ML20024G418
| ML20024G418 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 10/12/1977 |
| From: | Desiree Davis Office of Nuclear Reactor Regulation |
| To: | Mayer L NORTHERN STATES POWER CO. |
| References | |
| NUDOCS 9102120418 | |
| Download: ML20024G418 (3) | |
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RIBUTION:
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DDavis Northern States Poser Campany RDiggs ATTN: Mr. L. 0.' MSyer, Manager Eisenh"t u
Nuclear Support Services TAbernathy 414 Nicollet Mall - 8th Fleer JBuchanan Minneapolis Minnesota $5401 ACR$(16)
TCarter Gentlemen:
MGrotenhuis f
By letter dated September 15 fLtGhkou provided a reevaluation of 1977 the Loss of Coolant Aggjd)nto
- rtth p! Uon.ki r#3 J o29?t91hge ne ra t i n g l
Plant. This analysis was required by the NRC Order dated March 11, 1977, which reaffimed your comunitment of February 18,1977.
We have determined that the infomation requested in the attachment i
to this letter will be necessary to allow completion of our review
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of your LOCA reevaluation. Please provide the infonnation withie fifteen days of receipt of this letter.
Sincere 1y, Original signed by Don K. Davis, Acting Chief Operating Reactors Branch #2 Division of Operating Reactors
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Enclosure:
j Request for Additional Infonnation ec: See next page 4
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RSnaider:nm DDavis 1DJ l2 IlL 10L\\%I77 i
NRC PORM 318 (9 76) NRCM 0240 W u. G. novs amwent mMTING OmCte $976 - 93..G AA 9102120418 771012 PDR ADOCK 05000263 P
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cc w/ enclosure:
Gerald Charnoff, Escuire Hinneapolis Public LibraryTheEnv Shaw, Pittman, Potts and Trowbridge 300 Nicollet Mall f
1800 M Street, N. W.
Hinneapolis, Minnesota 55401 I
Washington, D. C.
20036 Arthur Renquist, Esquire Vice President - Law Northern States Power Company 414 N' collet Mall Minneapolis, Minnesota 55401 i
i Mr. L. R. Eliason 1
Plant Manager Monticello Mucle..
3enerating Plant Northern States Pcwer Comcany Monticello, Minnesota 55352 Russell J. Hatling, Chairman Minnesota Envir:nmental Centrol Citizens Association (MECCA)
Energy Task Force 144 Melbourne Avenue, S. E.
Minneapolis, Minnesota 55414 Mr. Kenneth Dzugan Environmental Plannin~. Consultant Office of City Planner Grace Building 421 Wabasha Street St. Paul, Minnesota 55102 Sandra S. Gardebring Executive Director Minnesota Pollution Control Agency 1935 W. County Road 52 Roseville, Minnesota 55113 Mr. Steve Gadler 2120 Carter Avenue St. Paul, Minnesota 55103 Anthony.Z. Roisman, Esquire Sheldon, Harmon & Roisman 102515th Street, N. W., 5th Floor Washington, D. C.
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O_SOFCOOLANTACCIDENTREEVALUGON MONTICELLO NUCLEAR GENERATING PLANT DOCKET NO. 50-263 i
REQUEST FOR ADDITIONAL INFORMATION
]i 1.
From the August 1975 analysis and from the present analysis, provide tabular MAPLHGR (Maximum Average Planar Linear Heat Generation Rate)
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values, without rounding off or truncation, to two significant figures to the right of the decimal point (XX.XX), for the following:
80219 fuel at 30,000 MWD /MTU exposure l
8D250 fuel at 15,000 MWD /MTV exposure 8D250 fuel at 20,000 MWD /MTU exposure If any of the requested MAPLHGR values correspond to a PCT (Peak Clad Temperature) below 2196*F, provide the corresponding PCT.
2.
Provide a qualitative explanation of hot node uncovery vs. break size (Figure 6).
The explanation should clarify how depressurization rate (in the new model as modified from the previous model) and the counter current flow limiting phenomenon as applied to the Monticello geometry (bypass area, vessel size, flow paths through the lower core region into the lower plenum, etc.) combine to cause the most limiting break to be 40% of the DBA (Design Basis Accident).
Also, explain why this combination of effects causes a greater increase in PCT for smaller breaks for Monticello than for the lead plant (Quad Cities), where PCT for smaller breaks remains slightly below the DBA PCT.
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