ML19331C137
| ML19331C137 | |
| Person / Time | |
|---|---|
| Site: | Indian Point, Zion  |
| Issue date: | 07/31/1980 |
| From: | Long J Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19331C132 | List: |
| References | |
| NUDOCS 8008140205 | |
| Download: ML19331C137 (5) | |
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NUCLEAR REGULATORY COMMISslON f
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+990 Docket Nos.: 50-247 50-286 50-295 50-304 LICENSEES: Consolidated Edison Company of New York Power Authority of the State of New York Commonwealth Edison Company FACILITIES: Indian Point, Units 2 and 3 Zion, Units 1 and 2
SUBJECT:
SUMMARY
OF TECHNICAL PRESENTATION MEETING ON JUNE 18, 1980, WITH CONSOLIDATED EDISON COMPANY OF NEW YORK (CON ED), POWER AUTHORITY OF STATE OF NEW YORK (PASNY), AND COMMONWEALTli EDISON COMPANY (CECO) TO PRESENT THEIR CURRENT VIEWS ON DEGRADED COOLING / CORE MELT ACCIDENT SEQUENCES.
Following the series of five technology exchange meetings on Zion / Indian Point (Z/IP), the utilities wished to present a sumary of their current results on dominant accident scenarios and related probabilistic studies.
(These studies are reported in "An Evaluation of the Residual Risk from the Indian Point and Zion Nuclear Power Plants," Report #36A75, OPS, February 1980.) The subject meeting was therefore arranged and held in the Holiday Inn, Bethesda, on June 18.
In part, this meeting was organized to fulfill the goal expressed at the bottom of page 3 of the meeting report for Technology Exchange Meetings 1 and 2:
"To give the utilities the opportunity to present the accident sequences they feel dominate the Z/IP risk as opposed to the sequences presently being considered by the NRC staff."
Dr. Dee H. Walker of OPS and Dr. Robert Henry of Fauske Associates gave the principal presentations.
Their view-graphs are attached, and a few notes on their presentations are as follows:
Accident Sequence Identification The rationale for deleting the TKQ and TKQM sequences is that OPS has concluded that they do not lead to core melt for the Z/IP configurations.
Although TML has been deleted, TMLB' (loss of all ac power) has been retained.
Sequences added are the "HF" sequences because the containment spray recirculation is not separate from the ECCS recirculation as it was in WASH-1400.
Summary of WASH-1400 Differences The probability o{ containment failure, givgn a stegm explosion scenario had been taken as 10. This is reduced to 10- or 10- due to more recent analyses of steam explosion phenomena. Operator error probabilities are reduced by taking credit for the Shift Technical Advisor.
The diesel generator common soosuolof
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. L 1 n; mode failure probability is reduced by two orders of magnitude because of the presence of five diesel systems.
Initiating Event Summary The IP-2 and Zion labels are reversed for the item " Loss of Offsite Power (T)."
Suggested Sequences for Design OPS sugges s omitting from consideration the AB-burn sequences as having very low probability, and the S C sequences because of the highly reliable containment 2
spray injection. They believe that TMLB' and TMLB" have a low enough probability to be eliminated as sequences, but they may have some value for systems evaluation, and thus are not being dropped from current studies.
Subsequent discussions were too preliminary to indicate the NRC degree of acceptance of these deletions.
The staff has never considered AB-burn as a sequence which dominates risk for Z/IP.
It has been used to envelope challenges to the containment and to the mitigation features being cosidered. NRC is continuous its evaluation of the TMLB' sequences.
Phenomenology in Reactor Cavity Dr. R. Henry of Fauske and Associates presented an analysis of the tendency for fuel debris to be swept out of the reactor cavity. His conclusion is that the escaping steam from the blowdown would have sufficient velocity to disperse the fuel fragments widely. The relationship between the high steam velocities he predicts and the associated containment pressure spike should be evaluated based on his proposed scenario.
An outline of the probabilistic studies being performed by Pickard, Lowe and Garrick was presented by Mr. George Klopp.
(These studies were reported more l
fully at a following meeting on June 25, and are scheduled for completion in the late summer.)
Agenda, attendance list and view-graphs are attached.
T d
John K. Long Reactor Systems Branch Division of Systems Integration
Enclosures:
As stated
'[
Attendance List - June 18, 1980 Jim Meyer NRC/NRR Dee H. Walker OPS - Washington Ed Reeves NRC/NRR John Olshinski NRC/NRR Peter Cybulskis Battelle - Columbus j
James Leas UCS Jan B. Van Erp ANL Raymond Alcouffe LASL Garry Thomas NSAC/EPRI Miles C. Leverett NSAC/EPRI Waheed Sayed Power Authority of State of N.Y.
James F. Davis S. S. Iyer Pedro J. Franceschi Con. Ed. N. Y.
Louis F. Liberatori Con. Ed. N. Y.
Bill Bennett Con. Ed. N.Y.
Don Paddleford Westinghouse S. Acharya NRC/NRR T. E. Fenstermacher NRC/NRR R. K. Frahm NRC/NRR G. Quittschreiber ACRS R. A. Bari BNL A. J. Buslik BNL P. M. Williams NRC/NRR T. P. Speis NRC/NRR E. R. Schmidt NUS P. F. Riehm NRC/NRR Karl J. Toth NUS
- 0. Akalin NRC/NRR R1ck Sherry NRC/RES Jeffrey Nibert NRC/RES Mel Silberberg NRC/RES Walter A. Von Riesemann Sandia Labs Er-Ping Chen M. H. Fontana ORNL L. N. Rib NRC/RES L. Sotfer NRC/NRR Armand A. Lakner NRC/NRR D. E. Bessette NRC/ ARCS W. F. Kortier Westinghouse Marty Oper Westinghouse Dennis C. Ricnardson Westinghouse B. W. Washburn DOE /LASL John Yevick 00E
- 0. Louis Peoples Consonwealth Edison Co.
D. K. Goeser Westinghouse M. S. Medeiros, Jr.
NRC/SD G. T. Klopp Commonwealth Edison Jim Martin PAS /RES/NRC Mat Taylor PAS /RES/NRC Ray DiSalvo NRC/RES John Long NRC/NRR David A. Aldrich Sandia Roger M. Blond NRC/ PAS Nancy B. Willoughby Bechtel Bob Radlinski Bechtel
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Michael J. Hitchler Westinghouse
' Jay D. Dunkleberger NYS Energy Office i-
- Dennis C. Bley' Rickard, Lowe & Garrick, Inc..
Gary Boyd Sandia R. D. Pdccent LILC0
,i L. Olshan NRC/NRR 1
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