ML20125D476
| ML20125D476 | |
| Person / Time | |
|---|---|
| Issue date: | 02/11/1977 |
| From: | Ross D Office of Nuclear Reactor Regulation |
| To: | Bender M Advisory Committee on Reactor Safeguards |
| Shared Package | |
| ML20125D471 | List: |
| References | |
| REF-GTECI-D-03, REF-GTECI-SY, TASK-D-03, TASK-D-3, TASK-OR NUDOCS 8001140322 | |
| Download: ML20125D476 (2) | |
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FEB 1 1 1977 MEMORANDUM FOR: M. Bender, Chairman, ACRS FROM: Denwood F. Ross, Jr., Assistant Director for Reactor Safety, DSS
SUBJECT:
BWR ROD DROP ACCIDENT (GENERIC ITEM IIA-2)
The latest letter from Birkhofer, et al, (enclosed) to the General Electric Company on the analysis of the central rod drop accident does not cause us to modify the conclusion stated in our report of 1 June 1976 that GE's analysis method is suitable even though it does not consist of a full three-dimensional representation.
The following brief comments may assist your review of this material.
- 1. The comparison of the spatial vs point kinetics results are basically irrelevant because, while the G.E. method is in a sense point kinetics in nature, the German l point kinetics differs in detail from that of G.E., thus invalidating any direct comparison.
- 2. The nature of the problem, especially the important limitin5 G.E. cases, make any 2D-XY calculations and comparisons also irrelevant.
- 3. Only the 3D-XYZ central vs asymmetric rod cases are of interest. These show a small increase (about eight percent) in peak energy for the asymmetric rod vs the central rod, llowever, as in the original report, the calculation is confused by the requirement to maintain a given rod reactivity worth in both cases. This implies (the information presented is insufficient in this area) that a somewhat different tod geometry must have been used for the two cases since the " correct" identical areas would not have given the same reactivity worth at the two radii. Thus, the comparison is of uncertain value. The eight percent difference, if valid, however, would not, in any case, significantly alter our previous conclusions.
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4..-As indicated in our report, we are continuing our generic review of this area. The Staff and BNL efforts to get the MEKIN code operational are still underway.
We hope to be able to carry out some of our own calculations in the near future.
n r; D { C' c t,Denwood F. Ross, Jr., Assistant Director for Reactor Safety Division of Systems Safety
Enclosure:
As stated .
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