ML19257B002
| ML19257B002 | |
| Person / Time | |
|---|---|
| Issue date: | 03/28/1979 |
| From: | Mattson R Office of Nuclear Reactor Regulation |
| To: | Buhl A NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| References | |
| REF-GTECI-A-30, REF-GTECI-EL, TASK-A-30, TASK-OR NUDOCS 8001150054 | |
| Download: ML19257B002 (3) | |
Text
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s UNITED STATES
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t NAR 2 81979 MEMORANDUM FOR Anthony R. Buhl, Director Probabilistic Analysis Staff FROM Roger J. Mattson, Director Division of Systems Safety SUBJECT REVISIONS TO A-30 Attached are comments on the revisions to TAP A-30. We agree with the change in approach to evaluate a D.C. system which just meets minimum requirements. However, we believe that an analysis limited to determining the relative probability of core melt is insufficient and counter to Comission policy.
We also request that the manpower requirements for DSS be reduced to be consistent with that available.
ZR
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oger J.
tsoni Director Division Systems Safety cc:
G. Edison P. Baranowsky J,. Pittman
- 4. Hanauer R. Tedesco F. Rosa V. Benaroya T. Novak W. Minners 1750 212 8 0 01150 OFy
Coments on the Revisions to TAP A-30 Adequacy of Safety Related D.C. Power Supplies Because of the workload situation in DSS, the manpower available for this task is very limited. The DSS manpower requirements specified in the plan are more than can be provided.
In order to make the requirement consistent with the amount that can realistically be expected to be available, we request that the following changes be made:
PoderSystemsBranch Task 4:
reduce from 80 to 32 man-hours Task 8:
reduce from 160 to 80 man-hours Task 9:
reduce from 80 to 40 man-hours Reactor Systems Branch Task 6:
reduce from 60 to 40 man-hours Auxiliary Systems Branch Task 6:
reduce from 240 to 80 man-hours These reduced manpower assignments are insufficient to do the scope of work originally specified. Therefore the scope of work assigned to DSS branches should be reduced to a review and coment function which is consistent with the manpower available.
The conclusion of the plan, which is Task 7, Evaluate Acceptability of Minimum System, is to be based solely on the relative contribution to core melt. Although the probability of core melt may be one factor 1750 213
2 in determining acceptability, it is contrary to the Commission's policy and insufficient by itself. Other factors need to be included.
The uncertainty in the relative contribution needs to be evaluated.
The effect on the probability and consequences of possible radio-active releases that are less than those from a core melt should also be considered. A qualitative evaluation of the design of D.C.
power system relative to good practice, the requirements for redundant separation and independence, and defense-in-depth should also be made.
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