ML17276B400

Informs of Potential Reportable Condition in Hydrodynamic Loads in Piping & Supports of Control Rod Driveline Sys Causing Calculated Hydrodynamic Loads to Be Inaccurate. Requests Proposed Plan for Reinforcing Affected Components

ML17276B400
Person / Time
Site:	Columbia
Issue date:	04/05/1982
From:	Schwencer A Office of Nuclear Reactor Regulation
To:	Ferguson R WASHINGTON PUBLIC POWER SUPPLY SYSTEM
References
NUDOCS 8204190051
Download: ML17276B400 (6)

Text

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1982 9ocl,et Iles. 50:397 Mr.

R. L. Ferguson Managing Director Washington Public Power Supply System P. 0. Box 968 3000 George Washington Way

Richland, Washington 99352 Dear Mr.

Ferguson:

Subject:

"Fast Scram" Hydrodynamic Loads

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RHartfield, MPA on Control Rod Drive System We were recently informed by a vendor of control rod drive (CRD) systems of a potential reportable condition applicable to boiling water reactors (Enclosure 1).

Specifically, this vendor indicates that its analysis of the hydrodynamic loads in the piping and on the supports of a particular CRD system for a "worst case" condition resulted in structural loads which were larger than some of the previous design loads for this system.

These larger loads result from a rapid actuation of the CRD.

The conditions assumed by this vendor for its "worst case" calculation of the hydrodynamic loads were:

( 1) a design basis opening time of 20 milliseconds for the inlet line scram valve; and (2 )

a scram during the start-up phase of the plant with no pressure in the reactor vessel.

The vendor also stated that its modeling of the CRD system may not be appro-priate which could cause the calculated hydrodynamic loads to be insuf-ficiently accurate.

Our concern in this matter is that the hydrodynamic loads in the CRD system for your facility may not have been properly evaluated.

Accordingly, we still continue to regard this matter as an open item on your docket until we can resolve this issue.

As part of our continuing review of your application for an operatinq license, we request that you provide the following information, for your facility:

1.

The design basis opening time for the inlet line scram valve.

2.

An evaluation of the hydrodynamic loads in your CRD system resulting from actuation of the inlet line scram valve using the design basis opening time specified in Item 1.

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A'description of the conditions and configurations of the plant which result in the maximum hydrodynamic loads in the CRD system.

4.

A statement regarding the appropriateness of the mathematical model used to calculate the hydrodynamic loads in the CRD system resulting from a scram.

5.

A cenparison of the hydrodynamic loads evaluated in Item 2 with the present design basis loads for the CRO system.

In the event that the hydrodynamic loads calculated for your facility exceed the present design basis structural loads for the CRO system, indicate which components are affected and submit a proposed plan for structurally reinforcing the affected components.

Please indicate within 7 days of receipt of this letter, the date by which you can respond to our request.

If you have any questions on this matter, please contact the Project hiarhger',

R. Auluck, at (301) 492-9778.

Sincerely,

Enclosure:

As stated A. Schwencer, Chief Licensing Branch No.

2 Division of Licensin~g-cc:

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

0; Box 968 3000 George Wasington Way Richland, Washington 99352 CC:

Nicholas Reynolds, Esquire Debevoise 5 Liberman 1200 Seventeenth

Street, N.M.

Washington; D;C.

20036

.Mr.

G.

E.

Doupe, Esq.

Washington Public Power Supply System P.O.

Box 968 3000 George Washington May Richland, Washington 99352 Nicholas Lewis, Chairman Energy Facility Site. Evaluation Council 820 East 'Fifth Avenue Olympia, Washington 98504 Roger Nelson, Licensing Manager Washington Public Power Supply System P.O.

Box 968 Richland, Mashington 99352 Nr. W.G. Conn, Sr.

N/M Group Supervisor Burns, and

Roe, Incorporated 601 Milliams Boulevard

'ichland, Washington 99352 Mr. Richard Feil U.S.N.R.C.

Resident Inspector WPPSS-2 NPS P.O.

Box 69 Richland, Washington 99352 Dr. G.D.

Bouchey Deputy Director, Safety 5 Security Washington Public Power Supply System P.0; Box 968, HD 650 Richl'and, Washington 99352

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