ML19290F142
| ML19290F142 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 03/10/1980 |
| From: | William Jones OMAHA PUBLIC POWER DISTRICT |
| To: | NRC OFFICE OF ADMINISTRATION (ADM), Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19290F143 | List: |
| References | |
| NUDOCS 8003180176 | |
| Download: ML19290F142 (1) | |
Text
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Omaha Public Power District 1623 HARNEY a OMAHA. NEDRASMA 68102 e TELEPHONE 536-4000 AREA CODE 402 March 10, 1980 Director of Nuclear Reactor Regulation
% Distribution Services Branch, DDC, ADh U. S. fluclear Regulatory Commission Washington, D. C.
20555
Reference:
Docket No. 50-285 Gentlemen:
In accordance with 10 CFR 50, Appendix H, the Omaha Public Power District herewith submits eleven (11) copies of a technical report entitled " Evaluation of Irradiated Capsule W-225".
This technical report addresses the results obtained from evaluation of irradiated materials from surveillance capsule W-225, which was removed from the Fort Calhoun Station reactor vessel in October,1977, after 2.6 ef-fective full power years of reactor operation.
The measured results did not agree with those predicted for the reactor vessel beltline region due to unforeseen non-uniform flux dis-tribution.
This is caused by the small size of the core and its sub-sequent rough approximation of a cylinder.
The Commission was notified of this discrepancy by the District on May 17, 1979.
Interim pressure-temperature curves, based on the measured fluence values, were provided to the District by Combustion Engineering, Inc. (CE).
Additionally, a review conducted by CE verified that plant operations prior to the revised temperature-pressure curves had been withe, the limits of the revised curves and at no time were the revised limits exceeded.
The measured fluence and metal transition temperature shif ts were found to be in close agreement with the prediction, based upon the methods of Regulatory Guide 1.99.
Those methods have been adopted for use in predicting future temperature shifts.
The next surveillance specimen capsule is scheduled to be withdrawn at 10 effective full power years (EFPY) reactor operation.
The curves for pressure-temperature limitations provided in the enclosed report are useful through 8.3 EFPY; however, the District has the capability of generating curves to 10 EFPY.
Sincerely, W.C.'Jo&
M nes Division Manager Produ' tion Operations c
WCJ/KJM/BJH:jmm Enclosures cc:
LeBoeuf, Lamb, Leiby & MacRae 800378ot%