ML042150046

Project Number 689, NRC Response Regarding the Manual Lockout of Automatic CO2 Fire Suppression Systems

ML042150046
Person / Time
Site:	Nuclear Energy Institute
Issue date:	08/23/2004
From:	Black S Division of Systems Safety and Analysis
To:	Marion A Nuclear Energy Institute
References
Download: ML042150046 (4)

Text

August 23, 2004 Mr. Alexander Marion Senior Director, Engineering Nuclear Generation Division Nuclear Energy Institute 1776 I Street, NW, Suite 400 Washington, DC 20006-3708

SUBJECT:

PROJECT NUMBER: 689 U. S. NUCLEAR REGULATORY COMMISSION (NRC) RESPONSE REGARDING THE MANUAL LOCKOUT OF AUTOMATIC CO2 FIRE SUPPRESSION SYSTEMS

Dear Mr. Marion:

This letter responds to your letter to Sunil Weerakkody dated July 2, 2004, in which you discussed NRC concerns related to manual lockout of automatic carbon dioxide (CO2) fire suppression systems installed in the nuclear power plants.

Thank you for taking the initiative to prepare guidelines considering alternatives to the CO2 fire suppression system. We look forward to receiving your proposed white paper for peer review and comments. In the mean time, we would like to share the following observations.

Your letter stated that the automatic CO2 systems present a potential for personnel hazard, and licensees are justified in considering alternative means for suppression. We also recognize the potential personnel safety and plant risks associated with the inadvertent discharge of automatic CO2 fire suppression systems.

Your letter stated that alternatives that may achieve an appropriate measure of fire protection defense-in-depth include (a) conversion of an automatic system to a manual system, or (b) replacement of an automatic CO2 system with another form of automatic fire suppression.

We too place emphasis on the need to pursue these alternatives while maintaining adequate safety.

You stated in your letter that the plant risk studies performed to date indicate that there is no significant impact on plant risk from automatic CO2 system conversion or replacement with alternative means of suppression. Based on our experience with several amendments under review, we believe that the fire risk is plant specific depending upon a number of factors such as, combustible loading, ignition sources, and the reliability of operator manual actions in the fire areas or zones. Our experience indicates that the risk-significance depends on the above factors as well as the reliability of the alternate suppression systems

A. Marion 2 used in lieu of the automatic CO2 system, and in selected cases could result in an "adverse impact on the ability to achieve safe-shutdown.

Licensees of Appendix R plants will be expected to submit an exemption and license amendment request to the NRC before modifying the CO2 systems from automatic to manual.

Licensees of SRP plants will be expected to seek prior NRC approval of any modification via a license amendment when the change adversely affects the ability to achieve and maintain safe-shutdown in the event of a fire.

Please contact Naeem Iqbal of my staff if you require any additional information on this matter.

Naeem can be reached at (301) 415-3346 or nxi@nrc.gov.

Sincerely,

/RA/

Suzanne C. Black, Director Division of Systems Safety and Analysis Office of Nuclear Reactor Regulation

ML042150046 OFFICE NRR/DSSA/SPLB SC:NRR/DSSA/SPLB BC:NRR/DSSA/SPLB D:NRR/DSSA NAME NIqbal SWeerakkody JHannon SBlack DATE 08/05/04 08/05/04 08/12/04 08/ 23 /04