ML20084B009

AO 50-244/75-1:on 750108,turbine Governor Valve & Associated Trip & Throttle Valve Tripped to Closed Position Approx 15 After Steam Supply Quick Start Valves Opened.Caused by Degraded Lube Oil Supply Pressure Due to Instrument Drift

ML20084B009
Person / Time
Site:	Ginna
Issue date:	01/17/1975
From:	White L ROCHESTER GAS & ELECTRIC CORP.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20084B012	List: ML20084B009 ML20084B021
References
AO-50-244-75-1, NUDOCS 8304060068
Download: ML20084B009 (3)

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ROCHESTER GAS AND El.ECTRIC CORPORATICH e 89 EAST AVENUE,. ROCHESTER. N.Y.14649

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LEON O. 'A HITE. JR t r $ a *-e .r weet rat t.oteer ama a coct 7.e 5 3 6 2 */OO January 17, 1975

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Mr. James P. O'Reilly, Director  ;

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Directorate of Regulatory Operations -

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Region I , ,e U. S. Atomic Energy Commission ,

631 Park Avenue sfgj T3]T p King of Prussia. Fenr sylvania 19406

Subject:

Abnormal Occurrence 75-1, Turbine Driven Auxiliary Peedwater Pump Trip R. E. Ginna Nuclear Power Plant, Unit No.1 Docket No. 50-244 i

Dear Mr. O'Reilly:

In accordance with Technical Specifications, Article 6.6.2a, the attached report of Abnormal Occurrence 75-1 is hereby submitted.

Very truly.yours, L. D. White , Jr.

Attachment

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' o22 8304060068 750117 gDRADOCK 05000244 PDR

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, o Rnport Number: 50-244/75-1 o

~2a. Report Date: January 17, 1975 2b. Occurrence Date: January 8,1975

3. Facility: R. E. Ginna Nuclear Power Plant, Unit No.1 ,

4. Identification of Occurrence:

This abnormal occurrence is defined by Technical Specifications Article 1.9d: Failure of one or more components of an engineered safety feature or plant protection system that causes or threatens to cause the feature or system to be incapable of performing its intended function. -

5. Coriditions Prior to Occurrence:

The unit was operating at steady state level of 97% power.

6. Description of Occurrence:

While performing surveillance testing (Pt 16) on the turbine driven auxiliary feedwater pump the turbine governor valve and associated trip and throttle valve tripped to their closed position in approximately 15 seconds after the steam supply quick start valvcs were opened.

Investigation revealed that the low lube oil pressure trip device had been actuated. Attention was directed to the gauge monitoring.the oil pressure in the low lube oil pressure trip device. At essentially static condition (turbine rolling slowly) the gauge reading was 7 psig.

i This pressure reading decreased to 4 psig as another turbine start was-effected and the unit accelerated to operating speed. The control board operator was beginning to throttle closed the auxiliary feedwater control valves to reduce the flow delivery rate to the steam generators to that required by Plant Technical Specifications as proof of proper pump.

operability, and, as before, the unit tripped.

Adjustments were made to reduce the lube oil low pressure trip, set point, after which the. surveillance test was c.ompleted, successfully. . ,

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7. Desionation of Apparent Cause of Occurrence:

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It was determine'd that the turbine driver was tripping because of a degraded lube oil supply pressure due to drift of the lobo' oil supply regulator. The surveillance test procedure did not provide for checking l the performance of the lube oil supply regulator, and, although it pro-vided for verification of the actuation of the iube oil low level trip device, it did not provide for noting the pressure at tri'p.

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• Analysis of Occurrence:

Three auxiliary feedwater pumps exist at the Ginna plant, two motor driven and the one steam driven. .

Plant Technical Specification requirement 3.4.1 states that.

when the' reactor coolant is heated above 350 F, 0 the reactor shall not -

-be taken critical unless two of the three auxiliary feedwater pumps are operable. It can be postulated that the lowering of the oil supply pressure occurred some time after the previously performed monthly test of the steam driven auxiliary feedwater pump. However, as thel -

remaining two motor driven pumps were at all timesoperable during this period, adequate plant protection existed. The health and safety of the public was not affected or placed in jeopardy in any manner due to this incident.

9. Corrective Action:

The PORC reviewed this incident and recommended the following l a ction s .

The lube oil supply pressure and the low lube oil pressure trip cctting v? crc cdjucted tc th :ncnufccturcr cpecificcticn,- O peig cnd 3 psig respectively.

To prevent recurrence of this incident the desired lube oil supply '

pressure and the desired pressure at trip will be included in the sur-veillance procedure and will be verified with each test performance.

10. Failure Data:

a. There has been no prior incident'of a low lube oil pressure trip occurring on this unit.

b. Equipment Identification:

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Type: 525 reducing regulator i

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