ML20084A014

AO 4-2-2:limiting Safety Sys Settings of Channels I & III Discovered Below Tech Spec Requirement.Cause of Setpoint Drift Problem Under Investigation

ML20084A014
Person / Time
Site:	Indian Point
Issue date:	01/25/1974
From:	Cobean W CONSOLIDATED EDISON CO. OF NEW YORK, INC.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084A017	List: ML20084A014 ML20084A026
References
AO-4-2-2, NUDOCS 8304050068
Download: ML20084A014 (2)

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,g ; t b w b a b b .}'A Consolidated Edison Company of New York. Inc. g g 6 4 Irving Place, New York, N Y 10003 A January 25, 1974

. Re: Indian Point Unit No. 2 Facility Operating License DPR-26, A.O.-4-2-2 50-247 .

Mr. John F. O' Leary, Director Directorate of Licensing-Office of Regulations

• U.S. Atomic Energy Commission Washington, D. C. 20545 " *^-

Dear Mr. O' Leary:

The following report is provided pursuant to the requireme$ts of.

Section 6.12.2 (a) of the Technical Specifications to Facility ./

Operating License No. DPR-26.

Periodic surveillance test PT-M2, " Reactor Coolant Temperature Analog Channel Functional Test -A T Overtemperature ando T Over-power", was performed with Unit No. 2 in the cold shutdown con-dition. The limiting safety system settings of Channels I and III of the Overpower 4 T Reactor Trip circuitry were found to be below that required by Technical Specification 2.3.1.B95). Chan-nels I and III have since been recalibrated and tested satisfac-torily.

These par'ticular devices are part of a four channel reactor trip logic where activation of any two of the four bistables (one per channel) will produce a reactor trip signal, Since the Channel II and IV bistables were found to be operating correctly, over-power /1T would have caused a reactor trip to occur within the range prescribed by the Technical Specifications. -

.I As stated in our January 18, 1974 letter to you, Nuclear Power Generation Department is investigating the setpoint drift problem in conjunction with the manufacturer and our Engineering Depart-ment. If our investigation substantiates that a particular bi-stable component is the cause of the setpoint drifts experienced, we plan to replace these components on an appropriate progressive schedule with priority given to those components in the reactor i protection. circuitry. ,

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s Because*the logi7 circuitry wps still operating, safety implica-tions to the occurrence were not considered'significant. However, the, investigation into the! reasons for recently reported setpoint drift will c'o,ntinue 5/ith the intent of reditcing the likelihood of

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