ML20210B280
| ML20210B280 | |
| Person / Time | |
|---|---|
| Issue date: | 09/11/1986 |
| From: | Rosztoczy Z Office of Nuclear Reactor Regulation |
| To: | Congel F Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20209E138 | List: |
| References | |
| FOIA-87-10 NUDOCS 8609180023 | |
| Download: ML20210B280 (1) | |
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+ UNITED STATES 8' o NUCLEAR REGULATORY COMMISSION
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MEMORANDUM FOR: Frank Congel, Branch Chief Reliability and Risk Assessment Branch Division of Safety Review and Oversight FROM: Zoltan R. Rosztoczy, Branch Chief .
Regulatory Improvements Branch Division of Safety Review and Oversight
SUBJECT:
DOSE CONSEQUENCES FROM VENTING CONTAINMENT As you are aware, RIB is implementing the Severe Accident Policy which in-cludes the development of Guidelines and Criteria for existing plants. One of the criterion addresses venting'the containment. The analyses summarized
+ in your memorandum (Memorandum for: M.W. Hodges, RSB, from F.J. Congel, sub-ject: POST-ACCIDENT DOSES OFF-SITE FROM NOBLE GASES, dated September 8, 1986) contain the bases for a very impor'thnt caution in establishing criteria related to such a complex issue as containment venting. Per the analyses summarized in -
your memorandum, it is apparent that the venting of 100% of the noble gases, contained subseouent to the occurence of a severe accident sequence, yields calculated health consequences that are severe.
The purpose of this memorandum is to request sensitivity studies on the re-sults reported in your September 8th memorandum. The analyses which you per-formed employed selected sequences. Since the consequences of containment venting appear very sensitive to sequence-wise variations, we are requesting sensitivity studies for alternative sequences where the containment would not beventedat1 hour (pertheassumptionsinyouranalyses). We would suggest two sensitivity studies, (1) varying the time at which the release is assumed from I hour to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> by some convenient increment, and (2) varying the frac-tion of the noble gases released from 100% to the threshold value at which no early fatality would occur. The purpose of sensitivity studies would be to have an indication of the trade-off between the beneficial effects of radio-active decay of the noble gases and the detrimental effects of unfiltered re-l _
leases. Since we are looking or an indication only, it would not be necessary j to include the contributions from species other than the noble gases.
Because we are to discus the draft Guidelines and Criteria with IDCOR and the ACRS on September 23rd and 24th, it would be most useful to have the preliminary results of the sensitivity study before September 23, 1986.
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I hw e hZoltanR.Rosztoczy,BranchChief Regulatory Improvements Branch Division of Safety Review and Oversight cc: T. Speis B. Sheron w(.Acharya hhkdkOb Xb Q-