ML20127G580

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Informs of Withdrawal of 850321 Commitment to Install line-type Thermal Detectors in Nuclear Svc Electric Bldg. Installation Will Not Significantly Increase Level of Fire Protection
ML20127G580
Person / Time
Site: Rancho Seco
Issue date: 05/14/1985
From: Reinaldo Rodriguez
SACRAMENTO MUNICIPAL UTILITY DISTRICT
To: Stolz J
Office of Nuclear Reactor Regulation
References
RTR-NUREG-0737, RTR-NUREG-0800, RTR-NUREG-737, RTR-NUREG-800 RJR-85-238, TAC-52606, NUDOCS 8505210095
Download: ML20127G580 (1)


Text

$SMUD SACRAMENTO MUNICIPAL UTILITY DISTRICT C 6201 S Street, P.O. Box 15830, Sacramento CA 958521830,1916) 452-3211 AN ELECTRIC SYSTEM SERVING THE HEART OF CALIFORNIA RJR 85-238 May 14, 1985 DI' RECTOR OF NUCLEAR REACTOR REGULATION ATTENTION: JOHN STOLZ, CHIEF OPERATING REACTORS BRANCH N0 4 US NUCLEAR REGULATORY COMMISSION HASHINGTON, DC 20555 DOCKET 50-312 RANCHO SECO NUCLEAR GENERATING STATION UNIT NO 1 USE OF LINE-TYPE HEAT DETECTORS IN THE NSEB By letter dated March 21, 1985 (R. J. Rodriguez to H. L. Thompson, Jr.), the District provided a comparison between the design of the Nuclear Service Electric Building (NSEB) fire protection features and NUREG - 0800, SRP9.5.1, section 6. In this response, the District committed to provide line-type thermal detectors in NSEB cable trays upon completion of the installation of all NSEB cables - estimated to be complete in 1988.

Upon further evaluation, the District has concluded that the installation of the line-type thermal detectors will not significantly increase the level of fire protection in the NSEB. This is based on the other fire protection design features incorporated in the NSEB design, including classic separation of "A" and "B" divisions by three-hour rated barriers, and the use of ioniza-tion detectors for area smoke detection. The use of area wide ionization detection provides an acceptable level of early warning response for a fire in any NSEB fire area, including cable tray fires. Smoke detectors operating on the ionization principle provide rapid response to products of combustion resulting from burning cable insulation. Thus, the District hereby withdraws the commitment to install line-type thermal detectors in the NSEB cable trays.

If you have any questions and need additional information regarding this matter, please contact Mr. J. Delezenski, (916) 452-3211 ext. 4909, of my t enting staff.

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- %w n R. J. R rigue Assista t Genera, Manager, Nuclear 8505210095 850514 PDR ADOCK 05000312 l F PDR gf l

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