ML20071N048
| ML20071N048 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf, 05000000 |
| Issue date: | 07/23/1981 |
| From: | Dale L MISSISSIPPI POWER & LIGHT CO. |
| To: | Bernero R NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| Shared Package | |
| ML20071H243 | List: |
| References | |
| FOIA-83-123 AECM-81-18A, NUDOCS 8306060058 | |
| Download: ML20071N048 (2) | |
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MISSISSIPPI POWER & LIGHT COMPANY q
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MIS SISSIPPI 3 9205 July 23, 1981 NUOL E AR PRODL>OTsoN DEPART MENT Dr. Robert M. Bernero Director, Division of Risk Analysis Office of Nuclear Regulatory Research U. S. Nuclear Regulatory Commission Vashington, D. C.
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Dear Dr. Bernero:
SUBJECT:
Grand Gulf Nuclear Station Units 1 and 2 Docket Nos. 50-416 and 50-417 File:
0260/L-860.0/16684/
L-953.0 i
Reactor Safety Study Methodology Applications Program (RSSMAP) on Grand Gulf Nuclear Station Unit No. 1 AECM-81/184 Mississippi Power & Light (MP&L) is deeply concerned over the Reactor Safety Study Methodology Applications Program (RSSMAP) evaluation being conducted by Sandia National Laboratories for the Reactor Risk Branch.
The analysis as described in the draft report uses excessively
' conservative assumptions and calculations, which in combination with the simplified approach fundamental to RSSMAP, raises serious questions regarding the validity of explicitly and quantitatively comparing the Grand Gulf Nuclear Station (GGNS) to the reference Boiling Water Reactor in the Reactor Safety Study (VASH-1400), wherein realistic assumptions and analyses were used.
As a result, MP&L, Bechtel and General Electric met with Sandia Laboratories to express our concerns over the methodology of the report and to offer suggestions on more realistic calculations.
Subsequently, MP&L provided Sandia with more realistic data in the areas we believed to have excessively conservative assumptions or calculations.
In recent converr etions, Sandia indicated that the data supplied in several prime contributor areas were being incorporated, where appropriate, in the revised report, including inforraation on the Power Conversion System, A7VS assumptions and intersystem LOCA's.
However, Sandia stated that the remaining issues would not be incorporated into the revised report
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due to the scheduled completion date for the report and their opinion that the remaining items lacked significance.
We believe that the core melt probability in the revised report will be overstated and not representative of GCNS. We also believe most strongly that it is both irresponsible and inequitable to publish an admittedly conservative NRC sponsored report on GGNS and compare it to the more realistic Reactor Safety Study.
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Furthermore, 'during a period of time that probabilistic risk assessment is'of strong interest to both industry and the NRC, it is in the best
' interest of all to make the RSS!1AP report as realistic as possible.
Such an approach is also more consistent with the charter of RSS! LAP to use simplified methods to achieve results which can be compared meaningfully to the Reactor Safety Study.
We would like to take this opportunity to offer our assistance in any re-evaluation of the report to support this realistic approach.
In addition, we would like to meet with you and your staff to discuss this subject in more detail.
Yours truly, L. F. Dale Manager of Nuclear Servit.es S101/JDR:ad cc:
Mr. N. L. Stampley Mr. G. B. Taylor Mr. R. B. McGehee Mr. T. B. Conner Mr. Victor Stello, Jr., Director Office of Inspection & Enforcement U.S. Nuclear Regulatory Com:nission Washington, D.C.
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