ENS 43622
ENS Event | |
|---|---|
04:22 Sep 7, 2007 | |
| Title | Leakage From Reactor Coolant System >10 Gpm |
| Event Description | A relief valve (BG 8117) in the letdown system opened and released about 650 - 700 gallons of water from the reactor coolant system into the pressurizer relief tank. The rate of release from the letdown was 119 gpm. It was estimated that the pressurizer level lowered about 2-3%. The letdown system was isolated by closing the letdown orifice block isolation valve. Licensee is investigating the reason for the spurious lifting of the relief valve. Due to leakage from the reactor coolant system, the licensee entered EAL 4R. Plant is stable and operating at full power.
The licensee notified the NRC Resident Inspector.
The licensee stated that the Unusual Event was exited at 0120 EDT. The licensee notified the NRC Resident Inspector. Notified R4DO (Pruett) and NRR EO (Evans) and IRD MOC (Cruz).
The licensee is retracting this report based on the following: This is a follow-up notification to inform the NRC that Callaway Plant is retracting an Unusual Event declaration reported on 09/07/2007 at 00:52 EDT. EAL 4R was entered and the declaration was made due to leakage from the reactor coolant system. The basis for EAL 4R indicates that the initiating condition for an Unusual Event would include failure of a relief valve to properly close following reduction of applicable pressure and NOT simply the actuation of the relief valve as designed. Based on troubleshooting efforts and upon review of the event, it has been determined that relief valve BG8117 functioned as designed to reduce pressure and therefore the declaration of the Unusual Event was not required. The relief valve did sense an over-pressurization and did perform its intended function. The relief valve reseated when the letdown line was isolated. Based on this, the Unusual Event declaration is retracted. The licensee informed the NRC Resident Inspector. Notified R4DO (Cain), EO (MJ Ross) and IRD (Blount). |
| Where | |
|---|---|
Callaway  Missouri (NRC Region 4) | |
| Reporting | |
| Emergency class: | Unusual Event |
| 10 CFR 50.72(a) (1) (i), Emergency Class Declaration | |
| Time - Person (Reporting Time:+-3.5 h-0.146 days <br />-0.0208 weeks <br />-0.00479 months <br />) | |
| Opened: | Richard Thompson 00:52 Sep 7, 2007 |
| NRC Officer: | John Knoke |
| Last Updated: | Sep 13, 2007 |
| 43622 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 492192013-07-27T04:49:00027 July 2013 04:49:00
[Table view]10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release, 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unusual Event Declared Due to a Fire in the Turbine Building Lasting Greater than 15 Minutes ENS 472752011-09-18T15:56:00018 September 2011 15:56:00 10 CFR 50.72(a)(1)(i), Emergency Class Declaration Alert Declared Due to a Freon Gas Release Into a Safe Shutdown Equipment Area ENS 458372010-04-13T17:00:00013 April 2010 17:00:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration Unusual Event Declared Due to an Identified Leakage Exceeding 25 Gallons Per Minute ENS 448642009-02-19T16:21:00019 February 2009 16:21:00 10 CFR 50.72(a)(1)(i), Emergency Class Declaration Unusual Event Declared Due to Main Generator Hydrogen Gas Leak ENS 436222007-09-07T04:22:0007 September 2007 04:22:00 10 CFR 50.72(a)(1)(i), Emergency Class Declaration Leakage from Reactor Coolant System >10 Gpm ENS 432792007-04-05T15:23:0005 April 2007 15:23:00 10 CFR 50.72(a)(1)(i), Emergency Class Declaration Alert Declared Due to a Fire in the Control Bulding 2013-07-27T04:49:00 | |