ML20084L135

Ao:On 740419,nine of 16 High Temp Isolation Valves Tripped at Values Exceeding Tech Spec Limit.Caused by High Setpoint & Normal Instrument Drift.Setpoints Recalibr at Lower Limit

ML20084L135
Person / Time
Site:	Quad Cities
Issue date:	04/29/1974
From:	Kalivianakis N COMMONWEALTH EDISON CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084L137	List: ML20084L135 ML20084L140 ML20084L147
References
NJK-74-49, NUDOCS 8305200277
Download: ML20084L135 (2)

Text

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'y 4 C 's Outd Cita 2nerating Station Post Office cox 216

'O R ---'~f }7 Coraova,!!hnois 61242 h, *,,)

y Telephone 309/654-2241 cn (P ,q NJK-74-49 .

4 50-254 3 h 1, April 29,1974 9; d.*,$}rg k,'

e NGO s tr @MP" ig

'l; Mr. John F. O' Leary, Director '.- -

Directorate of Licensing #/ . / ' t Regulation '

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U. S. Atomic Energy Co:r:nission Washington, D. C. 20545

Reference:

Quad-Citics !!uclear Power Station Unit 1, Docket 1 o. 5 ~ - 4, DPR-29, Appendix A , Sections 1.A.2, 3.2.A. , Table 3.2.1.

and 6.6.B.l.a.

Dear Mr. O' Leary,

The purpose of this letter is to inform you of the details concerning the HPCI arra h15 h tc perature isolation terperature switchcs, which were found with setpoints excceding the Technical Specifications Limiting ,

Conditions for Operations, given in table 3.2.1. This abnormal occurrence was reported to you by telegram, and to Region III, Directorate of Regu- L latory Operations by telephone a rrd telegram, on April 20, 1974 PROBLE!! A?3 II.VESTICATIO:

On April 19, 1974, with unit one in the cold shutdown mode for refueling, routinc surveillance was perforscd on the HPCI area high terpcrature iso- 1 lation temperature switches and nine of the sixteen trippcd at values execcding the Limiting Condition for Operationof$200 F. f The "as found" setpoints are as follows:

EQUIF?:EUT PIECE IlWrERS SETPOIICS, F

'IS-1-23 70 A 208 B 202 TS-1-2371 A 206 C 2 03 TS-1-2372 A 209 D 230 TS-1-2373 P 202 g C 205 5 D 202 i These switches were recalibrated to trip at 185 F+5

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F, - 10 F. !j M

DETERI'II!ATIOI: OF CAU3E L:3 CO?FECTPjE ACTICI!

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it The switches were originally calibrated to trip at 200 F. Normal instru-ment drift caused the sctroints to execcd the limiting condition for oper-i ation, but they have since been recalibrated to 15 F below the limit to allow for this drift. I  !]

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g Mr. J. F. O' Lea () -

April 29,1974 SAFETY I?SLICATIO!!S The basis for Section 3.2 of the Technical Specifications states that a setroint of 200* F will enable leaks of 5 to 10 G.P.K. to be detected.

Because not all the switches had drifted, the isolation would still have occurred at 200* F. Iowering the setpoints 15' F makes smaller leaks detectable and therefore involves no safety implications.

CUMUIATIVE EXPERIEt:CE This occurrence represents the first recalibration of the HPCI area high temperature isolation switches at Quad Citics Station. No cumula-tive experiene.c data is available.

Very truly yours, CGT.0?MEALTH EDISON CO:PA!IY QUAD-CITIES IJUCLEAR POER STATIO:1 n

/[-l$f XhhI'Yb- ._ ,

H. J. Kalivianakis Station Superintendent NJK/ REQ /caa j

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