ML13322B127
| ML13322B127 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 03/29/1990 |
| From: | Nandy F SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9004060364 | |
| Download: ML13322B127 (2) | |
Text
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7 Southern California Edison Company 23 PARKER STREET IRVINE, CALIFORNIA 92718 F. R. NANDY TELEPHONE MANAGER OF NUCLEAR LICENSING March 29, 1990 (714) 587-5400 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Gentlemen:
Subject:
Docket No. 50-206 Generic Item B-24, Containment Purging/Venting During Normal Operation San Onofre Nuclear Generating Station Unit 1 This letter provides a description of the administrative controls implemented to limit the time the 6-inch containment vent valves are open to a small fraction of the total time that the plant is at power. These controls were implemented in response to your letter dated February 22, 1990.
The February 22, 1990, letter presented the results of the NRC's review of our June 7, 1989, submittal of Amendment Application No. 170 and concluded that leaving the containment vent valves open continuously is unacceptable. You requested that SCE take immediate action to implement administrative controls limiting the amount of time the containment vent valves are open. Valves CV-10, the Sphere Vent Valve, and CV-116, the Sphere Equalizing Valve, were closed at 2200 on February 27, 1990. The position of valve CV-40, a three way valve controlling flow of exhausted instrument air from the pressurizer spray valves and residual heat removal flow control valves, has been changed to exhaust the instrument air to the containment sphere. Previously, CV-40 was aligned to exhaust the instrument air through the sphere vent valve to the collection system. Containment venting is initiated by first opening CV-10, located outside of containment, and then opening CV-116, located inside of containment. Termination of venting is accomplished by closing both CV-10 and CV-116.
The procedural changes required for normal operation were also completed on February 27, 1990. The primary plant operating instruction which controls venting of the containment sphere during Modes 1 through 4 was updated to reflect valves CV-10 and CV-116 as maintained closed.
Containment venting is now performed on a periodic basis initiating when containment pressure reaches approximately 0.2 psig and stopping when the pressure drops to approximately 0.0 psig. Venting is initiated at the 90c04060364 900329 PDR ADOCKf 0!500 6E
Document Control Desk March 29, 1990 0.2 psig in order to ensure that the Technical Specification maximum containment pressure limit of 0.4 psig is not exceeded. Containment venting may also be conducted under certain special circumstances (i.e., surveillance testing, ALARA concerns to lower containment radiation levels, and pressure reduction to facilitate personnel entry, etc.) as directed by the Senior Reactor Operator Operations Supervisor.
Your letter also requested we revise, within 60 days, our submittal of Amendment Application No. 170 to include Limiting Conditions for Operation (LCOs) which limit the amount of time the 6-inch containment vent valves are allowed to be open during plant operation and that we revise surveillance requirements as needed. LCOs and surveillance requirements are currently being developed. We will provide a revised amendment application by April 30, 1990.
If you have any questions or need any additional information, please call me.
Very truly yours, cc: J. B. Martin, Regional Administrator, NRC Region V C. Caldwell, NRC Senior Resident Inspector, San Onofre Units 1, 2 and 3