ENS 44121
ENS Event | |
|---|---|
17:17 Apr 6, 2008 | |
| Title | Unusual Event from Reactor Coolant System Leakage |
| Event Description | Millstone unit 2 entered a refueling outage on 4/6/2008. The plant was in the process of placing shutdown cooling in service when at 1236 a 10-15 gpm leak was detected by decreasing pressurizer level. The release path was determined to be from the Reactor Coolant System (RCS) to the Refueling Water Storage Tank (RWST). Pressurizer level is stable and RWST level is rising slowly. Two charging pumps are available for RCS makeup. Decay heat is being removed with Atmospheric Dump Valves. The vent line on the RWST does not contain a radiation monitor and this is an potential unmonitored radiation release path.
The Unusual Event was declared at 1317. The leak was terminated at 1320. Monitoring of the potential release path commenced at 1610. The licensee notified the NRC Resident Inspector.
The leak path has been isolated by closing the two air operated ECCS recirc header stops 2-SI-659/660." The Unusual Event was terminated at 1856 and the NRC exited "monitoring mode" at 1920. Notified IRD (Cruz), NRR EO (Quay), and R1DO (Hansell). EPA Incident Report Number: 867171 The licensee notified the NRC Resident Inspector.
Upon further review, the times that the RCS leak occurred and was isolated require correction. The RCS leak occurred at 1243 when valve 2-SI-651 was opened to place shutdown cooling in service. The leak was terminated at 1356 when valve 2-Sl-659 was closed. The NRC Sr. Resident Inspector has been notified. Notified R1DO (Conte). |
| Where | |
|---|---|
| Millstone Connecticut (NRC Region 1) | |
| Reporting | |
| Emergency class: | Unusual Event |
| 10 CFR 50.72(a) (1) (i), Emergency Class Declaration | |
| Time - Person (Reporting Time:+-3.07 h-0.128 days <br />-0.0183 weeks <br />-0.00421 months <br />) | |
| Opened: | David Balfour 14:13 Apr 6, 2008 |
| NRC Officer: | Mark Abramovitz |
| Last Updated: | Apr 7, 2008 |
| 44121 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Hot Shutdown (0 %) |
| After | Hot Shutdown (0 %) |