ML20155F485

Summary of 750603 & 04 Meeting W/Util in Gaithersburg,Md & Bethesda,Md,Respectively Re Design Basis Loading & Design Methods for Plant

ML20155F485
Person / Time
Site:	Grand Gulf, 05000000
Issue date:	06/10/1975
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 8806160405
Download: ML20155F485 (4)

Text

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" UNITED STATES

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NUCLEAR REGULATORY COMMIS$10N '3 of W ASHINGTON, D. C. 20555 JUN 101975 Docket Nos- 50-416 and 50-417 Applicant: Mississippi Power & Light Company Facility : Grand Gulf Nuclear Station Units 1 and 2

SUMMARY

OF MEETINGS HELD ON JUNE 3 AND 4, 1975 TO~ DISCUSS DESIGN BASIS LOADING AND DESIGN METHODS FOR THE GRAND GULF MARK III CONTAIhMENT.

A meeting was held on June 3,1975 at the Bechtel Power Corporation offices in Gaithersburg, Maryland and on June 4, 1975 at the NRC offices in Bethesda, Maryland. The purpose of the meetings was to; l) establish the capability of containment structures (including I-beams and steel gratings) to accept loads in excess of the current design specification, and 2) establish the degree of uncertainty associated with the current design load

' specification. The discussions were centered around the clarification and expansion of information presented in the applicant's April 23, 1975 Contain-ment Structures Design and Loading Report. An attendance list is provided in the enclosure.

The June 3, 1975 session was devoted to a discussion of the design methods used by the architect engineer (Bechtel) to factor suppression pool dynamic loads into the Grand Gulf containment structures design. The capability of the structure to withstand loads in excess of the current specification was j examined using revised design methods acceptable to the NRC staff. Various load combinations in addition to those presented in the applicant's April 23, 1975 Report were examined.

It was concluded that there is substantial design margin, at least a f actor I of two, in the junction between the containment foundation and the dryvell wall to accept loads induced by suppression pool swell and impact on struc-ures above the pool. The junction between the containment wall and founda-tion is not sensitive to impact loads on structures above the suppression pool.

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The design of the traveling incore probe (TIP) station (approx. 6' above the pool) has no margin at present, however, the applicant indicated its inten-tion to lower the bottom of the station into the pool and thereby substan-tially reduce the loading. Wide flange beams and grantings at approximately the same elevation have some margin under conditions of plastic deformation and are capable of being strengthened.

An analysis by the applicant of the steam tunnel (approx.15' above the pool) shows that the floor could withstand a triangular load profile of 50 psid peak for 50 msec. The applicants were unable to provide an acceptable basis for the 15 psid load specified for this structure and will be required to provide an acceptable basis for the final design load or relocate the structure.

The HCU floor (approx. 24' above the pool) is supported by steel I-beams attached to the containment and drywell wall with brackets. There is approx- ,

imately a 50% design margin in the bracket design using a plastic-elastic analysis technique. The NRC staff was unable to determint. that this analysis technique is acceptable at the meeting and will require additional information.

The HCU floor design has no existing margin but is capeble of being strength-ened.

. The June 4, 1975 session was devoted to examining the design loads specified by the applicant and the uncertainties associated with the specification.

The applicant was unable to support its load specification to the NRC staff's satisfaction due to the limited test data base and uncertainties in their methods of interpreting the test data. The NRC staff was able to develop a conservative load specification for valves, pipes. I-beams, and small compo-nents and the applicant was offered the option of designing to this specifica-tion or waiting to provide additional test data to support its existing design 1 loads.

The meeting was concluded with the applicant's agreement to inform the NRC in the next several days of its intentics toi 1) Use a more conservative design load profile, or 2) provide additional test cata to support the design load profile currently being used, or 3) relocate or modify the affected structures.

Edward J. Butcher, Project Engineer f Light Water Reactors Branch 1-2 ]

Division of Reactor Licensing

Enclosure:

Attendance List I

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ENCLOSURE

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- ATTENDANCE LIST

• JUNE 3, 1975 NAME ORGANIZATION C. Reid Bechtel - Licensing

. A. J. Bingaman Bechtel - Chief Civil C. E. Bald Bechtel - Mgr. Proj . Operations J. B. Knotts Conner, Hadlock & Knotts (MP&L)

L. Pinzow Bechtel F. J. Champlin G.E.

R. P. Bart G.E.

L. J. Sobon G.E.

A. J. James G. E. - BWRSD E. U. Thomas Bechtel M. E. Palmer Bechtel B. L. Meyers Bechtel M. D. Archdeacon Bechtel R. Hails Bechtel F. C. Cheng Bechtel ,

W. N. Adams Bechtel J. J. Tkacik Bechtel J. P. McGaughy MP&L L. F. Dale MP&L H. P. Marsh Bechtel G. Bagchi TR, NRC (SEB)

F. Schauer TR, NRC (SEB)

Isa Sihweil TR, NRC (SEB)

Larry Shao TR, NRC (SEB)

Ed Butcher NRC - DRL J. M. Cutchin NRC - DRL S. Hou NRC - MEB Jeff Gitner NRC - ELD J. C. Glynn NRC - TR G. C. Lainas NRC - TR R. L. Cudlin NRC - TR R. J. Stuart NRC - SEB C. P. Tan NRC - SEB A. L. Gluckmann NRC - SEB R. Maccary NRC - TR

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1. ENCLOSURE 4

h ATTENDANCE LIST _

JUNE 4. 1975 j I

NAME ORGANIZATION l l

E. J. Butcher NRC - LWR 1-2 J. M. Cutchin NRC - LWR 1-2 L. C. Shao NRC - SEB Isa Sihweil NRC - SEB J. P. McGaughy MP&L MP&L L. F. Dale Bechtel Power Corp.

J. J. Tkacik Bechtel Power Corp.

W. N. Ad ams Bechtel Power Corp.

F. C. Cheng Bechtel Power Corp.

K. S. Jolly J. A. Kudrick NRC - CSB/TR R. L. Cudlin NRC - CSB/TR G. C. Lainas NRC - CSB/TR R. L. Tedesco NRC - TR GE - BWRSD A. J. James GE - Licensing L. J. Sobon R. P. Barr GE - Projects F. J. Champlin GE - Projects I

L. Slegers NRC - TR J. F. Stolz NRC - DRL W. F. Kane NRC - DRL .

1. Peltier NRC - DRL J. Glynn NRC - TR R. DeYoung NRC - DRL Bechtel Power Corp.

C. Reid R. Brems Gilbert Associates Bechtel Power Corp.

H. P. Marsh D. W. Halligan Bechtel Power Corp.

C. J. Anderson NRC - CSB C. I. Grimes NRC - CSB Bechtel Power Corp Bob Hails R. Maccary NRC - TR

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