05000245/LER-1982-010, Forwards LER 82-010/03L-0.Detailed Event Analysis Encl

Forwards LER 82-010/03L-0.Detailed Event Analysis Encl

ML20053A332
Person / Time
Site:	Millstone
Issue date:	05/13/1982
From:	Mroczka E NORTHEAST NUCLEAR ENERGY CO.
To:	Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20053A333	List: 05000245/LER-1982-010, Forwards LER 82-010/03L-0.Detailed Event Analysis Encl 05000245/LER-1982-010-03, /03L-0:on 820413,while Performing Emergency Svc Water Sys Operational Readiness Test,Valve 1-LPC-4A Failed to Open When Emergency Svc Water Pumps Started.Caused by Excessive Play in Potentiometer.Slider Adjusted
References
MP-1-2069, NUDOCS 8205250216
Download: ML20053A332 (2)

LER-1982-010, Forwards LER 82-010/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
2451982010R00 - NRC Website

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May 13, 1982 MP-1 2069 Mr. Ronald C. Haynes Regional Administrator, Region 1 Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406

Reference:

Provisional License DPR-21 Docket No. 50-245 Reportable Occurrence R0-82-10/3L

Dear Mr. Haynes:

This letter forwards the Licensee Event Report for Reportable Occurrence R0-82-10/3L required to be submitted within 30 days pursuant to the requirements of the Millstone Unit 1 Technical Specifications, Section 6.9.1.9.b.

An additional three copies of the report are enclosed.

Yours truly, NORTHEAST NUCLEAR ENERGY COMPANY

• C, E. J. Mroczka Station Superintendent Millstone Nuclear Power Station EJM/TST:mo

Attachment:

LER R0-82-10/3L 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 8205250216 820513 PDR ADOCK 05000245 S

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0 ATTACHMENT TO LER 82-10/3L NORTHEAST NUCLEAR ENERGY COMPANY MILLSTONE NUCLEAR POWER STATION - UNIT 1 PROVISIONAL LICENSE NUMBER DPR-21 DOCKET NUMBER 50-245 Identification of Occurrence Operation in a degraded mode permitted by a limiting condition for operation occurred when the emergency service water discharge valve on the Low Pressure Coolant Injection heat exchangers failed to open.

Conditions Prior to Occurrence Prior to occurrence the unit was operating at a steady state power level of 100 percent.

Description of Occurrence On April 13,1982, at 1015 hours0.0117 days <br />0.282 hours <br />0.00168 weeks <br />3.862075e-4 months <br />, while performing Emergency Service Water System Operational Readiness Test, valve 1-LPC-4A failed to open when the emergency service water pumps started.

Technical Specifications 3.5.B.1 requires both containment cooling subsystems be operable whenever irradiated fuel is in the reactor.

Apparent Cause of Occurrence Investigation of the gear train revealed excessive play in the potentiometer.

This allowed the slider on the potentiometer to crossover and indicate full open.

This prevented the valve from opening.

Analysis of Occurrence The Emergency Service Water (ESW) system supplies cooling water to the Low Pressure Coolar.t Injection (LPCI) heat exchangers.

Two LPCI subsystems are designed to provide emergency cooling to the cure by flooding in the event of a loss of coolant accident.

Valve 1-LPC-4A, located on the ESW outlet side of LPCI heat exchanger A, auto-matically opens when the ESW pumps start. This valve also automatically throttles to maintain ESW pressure 15 psig above LPCI system pressure.

Failure of 1-LPC-4A to open did not result in a condition that had not been previously analyzed.

LPCI consists of two independent subsystems A & B, each designed to provide adequate cooling.

LPCI subsystem B was available and would j

had provided the emergency cooling in the event of a loss of coolant accident.

Corrective Action

The slider on the potentiometer was adjusted to indicate the proper position.

The test was repeated and valve 1-LPC-4A opened.

In addition, as much excessive play from the gear train as possible was removed.