ML20135H791
| ML20135H791 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 09/19/1985 |
| From: | Cutter A CAROLINA POWER & LIGHT CO. |
| To: | Vassallo D Office of Nuclear Reactor Regulation |
| References | |
| NLS-85-303, NUDOCS 8509240234 | |
| Download: ML20135H791 (2) | |
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y Cp&L Carolina Power & Ught Company SEP 191985 SERIAL: NLS-85-303 Director of Nuclear Reactor Regulation Attention:
Mr. D. B. Vassallo, Chief Operating Reactors Branch No. 2 Division of Licensing United States Nuclear Regulatory Commission Washington, DC 20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NOS.1 AND 7 DOCKET NOS. 50-325 & 50-324/ LICENSE NOS. DPR-71 & DPR-62 DIESEL FIRE PUMP FUEL LINE RUPTURE PROTECTION
Dear Mr. Vassallo:
By letter dated June 23,1977, Carolina Power & Light Company (CP&L) committed to install a flow switch and shut-off valve in the fuel oil supply line for the diesel-driven fire pump. The intent of this modification was to automatically isolate the fuel oil l
supply line in the event of a line rupture. The modification was completed; however, technical difficulties with calibration of the flow switch have prevented the switch from performing its intended function. The Company has reevaluated the diesel-driven fire pump system design and location and determined that the automatic isolation feature is neither necessary nor desirable. Therefore, following a 10 CFR 50.59 review, the flow switch has been removed.
The diesel engine fuel system is designed to draw fuel from a diked, aboveground, 1
500-gallon storage tank which is located outside the Makeup Water Treatment Building.
A positive displacement fuel pump, located on the diesel engine, transfers the fuel from the tank through a 1/2-inch suction line into the diesel's six injectors and a 1/2-inch return line. The overall system flow is approximately 70 gallons per hour. The expected fuel flow due to a double-ended pipe break is 72 gallons per hour. Since normal flow is within 97 percent of line-break flow, proper calibration of the flow switch could result in disruption of fuel flow to the diesel engine during normal operation.
The following mitigating factors obviate the need for the automatic isolation features:
- 1) automatic sprinklers provide fire suppression capability for the area; 2) the diesel fire pump is separated from the electric fire pump by a curb and flame impingement barrier;
- 3) the diesel and electric fire pumps are separated from the diesel fuel tank by.a three-hour fire barrier; 4) the floor around the diesel fire pump drains into a sump, thus, limiting the amount of fuel oil which could be directly exposed to the pump and driver;
- 5) fire detection instrumentation, located in the area, annunciates in the Control Room; l
- 6) fire extinguishers and hose stations are located in the immediate vicinity; and 7) the exister.ce of a well-trained fire brigade at Brunswick. In addition, the National Fire Codes discourage the use of any valves in the fuel supply line except the valve at the outlet of the fuel supply tank.
Based on the above, CP&L has determined that removing the automatic isolation function in the fuel supply line presents no safety concern.
I 8509240234 850919 PDR ADOCM 05000324 PDR j
F 00F 411 FayettevHte Street
- P. O. Box 1551
- Ralegh, N. Q. 27602 -
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Mr. D. B. Vassallo NLS-85-303 / Page 2 Should you have any questions regarding this issue, please contact Mr. Sherwood R.
9 Zimmerman at (919) 836-6242.
You very ly, W
. B. Cutter - Vic resident Nuclear Engineering & Licensing ABC/ MAT /ccc (1853 MAT) cc:
. Mr. W. H. Rutand (NRC-BNP)
Dr. J. Nelson Grace (NRC-RII)
Mr. M. Grotenhuis (NRC)-
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