ML20084L116

Ao:On 740422,high Temp Isolation Temp Switch Tripped at 231 F,Exceeding Tech Spec Limit.Caused by High Setpoint & Normal Instrument Drift.Switch Setpoints Lowered

ML20084L116
Person / Time
Site:	Quad Cities
Issue date:	05/01/1974
From:	Kalivianakis N COMMONWEALTH EDISON CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084L119	List: ML20084L116 ML20084L120 ML20084L127
References
NJK-74-50, NUDOCS 8305200267
Download: ML20084L116 (2)

Text

_ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ - _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

A

1. O

> ~*:3 C:m rlth Edisin Quad , , Generating Station Post Othee Box 216 .

O- 50-254 N/ Cordova, Illinois 61242 '

s

' 1' Telephono 303/654 2241 e ..

NJK-74-50 / -

,e g, Mg

May 1, 1974 4 Q QN~~ h A

-A '

~

g Mr. John F. O' Leary, Director Directorate of Licensing Regulation U.S. Atomic Energy Commission Washington, D. C. 20545

]

l Rcrerence: Quad Citics Nuclear Power Station Unit 1, Docket Ko. 50-524, DPR-29, Appendix A; Section 1.A.2, 3 2.A. , 6.6.B.l.a, and Table 3.2.1.

i

Dear Mr. O' Leary,

4 The purpose of this letter is to inform you of the details concerning the RCIC area high temperature isolation temperature switch which was found with a setpoint in excess of the Limiting Condition for Operation, given

in Section 3 2.A. of the Technical Specifications. This abnormal occur-rence was reported to you by telegram and to Region III, Directorate of Regulatory Operations by telephone and telegram, en April 22, 1974.

PROnLDI AIO I?NESTIGATION On April 22, 1974, with unit one in the cold shutdown condition for the refueling outage, routine surveillance calibration was perfomed on the RCIC area high temperature isolation temperature switches. One switch, l TS-1-1360-143,* was found to trip at 231* F. This is in execes of the limit of1200* F, given in Table 3 2.1 of the Technical Specifications. 4 l All sixteen of the temperature switches were recalibrated to trip at

185* F + 5' F, - 10* F.

l DETERMTt!ATIO:I 0? CAUSE Al:D CORRECTIVE ACTIO?!

The switches were originally calibrated to 200* F 14* F within the t

allowable setpoint range of from 186* F to 214* F. This high setpoint, l along with nomal instrument drift, was the cause of the setpoint to exceed the <2CO F limit. With the switch sctroints now at 185*, possible

! drift can still occur, with the instrumait tripping within allowabic limits.

! SAFETY IFPLTCATIONS

There are no safety 11rplications of continued operation with one of sixteen switches over the limiting condition for operation. Likcuise, since the sctroint was lowered in a safe direction, the setpoint change of the switchco involved no safety implications. 4 -

e c, - s--6

j Mr.J.F.O'LearyO O May 1, 1974 s

CUMUIATIVE' EXPERIFJ:CE Since this refueling outage presents the first requirement for recalib-ration of the high temperature isolation temperature switches, no data for an evaluation based on cumulative experience is available.

Very truly yours, C010:0MEALTH EDISON COMPA!.T QIIAD-CITIE3 NUCIEAR POER STATION

/i-6

• 5 .b9%'

N. J. Kalivianakis

Station Superintendent NJK/LDR/saa cc: Region III, Directorate of Regulatory Operations ,

J. S. Abel S

w ll I

l 1

1 I

d L

l;

w. -