ML20004B049

Responds to Generic Ltr 81-19 Re Thermal Shock to Reactor Pressure Vessels.Util Will Participate in Program Defined at 810604 Meeting.Surveillance Capsule Calculations Provided in 800310 & s

ML20004B049
Person / Time
Site:	Fort Calhoun
Issue date:	05/22/1981
From:	William Jones OMAHA PUBLIC POWER DISTRICT
To:	Eisenhut D Office of Nuclear Reactor Regulation
References
GL-81-19, NUDOCS 8105270155
Download: ML20004B049 (2)

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1623 MARNEY 8 OMAMA. NESRASKA 64i02 a TELEPHONE S38 4000 AREA CODE 402 May 22, 1981 p \\ t% fpV'/

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Mr. Darrell G. Eisenhut, Director

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Office of Nuclear Reactor Regulation

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Division of Licensing Washington, D.C.

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References:

1) CEOG Letter from K. P. Bask 3a to Darrell Eisenhut dated May 15, 1981.

2) OPPD Letter from W. C. Jones to Director of Ni1R dated March 10, 1980.

3) OPPD Letrer from W. C. Jones to Director of NRR dated January 23, 1981.

Dear Mr. Eisenhut:

Subj ect: Reactor Vessel Pr ssurizer Thermal Shock This letter is in response to Generic Letter 81-19 of April 20, 1981, on thermal shock to reactor pressure vessels. Reference 1 transmitted to you the CE Owners Group's response to your request at a meeting on March 31, 1981, and responds to further reports and clarifications which you provided at a meeting on April 29, 1981. Omaha Public Power Dis-trict intends to fully participate in the CE Owners Group program on the issue of reactor vessel prersurized thermal shock. Reference 1 outlined the proposed program which will be acted on at the CE Owners Group meeting on June 4, 1981. Omaha Public Power District will participate in th> program defined at this meeting.

Omaha Public Power District has removed the first surveillance capsule

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from its Fort Calhoun Station. The reports on this capsule are con-l tained in References 2 and 3.

The measured fluence at 2.6 EFPY was 5.1 2

x 1018 n/cm. The original target, contained in the FSAR was 1.8 x 2

3 1018 n/cm. The calculations for the specimen are contained in Reference 3 and show a calculated fluence of 5.1 x 1018 n/cm. The calculations 2

show an 20L fluence of 4.2 x 1019 n/cm2 versus a design estimate of 2.9 i

x 1019 n/cm. Therefore, the measured fluence and calculations show the 2

fluence to be a factor of 2.1 higher than the design estimate. At E0C 6 the vessel will have received a fluence equivalent to approximately 5.3 EFPY exposure. Based upon the calculations contained in Reference 1, it fool 5

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Mr. Darrell G. Eisenhut May 22, 1981 Page Two is estimated that reactor vessel pressurized thermal shock will not become a problem at the Fort Calhoun Station for at least another four (4) EFF. Therefore, the District concludes there is sufficient time for i

an orderly resolution of this problem.

Sincerely, Aw yp/

W. C. Jones j

Division Manager Production Operations

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