ML20198F775

Discusses Design Deficiency Concerning Plant Spray Pond Design Which Could Delay CP Decision on Unit 4.CP Decision Could Be Made Pending Receipt of Util Description of Mechanical & Civil Engineering Solutions

ML20198F775
Person / Time
Site:	Washington Public Power Supply System
Issue date:	01/30/1978
From:	Cox T Office of Nuclear Reactor Regulation
To:	Parr O Office of Nuclear Reactor Regulation
References
CON-WNP-1157 NUDOCS 8605290086
Download: ML20198F775 (2)

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JAN 3 01978 Ex DocketHos.50-460k MRushbrook and 50-513 MEMORANDUM FOR: Olan D. Parr. Chief, Light Water Reactors Branch No. 3, DPM FROM:

Thomas H. Cox, Project Manager, Light hater Reactors Branch No. 3, DPM

SUBJECT:

DESIGN DEFICIENCY - WP-1 AND WP-4 The staff is submitting proposed findings of fact and conclusions of law to the ASLB on January 27, 1978 concerning the WP-4 project. The Board could rule on these and the applicant's findings and reach a decision in the near future. A potential issue has surfaced concerning the spray pond design. The issue may be reportable, and could delay the CP decision on WP-4.-

The Washington Public Power Supply System (WPSS) notified me earlier this month, in a telephone conversation, that they had reported to Pegion V, IE, that the original spray pond design approved in 1975 for both WP 1 and 4 may have been deficient in that there could be excessive loss of water due to drift curing spray operations. This situation arose when WPSS concluded that their assumption for wind velocity that was used to calculate maxicam drift loss was not high (conservative) enough. The velocity that

'PPSS originally used is 5.54 miles per hour, as stated in Section 9.2.5.3.

of the PSAR, Amendment 19. WPSS now states that they are designing for drif t losses based on a wind velocity of approximately 13 miles per hour. This revised velocity results from:

1.

Correcting an earlier error in selecting a conservative maxt:::um velocity from the aata then available.

2.

The use of a more conservative velocity averaging method than required by Regulatory Guide 1.27, Revision 2.

3.

The use of newer meteorological data now available from Battelle Northwest Laboratories.

l Drift losses will be limited by the addition '(over that now shown in PSAR) of "a 16 foot wide, sloping apron", around the pond perimeter. A report on the modification is expected to be submitten to IE Region Y in about one m M th. The report will be forwarded to OHRR for infor:aation. WPSS t's t 9 to me that they do not consider the change in assumed wind velocity (for crif t analysis) or the resultant pond design changes to De a change in the principal engineering criteria. I concur in that assessment.

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o JAN 3 01978 Olan D. Parr 2-IE, Region V discussed this matter in a report dated December 15, 1977 (copy enclosed). Jack Garvin, Region V Reactor Inspector, stated that IE coes not consider this item to be a 50.55(e) item because it was identified prior to the release of construction drawir ]s for that portion of the pond design in which the design modifications are planned.

I discussed this matter on January 27, 1978 with Gary Staley, the responsible technical reviewer for the WPSS spray pond design as approved on the-I WP-1-4 docket (Supplernent No. 2, August 1975, NtJREG 75/036, page 2-3 The staff's independent analysis of the WPSS design included our own wind velocity assutsption for drift loss calculations, and it was higher than the 012 that WPSS used, be found the design acceptable at the CP stage of r? view.

WPSS has apoarently elected to improve their design ourino the post-CP period (WP-1). They nave, however, icentified (to Cox, in conversation en January 27,1978), that their improvement is based partially on the use of data not previously available (the BNL meteorological data).

These data may show that staff's previous, assur:ption of maxime wind velocity (for calculating drif t losses) asy he non-conservative.

However, because there are known icechaniol and civil engineering solutions to the proolem of too much drif t loss, I believe that we could, once we have WPSS' description of what they have done, move forward to a CP decision on WP-4 based on the provisions of 10 CFR 50.35(a).

I believe we should discuss:

1.

The content of a report to the sitting ASLB, if one is to be maco..

2.

'nhat the applicant should be requested to do.

Origind Signed By ThNs Dbf i

l Light Water Reactors Branch No. 3 Division of Project Management ccs:

D. B. Vassallo E. Ketchen

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G. Staley G. Hulman R. DeYoung DPM:LUR #'.DPg@ #3-ome,

THCox:ab 1()DParr 1/37/78_

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