ML20234C986
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CY April 22, 1975 David Okrent, Chairman Grand Gulf Subconsnittee GRAND GULF SUBCO)ti1TTEE MEETING, MAY 3-4, 1974 Working paper minutes of the subject meeting are attached for your review and comment or approval. Copies are being ' distributed to the other members of the ACRS for their information.
Following any required revisions / corrections and your certification as to i
accuracy, these minutes will become the official record of the May 3-4, i
1974 meeting of the Grand Gulf Subcommittee.
At this meeting the Subcommittee's consultants agreed with the applicant's and Staff's SSE value of 0.20g on soft foundation material and 0.13g on j
the Catahoula formation.
Some concern was expressed for low frequency, i
long duration ground shaking; the applicant said that this was being considered. The applicant did not expect the main turbogenerators to i
trip from sefsnic accelerations below 0.2g.
There was an extended discussion l
of the probability of a major (IOi-VII) earthquake occuping at the site l
and the Staff's objective of having this as low as 10 per year.
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The design of the guard pipes for high pressure process lines traversing i
the containmaat was discussed in detail. The Staff was asked to be l
prepared with a presentation for the ACRS on the bases for concluding that the proposed design is acceptable.
l 1
An energy absorbing restraint system was described to protect against pipe whip.
i Containment performance was discussed and the model test program was i
reviewed. The pool surface was observed to rise about ten feet during the pool swell phase of the blowdown. The applicant has decided to relocate all floors above the pool so that their undersides are at least 20 feet above the still pool surface.
Dr. Zaloudek and Dr. Zudans were satisfied with the applicant's analyses of the suppression system performance.
3r. Theof anous had no major reservations on the topics covered during this session.
I GE clarified that the u.ajor factor contributing to the reduction in the calculated peak clad temperature in the IWTR/6 ECCS analysis was the use i
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of 8x8 fuel. A parameter study was shown of the offacts of increasing the reflood rates.
t The applicant described his proposed leak detection and location system.
l lid was reminded that the ACRS on a number of occasions had suggested the j
development of improved systems.
t The applicant described the measures he had taken to assure that debris in i
the containment, displaced by a LOCA, could not disable vital ECC systems.
The Regulatory Staff was akked to be prepared to give the ACRS positive assurance that loose insulation would not cause a problem with the ECCS.
The applicant described a new and simpler system of combustible gas control.
l The applicant reaffirmed his belief that hydrogen could burn in the drywell l
without causing the loss of important safety systems.
Four electrical and rod control systems are currently unresolved but the applicant has agreed to install systems acceptable to the Regulatory Staff.
I The appliaant was requested to be prepared to make presentations on the
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following topics at the May 9,1974 ACRS meeting:
j 1.
Summary site description and basis for selection of the safe f
shutdown earthquake acceleration and spectrum.
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2.
Design of the process lines that transit the containment and the guard pipes that are to be provided.
3.
Insulation in the drywell and its potential affect on ECC systems.
l 4.
Combustible gas control.
5.
ECCS performance under degraded conditions as presented at this j
meeting.
I The applicant was also advised to be prepared to answer questions on all t
topics.
Please provide comments or an indication of approval of these minutes by May 9, 1975.
i J. C. McKinley Senior Staff Assistant i
ec: ACRS Members ACRS Staff FTTP!
Crnnel Ct:1 f orriCa
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