ML19312C227
| ML19312C227 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 07/21/1976 |
| From: | DUKE POWER CO. |
| To: | |
| Shared Package | |
| ML19312C220 | List: |
| References | |
| RO-269-76-12, NUDOCS 7912100703 | |
| Download: ML19312C227 (1) | |
Text
-4
)
DUKE POWER COMPANY OCONEE UNIT 1 Report No.:
R0-269/76-12 Report Date:
July 21,1976 Occurrence Date: July 7, 1976 Facility: Oconee Unit 1, Seneca, South Carolina Identification of Occurrence:
Increased activity in the Component Cooling System resulting from letdown cooler leakage Conditions Prior to Occurrence:
Unit at 100 percent full power Description of Occurrence:
On July 7, 1976, routine radiochemistry monitoring revealed an increasing level of radioactivity in the Component Cooling System.
By isolating letdown coolers singly and observing the resulting change in activity in the CCS, the source of the radioactivity was identified as letdown cooler "A," from which primary coolant was leaking into the Component Cooling System.
Letdown cooler "A" was isolated to prevent further leakage and increase in CCS activity.
Apparent Cause of Occurrence:
As stated above, the apparent cause of this occurrence was a leak in letdown cooler "A," allowing leakage of primary coolant into the Component Cooling System.
Analysis of Occurrence:
Isolation of letdown cooler "A" prevented further increase of activity in the Component Cooling System.
The CCS is a closed system; therefore, any activity present will remain within the system.
The level of activity in the system does not adversely affect the operation of the unit or its components. Activity in the system will be reduced through normal makeup to the system and decay of the isotopes.
Also, since the CCS liquid is chemically buffered to a high pH value, primary coolant that has leaked into the system is quickly neutralized and its possible corrosive effects minimized.
From these considerations it is concluded that this occurrence did not adversely affect the health and safety of the public.
Corrective Action:
Letdown cooler "A" has been isolated terminating further contamination of the Component Cooling System. During the next refueling outage or maintenance outage of sufficient duration, the cooler will be either repaired or replaced.
In the interim, it is intended that unit operation will continue with letdown cooler "A" out of service pending completion of an evaluation of the impact of limited usage of the cooler. This evaluation will be completed and a supplemental report to this occurrence submitted by September
, 1976.
- 1912100703