05000245/LER-1981-020, Forwards LER 81-020/03L-0.Detailed Event Analysis Encl

Forwards LER 81-020/03L-0.Detailed Event Analysis Encl

ML20010B918
Person / Time
Site:	Millstone
Issue date:	08/06/1981
From:	Mroczka E NORTHEAST UTILITIES
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20010B919	List: 05000245/LER-1981-020, Forwards LER 81-020/03L-0.Detailed Event Analysis Encl 05000245/LER-1981-020-03, /03L-0:on 810714,gas Turbine Failed to Accelerate Upon Receipt of Block Start Signal.Caused by Shutoff Valve for Air Start Motor Sticking in Closed Position Due to Rust Accumulation from Air Receiver
References
MP-1-1836, NUDOCS 8108180479
Download: ML20010B918 (3)

LER-1981-020, Forwards LER 81-020/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
2451981020R00 - NRC Website

text

JA NOIFIDIEAST IFFII.FFIES P.O. BOX 270 EsNEsE.Ir sN Mn,,

HARTFORD CONNECTICUT 06101

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L J :"':::L':3:,","lll,7ll MP-1-1836 August 6, 1981 Mr. Boyce H. Grier 3

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Director, Region I g

Office of Inspection and Enforcement ec U. S. Ntclear Regulatory Commission

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631 Parc Avenue k Sh1 J

7 )ggj > 1 King of Prussia, Pennsylvania 19406

Reference:

Provisional License No. DPR-21 mag,,T 7

'f Docket No. 50-245 Reportable Occurrence R0-81-20/3L 4

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Dear Mr. Grier:

This letter forwards the Licensee Event Report fr-Reportable Occurrence R0-81-20/3L required to be submitted within 30 ao,_ pursuant to the requirements of the Millstone Unit 1 Technical Specifications, Section 6.9.1.9b.

An additional three copies of the report are enclosed.

Yours truly, NORTHEAST NUCLEAR ENERGY COMPANY

//M 'N E.-

. Mroczka Station Superintendent Millstone Nuclear Power Station i

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EJM/TST:jf

Attachment:

LER R0-81-20/3L cc:

Director, Office of Inspection and Enforcement, Washington, D.C. (30)

Director, Office of Management Information and Program Control, i

Washington, D. C. (3)

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

20555 1

7 8108180479 810806 '

PDR ADOCK 05000245 g

PDR S

ATTACHMENT TO LER 81-20/3L 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 Gas Turbine Generator Failed to start.

CONDITIONS PRIOR TO OCCURRENCE Prior to occurrence the unit was increasing power from 85 percent of rated.

DESCRIPTION OF OCCURRENCE On July 14, 1981, at 1425 hours0.0165 days <br />0.396 hours <br />0.00236 weeks <br />5.422125e-4 months <br />, while testing the Gas Turbine for Unresolved Safety Issue A-44 " Station Blackouts", the Gas Turbine failed to accelerate upon receipt of a black start signal.

The Bla d Start signal for the Gas Turbine was initiated from the control room. The Gas Turbine followed its planned sequence of start up, to the point where the start relays picked up.

The " start signal received", and " sequence in process" indicators illuminated.

The next step in this sequence never occurred.

APPARENT CAUSE Investigation into the incident revealed that the shut off valve for the air start motor stuck in a closed position.

This valve is one of two that functions to admit air to the air start motor, which in turn accelerates the gas turbine to light off speed.

ANALYSTS GT ACCURRENCE Failure of the Gas Turbine to accelerate upon receipt of a black start signal did not create a condition which had not been analyzed.

The Gas Turbine is one out of two emergency power sources that are utilized'for engineered safeguard systems.

In an actual emergency condition where emergency core cooling systems are required and a loss of off-site power accompany it, The Gas Turbine and the Diesel provide emergency pov..r.

Each power source is independent of the other, thereby allowing the Gas Turbine or Diesel to solely provide emergency power if the other fails.

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CORRECTIVE ACTION

The valve was removed from the engine for disassembly to determine the cause of its malfunctioning.

Inspection of the internals showed accumulations of rust. The valve and valve operator internals were thoroughly cleaned, and teflon seats in the ball valve were replaced. The valve was bench tested and reinstalled.

The source of the contaminant is the starting tir compressor receiver which is fabricated of steel and has a large internal surface area that is susceptable to rustir:] from condensation.

Investigation into the type of paint to paint the internals of the air receiver to eliminate the rust particles that settle in the valve is in process.

In addition installing filters in the air lines is also a consideration.

There are no past occurrences of this shut off valve failing since the installation of the Gas Turbine 11 years ago; however, the air start regulator shut off valve Jid fail in a closed position because of rust accumulation this past year.

EJM/TST:jf w------- ----

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