ML20084A048

AO 4-2-1:low Steam Line Pressure Bistables Found Below Required Limit of 600 Psig.Cause of Setpoint Drift Under Investigation.Bistable Recalibr

ML20084A048
Person / Time
Site:	Indian Point
Issue date:	01/18/1974
From:	Cobean W CONSOLIDATED EDISON CO. OF NEW YORK, INC.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084A050	List: ML20084A048 ML20084A141
References
AO-4-2-1, NUDOCS 8304050079
Download: ML20084A048 (2)

Text

O o' 0

v J 9  % '.

'~

p g f'hCD Consolidated Edison Company of New York. Inc.

% 24 kg ,

Ri' 4;.

sf,.

~*M' '^

d C["q3 d a I 4 Irving Place. New York N Y 10003 . *

[rgf,j4 g, l

't,  %'hir m gl sy January 18, 1974 ' #

Re: Indian Point Unit No. 2 50-247 Facility Operating License i DPR-26 A.O. 4-2-1 Mr. John F. O' Leary, Director

Directorate of Licensing Office of Regulation U. S. Atomic Energy Commission Washington, D. C. 20545

Dear Mr. O' Leary,

The following report is provided pursuant to the requirements of

Section 6.12. 2 (a) of the Technical Specifications to Facility Op-

erating License No. DPR-26.

1 An analysis of the results of monthly periodic surveillance test PT-Mll (Steam Line Pressure Analog Channel Function Test) indicated I that one of the low steam line pressure bistables associated with high steam flow protection was found to be below that specified in Table 3-1 of the Facility Technical Specifications. Item 5 in this table specifies the setting limit to be equal to or greater than 600 psig. The setting found for this particular bistable was

approximately 586 psig. The other three bistables were found to be set correctly.

j This particular pressure setpoint is part of a four channel safety injection logic where activation of two of four high steam ficw in coincidence with low steam pressure channels are required to pro-duce a safety injection signal.

j At the time the test was conducted, the reactor was in the cold shut-down condition for maintenance work associated with repair to the feedwater piping for No. 22 steam generator. .The bistable found out of calibration was reset correctly and the channel associated with the device was retested satisfactorily.

Because this portion of the safety injection circuitry is actuated f by any two of these four pressure channels and since the other three j pressure bistables in the remaining three channels of this system .

l were found to be operating correctly, high steam flow in conjunction f

\

8304050079 740118 \i N 0S i PDR ADOCK 05000247 \ , b -

~

S PDR Q V

g j

_EOl'YJEN1'IEfrIOY - ,-l

O . O

/

NW., John F. O' Leary January 18, 1974 Re: Indian Point Unit No. 2 Facility Operating _ License DPR-26 A.O. 4-2-1 with low steam line pressure would have caused safety injection?

to actuate within the range prescribed in the Technical Specifi-cations.

I As stated in our letter to you of December 28, 1973 and January 4, 1974, we are investigating recent setpoint drif ts. Our Engineer-ing Department is conducting this investigation in conjunction with site personnel and the manufacturer of these devices. As a result of discussions with other utilities and the manufacturer, we de-termined that a suspect bistable component might have accounted I for the drifts experienced. If our investigation proves this to be the case, we plan to replace these components on an appropriate progressive schedule, with priority given to those components in the reactor protection circuitry.

Because the logic circuitry was still operating, safety implications to the occurrence are slight. However, the investigation into the reasons for recently reported setpoint drift will continue with the intent of reducing the likelihood of their incidence, very truly yours, ah% [ b') Oh <I Warren R. Cobean, Jr., Manager Nuclear Power Generation cc: Mr. James P. O'Reilly i

l l

l e

d 4

w w