ML17276B620

Forwards Request for Addl Info Re Applicability of Square Root of Sum of Squares Combination of Dynamic Responses

ML17276B620
Person / Time
Site:	Columbia
Issue date:	09/16/1982
From:	Schwencer A Office of Nuclear Reactor Regulation
To:	Ferguson R WASHINGTON PUBLIC POWER SUPPLY SYSTEM
References
NUDOCS 8209300023
Download: ML17276B620 (5)

Text

ee 1

SEP 16 1982 CDocket No.:

50 397%

Hr.

R. L. Ferguson Managing Director Washington Public Supply System 3000 George Hashfngton Hay Richland, Hashington 99352 DISTR I 8 UTION:

Docket Fil e bcc:

NRC PDR LB42 File Local PDR RAul uck NSIC EHy1ton PRC I&E Region V

ACRS (16)

Paton, OELD RLi

Subject:

HNP-2 Request for Additional Information In Section 3.9.3.1 of the Safety Evaluation Report for HNP-2 (NUREG-0892),

we identified a confirmatory issue concerning the applicability of SRSS combination of dynamic.responses for the HNP-2.

The staff's specfff cI concern fs that the primary containment for the HNP-2 plant fs a free-standing steel pressure vessel and the plant is fn a higher seismic zone.

Based on 8 review of tyou'r submittal dated July 28, 1982, we have determined that some areas have not been addressed adequat'ely.

To maintain our Tic.,ensfng review schedule Cfor the HNP-2, please provide responses to the enclosed request by October 29, 1982. If you desi;re any clarification, please contact Raj Auluck at (301) 492-9778.

Sf ncere ly,r A. Schwencer, Chief Licensing Branch No.

2 Division of Licensing Enclo',sure:

As stated cc w/ enclosure:

See next page 8209300023 820'9iib PDR ADDCK 05000397 181 PDR K

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NRC FORM 318 u0-80) NRCM 0240 OFFICIAL RECORD COPY USGPO 1981~980

Pl

WHP-2 0

Mr. R. L. Ferguson Managing Director Washington Public Power Supply System P.

0.

Box 968 3000 George Ma shing ton May

Richland, Washington 99352 CC:

Nicholas Reynolds, Esquire Oebevoise 5 Liberman 1200 Seventeenth

Street, H. M.

Mashington, D. C.

20036 Mr. G.E.

Doupe, Esquire Washington Public Power Supply System P.O.

Box 968 3000 George Mashington May

Richland, Mashington 99352 Nicholas Lewi s, Chairman

~ Energy Facility Site Evaluation Council Mail Stop PY-11 Olympia, Mashington 98504 Roger Helson, Licensing Manager Mashington Public Power Supply System P.O.

Box 968

Richland, Mashington 99352 Mr. M.G. Conn, Sr.

H/M Group Supervisor Burns and Roe, Incorporated 601. Williams Boul.evard Richl and, Washington 99352 Mr. Richard FeH.

U.S.

HRC Resident Inspector MPPSS-2 NPS

'.O.

Box'69 Richl and, Washington 99352 I

. Dr. G.D. BoucAey Deputy. Di rector, Safety

& Security Mashington Public. Power Supply System P.O.

Box 968, MD 650

Richland, Washington 99352

ENCLOSU

-,r 110.39 In order to assess the. applicability of SRSS combination of'ynamic responses for WNP-2, the applicant reviewed the data of the 26 response combinations pertaining to the free-standing steel containment contaiqed in Tables 3-6, 3-9 and 3-13 of Reference 2.

Based on a review of these data the applicant concluded that the use of SRSS method is adequate for WNP-2 (Reference 1).

We reviewed the information in Referen'ces 1,

2 and' and determined, that -.

the applicant has not provided adequate information required to reach a

quantitative conclusion on the applicability of SRSS combination of dynamic responses.

The sample number of cases mentioned above is not large or convincing enough (only 26 cases, and many of the 26,.cases have NEP levels of the SRSS combined responses which are only marginal) to

~

justify an across-the board application of SRSS for all mechanical systems and components in an application which differs significantly

from other Hark II and Mark III plants.

.Additional quantitative' evidence is necessary to support SRSS applicability based on the actual dynamic responses and containment structure configuration of WNP-2 since (1) the configuration of the Hark II containment and the hydrodynamic loads used in WNP-2 differ significantly from those ef Hark III plants

'n which the mentioned sample cases were based, (2) the earthquake le'vel.

used in the WNP-2 design is higher than the levels used in thi referenced Mark. III plants.

Thus the seismic responses of systems and components in WNP-2. cannot be expected to duplicate those in Hark III

plants, and may differ significantly from them.

It is 'recon>ended that the'pplicant choose one of the following options in demonstrating the applicability of SRSS.

. I.

Generate CDFs and show that the NEPs of SRSS combinations of responses at selected sample locations exceed 84K.

The number, and distribution of sample locations should be sufficient by compre-h'ensive to cover all essential systems and componen'ts as shown in Ref.

2 and 3.

2.

Yerify that the dynamic loads to be combined are conservatively'efined at the 84th percentile or greater.

Generate

'.CDFs.-andwhow that the NEPs of SRSS combination of responses at selected sample

'ocations are at or exceed 50% and the NEPs of 1.2 SRSS are at or exceed 84$.

3.

VerHy quantitatively the similarity of response characteristics of systems and components in RNP-2 to those in Mark II or III as indicated in Ref.

2

8. 3, such that the same conclusion on SRSS applicability may be justified for WNP-2..

Such an effort might include comparisons of containment modal frequencies and the nature of the dynamic loads, such as the general shapes and durations of the earthquake and the suppression pool dynamic loads.

4.

Combine dynamic responses by absolute summation.

References:

1.

Letter from G.

D. Bouchey to A. Sbhwencer, "Nuclear Project No.

2 Application of SRSS Rule for Steel Containment".,

dated July 28, 1982.

2.

Report,.SMA 12109.01-R001, "Study to Demonstrate the Generic Applicability of SRSS Combination. of Dynamic Responses for 'Mark II'I Null'ear Steam Supply System and Balance-of-Plant Pip'ing and Equipment Components",<

General Electric Company, dated November 24,. 1981.

3.

Report, NEDE-24010-P, "Technical Bases for the use of the Square-Root-'

of-the-Sum-of-Squares (SRSS)

Method for Combining.Dyamic Loads for Hark II'Plants",,

General Electric Company,'ated'July 1977.