ML20134D030

Informs That on 961104,NRC Identified Three Major Issues Associated W/Seismic & Structural Review of Westinghouse AP600 Advanced Reactor Design.Nrc Position Encl

ML20134D030
Person / Time
Site:	05200003
Issue date:	01/31/1997
From:	Martin T NRC (Affiliation Not Assigned)
To:	Liparulo N WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
References
NUDOCS 9702040261
Download: ML20134D030 (3)

Text

'

January 31, 1997 Mr. Nicholas J. Liparulo, Menager Nuclear Safety and Regulatory Activities Westinghouse Electric Corporation P.O. Box 355 Pittsburgh, PA 15230

SUBJECT:

AP600 ADVANCED REACTOR DESIGN SITE PARAMETERS FOR SEISMIC DESIGN AND NUCLEAR ISLAND FOUNDATION MAT ADEQUACY

Dear Mr. Liparulo:

In a letter dated November 4,1996, the U.S. Nuclear Regulatory Commission (NRC),' Civil Engineering and Geosciences Branch, identified three major issues associated with the seismic and structural review of the Westinghouse AP600 advanced reactor design. The NRC staff subsequently met with representatives of Westinghouse on December 9 through 13, 1996, to conduct an AP600 structural design review in Monroeville, Pennsylvania. On the basis of the interaction between Westinghouse representatives and the NRC staff during that meeting, 1 the staff has concluded that its position on the subject issues should be 1 recommunicated to Westinghouse for a clearer understanding. The staff's position is enclosed.

If you have any questions on this matter, please contact Diane Jackson at (301) 415-8548.

Sincerely, l original signed by:

Thomas T. Martin, Director <

Division of Reactor Program Management Office of Nuclear Reactor Regulation Docket No.52-003 '

Enclosure:

As stated

• cc w/ enclosure:

See next page

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Mr. Nicholas J. Liparulo Docket No.52-003 Westinghouse Electric Corporation AP600 l

l cc: Mr. Nicholas J. Liparulo, Manager Mr. Frank A. Ross l

Nuclear Safety and Regulatory Analysis U.S. Department of Energy, NE-42 Nuclear and Advanced Technology Division Office of LWR Safety and Technology l Westinghouse Electric Corporation 19901 Germantown Road P.O. Box 355 Germantown, MD 20874 Pittsburgh, PA 15230 Mr. Ronald Simard, Director l Mr. B. A. McIntyre Advanced Reactor Program l Advanced Plant Safety & Licensing Nuclear Energy Institute Westinghouse Electric Corporation 1776 Eye Street, N.W.

Energy Systems Business Unit Suite 300 Box 355 Washington, DC 20006-3706 Pittsburgh, PA 15230 Ms. Lynn Connor Mr. John C. Butler Doc-Search Associates Advanced Plant Safety & Licensing Post Office Box 34 Westinghouse Electric Corporation Cabin John, MD 20818 Energy Systems Business Unit Box 355 Mr. James E. Quinn, Projects Manager Pittsburgh, PA 15230 LMR and SBWR Programs GE Nuclear Energy Mr. M. D. Beaumont 175 Curtner Avenue, M/C 165 Nuclear and Advanced Technology Division San Jose, CA 95125 Westinghouse Electric Corporation One Montrose Metro Mr. Robert H. Buchholz 11921 Rockville Pike GE Nuclear Energy Suite 350 175 Curtner Avenue, MC-781 Rockville, MD 20852 San Jose, CA 95125 Mr. Sterling Franks Barton Z. Ccwan, Esq.

U.S. Department of Energy Eckert Seamans Cherin & Mellott NE-50 600 Grant Street 42nd Floor 19901 Germantown Road Pittsburgh, PA 15219 Germantown, MD 20874 Mr. Ed Rodwell, Manager Mr. S. M. Modro PWR Design Certification Nuclear Systems Analysis Technologies Electric Power Research Institute Lockheed Idaho Technologies Company 3412 Hillview Avenue Post Office Box 1625 Palo Alto, CA 94303 Idaho Falls, ID 83415 Mr. Charles Thompson, Nuclear Engineer AP600 Certification NE-50 19901 Germantown Road Germantown, MD 20874 1

i .

AP600 SITE PARAMETERS FOR SEISMIC DESIGN 3

AND NUCLEAR ISLAND FOUNDATION MAT ADEQUACY i

Seismic Design Parameter The AP600 standard seismic design parameter is 0.3g peak ground acceleration with the response spectra shown in Figures 3.7.1-1 and 2 of the AP600 standard safety analysis report (SSAR). If Westinghouse' intends to use this standard seismic design for the j AP600, it must either (1) demonstrate that the design meets the

' full range of site parameters, including shallow soil site condi-tions, or alternately, (2) revise the seismic design parameters and specify a separate design parameter for shallow soil sites l that the AP600 design will meet.

In the AP600 SSAR, Revision 10, Subsection 2.5.4.5.5, " Response of Soil and Rock to Dynamic Loading," Westinghouse states that for sites at which the soil characteristics are outside the range i

considered in Appendix 28.2 of the SSAR, site-specific soil-structure interaction analyses may be performed by the combined operating license (COL) applicant to demonstrate acceptability and that the analysis would use the site-specific soil conditions and the site-specific safe shutdown earthquake. The NRC staff has {

. previously discussed this issue with Westinghouse and concluded l that the proposal is unacceptable. Therefore, Westinghouse should {

revise the SSAR to reflect one of the two alternatives cited '

, above.

Design of the Containment Foundation Basemat 1 The AP600 basemat is only 6-feet thick. As a result, the NRC staff has identified two issues

(1) the basemat needs to be designed so that it can be located at sites with a full range of conditions of soil stiff-j ness variability, and (2) during the construction phase, structural cracking of the basemat can occur unless the basemat is constructed

following a precise sequence.

The NRC staff has determined that the basemat thickness should be changed to demonstrate its acceptability over a full range of soil i

stiffness variability and without reliance on a specific construction l j sequence.

1 i

i Enclosure l