ML20028E061
| ML20028E061 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 01/13/1983 |
| From: | Fiedler P GENERAL PUBLIC UTILITIES CORP. |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8301200312 | |
| Download: ML20028E061 (3) | |
Text
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GPU Nuclear
- g g{ P.O. Box 388 Forked River, New Jersey 08731 609-693-6000 Writer's Direct Dial Number:
January 13, 1983 Mr. Dennis M. Crutchfield, Chief Operating Reactors Branch #5 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555
Dear Mr. Crutchfield:
Subj ect: Oyster Creek Nuclear Generating Station Docket No. 50-219 Containment Vent / Purge System Ref erence s : GPU Nuclear Letter from Mr. Fiedler to Mr. Crutchfield, dated March 18, 1982 GPU Nuclear Letter from Mr. Fiedler to Mr. Crutchfield, dated July 15, 1982 In accordance with your letter of January 4,1982 and our referenced letters addressing the subject matter, please find attached responses to Items 2 and 4. As stated in our previous letters, the information presented will represe nt the subject system following its modification in the future.
If there are any questions concerning this matter, please contact Mr. J. Knubel at (201) 299-2264.
Very truly yours, Y_
Pet'er B. rIedler Vice President and Director Oyster Creek PBF:lse At tachment s O/ [
cc: Mr. Ronald C. Haynes, Administrator Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 NRC Resident Inspector Oyster Creek Nuclear Generating Station Forked River, NJ 08731 8301200312 830113 PDR ADOCK 05000 P
GPU Nuclear as a part of the General Pubhc Utihties System
l ATTACHMENT OYSTER CREEK CONTAINMENT VENT / PURGE SYSTEM
- 2. During normal power operation of the reactor, the drywell and torus are inerted with nitrogen, and all the normal ventilation isolation valves are closed to prevent nitrogen f rom escaping the drywell. The vent and purge valves are allowed to be open for short periods while at or near operating pressure and temperature. In the unlikely event that a LOCA occurs while the valves are open, escaping gas must travel up to elevation 85'-10" and 21'-8" for valves V-27-3 & 4 and V-27-1 & 2, respectively. Radiation shields, which serve as debris barriers, are located 12" from the inlet pathways inside containment and prevent direct access to the subject systems. At these elevations, the escaping gas must turn 900 to enter the 18" horizontal pipe.
Once inside the pipe, the escaping gas has to travel approximately 24' of pipe through two (2) 450 elbows before it reaches V-27-3 & 4. In a similar manner, the escaping gas must. travel approximately 21' through one (1) 450 elbow and one (1) 900 elbow before it reaches V-27-1 & 2. The change of velocity in traversing the 450 and 900 turns will slow down any entrained debris before it can prevent the closure of the isolation valves. The closing time of these valves is five (5) seconds. Debris screens are not required in this cond ition. Exhaust valves V-23-29, 30,35 & 36 (which isolate in five secondo) are part of a 2" flow path to the SGTS utilized during normal plant operation to maintain drywell pressure within operational limits. The exhaust valves share the same containment penetration as V-27-1 and V-27-2, thus benefiting from the radiation shields located at the inlet. In addition, if debris were to enter this small diameter pipe, it must travel an average distance of 15' and traverse four (4) 900 elbow turns before reaching the isolation valves.
The change of velocity in traversing a 900 turn will slow down any debris entrained in the air or steam before it can prevent the closure of the valves.
Debris screens are not required in this condition..
The drywell atmosphere is connected to the torus atmosphere through pipes submerged in four (4) feet of suppression pool water. Any debris in the escaping gas from the drywell will be slowed down by the water, thereby insuring the closure of V-28-17,18 & 47 and V-23-15 & 16. These valves close in five (5) seconds. Debris screens are not required in this condition.
Isolation valves V-26-15,16,17 & 18 are part of the reactor building to torus vacuum breakert ,- and, as such, these valves are normally closed during reactor power operation. The valves open automatically when the torus is under vacuum with respect to the reactor building in order to prevent damage to the t oru s . Debris screens are not required in this condition.
All isolation valves connected to the nitrogen supply system, which is a closed system not open to atmosphere, will not be af fected by the entrained debris because the nitrogen supply system is maintained at a pressure of 60 psig. The expected drywell pressure during a LOCA is 35 psig. Therefore, the high pressure gas or steam in the drywell cannot flow into the nitrogen supply system.
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- 4. The SGTS is the only safety-related equipment located downstream of the purge isolation valves. The SGTS is connected to containment isolation valves V-27-1 & 2 via normally closed filter isolation valves V-28-23 or V-28-27. The filter isolation valves have a 60 second opening time. Upon receipt of a cont ainment isolation signal, the above valves change state. During the closure time of the containment isolation valves, V-28-23 & 27 are still partially closed, thus preventing any damage to the SGTS.
The drywell atmosphere is connected to the torus atmosphere through pipes submerged in 4' of suppression pool water. The SGTS is connected to the torus atmosphere via isolation valves V-28-18,17 & 47 which close in five (5) s econd s . Escaping gas from the drywell will be slowed down by the water, thereby insuring the closure of the isolation valves and protection of the SGTS.
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