ML19323D482
| ML19323D482 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/30/1980 |
| From: | Silver H Office of Nuclear Reactor Regulation |
| To: | Tourtellotte J NRC OFFICE OF THE EXECUTIVE LEGAL DIRECTOR (OELD) |
| References | |
| NUDOCS 8005210599 | |
| Download: ML19323D482 (2) | |
Text
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April 30,1980 MEMORANDUM FOR:
J. R. Tourtellotte Office of the Executive Legal Director FROM:
Harley Silver, Project Manager TMI-l Restart Program Division of Licensing
SUBJECT:
TMI-l RESTART-RESPONSE TO C 1.9 BOARD ORDER Following is the text I recommend for the preliminary response required by May 2 to the Boards Order of March 31 on Class 9 scenarios.
Please note that NRR concurrence for this text has not been obtained; those receiving copies of this memorandum are herewith requested to concur by May 1, 1980.
In our motion of 4/15/80 for an extension of time to respond to the Board's Memorandum and Order to NRC staff regarding Class 9 accidents dated March 31, 1980, we noted that we wished to confirm our approach in order to ensure -that we would indeed comply with the Board's wishes.
The following description is, therefore, presented for the Board's consideration.
To describe the possible accident sequences with reasonable nexus to the TMI-2 accident, we will provide " event trees" starting with both loss of feedwater transients and small break LOCAs.
For those event sequences of most significance, we will also provide a written descrip-tion of the sequence and its outcome.
As described in Appendix I to WASH-1400, an event tree begins with an initiating event and proceeds to define the possible outcomes of such an event. These outcomes are determined by permutations encompassed by the successful operation or failure of the applicable plant systems designed to cope with the effects of the initiating event. Thus, since mitigating and protective systems potentially affecting the course of events are included, each event tree is essentially a set of potential accident sequences for that initiating event.
For each event in the tree, we will identify items in the August 9 Commission Order and additional items in the NRC's TMI-2 Action Plan (NUREG-0660) not in the Order which may affect the probability of failure. Finally, for event sequences which may result in serious core damage or core melt, we will identify items in the Order and in the Action Plan which are intended to deal effectively with and mitigate the consequences of such events.
8005210 6 9 9 G
-. We believe our response of June 2,1980, based on the above description, will be fully responsive to the Boards Order of March 31, 1980. If the Board disagrees, or wishes to comment or discuss this matter further, we will endeavor to modify our response accordingly.
f i
e Harl ilver, Project Manager TMI-l estart Program Division of Licensing cc:
E. Case D. Eisenhut T. Novak R. Reid D. Ross R. Mattson T. Speis S. Israel A. Thadani P. O'Reilly
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