ML20132C161
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- 4 UNITED STATES NUCLEAR REGULATORY COMMISSION
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MAY 18 1984 MEMORANDUM FOR:
Thomas M. Novak, Assistant Director
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l for Licensing Division of Licensing FROM:
R. Wayne Houston, Assistant Director for Reactor Safety Division of Systems Integration
SUBJECT:
REVIEW OF ATTACHMENT 4 TO MAY 6,1984 LETTER FROM MISSISSIPPI POWER & LIGHT Plant Name:
Grand Gulf, Unit 1 Docket No.:
50-416 Licensing Stage:
5f. License Responsible Branch:
Licensing Branch #4 Project Manager:
Dean Houston Review Branch:
Reactor Systems Branch Review Status:
Awaiting Information Based on our meeting of May 14, 1984, I am supplementing the cover memorandum dated May 11, 1984, which transmitted Reactor Systems Branch questions on the May 6, 1984, letter from Mississippi Power and Light (MP&L). A copy of the May 11 memorandum and its enclosure is attached for reference.
The questions in my May 11 memorandum were predicated on the assump-tions that MP&L was seeking a full power license and that the TDI diesels would not be qualified prior to the granting of a license for power greater than five percent.
If the TDI diesels are found to be acceptable, then the questions address conditions which are more severe than design basis conditions and nead not be answered.
If the diesels are not found to be acceptable, and therefore no credit taken for them, then the analyses submitted by Grand Gulf do not address all of the requirements of 10 CFR 50.46 and we are unable to make a determination that they comply with 10 CFR 50.46.
CONTACT:
M. W. Hodges, RSB X29410
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.T. M. Novak,
The evaluation model analyses discussed in attachment 4 of the May 6 letter from MP&L which deal with reactor core performance are reasonable and acceptable for the cases analyzed.
They show that power levels as high as'90% of rated are allowable with only HPCS and RCIC available for core cooling following a break in a recirculation line. The more realis-tic' analyses presented in attachment 4 were done with models which do not comply with Appendix K but which have been demonstrated.in NED0-24708 to give reasonable results.
Reliance on RCIC in the evaluation model analyses means that RCIC cannot be regarded as a back-up to the HPCS as is presently assumed; thus a modification of technical specifi-cations may be in order if reliance is placed on these analyses. The scope of the analyses in attachment 4 is insufficient to provide a basis for determining compliance with 10 CFR 50.46 for Grand Gulf at powers greater than five percent but provides an indication of capability of the plant to withstand multiple failures.
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L w-R. Wayne Houston, Assistant Director for Reactor Safety Division of Systems Integration
Enclosure:
As stated cc:
R. Mattson D. Houston W. Butler A. Notafransesco J. Kudrick T. Collins