ML20008F812

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Informs That Heat Slabs Used in Large Break LOCA Modeling in Conjunction W/Lower Plenum Phase Separation Model Due to Addl Stored Energy.Heat Slabs May Have Effect on Predicted Lower Plenum Phase Model Addressed in to NRC
ML20008F812
Person / Time
Site: Yankee Rowe
Issue date: 05/05/1981
From: Kay J
YANKEE ATOMIC ELECTRIC CO.
To: Check P
Office of Nuclear Reactor Regulation
References
FYR-81-71, NUDOCS 8105120093
Download: ML20008F812 (1)


Text

YANKEE ATOM 10 ELECTRIC C0 PANY 1671 Worcester Road, Framingham, Massachusetts 01701 g

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May 5, 1981 P,

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United States Nuclear Regulatory Commission A

Washington, D. C.

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Attention:

Mr. Paul S. Check Assistant Director for Plant Systems M

Division of Systems Integration

References:

(a) License No. DPR-3 (Docket No. 50-29)

(b) YAEC Letter to USNRC dated April 1, 1981 (FYR 81-53)

(c) YAEC Letter to USNRC dated March 26, 1981 (FYR 81-52)

Subject:

Clarification on Use of Heat Slabs in Large Break LOCA Modeling for Yankee Rowe

Dear Sir:

During the review of the lower plenum phase separation model for Yankee Rowe, YAEC-1231 (Reference (b)), it was pointed out in phone conversations with your staff that some of the lower plenum internals (upper and lower tie plates and shroud tubes) were not represented by heat slabs.

In developing the original Yankee Rowe large break LOCA model it was felt that this small amount of metal would not have an effect on the large break LOCA results and was therefore neglected. However, these heat slabs might have an effect on the predicted lower plenum liquid mass, due to the additional stored energy and therefore have been included in the large break LOCA model in conjunction with the use of the lower plenum phase separation model in Reference (c).

We hope that the addition of the new heat slabs in the lower plenum region will alleviate your concerns. However, if there are further questions, please contact us.

Very truly yours, YANKEE ATOMIC ELECTRIC COMPANY J. A. Kay Senior Engineer - Licensing JAK/kab k<50.l., S Io 8105120 CSS P