ML20247H689

Requests Proposed Design Change to Containment Hydrogen Monitoring Sys,W/Schedule for Implementing Change or Justification for Existing Configuration

ML20247H689
Person / Time
Site:	Byron, Braidwood, 05000000
Issue date:	07/25/1989
From:	Olshan L Office of Nuclear Reactor Regulation
To:	Kovach T COMMONWEALTH EDISON CO.
References
NUDOCS 8907310103
Download: ML20247H689 (2)

Text

_

July 25,1989 y,,

.a 3-2 Docket Nosi.50-454, 50-455 50-456, aA 50-457 LMr.Tnomas'J.Kov$ch.

Nuclear Licensing Manager '

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Commonwealth Edison Company Post Office Box 7677 Chicago,IL;60690t

SUBJECT:

i DESIGN,0F' CONTAINMENT HYDROGEN MONITORIIG SYSTEM Aphendix E,' page E.30-7 of'the Byron /Braidwood Updated Final Safety Analysis Report (UFSAR) discusses the design of the containment hydrogen monitoring system..It states that " separate piping penetrations of the containment are-tutilized_by each train of this system. Each train is powered from a separate

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IE power source."

In'our or'iginal Safety Evaluation Report _(SER) NUREG-0876, dated z

February 1982, we acce)ted this design on pages 6-17, 6-22 and 7-26. On page 6-22, we stated that tie hydrogen monitoring system meets the single failure criterion.:

However, on ' July. 20,1989, the Senior Resident Inspector at Byron Station notified us that the' actual plant configuration in one area does not agree with c

your UFSAR or our SER. Each of the two containment piping penetrations for the

- suction of the hydrogen monitors has two isolation valves in series. One valve on each line is powered from DC Bus E11 and the other valve on each line is-powered from DC Bus E12. -Thus, a single failure, the: loss of either Bus E11 or Bus E12, could result in the loss of both containment piping penetrations and a loss of..the hydrogen monitoring system.

Please provide a response to this letter within 30 days of receist. Your responseLshould propose a design change to the system, with a sc1edule for implementing the change, or a justification for the existing configuration.

Sincerely, hcug Y 'Ah e907310103h$39 Leonard N. 01shan, Project Manager PDR ADOCK hNU Project Directorate III-2 P

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%.....,c July 25, 1989 L

Docket:Nos. 50-454;'50-455, 50-456, and 50-457 1

Mr Thomas J. Kovach

Nuclear Licensing Manager Commonwealth Edison Comoany

. Post Office Box 767

-Chicago, IL 60690-

SUBJECT:

DESIGN OF CONTAINMENT HYDROGEN MONITORING SYSTEM

' Appendix E, page E.30-7 of the Byron /Braidwood Updated Final Safety Analysis-Report (UFSAR). discusses the design of the containment hydrogen monitoring system. It states'that " separate piping penetrations of the containment are utilized by each train of this' system. Each train-is powered from a separate IE power source."

In our original Safety Evaluation Report (SER) NUREG-0876, dated February.1982, we accepted this design on pages 6-17, 6-22 and 7-26. On page 6-22, we stated that the hydrogen monitoring system meets the single failure

. criterion.

However..on July 20, 1989, the Senior Resident Inspector at Byron Station notified us'that the actual plant configuration in one area does not agree with

. your UFSAR or our SER.. Each of the two containment piping penetrations for the suction of the hydrogen monitors has two isolation valves in series. One' valve on each line is. powered from DC Bus Ell and the other valve on each line is -

powered from DC Bus E12. Thus, a single failure, the loss of either Bus Ell or Bus E12, could result in the loss of both containment piping penetrations and a loss of the hydrogen monitoring system.

Please provide a response to this letter within 30 days of receist. Your response should propose a design change to the system, with a s'cledule for implementing the change, or a justification for the existing configuration.

Sincerely, 1

Otat:[

^h;L Leonard N. 01shan, Project Manager Project Directorate III-2 Division of Reactor Projects III, IV, V, and Special Projects

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