Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 49134 | 19 June 2013 08:03:00 | An alarm was observed in the Technical Support Center (TSC). Initial investigation revealed the TSC to be warmer than usual and alarm 'TSC Vent Air Handling Unit B001 Disch Low Flow' was annunciated on the local panel. Annunciator response was followed as per 34SO-X75-002-0 with maintenance assistance. Further investigation revealed that the 1X75B001 Air Handling Unit fan belt was broken which made the TSC non-functional. The availability of the alternate TSC was verified as required. Actions are in place to return the TSC to functional status. If an emergency condition occurs that requires activation of the TSC, plans are to utilize the TSC as long as habitability conditions allow. Procedure 73EP-EIP-063-0, Technical Support Center Activation provides instructions to direct TSC management to the Control Room and TSC support personnel to the Simulator Building to continue TSC activities if it is necessary to relocate from the primary TSC. This event is reportable per 10CFR50.72 (b)(3)(xiii) as described in NUREG-1022, Rev. 2 and TRM T3.10.1 since the facility was rendered non-functional for greater than 30 minutes. The TSC was returned to FUNCTIONAL status at 0430 EDT on 6/19/2013. The licensee notified the NRC Resident Inspector |
| ENS 48772 | 20 February 2013 10:21:00 | On February 20, 2013, at 0538 EST, local leak-rate testing (LLRT) of the 'A' feedwater check valves 2B21-F010A and 2B21-F077A revealed that neither valve would pressurize. Based on this information this line would not remain water filled post-LOCA and would result in the 'as found' minimum pathway leakage exceeding the limiting condition of operation (LCO) for Technical Specification 3.6.1.1. The cause for the LLRT failures will be determined and required corrective maintenance will be performed and valves successfully tested during the current refueling outage. The licensee notified the NRC Resident Inspector.
Subsequent investigation into the reported LLRT failure revealed that the initial LLRT performed on feedwater check valve 2B21-F010A was not considered an acceptable test, since that LLRT was not representative of the 'as found' condition of this check valve. The test volume for this valve had been slowly filled such that the check valve did not have the normal expected differential pressure across the valve disc to achieve normal check valve seating. After draining the test volume and refilling it by allowing the test volume to gravity fill from the reactor pressure vessel, the expected differential pressure across the valve disc occurred and seated the disc in such a way that it was more representative of the 'as found' condition for the check valve. An LLRT was then performed with a leakage of 50 accm (actual cubic centimeters per minute) against an acceptance criterion of 194 accm. No maintenance or operation of the check valve had occurred between the initial invalid test and the subsequent test performed with the disc in its 'as found' condition. An engineering evaluation was performed that documented the acceptability of using this means for establishing the test volume for feedwater check valves 2B21-F010A and 2B21-F010B for the 'A' and 'B' loops of feedwater, respectively. This engineering evaluation concluded that establishment of the required test volume in the manner described for primary containment penetration 9A satisfies the Hatch LLRT program requirements and that the leakage acceptance criterion for feedwater check valve 2B21-F010A in its 'as found' state was satisfied. The 2B21-F077A valve will be retested at a later date. Based on this information, the LLRT of this check valve in its 'as found' state was successful which actually resulted in successful minimum pathway leak rate test results for primary containment penetration 9A. These conclusive test results clearly indicated that the initial test results were incorrect and the 'as found' condition of this penetration isolation capability did not represent a significant degradation of a principal safety barrier as described in 10CFR50.72(b)(3)(ii)(A). For these reasons Notification # 48772 is being retracted. The licensee notified the NRC Resident Inspector. Notified the R2DO (McCoy). |
| ENS 48529 | 21 November 2012 13:01:00 | A chlorine leak was discovered in an area near the Unit 2 cooling towers. The leak has been isolated; the amount leaked is under investigation. Sodium bisulfite has been used to neutralize the (leaked) chlorine. The Georgia Environmental Protection Division and U.S. Coast Guard have been notified. The licensee has notified the NRC Resident Inspector. |
| ENS 48067 | 3 July 2012 16:53:00 | Planned maintenance activities are being performed today (July 3, 2012) to remove temporary power from and restore normal power to the Technical Support Center (TSC) 480 VAC Distribution Panel 1R25-S012. This panel provides power to the TSC Emergency HVAC (TSC air handling unit, TSC condensing unit, TSC filter train and the fan unit for the TSC filter train) rendering the TSC non-functional (TRM - Section T 3.10.1 EMERGENCY RESPONSE FACILITIES) during the performance of this work activity. This work activity is planned to be performed and completed expeditiously within about 5 hours including establishing and removing the clearances. The temporary power was installed on 6/19/12 to support work activities on the Hatch Nuclear Plant's 1R24-S026-600/208V MCC under Work Order Number 1050889203 which is the normal power supply. If an emergency condition occurs that requires activation of the Technical Support Center, plans are to utilize the TSC during the time this work activity is being performed, as long as habitability conditions allow. Procedure 73EP-EIP-063-0, Technical Support Center Activation provides instructions to direct TSC management to the Control Room and TSC support personnel to the Simulator Building to continue TSC activities if it is necessary to relocate from the primary TSC. This event is reportable per 10CFR50.72(b)(3)(xiii) as described in NUREG-1022, Rev. 1 since this work activity affects an emergency response facility for the duration of the evolution. The TSC was returned to service today at 1645 EDT on 7/3/2012. The licensee has notified the NRC Resident Inspector. |
| ENS 44337 | 4 July 2008 10:04:00 | A Turbine Trip greater than 30% power caused a Reactor Trip (Scram), both Recirculation Pumps tripped. A low level (Reactor Vessel Water Level) of approximately 2 inches caused a Group 2 containment valve isolation signal, all valves closed as required. The cause of the Turbine Trip is under investigation All control rods fully inserted with no ECCS actuations. Unit 1 is currently stable in mode 3 (Hot Shutdown) with decay heat being removed via the bypass. Following the scram, one SRV lifted and reseated. At the time of the transient, an EHC pump autostart was in progress, however, there is no indication that this was the cause of the turbine trip. Unit 1 is in a normal shutdown electrical lineup. The licensee informed the NRC Resident Inspector. |
| ENS 43276 | 4 April 2007 14:01:00 | The following information is provided as a 60 day telephone notification to NRC under 10 CFR 50.73(a)(1) in lieu of submitting a written LER to report a condition that resulted in an invalid actuation of the 10CFR50.73(a)(2)(iv)(B) (general containment isolation signals affecting containment isolation valves in more than one system or multiple main steam isolation valves). NUREG1022 Revision 2 identifies the information that needs to be reported as discussed below. (a) The specific train(s) and system(s) that were actuated. This report is being made under 10CFR50.73(a)(2)(iv)(a). On February 25, 2007 at 3:58 AM EST Units 1 and 2 received an invalid full Secondary Containment Isolation. The following initiations and isolations were observed: All Fission Product Monitor Valves isolated, both Units' SBGT trains initiated and the reactor building ventilation supply and exhaust fans tripped and isolated, and the refueling floor ventilation supply and exhaust fans tripped and isolated. Operations personnel verified that all Secondary Containment isolations and initiations occurred as expected. The isolation was caused by a blown fuse. During investigation into the Secondary Containment isolation, fuse 1D11A-F14A in panel 1H11-P606 was found to be blown. After replacing this fuse, the isolation signal cleared and all related systems were returned to normal operation. Fuse 1D11A-F14A supplies the trip auxiliary units 1C51A-Z2A and 1C51A-Z2C. Loss of power to these units de-energizes several relays which are also deenergized as a result of a Refueling Floor Vent High Radiation signal which would actuate the same isolation logic and cause an SBGT initiation. (b) Whether each train actuation was complete or partial. The four Standby Gas Treatment (SBGT) fans auto started and both Unit One and Unit Two reactor building and refueling floor normal ventilation systems automatically shutdown and isolated. The SBGT initiation and the ventilation system shutdown were both complete actuations. (c) Whether or not the system started and functioned successfully. The above system functioned successfully. The licensee will inform the NRC Resident Inspector. |