ML19290C201

Submits Suggestion in Response to Aslab 791108 Request to VEPCO Re Use of Outdated Amplified Response Spectrum Curves. Housner Response Spectra Was Questionable Per Encl S&W 690820 Conference Notes Entered Into Record on Mar 1974

ML19290C201
Person / Time
Site:	North Anna
Issue date:	12/11/1979
From:	Allen J NORTH ANNA ENVIRONMENTAL COALITION
To:	Buck J, Mike Farrar, Rosenthal A NRC ATOMIC SAFETY & LICENSING APPEAL PANEL (ASLAP)
References
NUDOCS 8001100326
Download: ML19290C201 (4)

Text

.

NORTH ANNA ENVIRONMENTAL COALITION Charlottesville, Virginia Mailing Address: 412 Owens Drive Decemb er 11, 1979 Huntsville. Alabama 35801 (205) 536- 0678 Hessrs. Rosenthal, Farrar, and Buck d #1/ N Atomic Safety & Licensing Appeal Board g g U. S. NUCLEAR REGUIATORY COMMISSION t@o e/

Washington, D. C. 20555 2 O{g In the Matter of Virginia Electric and Power Company /8/g A [

(North Anna Power Station, Units 1 and 2)

Docket Nos. 50-338 and 50-339 OL 9  %. P Gentlemen: g

.cn The Coalition was gratified to read the Appeal Board request o November 8 to VEPCO, asking for more information on the use of outdated amplified response spectrum curves at the North Anna sta-tion, particularly as that use relate _ to pumphouse settlement.

For a complete understanding of the problem, we believe the Appeal 3oard should study the history of North Anna design, and note that 10 years ago, in 1969, VEPCO, Stone & Webster, and Dames & Moore knew that the use of the Housner response spectra was questionable:

" ...the Housner response spectra now being used for seismic design of the station could underestimate the response to earthquake ground motion of some structural components. Since the DRL has questioned the use of the Housner spectra, we should be cautious in our discussions with the AEC with regard to seismic design values and procedures...and avoid discussion of the applicability of the Housner response spectra..."

The foregoing (with emphasis added) was taken from an internal Stone and Webster document of August 20, 1969 These Stone & Webster con-ference notes were entered into the record of the thrch 1974 Show Cause hearing as Exhibit NX-16 by Coalition Attorney, William H.

Rodgers, Jr.

The Coalition would inquire the connection between this aware-ness of questionable response spectra which Stone & Webster hoped to " avoid discussio.1 of" in 1969 and the Biscovery" in 1979,.10 years later, of tne use of " outdated spectrum curves" at North Anna. This tardy and continuing revelation of error at the site can only add validity to intervenor contentions that the licensee had/has neither the commitment nor the technological skill to construct and operate the North Anna station with safety and integrity.

Exhibit NX-16 is enclosed for your study.

ncerely ec to . Service List eTen without enclosure @ resident, NAEC 8001100 3 2 (

.... . .- ,uur. rem ov waa 5 ; ; __ w. ,

.. wiu . < .- - - ~ - -

.~ - . < .

g .- u2.-

j /p y J.O.No. 11715 NAS-1291t .

FILE Ill"c10B.O37.gy-1 NOTES OF CONFERENCE s NORTH ANNA POWER STATION .

~

VIRGINIA ELECTRIC AND POWER COMPANY f'iby 6 "I Held in the Offices of  ; j 4-Virginia Electric and Power Company -

I g6@g#

Richmond,~ Virginia p -

August 20, 1969 os Present for: .

Virginia Electric and Power Company - Messrs. J.' B. Dischinger (VEPCO) C. H. Mays F. K. Moore J. Perkins Dames & Moore (D&M) ,,

Mr. J. A. Fischer Stone & Webster Engineering -

Mr. D. P. McKittrick Corporation (S&W) - - - - -

The meeting was held to discuss the sarthquake acceleration values of .08 and .15 g recommended by the A.E.C. consultants for the operational and design basis earthquakes for seismic design of the North Anna Power Station.

Subsequent to the DRL technical meeting, S&W reviewed the information submitted in the PSAR and made a summary assess-ment of the effects of the higher acceleration values on the design of various structural components of the station.

Mr. McKittrick stated that with regard to information submitted in' Appendix A, " Site Environmental Studies" (and keeping in mind more recent practices and suggestions of the DRL Staff with regard to earthquake acceleration values) there might be some basis for the A.E.C. to arbitrarily recommend values somewh H~ higher than .06 and .12 g. The A.E.C. is postulatirg

~

for the Design Basis Earthquake (DBE) at least a strong ~~

Intensity VII (Modified Mercalli) near'the'sife. For an earths '

quake of that intensity close in to the site, the Housner response spectra now being used.for seismic design.of ths,,

1731 068 tals. SEP 3 1969 VI.F.S.

b

2 Eh station could ugderestimitiis.the-'r.esponse-to. earthquake ground, motion of seme; structural.;icomponents. i Since . the,: DRL ' has ~

quJsti~oned the use of.the Housner-spectra, we2should'be ,j~

cautious in ourTdis~cuYs'ibns"with'"the?A'.E'.C.* with"r' e gard'to scismTc desi~gn values and: procedures; ~-For example, after pro-

~

longod-discussionCth.e..EE.'C'.E coilid ' concede to the accelera-tion values of .06 and .12 g cited in the PSAR but asks that structures be analyzed using response spectra that envelope more high frequency peaks.

~

Based on' S&W'.s tprelisiiEr}. revievlt[might .be . a'3visab1Do2r accept, somewhat~. rblE~ctantly,; the higher valuessor .0_84and s.15, g-7 and a. void di.sc_uss, ion ~ of..the rapplicability' of th6' Housner- .'

responsa spectra.

It was agreed that a decision on whether or not to officially e.ccept the DRL recorrenda tions could be delaved -

for 3-5 weeks. During that time, MM, with the assistance of Mr. Henry of S&W's Mineral office,would undertake an intensive literature review of the seismic history of the area. When additional data have been accumulated and reviewed VEPCO may request a meeting with the DRL to review the seismic design values. In the informal meeting with the DRL on August 15, the staff and its consultants were agreeable to this additional meeting. y 7 In the interim, design of the foundation mat for Unit No.1 containment will proceed on the basis of the higher accelera-tion values. The incremental cost increase for the mat designed on this basis is estimated to be on the order of S2, 500. Answers to DRL questions regarding stress levels in the Class 1 structures will also be based on the higher acceler-ation vhlues. These answers will be qualified or r.1odified 7 depending on the outcome of the meeting with the DRL Staff. -

If the final decision is to accept the higher acceleration values recommended by the A.E.C. and use the Housner response &

spectra for design, S&W estima tes the total incremental cost  !!

increase to be approximately S250,000 for two' units including

top charges. -

This increased cost does not include the total cost of diagonal reinforcing, only the incremental cost for the higher accelera-tion values.

1731 069

3 It was agreed that an additional meeting would be held when the review of the seismic history is completed. S&W will continue to review the effects on design of the higher acceleration values, and attempt to assess the effect on design of the use of response spectra different from the Housner Spectra.

e

• O m

h e

e

/

O 1731 070