ML20112F725
| ML20112F725 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 12/10/1984 |
| From: | Lempges T NIAGARA MOHAWK POWER CORP. |
| To: | Deyoung R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-83-03, IEB-83-3, NMP-7947, NUDOCS 8501160011 | |
| Download: ML20112F725 (2) | |
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.NMP-7947 NIAGARA MOHAWK POWER CORPORATION NIAGARA MOHAWK 300 ERIE BOULEVARD. WEST SYRACUSE. N. Y.13 202 December 10, 1984 Richard C. DeYoung, Director United States Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, Pennsylvania 19406 Re: Docket No. 50-220 IE Bulletin No. 83-03, Rev. 1
Dear Mr. DeYoung:
With regard to the response to IE Bulletin 83-03 (NMPC letter 6777 dated 6-14-84 Lempges to DeYoung) Nine Mile Point Unit 1 Nuclear Station committed' to perform two (2) tests on the check valves in the Emergency Diesel Genera-tor Cooling Water.(72)' system. One test is a quarterly forward and reverse flow test for valves 72-66 and 72-67, thereby proving the valves are opera-ting properly. The other test outlined in the response is to disassemble, inspe'ct and reassemble valves 72-68 and 72-69 every refueling outage to as-sure valve integrity. After evaluating these tests, NMPC will-combine them into maintenance and ISI procedures _ that shall be performed only during re-fueling outages.
The' rationale for combining these tests and performing them every refuel-ing outage is based on two reasons: first, each Emergency Diesel Generator-Cooling Water line has to be drained-to disassemble,-inspect and reassemble
.the check valve nearest the pump (72-68 or 72-69). Failure'of the other:
L Jcheck valve in the line (72-66 or 72-67) will be demonstrated if water col.
- 1ects in the disassembled valve cavity. Since there'is a constant back pres-sure on the downstream side of the check valves in the diesel generator room
-(72-66 or 72-67) from Service' Water and no restrictions between the disassem-
. bled valve and the check valve downstream of the Diesel Generator when each line is drained,' leakage from the diesel generator room valve will be forced
- into_the disasscebled. valve' cavity in the screenhouse.
If no water appears,_
then the valve in the diesel generator room is demonstrated as fulfilling its design function. In effect, while one valve is inspected, a reverse flow test-is being performed on the other check valve in the line because of the
'8501160011 841210 DR ADOCK 0S000220 :
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.O Page 2 NMP-7947 IEB 83-03, Rev. 1 drained line; the second reason to combine the tests is to reduce the num-ber of times the cooling water lines are drained thereby reducing the fre-quency of the Diesel Generator being inoperable as a result of mark-ups to perform these tests.
Since there is.no history of valve failure and considering the two reasons previously sited, this change to the original response is believed to be a reasonable and preferred method of testing the Emergency Diesel Generator Cooling Water check valves. Effective immediately, Nine Mile Point Unit 1 Nuclear Station will discontinue quarterly reverse flow testing and shall implement this response during refueling outages only unless directed otherwise.
Very truly yours, of Thomas E. Lempges Vice President Nuclear Generation TEL/RWS/rt l
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