ML17252A872

Letter Regarding Analysis of Results of Monthly Periodic Surveillance Test PT-M11 (Steam Line Pressure Analog Channel Function Test) Indicated That One of the Low Steam Line Pressure Bistables Associated with High Steam - Indian Point Unit

ML17252A872
Person / Time
Site:	Indian Point
Issue date:	01/18/1974
From:	Cobean W Con Edison, Consolidated Edison Co of New York
To:	O'Leary J US Atomic Energy Commission (AEC)
References
Download: ML17252A872 (2)

Text

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,I Consolidated Edison Company of New York, Inc.

4 Irving Place, New York, NY 10003 January 18, 1974 Re: Indian Point Unit No. 2 50-247 F~cility Operating License DPR-26 A.O. 4-2-1 Mr. John F. O'Leary, Director Directorate of Licensing Off ice 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.

An analysis of the results of monthly periodic surveillance test PT-Mll (Stearn Line Pressure Analog Channel Function Test) indicated 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.

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

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 sfearn 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 by any two of these four pressure channels and since the other three pressure bistables in the remaining three channels of this system were found to be operating correctly, high steam flow in conjunction

.. Mr.

John F. O'Leary *.' ,, *~..a;;;

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.

As stated in our letter to you of December 28, 1973 and January 4, 1974, we are investigating recent setpoint drifts. Our Engineer-ing Department is conducting this investigation in conj-unction 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 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, w~&_Gek~

Warren R. Cobean, Jr., Manager Nuclear Power Generation cc: Mr. James P. O'Reilly