B12238, Forwards Item II.K.3.31,NUREG-0737,Small-Break LOCA Evaluation,Large-Break LOCA Evaluation, Per Wg Counsil to DG Eisenhut & EP Rahe to Co Thomas. Analyses Will Be Ref in Proposed License Amend

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Forwards Item II.K.3.31,NUREG-0737,Small-Break LOCA Evaluation,Large-Break LOCA Evaluation, Per Wg Counsil to DG Eisenhut & EP Rahe to Co Thomas. Analyses Will Be Ref in Proposed License Amend
ML20209E838
Person / Time
Site: Millstone Dominion icon.png
Issue date: 08/29/1986
From: Opeka J
NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To: Thadani A
Office of Nuclear Reactor Regulation
Shared Package
ML20209E842 List:
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-2.K.3.30, TASK-2.K.3.31, TASK-TM B12238, TAC-48179, TAC-63133, TAC-63198, NUDOCS 8609110367
Download: ML20209E838 (2)


Text

3 O General Offices

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, (203) 865-5000 August 29,1986 Decket No. 50-336 B12238 Office of Nuclear Reactor Regulation Attn: Mr. Ashok C. Thadani, Director PWR Project Directorate //8 Division of PWR Licensing - B U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Gentlemen:

Millstone Nuclear Power Station, Unit No. 2 Item II.K.3.31, NUREG-0737 Small Break LOCA Evaluations In a letter dated September 11,1984(l), it was stated that Northeast Nuclear Energy Company (NNECO) had been informed by Westinghouse Electric Corporation, the fuel vendor for Millstone Unit Ng. 2, that WCAP-10054, Addendum I has been submitted to the NRC Stafft2) for its review. The Reference (2) cubmittal described the application of the NOTRUMP computer code to "small-break" Loss-of-Coolant Accident (LOCA) evaluations for those nuclear units of Combustion engineering design such as Millstone Unit No. 2. As stated in Reference (1), NNECO considered that submittal to address NUREG-0737 Item II.K.3.30 for Millstone Unit No. 2. Reference (1) also stated that completion of NRC Staff review of NOTRUMP and WCAP-10054, addendum I would facilitate future "small-break" LOCA evaluations for Millstone Unit No. 2.

Accordingly, attached for your information is a unit specific "small-break" LOCA evaluation for Millstone Unit No. 2. This evaluation was conducted using the NOTRUMP computer code described in Reference (2). It is the conclusion of NNECO that this submittal addresses Item II.K.3.31 for Millstone Unit No. 2.

In addition to the "small-break" LOCA reanalysis, the "large-break" LOCA eval-uation for Millstone Unit No. 2 has also l een reanalyzed.

(1) W. G. Counsil letter to D. G. Eisenhut, dated September 11,19F' .

(2) E. P. Rahe letter to C. O. Thomas, dated August 10,1984 0

8609110367 860029 \

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  • The "large-break" LOCA evaluation is hereby being submitted at this time as -

well. Both of these analyses will be referenced in a proposed license amendment request with respect to Reactor Coolant Flow Rate, as defined in Technical Specification 3.2.6, that NNECO is planning to submit to the NRC Staff in the -

near future.

The attached "sma!!-and-large break" LOCA analyses conservatively assume that 23.4% of all steam generator tubes are plugged in order 'to fully bound the eifects of reduced RCS flowrate and steam generator heat transfer area on peak clad temperature. The present steam generator equivalent plugging level is approximately 12 % Therefore, the attached analyses inherently contain significant conservatisms with respect to the effects of tube plugging on peak clad temperature.

We trust you will find this information satisfactory to result in a favorable Safety Evaluation Report on TMI Action Plan Item I!.K.3.31, and to serve as a partial basis for the forthcoming license amendment request.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY

3. F. OpeWa Y.u W Senior Vice President Attachment l