ML19267A261
| ML19267A261 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 12/29/1978 |
| From: | Utley E CAROLINA POWER & LIGHT CO. |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| References | |
| GD-78-4404, NUDOCS 7901030078 | |
| Download: ML19267A261 (2) | |
Text
- a CP&L
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Carolina Power & Light Company December 29, 1978 FILE: NG-3514(B)
SERIAL: GD-78-4404 Office of Nuclear Reactor Regulation ATTENTION:
Mr. T. A. Ippolito, Chief Operating Reactors Branch No. 3 United States Nuclear Regulatory Commission Washington, D. C.
20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. 50-325 AND 50-324 LICENSE NOS. DPR-71 AND DPR-62 VACUUM BREAKER MODIFICATION
Dear Mr. Ippolito:
In accordance with the request from your December 11, 1978 letter, this letter provides the staff with a description of the design details for our proposed modifications to the suppression pool-to-reactor building v scuum breakers at the Brt.nswick Plant.
The vacuum relief line between the suppression pool and the reactor building is designed with a single line penetrating the concrete containment. This line connects to a tee, each leg of which contains a butterfly valve and a vacuum breaker. The butterfly valves in these lines were purchased to the identical design specification as other containment isolation valves, except the pneumatic actuators were deleted.
These valves will now be modified by installing the same design (i.e.,
same vendor) pneumatic actuators as the other identical containment isolation valves. Air supply to the actuators of each butterfly valve will be from independent sources of the non-interruptable instrument air systems.
Power supply is from separate power divisions. The valves will be in the normally closed position and will fail closed.
Control for these valves will be designed to allow automatic opening on receipt of a signal from a newly installed pressure differential switch. Upon a pressure dif ferential of 0.5 psig between drywell (-0.5 psig) and reactor building (atmospheric pressure), the butterfly valves will be opened, and the vacuum relief function will be provided by the vacuum breaker valve located in this line.
Control switches will also be provided on the Reactor-Turbine-Generator (RTG) Board for manual or automatic operation of the valves. Valve position indicators will also be provided on the RTG Board.
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. The pneumatic actuators in compliance with our design specification were shipped via air freight to the Brunswick Steam Electric Plant on November 22, 1978.
The pressure differential switches, cabl., tubing, and other material required for the modification has been procured and will be delivered to meet an installation date in compliance with the requirement from your December 11, 1978 letter.
If you have any questions concerning this information, please contact our staff.
Yours very truly, hj E. E. Utley Senior Vice President Power Supply EEU/bwb
.