ML20137D881

Responds to ACRS 770117 & 0217 Recommendations for Review of Sys Design for Safe Shutdown & Shutdown Heat Removal to Assure Adequate Seismic Design Margins.Final Rept Will Be Developed Based on Current Available Info

ML20137D881
Person / Time
Site:	North Anna, 05000000
Issue date:	06/14/1978
From:	Case E Office of Nuclear Reactor Regulation
To:	Lawroski S Advisory Committee on Reactor Safeguards
Shared Package
ML20136A555	List: IA-85-363, Submits Topics for Discussion at Commission 830708 Meeting W/Acrs.Topics Include Seismic Design Margins ML20136A550 ML20136E176 ML20136E418 ML20136E423 ML20136E621 ML20136E929 ML20136F618 ML20137D336 ML20137D440 ML20137D455 ML20137D472 ML20137D477 ML20137D494 ML20137D511 ML20137D540 ML20137D551 ML20137D557 ML20137D562 ML20137D570 ML20137D576 ML20137D583 ML20137D588 ML20137D598 ML20137D601 ML20137D609 ML20137D616 ML20137D621 ML20137D627 ML20137D635 ML20137D641 ML20137D646 ML20137D652 ML20137D659 ML20137D665 ML20137D670 ML20137D849 ML20137D867 ML20137D881 ML20137D911 ML20137D924 ML20137D951 ML20137D978 ML20137E016 ML20137E026 ML20137E044 ML20137E056 ML20137E075 ML20137E098 ML20137E113 ... further results
References
FOIA-85-363 NUDOCS 8508230076
Download: ML20137D881 (2)

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MiMORANDUM FOR: Dr. Stephen Lawroski, Chairman Advisory Committee on Reactor Safeguards FROM: Edson G. Case, Acting Director Office of Nuclear Reactor Regulation

SUBJECT:

NORTH ANNA POWER STATION UNITS NO. 1 AND 2 SEISt11C DESIGN MARGIN The Advisory Comittee on Reactor Safeguards, in its letter of January 17, 1977, to Chairman Rowden and in a supplemental letter of February 17, 1977, to B. C. Rusche, recomended that the staff review in detail the design of systems for safe shutdown and continued shutdown heat removal at North Anna Power Station Units No. 1 and 2 to assure that significant seismic margins

. exist.

On fiarch 9,1978, the staff made a presentation to the Committee summarizing our findings with respect to seismic design margin for the shutdown systems.

The presentations were made following a series of meetings with the licensee and site visits to view and discuss specific systems, components and supports. The staff concluded that significant margin existed, although in some cases the margin could not readily be expressed in quantitative terms.

During the March presentation several of the Committee members requested additional information to further quantify the available seismic margin.

As a result, the staff agreed to investigate this matter with the licensee and to prepare a written summary report, following receipt and review of the licensee's response. The staff, in a letter of March 27, 1978, The licensee responded requested further information from the licensee.

to this request in a letter dated May 5,1978 (attached), indicating that a major commitment of engineering manpower would be necessary to develop, prepare and submit the detailed information required. Considerable effort by the staff, at a time when our resources are already overburdened, would be necessary to review and comment on such submittals.

In light of the extensive effort required by the licensee to further support our finding that significant margins exist and our own resource limitations we believe that our most responsible course is to develop

Contact:

R. J. Bosnak, NRR X-27456 8508230076 850722 PDR FOIA DELL 85-363 PDR ,

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Dr. Stephen Lawroski - ?- JUN 14 578 a final report based on available information. While most'of this information is already known to the' Committee, the preparation of the report will place it in a single document and should fulfill -the under-standing reached at the March ACRS meeting concerning submission of such a report by the staff.

We have scheduled this effort to be completed during the month of August and will be sending our report to the committee shortly after that time.

PA'N -

Edson G. Cas , Acting Director Office of Nuclear Reactor Regulation ,

Attachment:

VEPC0 Ltr. dated May 5,1978 cc w/att.:

R. Boyd, DPM R. Mattson, DSS D. Vassallo, DPM J. Knight, DSS R. Bosnak, DSS v

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