ML20132C121
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DISTRIBlfTION
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Docket File
. RSB R/F RSB P/F: Grand Gul.f' WHodges R/F AD/RS Rdg.
BSheron WHodges AMY f I fgg MEMORANDUM FDR:
Thomas M. Novt.k. Assistant Director for Licensi.,g Division of Licensing FRDM:
R. Wayne Houston, Assistant Director for Reactor Safety Division of Systems Integration
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StBJECT:
REVIEW OF ATTAQ{ MENT 4 TO MAY 6,1984 LETTER FROM MISSISSIPPI POWER & LIGiT Plant Name:
Grand Gulf. Unit 1 Docket No.:
SD-416 Licensing Stage:
5% License Responsible Branch:
. Licensing Branch f2 Project Manager:
Dean Houston Review Branch:
Reactor Systens Branch Review Status:
Awaiting Information We have reviewed attachment 4 to the subject letter and we find insuffi-cient information to determine acceptability of operation above five percent power. The enclosed -questions need to be answered bef. ore we can make a finding of acceptability.
Crisinal signed by' R. Wayne Houstoe' R. Wayne Houston, Assistant Director for Reactor Safety Division o stems Integration ec:
R. Mattson D. Eisenhut b
A. Schwencer
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D. Houston
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W. Butler A. Notafransesco J. Kudrick T. Collins b/~
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s-1.
10 CFR 50.46 states, in part, "ECCS Cooling Performance shall be calculated in accordance with an acceptable evaluation model, and shall be calculated for a number of postulated less-of-coolant i
accidents of different sizes, locations, and other properties sufficient to provide assurance that the entire spectrum of postu-
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lated lossiof-coolant accidents is sokered." For BWRs with quali-fied onsite AC power, a recirculation line break is usually the most restrictive and is sometimes referred to as "the DBA break".
For the operation of Grand Gulf at power levels exceeding 57, and where the TDI diesels must be ass'umed to be unavailable, a recir-culation line break is not likely to be the most restrictive break.
Therefore other breaks must be analyzed to determine the most limiting case.
A break in the high pressure core spray line. may be the limiting case.
Also, the worst single failure in a' safety related system must be considered in conjunction with the break.
Therefore, provide an analysis of a break in the high pressure core spray line assuming the TDI diesels are unavailable and assuming i
the worst single failure.
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2-2.
For the most limiting break, assuming the TDI diesels inoperable and the loss of-normal offsite power, provide time dependent plots of:
a) claddirg temperature, j
. b) vessel water level, c) heattransfercoefficient(cladding),
d) vessel pressure e) local oxidation, f) core-wide metal-water reaction.
3.
Identify the break / single failure combinations analyzed to identify the worst (most limitfng) break.
4.
For the recirculation line breaks analyzed in your 5/6/84 submittal, there seems to be no single failure assumed.
Provide the results of analyses assuming the most limiting single failure (probably the HPCS).
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