ML20127J060

Submits Info Justifying Continued Plant Operation Until Seismic Qualification of Valves 1RF026 & 1RF027 Established. Valves Administratively Controlled in Closed Position Until Reinforcing Brackets Installed

ML20127J060
Person / Time
Site:	Byron
Issue date:	05/16/1985
From:	Ainger K COMMONWEALTH EDISON CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
0140K, 140K, NUDOCS 8505210361
Download: ML20127J060 (2)

Text

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i Commonwealth Edison One First National Plazn, Chicago, tilinois Address Reply to: Post Office Box 767 Chicago, Illinois 60690 May 16, 1985 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

Byron Station Unit 1 Seismic Qualification of Equipment NRC Docket No. 50-454

Dear Mr. Denton:

This letter provides information to justify continued operation of Byron Station Unit 1 until seismic qualification of vs1ves 1RF026 and 1RF027 is established.

These valves are active cantainment isolation valves used to isolate the 3" drain line from the containment floor drain and reactor cavity sumps.

It has been determined that these valves, as installed, are

.not covered by the seismic qualification report submitted by the

'7alve manufacturer.

The valves have a low natural frequency that

>could prevent them from performing their active function under a seismic event.

A reinforcing bracket has been designed for attachaent to the valves to eliminate the low natural frequency.

This will provide full seismic qualification of the valves.

This modification to the valves will be installed within two weeks.

To justify continued plant operation until the reinforcing brackets can be, installed, these valves are now administrative 1y controlled in the closed position.

Thus, containment integrity is being maintained.

Sargent & Lundy and the valve manufacturer have confirmed that the valves, as installed, will remain closed during a postulated seismic event.

During plant operation, there are inputs to the containment floor dra(n sump that will require the sump to be pumped down periodi-cally.

Valves 1RF026 and 1RF027 must be opened for approximately 30 minutes to accomplish this.

This operation will be necessary about once every two days and can be controlled by remote operation of the valves.

Due to the limited amount of time these valves would be opened and the low probability of occurrence of a concurrent seismic event, we believe continued operation of the plant is justified.

8505210361 850516 PDR ADOCK 05000454 P

PDR 1

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R. Denton May 16, 1985 3

Immediate NRC approval ofothis justification for-continued

operation is'ne,eded to-support the present Byron Unit 1 startup testingLschedule.

t Please address any-questions regarding this matter to this office.

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One signe~d original and fif teen copies of this. letter are provided?for NRC review.

Very truly yours, (7!

K. A. 41nger Nuclear Licensing Administrator slm:

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- cc:

Byron Resident Inspector 5

1 0140K

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