ML20138C250
| ML20138C250 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 09/09/1985 |
| From: | Tien C CALIFORNIA, UNIV. OF, BERKELEY, CA, Advisory Committee on Reactor Safeguards |
| To: | Boehnert P Advisory Committee on Reactor Safeguards |
| References | |
| REF-GTECI-A-43, REF-GTECI-ES, TASK-A-43, TASK-OR ACRS-CT-1819, NUDOCS 8510220390 | |
| Download: ML20138C250 (2) | |
Text
UNIVERSITY OF CALIFORNIA, BERKELEY PAC /d/7P n
BERKELEY
- DAVI5
- 3RVINE
- LO$ ANCILES
- RIVERSIDE
- SAN DIEGO
- SAN FRANCISCO
- j j-SANTA BARBARA
- SANTA CRUZ
(
COLLEGE OF ENGINEERING BERKELEY, CALIFORNIA 94720 MEC)(ANICAL ENGINEERING September 9, 1985 Mr. Paul A. Boehnert ACRS Nuclear Regulatory Comission Washington, D.C.
20555 RE: ACRS ECCS Subcomittee Meeting, August 27, 1985, Washiedton,D.C.
Dear Paul:
This constituts my report on the above-referenced one-day meeting which reviewed the resolution efforts for the hydrodynamic loads issue in Mark I-III containment, the implementation proposal for resolution of USI A-43, and the feed-and-bleed calculations for the Davis Besse plant.
Hydrodynamic Loads in Mark I-III Containment Vacuum Breakers. Total empirical reliance on the 193 pool swell tests does not givt sufficient confidence in the arrived criteria. Analytical models should be used in parallel to the tests to understand the physics of the asso-ciated phenomena and to establish the adequacy of these models. The established analytical model can then be employed to predict failure (i.e., saturation of the vacuum breaker) and to check further with experiments.
Humphrey Issues.
On the 1/10-scale tests on encroachment, a more careful assessment is needed on the validity and limitations of linear scaling. To increase confidence in the scaling tests, detailed comparison should be made about the flow patterns between different scale tests and between the encroached and unencroached cases. Camera coverage of flow behaviors may be adequate for some special situations, but should not be totally relied upon without other backup measurements.
In particular, parallel measurements by pressure trans-ducers and level indicators are needed.
Resolution Approach for USI A-43 This concerns containment emergency sump performance, especially the poten-tial blockage due to particulate ingestion. The revised resolution position of NRR is generally sound, but a follow-up effort should be made specifically with plants of significant blockage vulnerability on the basis of the estimated core melt frequency. This follow-up effort was not made clear in the NRC presen-tation and answers to questons.
8510220390 850909 PDR ACRS CT-1819 PDR
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Page 2.
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l Feed and Bleed Calculations for the Davis-Besse Event It is, interesting and informative to have three separate calculations with differing degrees of sophistication, although no direct comparisancan be made because they do not correspond exactly to the same physical situation. They do demonstrate a fine capability to predict the plant behavior under the ned and bleed conditions. More efforts, however, are recommended to evaluate these calculations in terms of the physics of the associated phenomena and processes for model improvement and qualification.
S n rely y s,
s W
h g-L n Tien Pr essor and Vice Chancellor-Research CLT:LCHD s
O