ML20084J502
| ML20084J502 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 01/03/1973 |
| From: | Stephenson B COMMONWEALTH EDISON CO. |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20084J493 | List: |
| References | |
| BBS-73-2, NUDOCS 8305130329 | |
| Download: ML20084J502 (2) | |
Text
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Ouad Cit, Jucicar Pow;r Station 0
J g - O P;st Offica Box 216 Cordova, tihnois 61242 Telephono 309/654 2241
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4 Mr. Angelo Giambusso a
Deputy Director of Reactor Projec s l
Directorate of Licensing U. S. Atomic Energy Commission Washington, D. C. 20545 Re fe rence :
Quad-Cities Nuclear Power Station - Unit 2 Docket No. 50-265; DPR-29, Appendix A i
Sections 1.0.A.2, 3.7.D.1, and 6.6.B.s l
Dear Mr. Giambusso:
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The purpose of this letter is to inform you of the details relating to an incident in which the closure time for Main Steam Isolation Valve (VSIV) A0-2-203-lD apparen'bly exceeded technical npecification limits.
This incident was reported to you by telegram on December 20, 1972.
DESCRIPTION OF INCIDENT On December 20, 1972 at 3: 15 a.m.,
full closure timing tests were performed on Unit 2 MSIV's 203-1A and 203-1D.
The unit was shutdown to locate and repair condenser tube leaks.
MSIV 1A closed in 4.0 seconds, but MSIV 1D took 51 seconds to close.~~The T6dhnical Specifications requ'.re that these
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5 seconds.
The valve was inspected valves close in 3 s t 4
and appeared to be operating normally.
The valve timing was adjusted and three successive closure tests were performed l }
and the valve closed in 3.0 seconds each time.
INVESTIGATION I
During a two day outage prior to this abnormal occurrence M
repairs were made to the position indicating limit switches (10 on MSIV's lA and 1D.
This minor maintenance should not have affected the valve times, however, timing tests were performed as a precautionary measure prior to returning the valves to service.
The last full closure timing on these valves was conducted on October 6,1972 when valves lA and 1D closed in 4.2 and 4.4 seconds respectively.
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' COPY FENT REGION 3 A
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'Mr. Angelo Giambusso January 3,1973 i
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_ CORRECTIVE' ' ACTION In addition to rc-timing the valve, a new method of timing is being reviewed.
The present method used to time isolatior valves is a stop watch from the control room.
using re cor_ der.is being developed which will allow these valves to b A modificatim d
'Ihis will provide us with more accurate crosure times in the future and enable us to spot any trends in closure times by providing a permanent record for analysis y)fd
,h Very truly yours, b q COMMONWEALTH EDISON COMPANY
.Y QUAD-C LEAR POWER STATION '
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B.B.Ste{phenson Superintendent BBS/zm
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