COMMONWEALTH EDISON CO. |
| To: | Murley T Office of Nuclear Reactor Regulation |
| References | |
| 3684K, NUDOCS 8710210246 | |
| Download: ML20235Z656 (2) | |
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Y Comm:nwrith Edison
$ j"J Address Reply to: Post Othce Box 767 One First National Plaza, Chicago, Illinois V
j Chicago, Illinois 60600 0767 l
October 9, 1987' ElbNOC~Db 1198100120 /\\ K) 00 Mr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Quad Cities Station Units 1 and 2 "Timelines for Reactor Water Makeup and Fuse Pulling" NRC Docket Nos. 50-254 and 50-265 References (a):
Letter from I.M. Johnson to T.E. Murley dated October 1, 1987.
(b): Letter from I.M. Johnson to H.R. Denton dated March 13, 1987.
(c): Letter from I.M. Johnson to T.E. Murley dated September 30, 1987.
Dear Mr. Murley:
In a October 5, 1987 telephone conversation with Mr. Grotenhuis and Dr. Chandrasekaran of your staff, Commonwealth Edison provided clarification for the above referenced exemmption requests / licensing submittals.
1.
Section 12.1.1 of Reference (a) refers to the safety relief valves while Section 12.2.1 of the same reference refers to the reactor relief valves. Dr Chandrasekaran wanted to know if there was a difference and which valven were being referred to.
Ceco _gesponse:
Both the reactor relief valves and safety relief valves refer to the Target Rock (203-3A) and Electromatic Relief Valves (203-3B, 203-3C, 203-3D and 203-3E). The Target Rock valve has both a, safety and relief function.
2 A 14 minute time limit for pulling fuses has been given in some submittals and it was stated that a 10 minute limit was required for pulling the reactor relie;f valve fuses.
Dr. Chandrasekaran wanted to know the reason for the different time limits.
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4 T.E. Murley October 9, 1987 l
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1 CECO Response:
Earlier calculations showed that if raactor water makeup was fnitiated i
within 14 minutes of reactor scram, the core would remain covered. This was the basis for the 14 minute time limit in previous submittals for completing fuse pulling. Recently, the General Electric (GE) Company 1
performed more refined calculations to see if reactor water makeup l
initiation could be delayed longer than 14 minutes. This analysis showed that if reactor water makeup was initiated within 30 minutes of
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reactor scram, the core would remain covered. Thus, al1 previous submittals containing the 14 minute time limit for fuse pulling are now 1
revised by this letter to allow 30 minutes for fuse pulling.
The 10 minute limit for fuse pulling to prevent the spurious operation of the reactor relief valves is based on an assumption made in the above i
mentioned GE calculation.
In that calucation, it was assumed that one i
reactor relief valve was open for 10 minutes.
If that valve is closed within 10 minutes, then reactor water makeup will not have to be initiated for 30 minutes. Pulling the reactor relief valve fuses will ensure that the valve is closed.
I plesse direct any questions you may have regarding this matter to this office, i
Very truly yours, i
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I. M. Joh oon Nuclear Licensing Administrator
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l cc:
A. B. Davis - Region III i
T. Ross - NRR j
Dresden Resident Inspector i
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