ML20155F302

Summary of 750423 Meeting W/Util in Bethesda,Md Re Util Proposed Response to NRC Requesting Info on Design Basis Loading for Containment Structures Per Mod from Design in PSAR

ML20155F302
Person / Time
Site:	Grand Gulf, 05000000
Issue date:	05/01/1975
From:	Butcher E Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
Shared Package
ML20155E140	List: ML20155E133 ML20155E182 ML20155E227 ML20155E338 ML20155E354 ML20155E367 ML20155E405 ML20155E430 ML20155E447 ML20155E473 ML20155E503 ML20155E550 ML20155E557 ML20155E565 ML20155E578 ML20155E600 ML20155E714 ML20155E728 ML20155E753 ML20155E770 ML20155E794 ML20155E948 ML20155E967 ML20155E986 ML20155F001 ML20155F053 ML20155F176 ML20155F191 ML20155F203 ML20155F217 ML20155F228 ML20155F252 ML20155F279 ML20155F302 ML20155F332 ML20155F378 ML20155F477 ML20155F485 ML20155F516 ML20155F534 ML20155F545 ML20155F560 ML20155F589 ML20155G308
References
FOIA-88-91 NUDOCS 8806160342
Download: ML20155F302 (3)

Text

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LMITED STATts NUCLEAD REGULATORY COMMISSION W ASHINGTON. D. C. 20665 MAY 01 1975 Docket Nos. 50-416 and 50-417 Applicant: Mississippi Power & Light Company Facility : Grand Gulf Nuclear Station Units 1 and 2

SUMMARY

OF MEETING HELD ON APRIL 23, 1975 TO DISCUSS MARK III CONTAINMENT DESIGN BASES A brief unscheduled meeting was held on April 23, 1975, at the NRC offices in Bethesda, Maryland. The meeting was requested by the applicants to dis- l cuss their proposed response to the NRC letter of March 3,1975, requesting i' information on the design basis loading for containment structures as they are modified from the design presented in the PSAR. An attendance list is provided in the Enclosure.

l The applicants stated that the design of the safety / relief valve discharge j system has been changed to the standard G.E. design with the rams head dis-charge, and that the containment design loading will be that provided by C.E. The NRC staff asked how the G.E. furnished loads would be justified.

The applicants replied, by referet. a to the G.E. Topical Report NED0-10859 vith certain refinements. The NRC staff stated its position that a refer-ence to NEDO-10859 alone would not be adequate justification for the loads' and taat written justificatien would be required either on the Grand Gulf docket or by a suitable reference. A three part approach to justifying the loads was discussed as follows:

1) Written dpeumentation of the refinements to the calculational methods presented in NEDO-10859 should be provided, taking into consideration all of the NRC staff concerns outlined in its evaluation of NEDO-10859 dated September 12, 1974;

2) The results of recent tests performed to determine safety relief valve discharge loads should be provided; and

3) A commitment to perform follow-up in plant tests to verify calculated loads should be made.

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l Suppression pool swell loads were also discussed. The applicants stated that the additional test data requested by the NRC staff would have to come from the G.E. test f acility and would not be available for NRC review until September 1975 due to G.E. manpower limitations. They also stated that they intend to begin placing concrete for the containment base mat on June 26, 1975 and that structures up to the 135 ft elevation will be in place by January 1976. The NRC staff noted that structures as low as the 119 ft elevation level are subject to suppression pool swell loads and that the test data nec-essary to fully justify the design basis loading at this elevation has not been provided to the NRC by G.E. The applicants intend to proceed with con-structton without consider q the additioul test data, that won't be avail-

-able unt 1 September 1975, eecause they feel adequate conservatism is built into the containment structures design and the structures are capable of being strengthened at a later date, if found to be required.

The NRC staff summarized the status of its review of the Grand Gulf contain-ment design by stating that the information provided to date by G.E. and the applicants was not adequate, to justify the loads that have been specified.

In order for the NRC staff to complete its evaluation of this matter, a com-plete response to its letters, of March 3, 1975 on pool dynamic loads and

. April 23, 1975 on safety / relief valve discharge loads, will be required.

' N Edward J. Butcher, Project Engineer Light Water Reactors Branch 1-2 Division of Reactor Licensing

Enclosure:

Attendance List

ATTENDANCE LTST i

NAME ORGANI7,ATI;ON E. J. Butcher NRC C. L. Cudlin NRC J. A. Kudrick NRC G . C . La ina s . NRC L. Slegers NRC J. P. McGaughy MP&L C. L. Reid Bechtel R. P. Barr G.E.

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