ML19260D895
| ML19260D895 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 01/30/1980 |
| From: | Mattimoe T SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8002120564 | |
| Download: ML19260D895 (2) | |
Text
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esuuo SACRAMENTO MUNICIPAL UTILITY DISTRICT C 6201 s street, Box 15830, sacramento, Cahfernia 95813; (916) 452 3211 Janua ry 30, 1980 Director of Nuclear Reactor Reculation Attention:
Mr. Robert W. Reid, Chief Operating Reactor, Branch 4 U.S. Nuclear Regulatory Cor.ission Washington, D.C.
20555 Docket No. 50-312 Rancho Seco Nuclear Generating Station, Unit No. I
Dear Mr. Reid:
Paragraph 3.1.27(1) of the Fire Protection Safety Evaluation Report (SER) attached to License Amendment No.19, dated February 28, 1978, describes the following modification for Fire Area 47, the corridor to the (-) 47'
-0" elevation of the Auxiliary Building:
" Reroute cables, apply heat shield or install thennal barriers to protect redundant high pressure injection and decay heat removal systems."
Paragraph 3.1 of the SER requested that design details be submitted to the NRC for approval for the modification proposed in Paragraph 2.1. 27(1). The design details are listed below:
DESIGN DETAILS Decav Heat System Required circuits for both channels of the decay heat renoval system are in Fire Area 47.
However, the District finds this acceptable for the following reasons:
a) The circuits are separated horizontally by 25 feet without any combustibles bridging the aap.
b) The design basis fire in this area is a low temperature (2500 F) and low duration (15 minute) fire.
Therefore, it is improbable that a fire will bridae the 25 foot separation distance and effect both systems.
c) The fire area is monitored with ionization detectors
[
that alarm in the control room.
Therefore, no modifications are recuired for the Decay Heat U
Sys ten.
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1950 230 80021co g g g_
Mr. Reid January 30, 1980 Hich Pressure Injection System The District will reroute the channel B cables associated with the high oressure injection pump out of this fire area.
The cable will be routed in fire areas where a design basis fire will not make the high pressure injection system inoperative.
This modification will assure for a normal plant line-up, which is with both high pressure injection pumps and the make-up pump in service, only one channel of the high pressure injection system is in the fire area.
- Powever, if the B high pressure injection pump is out of service and the make-up pumo is operating as the B high pressure injection pump, both channels of the high pressure injection system are in the fire area.
However, the following assures operation of the high pressure injection system in this mode:
a) Horizontal separation of ten feet between the channel A and B systems with no combustibles bridging the gap.
b) The design basis fire in this area ia a low temperature (2500 F) and short duration (15 minutes) fire.
Therefore, it is improbable that a fire will bridge the 10 foot separation distance and effect both systems.
c) The fire area is monitored with ionization detectors that alarm in the control room.
Therefore, the District's modification assures operation of the high pressure injection and decay heat system with a design basis fire in this fire area.
For the District to meet the coroletion requirement, stated in Table 3.1 of the SER, the District requests that the NRC coment and/or aporove this modification by February 30, 1980.
Sincerely yours, L
,,ohn. Mattimoe Assistant General Manager and Chief Enoineer 1950 231