ML19260C460
| ML19260C460 | |
| Person / Time | |
|---|---|
| Issue date: | 02/02/1978 |
| From: | Ross D Office of Nuclear Reactor Regulation |
| To: | Scherer E ABB COMBUSTION ENGINEERING NUCLEAR FUEL (FORMERLY |
| Shared Package | |
| ML19260C458 | List: |
| References | |
| REF-GTECI-A-02, REF-GTECI-RV, TASK-A-02, TASK-A-2, TASK-OR NUDOCS 8001030515 | |
| Download: ML19260C460 (2) | |
Text
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FEB 0 2 IIUS fir. Edward A. Scherer Licensing Manager fluclear Power Systems C-E Power Systems Dhh Windsor, Connecticut 06095 hhh j ff Combustion Engineering, Inc.
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Dear l'r. Scherer:
In response to our July 1974 request, you submitted a licensing topical report entitled "Strc:tural Analysis of Fuel Assemblics for Combined Seismic and Loss of Coolant Accident Loading," CEllPD-178-P, dated August 1976.
Because of other priority work, we were unable to begin reviewing that report until recently, and we have found from our review that there are serious shortcomings in the report.
In particular, even though the core is represented by a multiple-assembly model for the seis,aic analysis nnly a single assembly is used when the asymmetric LOCA response is investigated. This procedure will not adequately account for the core response to lateral impact forces on the fuel assembly spacer grids due to LOCA-induced core barrel motion.
.e believe that this load is a major part of toe total impact load on the spacer grids. We request, therefore, that you perform an assessment of lateral loads using a multiple-assembly model and that CEllPD-178 be revised accordingly and resubaitted for our continued review.
We also note that the report lacks a good description of the spacer grid tests especially in the area of ceformation characteristics at different impact levels, including the amount of deformation beyond the critical load.
In particular we would like to know how the deformation changes when a load larger than the critical load is applied repeatedly.
Such deformation data should be statistically significant since the grid deformation mode is expected to be an important factor in deciding the safety factor. We, therefore, urge you to provide detailed information for our consideration.
As a practical matter you may want to submit grid-deformation data separa-tely from the revision of CENPD-178 since such a division may make it easier for us to complete our review of your methods more quickly.
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f1r. E. Scherer,
FEB P O 1976 On a related matter, we held a meeting on November 29, 1977 with nuclear fuel suppliers (including C-E) on the general subject of fuel assembly mechanical response to seisn'c and LOCA forces. At that meeting we distributed a standard problem for comparative calculations with all vendor analytical codes.
Please note that we would like C-E to do the sample calculation with a multi-assembly core representation as it will be described in the revision of CENPD-178.
In summary, we are requesting three different items from C-E:
(1) a revision of CENPD-178, (2) information on grid deformation, and (3) the results from a sample calculation. To aid in our planning, please provide us with dates when we might expect tg receive these items. We would also welcome comments, as they are supported by your data, on the safety factor and on appropriate statistical procedures for establishing the crushing load.
Sincerely, wvCr6k h
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Denwood F. Ross, Jr., Assistant Director for Reactor Safety Division of Systems Safety Office of Nuclear Reactor Regulation 4
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