ML20084J567

Ro:On 721223,pump Seals of Reactor Water Cleanup Recirculation Pump Leaked.Caused by Failure of Torque Switch to Return Valve to Close Position.Status of Valves & Corrective Action Will Be Submitted by 730115

ML20084J567
Person / Time
Site:	Quad Cities
Issue date:	01/05/1972
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084J570	List: ML20084J567 ML20084J572
References
BBS-73-4, NUDOCS 8305180242
Download: ML20084J567 (2)

Text

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h Comi Quad-ealtn Edison C 7' Post On uclear Power Station Dax 216 aff

.7.- Cordova,Ilknois 61242

• Te cphone 309/654-2241 BBS-73-4 - \

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% J' AN121973 :, '7es u mt'.m m n,y ,

g 7 January 5, 1972 d,$ ; p

% ,,,Z 1b Mr. Angelo Giambusso Deputy Director of Reactor Projects Directorate of Licensing U. S. Atomic Energy Commission Washington, D. C. 20545

Reference:

Quad-Cities Nuclear Power Station - Unit 2 DPR-30, Appendix A, Docket No. 50-265 Se ctions 1. 0. A .2, 3 7. D.1,, and 3. 7. D. 2.

Dear Mr. Giambusso:

The purpose of this letter is to inform you of the details re'garding an incident in which the Reactor Water Cleanup system outboard isolation valve, MO 2-1201-5, failed to close. This incident was reported- to you by telegram on December 24, 1972.

DESCRIPTION OF THE INCIDENT

• At 6: 00 a.m. on December 23, 1972, Reactor Water cleanup recirculation pump 2A was taken out of service due to leakage at the pump seals. The system was isolated by closing valves 2-1201-2, 5, and 80. All valves operated satisfactorily.

The cleanup system was returned to service later that day with pump 2B in operation. At approximately 9: 00 p.m., 2B cleanup pump developed seal leakage. The load on the unit was re-duced to 60% to maintain a low con'ductivity.

At 11:20.p.m. , the cleanup system was removed from service in order to work on the cleanup recirculation pump seals' or both A and B pumps. At this time , MO-2-1201-5 did not close when actuated from the control. room. Af ter giving the valve a "close" signal, a double indication was roccived and the valve would not reach the fully closed position. Inboard isolation valve MO 2-1201-2 was closed to comply with Technical Specifications.

8305180242 720105 PDR ADOCK 05000265 M

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l Mr. Angelo Giambuss o January 5, 1973 i

Electrical maintenance personnel were called in to repair the valve operator on December 24, 1972. After repairs were completed later that day, the valve was operated three times from the control room. Each time the valve closed in 22 seconds. Cleanup recirculation pump 2A was returned to service at 10: 30 p.m. and the cleanup system returned te normal. .

INVESTIGATION AND CORRECTIVE ACTIOll The problem was identified as a failure of the torque skitch to return to the "close" position af ter the last valve operation. When maintenance personnel checked out the torque switch, the internal torsion spring was found to be weak and unable to reclose the switch af ter it had actuated. The switch must reclose to set up the valve motor closing circuit. The switch is a type 00 Limitorque.

When it was replaced and reset, the valve operated success-fully. .

Similar problems have been encountered in the past as reported in my letters dated July 10, August 3, September 3, and De cembe r 6, 19 72. A review of the status of all valve operators is being conducted by Commonwealth Edison's Station Electrical Engineering Department. This review has not been completed as of this date; however, a program of corrective action is being developed and will be formally submitted to Region III Regulatory Operations in response to a request by them on this s ame s ub j e ct . This program will be finalized by January 15, 1973 Very truly yours ,

COMMONWEALTH EDISON C0??PANY QUAD-CITIES NUCLEAR POWER STATION

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cr # f/6aeb N *B. B. Stephenson Superintendent LFG/zm L __ J