NUREG/CR-2497, Forwards Draft Abstract of NUREG/CR-2497, Precursors to Potential Severe Core Damage Accidents:1969-79. Comments Requested by 820220
| ML17298A028 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 01/22/1982 |
| From: | Bernero R NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| To: | Eisenhut D, Hanauer S, Mattson R Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML13308A086 | List: |
| References | |
| RTR-NUREG-CR-2497 NUDOCS 8202110170 | |
| Download: ML17298A028 (6) | |
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UNITED STATES NUCLEAR REGULATORY COMMISS!ON WASHINGTON, O. C. 20555 January 22, 1982 MEMORANDUM FOR:
9; S.
R.
C.
T.
H.
R.
- Eisenhut, DL, NRR
- Hanauer, DST, NRR
- Murley, ROGR
SUBJECT:
.Robert M. Bernero, Director Division of Risk Analysis Office of Huclear Regulatory Research ACCIDENT SEQUENCE PRECURSOR PROGRAM DRAFT REPORT The attached Accident Sequence Precursor report is currently being edited>
by ORHL with expected publication in late March 1982; We.are providing a limited distribution of the draft report for information purposes.
The.
'techniques and methodology used in.the report are somewhat controversial.
For example, a question has been raised of whether the correct probabilities (absolute vs. cohditional) were calculated and used to determine severe core melt probability.
We are reviewing this and other methodology questions within DRA.
The Precursor Report tends to indicate a core melt probability higher than calculated in typical PRAs.
The report igdicates core melt probability in the range of 10 3/reactor/year vs.
10 "/reactor/year for typical PRAs.
The precursor program tentative findings-were presented by ORNL (Joe Minarek) to NRC in meetings on 9/18/81 and 12/9/81.
Two earlier draft versions of this report were given limited distribution within NRC, the first in early 1981 and the second draft. report was distributed following the 12/9/81 meeting.
We have indicated to ORNL that'e wilt provide them
. timely comments before report publication.
Please provide us with any coIITIIents you may have on this report by February 20, 1982.
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Attachment:
As Stated Robert M. Bernero, Director Division of Risk Analysis Office of Nuclear Regulatory Research cc:
R.
D.
D.A'ennig, AEOD
- Okrent, ACRS
- Ross, RES
- Tong, RES
- Thadani, RRAB, HRR
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DRAFT NUREG/CR-24 97 Volume 1 ORM/NSZC-182 PRECJRSORS TO POT:.hTIAL S~c.
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CORE DAMAGE ACCEDES:
1969-1979 Joseph H. ?Znarick Casimir A,. Kukielka Prepared for the U.S. Nuclear Regulatory Commission Office of Nuclear Regulatory Research Under interagency Agreements DOE 40-551-75 and 40-552-75 NUCLEAR PIETY XNPORMTZON C:"bTER NSIC
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Descriptions of 170 operational
- events, reported as LERs, rhich, oc-curxed at commercial light eater xoactox'lants duxing 1969-1979 snd vhich are considered to be potential precursors to severe coro damage are pre-4'ented, along with associated event trees and categoric'ations and'ubse-quent analyses.
The rcpoxt summarixes cwork in (1) the development of methods used to screen about 19,400 IZR abstracts fox potential precur
- sors, (2) the initial screening of those abstracts to dctczmiue which should be revieved in detail, (3) the detailed reviex of those selected LERa vhich then yielded the 1'70 events
~ (4) the categorixation of the 170 events, (5)'he calculation of function failuxo estimates based on precur-sor data, (6) the use of probability-of-severe coro damage estimates to rank precuxsor events and the identification of 52 events conside ed sig-
- nificant, (7) trends analyses of significant events, (8) the identifica-tion of the other events of interest vh'ich occur ed within one month of significant events, and (9) calcula'tion of an estimate of severe core dam-age probability pex'eactor yeax based on the event rankings
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DUE TO THE VOLUME OF THIS REPORT, ONLY THE ABSTRACT IS BEING SENT.
THE BODY OF THE REPORT IS AVAILABLE UPON REQUEST.
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