ML16341C374
| ML16341C374 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 11/12/1980 |
| From: | Plesset M Advisory Committee on Reactor Safeguards |
| To: | Ahearne J NRC COMMISSION (OCM) |
| References | |
| ACRS-R-0903, ACRS-R-903, NUDOCS 8011190385 | |
| Download: ML16341C374 (4) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION ADVISORYCOMMITTEE ON REACTOR SAFEGUARDS WASHINGTON, D. C. 20555 November 12, 1980 Honorable John F. Ahearne Chairman U-S. Nuclear Regulatory Commission Washington, D.C.
20555
SUBJECT:
DIABLO CANYON NUCLEAR STATION
Dear Dr. Ahearne:
As part of its broad examination of the implications of the accident at Three Nile Island Unit 2, the Advisory Committee on Reactor Safeguards recommended that, at least for a plant in a region of high seismicity, a review be made of the possible adverse interactions of nonsafety systems on plant safety as the result of an earthquake.
The Pacific Gas 8 Electric Company (PGRE) decided to perform a
study of such interactions for its Diablo Canyon Nuclear Station and the
- ACRS, during its 247th
- meeting, November 6-8,
- 1980, reviewed the methodology used and some of the results of this effort.
In our review we had the benefit of discussions with representatives of PGSE and the NRC Staff and of a
Subcommittee meeting held on October 8,
1980.
The Committee also had the benefit of the documents listed.
PGRE utilized a walkdown technique and interdisciplinary teams for this review.
This procedure is similar to that recommended as a possible approach for the Indian Point 3 reactor in our letter to Hr. L. Gossick of October 12, 1979 titled, "Systems Interactions Study for Indian Point Nuclear Generating
- Station, Unit No. 3."
PG8E prepared a very thorough and systematic plan for this study and devoted a considerable amount of resources to its accomplish-ment.
We agree that the approach taken by PG8E was suitable for the task.
We were told that the NRC Staff has audited the effort and that the bulk of the" work has been completed.
A considerable number of adverse interactions which might occur during a strong earthquake at the site were found and have been remedied.
When PGSE completes the work, the NRC Staff will review and evaluate the final results.
We believe that, subject to final NRC Staff appr oval of the study and the resulting plant modifications, the PGBE examination of seismically induced
-~
P
Honorable John F. Ahearne November 12, 1980 interactions is suitable and provides additional assurance concerning the ability of the plant to withstand a
severe earthquake and accomplish safe shutdown.
Milton S. Plesset Chairman
References:
y 1
1 R
p R
1 d
tp Pp 1
P Pt t
y Nuclear Power Station Units 1
and 2,"
USNRC Report NUREG-0675, Sup-plement 11, dated October, 1980 2.
"Description of the Systems Interaction Program for Seismi cally-Induced Events, Diablo Canyon Units 1
and 2," Revision 4, Pacific Gas and Electric Company report dated August 29, 1980
I 1
t h