ML20215F376
| ML20215F376 | |
| Person / Time | |
|---|---|
| Issue date: | 04/16/1975 |
| From: | Harris J NRC OFFICE OF PUBLIC AFFAIRS (OPA) |
| To: | Anders, Gilinsky, Kennedy NRC COMMISSION (OCM) |
| Shared Package | |
| ML20215E975 | List: |
| References | |
| FOIA-87-40 NUDOCS 8706220360 | |
| Download: ML20215F376 (3) | |
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April 16, 1975 i
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Chairman Anders j.
Comissioner Gilinsky Comissioner Kennedy Comissioner Mason Comissioner, Rowden
SUBJECT:
PUBLIC ANNOUNCEMENT ON NRC REQUEST FOR ADDITIONAL i
INFORMATION ON DESIGN OF SOME REACTOR CONTAIfMENT SYSTEMS The attached public announcement, which reflects action discussed with the Comission last week by Mr. Case, will be issued on
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Friday, April 18, concurrent with the mailing of Mr. Case's i
letters to the utilities.
John A. Harris, Director l
Office of Public Affairs
Attachment:
1 Public Announcement l
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i NRC STAFF REQUESTS ADDITIONAL INFORMATION l
ON DESIGN OF SOME REACTOR CONTAINMENT SYSTEMS
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l The Nuclear Regulatory Commission staff has requested.
I additional information on the design of containment system structures from operators of 20 boiling water. nuclear power plants as well as from utilities building 17-such plants.
The information is b'eing sought as a. result of new data developed by the General Electric Company, the reactor i
e manufacturer, on a proposed new containment system- (Mark III).
- The' data relate to additional stresses--which engineers describe as hydrodynamic forces--that could develop in the pool.of water located beneath the reactor, called the suppression pool, used to condense steam.
The suppression pool is part of the c'ontainment system and would be used to reduce pressure in the containment in l
the event of a loss-of-coolant accident.
It also is used when relief valves are opered to depressurize the reactor.
The NRC staff has concluded that, even in the' remote event of a large loss of coolant accident in anLoperating. plant, these additional stresses would not cause. serious. impairment to the containment system.
However, the new information will provide a more complete basis for assessing the effect of-these forces on individual structures within the: containment system.
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The' additional forces me_as.ured in the Mark III tests are j
expected to occur in' varying degrees in the earlier contain-
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j ment designs (Mark I and Mark II).
Twenty operating GE
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plants have Mark I or similar containment.
All but~one of the GE plants under construction have either Mark I or Mark II containments.
GE has made design modifications in the proposed Mark III l
containment system. which are being reviewed by the NRC.
The NRC staff letter requests utilities. operating 20.
j nuclear power plants with the earlier containment system j
(Mark I or similar) to re-evaluate the design of containment I
structure to assure that the dynamic forces could be accommodated.
A similar request is being sent to-utilities constructing 11 nuclear plants with the Mark II system and 6. nuclear. plants with the Mark I system.
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