ENS 42343
ENS Event | |
|---|---|
04:45 Feb 16, 2006 | |
| Title | Potential Uncontrolled Radiological Release |
| Event Description | This is an 8-hour notification being made to report exceeding the design basis for reactor coolant leakage outside of containment. The normal daily RCS leakrate was completed at 2345 on 2/15/06. This leakrate indicated a step change in unidentified leakrate to .8 gpm from .09 gpm. This leakage value is within the 1 gpm allowed by Technical Specifications. Investigation is on going, and the source of the leak has not been determined at this time, however preliminary conclusion is that the leakage is outside of containment and related to the centrifugal charging pumps. The design requirement ECCS leakage outside of containment is 3840 cc/hour ( .1 gpm) to support GDC-19 limits for control room habilitability.
No safety system actuation occurred or were required. No injuries have occurred due to this event. The licensee has performed troubleshooting to identify the source of the leak and to narrow down the portion of the charging system where they believe the leak to be located. The licensee believes the leak is in a relief valve or hard pipe system to the waste tanks, and that the leak is not external to the system. The licensee notified the NRC Resident Inspector.
On February 16, 2006, PSEG made an 8-hour report (event number 42343) in accordance with 10CFR50.72(b)(3)(v) because of exceeding the design basis limits for ECCS leakage outside containment. The leakage was determined to be approximately 0.8 gpm with a limit of 3840 cc/hour. Further investigation into this event determined that the leakage was not in the ECCS recirculation flow path. The cause of the elevated RCS unidentified leakrate was the failure of the automatic three-way high level divert valve (2CV35), which prevents a high level from occurring in the Volume Control Tank (VCT). This valve failed to fully isolate flow to the Chemical Volume Control (CVC) Hold-Up Tanks (HUTs) after VCT level dropped below the divert setpoint of 77% . This conclusion is based on the VCT level being at the divert setpoint a number of times during the shift, the increased use of the valve to control level, and valve performance to fully isolate flow to the CVC HUT'S. Because this flow path is automatically isolated on a Safety Injection signal by other means (valves), the leakage through this valve is not considered part of the ECCS recirculation flow path and therefore is not included in the calculation for ECCS leakage outside containment. The event is being withdrawn. The licensee will notify the NRC Resident Inspector. R1DO(Finney) notified. |
| Where | |
|---|---|
Salem  New Jersey (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | |
| Time - Person (Reporting Time:+1.88 h0.0783 days <br />0.0112 weeks <br />0.00258 months <br />) | |
| Opened: | Eric Powell 06:38 Feb 16, 2006 |
| NRC Officer: | Joe O'Hara |
| Last Updated: | Apr 6, 2006 |
| 42343 - NRC Website | |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |