Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 45370 | 21 September 2009 01:44:00 | At 1826 on Sept 20, 2009, a lightning strike caused a disruption of power to offsite communications. At 1853, ENS communications from Sequoyah Nuclear Plant to the NRC were verified. At 2129, Sequoyah Nuclear Plant was notified the ERDS was not linked to the CECC (Offsite Emergency Operating Facility) or the NRC. At 2218, it was discovered the NRC could not contact Sequoyah Nuclear Plant by the ENS, but Sequoyah Nuclear Plant could still contact the NRC using ENS. At 2240, backup phone communications with satellite phone and cell phones were established between Sequoyah Nuclear Plant and the NRC. Efforts are in progress to restore power to the communications NODE building to restore normal communications. At 0155 the NRC verified 2 way communications via ENS with the licensee. The licensee will notify the NRC Resident Inspector. |
| ENS 45172 | 29 June 2009 12:53:00 | A notification to the Tennessee Department of Environment and Conservation (Chattanooga Field Office) was made at 1134 (EDT), 29 June 2009, pursuant to a failed pressure test on an underground section of diesel generator fuel oil transfer piping. This section of piping is not required for operability of the emergency diesel generators. The section of piping has been isolated. Efforts are in progress to determine if fuel oil was released to the environment. The licensee notified the NRC Resident Inspector.
During work to remediate the above concern, an offsite notification was required as described below: A notification to Hamilton County Air Pollution Control Bureau was made on July 23, 2009 at 1505 in accordance with the Site's Annual Asbestos Removal Notification . Work was being performed on buried piping when the pipe wrapping was determined to contain asbestos. Work was stopped and the work area controlled by site work documents. The licensee informed the NRC Resident Inspector. Notified R2DO (Vias). |
| ENS 44649 | 9 November 2008 23:29:00 | On 11/19/08 at 1821 with unit 2 in Mode 3, the unit 2 reactor trip breakers were opened from the Main Control Room (MCR) due to indications of a Shutdown Bank "A" Rod E-11 dropping into the Reactor Core. At the time the reactor trip breakers were opened, the MCR Operators were in the process of withdrawing Shutdown Banks in preparations for entry into Mode 2. All other Shutdown Banks and Control Banks were inserted at the time the reactor trip breakers were opened. In addition, a Feedwater Isolation Signal was generated as designed. All safety related equipment operated as designed. The Plant is being maintained in Mode 3 at NOT/NOP, approximately 547 F and 2235 psig, with AFW supplying the S/G's and Steam Dumps to Main Condenser removing decay heat. No primary system or steam generator safety valves opened due to this trip. An investigation has been initiated to determine the cause of the indications of Shutdown Bank 'A' Rod E-11 dropping into the Reactor Core. The licensee notified the NRC Resident Inspector. |
| ENS 44627 | 4 November 2008 02:58:00 | On 11/3/08 at 2322, Unit 2 was manually tripped due to the failure of Loop 4 Feed Water Reg. Valve (FRV Controller). Manual control was attempted to control level in Loop 4 Steam Generator (S/G); however, Loop 4 FRV failed to respond. A manual Reactor Trip was initiated as a result of this failure. In addition, Auxiliary Feedwater (AFW) initiated as required due to a Feedwater isolation signal The Loop 4 FRV did isolate from the Feedwater isolation signal. The Plant is being maintained in Mode 3 at NOT/NOP, 547 F and 2235 psig, with AFW supplying the S/G's and Steam Dumps removing decay heat. Additionally, Unit 2 has an indication of a primary leak inside lower containment. The leak rate is calculated to be approximately 2.0 gallons per minute. Based on current indications, the leak is suspected to be from a Pressurizer level transmitter No primary system or steam generator safety valves opened due to this trip. An investigation has been initiated to determine the cause of the Loop 4 Feed Water Reg. Valve (FRV Controller) failure and the source of the approximately 2.0 gallons per minute primary leak. A recovery plan will be developed. Pressurizer (PRZ) level is stable. All safety related systems are available and OPERABLE for safe plant shutdown. There is no impact on Unit 1. The loop 2 S/G blowdown sample line valve did not go closed as expected on the Feedwater isolation signal. The licensee is taking action to isolate it. The licensee notified the NRC Resident Inspector.
The Sequoyah Nuclear Plant Unit - 2 reactor coolant system unidentified leakage was terminated on Nov. 4, 2008 @ 2205 hours when a manual valve was closed isolating the reactor coolant system from the leak location." The licensee closed the root valve to the PZR pressure channel 2-VLV-68-446A. The licensee will notify the NRC Resident Inspector. Notified R2DO(Desai) |