ML20084J506

Ao:On 721220,during Routine Calibr,Electro Hydraulic Control Fluid Low Pressure Switches Found to Open Below Tech Spec Limit.Switches Recalibr

ML20084J506
Person / Time
Site:	Quad Cities
Issue date:	12/27/1972
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084J493	List: ML20084J490 ML20084J495 ML20084J499 ML20084J502 ML20084J506 ML20084J509
References
BBS-72-30, NUDOCS 8305130334
Download: ML20084J506 (2)

Text

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Com salth Edison -en s Nucinr Power Station .G '

r. Ouzd-l Post Offico Box 216 * .

Cordova, Illinois 61242 h Telephono 309/654-2241 [g co g/

F+ p) W; AC h f ]hy bY 1 Q, f -j December 27, 1972  % fa p

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BBS-72-30 l Mr. A. Giambusso Deputy Director for Reactor Projects Directorate of Licensing l 'U. S.- Atomic Energy Commission

, Washington, D. C. 20545

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REFERENCE:

Quad-Cities Nuclear Power Station Unit 2

! Docket 50-265 <

l License DPR-30 Appendix A Sections 1.0.A.2, 3.1, and 6.6.B.3

Dear Mr. Giambusso:

The purpose of this letter is to inform you of the i details of the drift of three Reactor Protection )

System Scram Instruments. This abnormal occurrence involved three E.H.C. Control Fluid Pressure Switches and was reported to you by telegram on December 20, 1972 A routine calibration of the E.H.C. Control Fluid Low Pressure switches was being conducted on Dec-ember 20, 1972 on Unit 2 in accordance with sur-veillance requirement 4.1.A of the Technical Spec- ,

ifications . The Technical Specification for the switches is that they open at 2 900 psig. While doing the calibration it was found that PS-2-5600-PS-1 opened at 880 psig, PS-2-5600-PS-2 opened at 890 psig and PS-2-5600-3 opened at 890 psig. These switches are Barksdale Model #C 9622-3 with an accuracy of + 10 psig. The switches were recal-ibrated in accordance with station procedures.

The drifts in set point of these switches are not considered to be of major safety significance since the scram resulting from an E.H.C. Control Fluid Low Pressure is an anticipating scram. Also as described in the bases for the specification, the 4- control valves would not actually close on low oil

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pressure until the pressure drops below 600 psig..

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B305130334 730111 -

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Mr. A. Giambusso December 27, 1972 The corrective action outlined in.my letter to you dated December 1, 1972 will result in a new setpoint and/or calibration frequency for these switches which will prevent their drifting be-yond the Technical Specifications limit.

Very truly yours, Commonwealth Edison Company Quad-Cities Nuclear Power Station

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- B. B. St'ephenson Superintendent BBS/lk s

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