ML20042G776

LER 90-003-00:on 900409,determined That Piping & Supports in Fuel Oil Pumphouse Could Not Be Demonstrated to Perform Support Functions.Caused by Design Base Not Sufficiently Documented.Mod Performed to Support Fuel Oil Piping

ML20042G776
Person / Time
Site:	Point Beach
Issue date:	05/09/1990
From:	Fay C WISCONSIN ELECTRIC POWER CO.
To:
Shared Package
ML20042G745	List: ML20042G744 ML20042G776
References
LER-90-003, LER-90-3, NUDOCS 9005160075
Download: ML20042G776 (3)

Text

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As a result of evaluating the seismic adequacy of the fuel oil piping from the emergency fuel oil tank to the emergency diesel generators, in response to item 4(a) of NRC inspection reports 1 50-266/89012 (DRS) and 50-301/89011 (DRS) we determined that piping and supports in the fuel oil pumphouse could not be demonstrated to perform their support functions under the loading conditions imposed by an operating basis seismic event. On April 9, 1990, we entered into a 3-hour limiting condition for operation since the ability to transfer the required 11,000 gallons of fuel to the diesel generators could not be assured following a seismic event. A Temporary Waiver of Compliance was requested from NRC-Region III and granted. Modifications were performed to the system to insure its operation following a design basis event.

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.n. .. .ac=amawn EVENT DESCRIPTION On April 9, 1990, Unit 1 was shutdown for its annual maintenance outage. Unit 2 was operating at 100% power.

The seismic adequacy of the fuel oil transfer piping was evaluated in response to item 4(a) of NRC Inspection Report 50-266/89012 (DRS) and 50-301/89011 (DRS) dated June 6, 1989. We had committed to perform this evaluation of the as-built design of the system by ,.

I July 1990. Information was provided by the engineering staff that there existed the potential for a seismic induced failure of the "

fuel oil transfer piping from the emergency fuel oil storage tank to the diesel generators and a formal operability. determination requested. At 1600 on April 9, 1990, the Manager declared the fuel ,

oil transfer system inoperable. i

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Technical Specification 15.3.7.A'.l.e requires a fuel oil supply of 11,000 gallons be available in order for one or both reactors to be >

made critical. Technical Specification 15.3.7=.B.1.e permits one of .

the two diesel generators to be inoperable for a period not to exceed 7 days. Since a seismic event could render the fuel oil'  :

transfer system inoperable, the supply of 11,000' gallons of fuel to l

the diesels could not be guaranteed. We entered a 3-hour limiting condition for operation in accordance with Technical Specification 15.3.0.A which would require us to place UnitL2, the operating unit, into hot shutdown within the three hours. We immediately requested a Temporary Waiver of Compliance to allow time for corrective action-to be taken.

SYSTEM DESCRIPTION The Point Beach Nuclear Plant has two diesel generators shared between the two units. Each diesel'has a base mounted fuel-oil-tank-and a fuel oil day tank, each with a capacity to supply the associated diesels with enough fuel for about two hours of operation at. rated-  !

capacity. Fuel is made up to the day tanks by the fuel oil transfer system which consists of a below ground, seismically designed emergency tank of 12,000 gallon capacity,-two transfer pumps, and associated piping. There are also two above ground non-seismic.

storage tanks each with about 60,000 gallon capacity. 3 CAUSE The Point Beach Nuclear Plant was built as a turnkey project from July 1967 through November 1971 by the Westinghouse Electric Corporation as the NSSS contractor with the Bechtel Corporation as Architect Engineer. We have found, that given the turnkey nature of the plant and vintage, design bases are not~always sufficiently documented. We have recently initiated efforts to re-examine and g,. ~. . . . u - 4.

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reconstitute the design basis for selected systems, including the Emergency Power System. It was during this evaluation that the  !

potential for seismically induced failure of the fuel oil transfer  !

system was identified. t REPORTABILITY This event was reportable in accordance with the requirements of 10 CFR 50.73 (a)(2)(v), "The licensee shall report...any event or condition that alone could have prevented the fulfillment of the safety function of structures or systems...". 10'CFR 50.73 (a)(2)(vi)

• provides further clarification of the above which includes design.

inadequacies, i CORRECTIVE ACTION Short-term 2

1. Two fuel oil tanker trucks were obtained with approximately 14,000 gallons of fuel oil and placed in a safe location on site. The capability to transfer fuel from the trucks to the day-tanks was verified.

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2. The above ground bulk storage tanks were isolated from the

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emergency tank and placed under the administrative control of the Duty Shift Superintendent who would designate a person to operate the isolation valves if required to accomplish fuel oil transfer.

Long-term

1. A modification was performed to seismically support the fuel oil piping within the fuel oil pumphouse. This modification was completed on April 15, 1990.

SAFETY ASSESSMENT Upon the discovery of the design inadequacy of the fuel oil transfer -

system, prompt action was taken to insure that a fuel oil supply was '

available to the diesel generators if required. The probability of a seismic event with a concurrent loss of offsite power is low.

Therefore, the health and safety of the public and workers at the plant site were not je6pardized.

GENERIC IMPLICATIONS There are no known generic implications from this event,

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