05000245/LER-1981-019, Forwards LER 81-019/03L-0.Detailed Event Analysis Encl

Forwards LER 81-019/03L-0.Detailed Event Analysis Encl

ML20030B282
Person / Time
Site:	Millstone
Issue date:	07/27/1981
From:	Mroczka E NORTHEAST NUCLEAR ENERGY CO.
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20030B284	List: 05000245/LER-1981-019, Forwards LER 81-019/03L-0.Detailed Event Analysis Encl 05000245/LER-1981-019-03, /03L-0:on 810701,switch PS-263-55A Tripped Outside Allowable Setpoint Band.Caused by Setpoint Drift.Switch Recalibr to Required Setpoint & Satisfactorily Tested
References
MP-1-1828, NUDOCS 8108060284
Download: ML20030B282 (2)

LER-1981-019, Forwards LER 81-019/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
2451981019R00 - NRC Website

text

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July 27, 1981 MP-1-1828

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U. S. Nuclear Regulatory Commission

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Reference:

Facility Operating License No. DPR-21 Docket No. 50-245 Reportable Occurrence R0-81-19/3L 3

Dear Mr. Grier:

This letter forwards the Licensee Event Report for Reportable Occurrence R0-81-19/3L required to be submitted within thirty days pursuant to the requirements of the Millstone Unit 1 Technical Specifications, Section 6.9.1.9.a.

An additional three copies of the report are enclosed.

Yours truly, NORTHEAST NUCLEAR ENERGY COMPANY 45

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. Mroczka Station Superintendent Millstone Nuclear Power Station I

EJM/TST:bjo

Attachment:

LER R0-81-19/3L cc:

Director, Office of Inspection and Enforcement, Washington, D. C.

(30)

Director, Office of Management Information and Program Control, Washington, D. C.

(3)

U. S. Nuclear Regulatory Commission, c/o Document Management Branch, Washington, D. C.

20555 4'll 8108060284 810727 PDR ADOCK 05000245 S

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ATTACHMENT TO LER 81-19/3L NORTHEAST NUCLEAR ENERGY COMPANY MILLSTONE NUCLEAR POWER STATION - UNIT 1 PROVISIONAL LICENSE NUMBER DPR-21 DOCKET NUMBER 50-245 IDENTIFICATION OF OCCURRENCE A reactor protection system instrument setting was fcJnd to be less conservative than that established by Technical Specifications.

CONDITIONS PRIOR TO OCCURRENCE The plant was operating at a steady state level of 100 percent.

DESCRIPTION OF OCCURRENCE On July 1,1981 during routine surveillance, Reactor Vessel High Pressure Scram Functional and Calibration Test, it was discovered that pressure switch 263-55A tripped at 1110 psig.

The trip level setting of this switch is required by Technical Specifications (T.S. 3.1, Table 3.1.1.) to be less than or equal to 1085 psig.

The switch setpoint limit is 1098 psig (1085 psig 'lus 13 psi head correction).

APPARENT CAUSE The failure of this switch to trip at its desired setpoint was attributed to setpoint drift.

ANALYSIS OF OCCURRENCE The switch in question is one of four switches arranged in a one-out-of-two-twice logic system that initiates a reactor scram and actuates the Isolation Condenser System, based on the high pressure signal (1085 psig for 15 seconds, Technical Specification 3 2 Table 3.2.2).

Failure of one of the switches to trip at the desired setpoint did not impair operability of the system. The remaining switches were found to be at the proper setpoint and would have initiated the required action upon receipt of a reactor vessel high pressure. Therefore, no safety was compromised.

CORRECTIVE ACTION

The pressure switet was reset to its required setpoint and satisfactorily tested.

The switch is a Meletron Model No. 372 with a range of 28 to 1400 psig.