ML19347C810

Ao:On 731221,four Isolation Condenser High Flow Sensors Failed to Trip on Delta P Values During Surveillance Testing Due to Setpoint Drift.Cause of Setpoint Drift Investigated. Sensors Reset & Procedures Reviewed

ML19347C810
Person / Time
Site:	Oyster Creek
Issue date:	01/04/1974
From:	Ross D JERSEY CENTRAL POWER & LIGHT CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 8103040798
Download: ML19347C810 (2)

Text

-

ND Infery g Jersey Central Power & Light Company T V'

MADISON AVENUE AT PUNCH BOWL ROAD

• MORRISTOWN, N.J.07960

• 201-539-6111 ma mean or rue General { , Pubhc Utilities Corporation srsrs = , ..

. ~,

January 4, 1974 , y / . . ;: _ N. ,

j' Ci, /,/ / / \, \q l' Ll)

Mr. A. Giambusso 4ryy' A

v 1pt 4-

. a [

(_ 7 ~f Deputy Director for Reactor Projects \

,J Directorate of Licensing /v United States Atomic Energy Com.nission \(, * . s{,; -

Washington, D. C. 20545 x .y

Subject:

Oyster Creek Station Docket No. 50-219 Drift in Set Point of Isolation Condenser liigh Flow Sensors This letter serves to report the failure of four isolation condenser high flow sensors to trip on AP values that conform to those stated in Tech-nical Specification Table 3.1.1.11 (<20 psid - steam, <27 inches AP 110 _ 2 -

condensate).

This event is considered to be an abnormal occurrence as defined in the Technical Specifications, paragraph 1.15A. Notification of this event, as required by the Technical Specifications, paragraph 6.6.2.a, was made to AEC Region I, Directorate of Regulatory Operations, by telephone on Friday, Decem-ber 21, 1973, and by telecopier on Wednesday, December 26, 1973.

On Friday, December 21, 1973, while performing surveillance testing on the isolation condenser high flow sensors (two each per condensate and steam line per condenser), four of the sensors were found to trip at set points in excess of their respective limits. Specifically, the sensors of concern and their corresponding "as found" set points were as follows:

Condensate ,

"A" Condenser IB11A1 - 29" of water d'f i l 4}[.f. ,

4j3 ef%; k IB11A2 - 31" of wate y 1B11B2 - 29" of wat r'i <

~

% b

& r 4,o W k .'

Steam , . , . N , ., 4  !

Q' jy if';r

/ ~ f A.

"B" Condenser IB05B1 - 22 psid J 74,y* -[g xy The reason for the drift in set points is yet to be ' ed.

%io3o10798 1 1

- (

Mr. Giambusso January 4,1974 Upon discovery of the condition, the instrument technician performing the surveillance test reset the affected differential pressure (d/p) sensors to their required values ($,27 inches H O 2 on condensate and 3,20 psid on the steam).

The safety implication of this event is minimal, since the sensors were operable and would have performed their function. Past data has shown that upon initiating the condensers, the condensate line senses d/p in excess of 60 inches of water; therefore, although the set point had drifted, the new value was well within the range of the expected signal and the sensor was capable of performing its protective action.

A review of the surveillance procedures will be made to insure that the test and calibration methods and instruments are consistent with the capability of the instruments under surveillance.

In addition, an investigation will be made into the feasibility of submitting a Technical Specification change to include tolerances on instrument trip set points to account for instrumentation design accuracies where applicable.

Enclosed are forty copies of this report. ,

Very truly yours, A W v Donald A. Ross Manager, Nuclear Generating Stations es Enclosures  ;

cc: Mr. J. P. O'Reilly, Director ,

Directorate of Regulatory Operations, Region I l

[

i E

I I

r I

,