ML18192A628

Letter from Arizona Public Service Co to NRC Consisting of Request for Information Regarding Postulated Pipebreak Outside the Containment, Specifically Inside the Main Steam Support Structure of Palo Verde Nuclear Generating Station, Units

ML18192A628
Person / Time
Site:	Palo Verde
Issue date:	05/24/1977
From:	Van Brunt E Arizona Public Service Co
To:	Boyd R Office of Nuclear Reactor Regulation
References
Download: ML18192A628 (6)

Text

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$ 3 FILE NVMOEA TO r Mr. Roger ST Boyd FROM:

Arizona Public Service Company

Phoenix, Arizona E

ED Van Brunt, Jr+

DATE OF DOCUMENT 5/24/77 DATE AECEIVED 5/30/77 ETTEA OAIGIMAL QCOI V QNOTO BIZ E D 8kINCLASSIFIE D PA OP DESCIIIPTION Consists of request for information regarding

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PHOENIX, ARIZONA 85036 May 24, 1977 ANPP-8642

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i.'q(QA Director of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Attn:

Mr. Roger S.

Boyd, Director Division of Project Management Office of Nuclear Reactor Regulations Washington, D.

Q.

20555

Reference:

PVNGS Units '1, 2

6 3 - Docket Nos.

STN 50-528/529/530 Construction Permit No. CPPR-141/142/143 File:

77-055-026 KQIIQH5M(K We understand the NRC is reevaluating its pos~tzon re'g d'fh non-mechanistic pipebreaks in straight runs of piping outside the containment, such as in main steam support structures or steam tunnels.

This includes postulation of non-mechanic breaks in sections of "super-pipe" located in the main steam support structure.

We further understand at the present time that the NRC does not have a

firm official policy regarding the break that must be assumed and the effects that must be designed against.

From examining questions and responses on recent applications and reviews, it appears to us that an applicant must take a slot-break equivalent to a single-ended break in the main steam support structure.

However, one is not required to consider the effects of jet impingement or pipewhip.

We feel we have a design with some built-in conservatism;

however, the Palo Verde Nuclear Generating Station Units 1, 2

5 3 design is at that point where we need guidance from the NRC regarding the postulated pipebreak in the main steam support structure.

Any further delay on our part awaiting guidance from the NRC will greatly impact the design and construction of the Palo Verde Nuclear Generating Station and cause a

great economic impact at a later date if we are required to backfit.

Therefore, we are requesting the NRC staff to give us guidance regarding postulated pipebreak outside the containment, specifically inside the main steam support structure.

Specifically, we would like to know:

1) If a break is required in that area which presently is designed with "super-pipe."

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May 24, 1977 ANPP-8642 Page Two 2)

The break spectrum we must consider.

3)

The degree we must design to cope with jet'impingement and pipewhip.

4)

The degree we must design against environmental effects of the pipebreak."

Ne would like to ask for immediate resolution of this matter due to the high probability of significant impact upon design and construction of the Palo Verde Nuclear Generating Station.

Ne are available to dis-cuss this matter with your staff at any time.

Very truly

urs, a~

aWA E.

E.

Van Brunt, Jr.

APS Vice President, Construction Projects ANPP Project Director EEVBJr/JMA/pb cc:

R. L. Robb A. C. Rogers F.

W. Hartley lU. M. Petro 1U. )Uilson D. Keith C. Ferguson Admin.

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