ML13316B745
| ML13316B745 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 06/09/1980 |
| From: | Baskin K Southern California Edison Co |
| To: | Engelken R NRC/IE, NRC/RGN-V |
| References | |
| IEB-80-05, IEB-80-5, NUDOCS 8007310162 | |
| Download: ML13316B745 (3) | |
Text
Southern California Eo'ison Company
'a P. 0.
BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD CALIFORNIA 91770 K. P. BASKIN TELEPHONE MANAGER, NUCLEAR ENGINEERING (213) 572-1401 AND LICENSING June 9, 1980 U. S. Nuclear Regulatory Canmission Office of Inspection and Enforcement Region V Suite 202, Walnut Creek Plaza Walnut Creek, California 94596 Attention: Mr. R. H. Engelken, Director DOCKET NO. 50-206 SAN ONOFRE - UNIT 1
Dear Sir:
I. E.Bulletin 80-05 Vacuum Conditions Resulting in Damage to Chemical Volume Control System Holdup Tanks Reference is made to your correspondence of March 10, 1980, forwarding the subject IE Bulletin. Identified therein were potential deficiencies in liquid holdup tank'designs that could cause vacuum conditions resulting in tank damage and radioactive releases to the environment.
Responses to individual items are listed below in the order given in the Bulletin:
ITEM 1 Review the design of all systems that contain low pressure or holdup tanks that can be valved to contain primary system water.
Assure that adequate measures have been taken to protect against vacuum conditions that could result in tank damage with the potential for release of radioactive material or detrimental effects with regard to overall safety of plant operations.
RESPONSE
A review of San Onofre Unit 1 systems that could contain primary system coolant reveals that there are ten low pressure or holdup tanks that fall within the scope of this Bulletin.
All systems reviewed were found to be adequately designed to protect against low vacuum conditions.
8 07 3 1O6-~
U. S. Nuclear Regulatorjommission Page 2 ITEM 2 Provide a listing of those systems reviewed in Item 1. Describe any measures that already exist for those systems to protect against vacuum conditions and either:
(1) explain why those measures are adequate in light of the events referenced above, or (2) identify corrective actions taken or planned to provide acceptable pr6tection, and provide a schedule for any planned corrective actions.
RESPONSE
Systems considered within the scope of this Bulletin are the Chemical and Volume Control Systems, Radioactive Waste System, Reactor Coolant System and Miscellaneous Water Systems. Each system was reviewed to determine if low pressure tanks existed within the system that could contain primary coolant. If a tank was found to fall in this category, its specific design features were reviewed to determine its capability to prevent or sustain vacuum conditions. Low pressure tanks were defined as being tanks with design pressure less than 75 psig (with the exception of the Pressurizer relief tank which has a design pressure of 100 psig).
Tanks with cover gas systems were reviewed to confirm that the gas cover system was sized to accommodate the maximum liquid removal.
The attached table summarizes the results of this evaluation.
ITEM 3 Licensees of all operating power facilities shall submit the information requested within 90 days of the date of this letter. Include in your response to this Bulletin (a) your schedule for correcting these items, (b) if reactor operation is to continue prior to correcting identified deficiencies, include your justification for continued operation.
RESPONSE
This letter constitutes our response to this item.
Should you have any questions regarding this matter, please call me.
Sincerely, cc:
Director, Office of Inspection and Enforcement
U. S. Nuclear Regulatory Commission ATTACHMENT SYSTEM/TANK REVIEW
SUMMARY
FOR IE BULLETIN 80-05 SYSTEM TANK PROTECTION JUSTIFICATION Chemical and Volume Control Designed to withstand N/A Volume Control Tank external pressure of 15 PSIG Radioactive Waste Flash Tank Designed to withstand N/A Disposal external pressure of 15 PSIG Liquid Radwaste Atmospheric 2" Vacuum breaker standpipe.
Holdup Tank Vent Gas Stripper Designed to withstand N/A external pressure of 15 PSIG Monitor Tanks Atmospheric 1" Vent Radioactive Chemical Atmospheric 1" Vent Drain Tank Decontamination Drain Atmospheric 1" Vent Tank Reactor Coolant System
-Pump operation interlocked Drain Tank with tank level
-Nitrogen cover gas provides overpressure control
-Failure of the above desigrW features would not result in release of radioactivity from containment Reactor Coolant Pressurizer Relief Designed to withstand N/A Tank external pressure of 15 PSIG MISCELLANEOUS WATER SYSTEMS Refueling Water Atmospheric 7" Vent Storage Tank