ML20128A318

Discusses Status of Preoperational Load Testing of DGs for Sbo/Electrical Safeguards Upgrade Project

ML20128A318
Person / Time
Site:	Prairie Island
Issue date:	01/25/1993
From:	Parker T NORTHERN STATES POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
TAC-M80659, TAC-M80660, NUDOCS 9302020188
Download: ML20128A318 (2)

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Northern States Power Company 414 4 collet MiJl Minneapoks, Minnesota 55401 Telephone (612) 330 5500 January 25, 1993 10 CFR Part 50 Section 50.63(c)(d) ,

U S Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 PRAIRIE ISLAND NUCLEAR CENERATING PLANT Docket Nos. 50-282 License Nos, DPR-42 50-306 DPR 60 Preoperacional Load Testing of Diesel Generators for the Station Blackout / Electrical Safeguards Upgrade Project (TAC Nos. M80659/80660)

References:

1) Letter from Thomas M Parker, Northern States Power Company, to U S Nuclear Regulatory Commission dated September 29, 1989 titled " Project for Addition of Two Emergency Diesel Generators"

2) Letter from Dominic C Dilanni, U S Nuclear Regulatory Commission dated January 31, 1990 titled " Safety Evaluation Related to the Emergency Diesel Generator Qualification Plan (TAC No,s 68588 and 68589)

On September 29, 1989, we submitted for NRC Staff review the Qualification Plan (contained in Reference 1) for two new omergency diesel generators <that se were planning to install. Our qualification program was found acceptable by the Staff (Reference 2). .We have completed the installation and the qualification testing of the new diesel germtators. However, we did-not complete one of the tests in'the manner te which we had committed.

We had committed to a repetition of the factory 24-hour load test on-site for each of the two diesel generators. The commitment included a 24-hour run of-the diesel generator in which 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> are with the machine loaded at 100% of the continuous rating of the diesel generator and 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> are with the machine loaded at 110% of the continuous rating. We ran the test on each of our diesel generators with the machine loaded at 75% of continuous rating 'for.2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />,100% of continuous rating for 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br />, and 110% of continuous rating for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. Prior to placing the'new diesel generators in service, we realized our error and brought it to the attention of the NRC Staff on January 7, 1993.

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"I Northern States Power Company :

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-January 25,:1993 Page 2 of~2 We evaluated the as completed testing program and determined that the testing

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was adequate to establish the-initial operability of the diesel generators.

We believe that even the 24-hour lond test as we performed it was more than ~

adequate to demonstrate the capability of-the diesel generators-to meet the- ,

design accident load requirements. We installed diesel generators that have-excess load capacity. The continuous load capacity of; each new- diesel._

generator is 5400 kW whereas the loading during a desig basis accident with-an accompanying loss of offsite power is _less than 3400 kW. So, even testing at 75% of the continuous rating (4050 kW) exceeds the accident _ loading.

Therefore, we believe that this test was adequate to-test the machines for their current application.

We will repeat these tests during our first 18-month surveillance of the diesel generators. During these 24-hour tests, we will sequentially load each -

diesel generator to 110% of the continuous rating for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and to-100% of the continuous rating for 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br />, in that order. -Until these tests are completed, we will programmatically limit the addition of any safeguards -loads.

su that the accident loads on each diesel generator will not exceed 4050 kW.

In summary, we concluded that our as-completed test program was adequate-to establish the operability of the new safeguards diesel generators. In addition, we have made two new NRC commitments to: 1) re perform the-24-hour load-tests and 2) limit additional loads on the diesel generators until these tests are completed.

Please contact Jack Leve111e (612-388-1121, Ext, 4662) if you have any questione related to'this letter.

7)Ah Thomas M Parker -

Director Nuclear Licensing .

l c: _ Regional Administrator - Region III,-NRG L Senior Resident Inspector, NRC NRR Project Manager, NRC J E Silberg v

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