ML20091B584

Forwards Rept NEDO-24050, LOCA Rept for Monticello Nuclear Generating Plant

ML20091B584
Person / Time
Site:	Monticello
Issue date:	09/15/1977
From:	Mayer L NORTHERN STATES POWER CO.
To:	Stello V Office of Nuclear Reactor Regulation
Shared Package
ML20091B589	List: ML20091B584 ML20091B591
References
NUDOCS 9106100522
Download: ML20091B584 (2)

Text

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NSIB HOMTHEMN STATES POWEM COMPANY uiNNs Apo u s. MIN N E GOTA 99404 September 15, 1977 D

/S

Hr Victor Stello, Director 18> ( 9 Division of Operating Reactors [ci -

c/o Distribution Services Branch, DDC, AIH F g g 11 S Nuclear ReguFatory Cocuission 9  %

Washington, DC 20555 g/ / //

Dear Mr Stellot k MONTICELLO INCLEAR GENERATING PIANT Docket No. 50-263 License No. DPR-22 Filing of ECCS Analysis On February 18, 1977, we sulaitted a letter stating that we would provide a re-evaluation of the loss of coolant accident for Monticello incorporating ECCS model changes which vere under discussion at that time. Our voluntary cocuitnent was confitned by a Nuclear Regulatory Commission Order dated March 11, 1977. The attached doctanent entitled, " Loss of Coolant Accident Analysis Report for Monticello Nuclear Generating Plant, NEDO 24050, September,1977" fulfills the cocuitments of the two above referenced docu-ments.

'Ihe litnitations resulting from the new evaluation are in general less re-strictive than those in the existing technical specifications. There are, however, points where the newly calculated limits are slightly more restrictive than those in the technical specifications for the fuel types in service at Monticello. As has been the practice in such situations in the past, ve will 4 adhere to the most limiting of the present technical specifications and the i

newly calculated limits until our technical specifications are appropriately revised. A formal license amendment request is in preparation, and will be sulnitted shortly.

'Ihe ECCS model previously approved in accordance with 10 CPR 50 Appendix K, was applied to a variety of specific break sizes to determine the response for i the spectrum from a small break to the DBA break size. Additional break aires have been analyzed to better define the response over the full spectrtun of break sizes using the currently approved ECCS model. This additional analysis has identified 407. of the DBA area as being slightly more severe than the full DBA area upon which limits were previously based.

Yours very truly, L 0 Mayer, PE l Manager of Nuclear Suppori Services cc: J G Keppler, G Charnoff, MPCA, Attn J W Teruan 7MMO l 9106100522 770915 .

I PDR ADOCK 05000263 P PDR

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