Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 44153 | 21 April 2008 14:24:00 | On April 21 2008, at approximately 1123 hours, during power ascension from a scheduled refueling outage, Unit 2 experienced an inadvertent main turbine runback. The runback initiated for unknown reasons from an initial reactor power of approximately 37%. As a result of the runback, operators observed decreasing steam generator levels and initiated a manual reactor trip at 1125 hours. As a result of the reactor trip, the auxiliary feedwater pumps actuated on a low steam generator level as designed. Prior to the runback, one of two main feedwater pumps was operating. The unit is stable and in Mode 3. Operators closed the main steam isolation valves as a result of indications of lowering RCS temperature. A 4-hour non-emergency notification is provided for a reactor trip while critical and 8 hour non-emergency notification is provided for a valid actuation of the auxiliary feedwater system. All rods inserted as expected. Decay heat is being removed by AFW through the atmospheric steam dumps. Offsite power is in a normal configuration. The licensee notified the NRC Resident Inspector. |
| ENS 42797 | 23 August 2006 13:19:00 | On August 23, 2006, at 1035 hours, the Reactor Protection System was manually actuated while at reduced load of approximately 68 percent reactor power upon indication of an apparent disparity in net electric load. It was determined that the cyclic operation of the condenser steam dumps varied steam to the turbine resulting in the indicated drop in electrical output power from about 500 Mwe to 150 Mwe. The manual trip is reportable under 10 CFR 50.72(b)(2)(iv). The event started when heater drain tank pumps 21 and 22 tripped, apparently due to a failure of the automatic heater drain level control valves that could not be manually corrected from the single controller. Reactor operators reduced load in accordance with station procedures to respond to the trip of the heater drain tank pumps and stabilized reactor power at 77%. As a result of the required load reduction delta flux was outside of the operational limit envelope specified at 77% reactor power. This required a further load reduction to less than 50 percent as per Technical Specification 3.2.3. At approximately 68% percent power the reactor was manually tripped due to the mismatch of primary power and secondary load indications. The Auxiliary Feedwater System actuated following the manual trip as expected. This is reportable under 10 CFR 50.72(b)(3)(iv)(A). A high-high water level signal was received on the 22 Steam Generator. This was due to a feedwater regulating valve that did not fully close. The feedwater isolation valves closed. All other safety systems actuated as required and safety equipment operated as expected. The Emergency Diesel Generators did not start as offsite power remained available and stable. No primary or secondary relief valves lifted. The plant is in Hot Standby at normal temperature and pressure with residual heat removal using auxiliary feedwater and normal heat removal through the condenser via steam dumps. There was no radiation released. A post trip investigation will be performed prior to restart. The licensee notified the NRC Resident Inspector.
This is an update of non-emergency Event Notification 42797 that was previously made on August 23, 2006. Clarification is provided to include reporting of the Event Classification for actuation of a second system (automatic feedwater isolation) as an 8-Hr. Non-Emergency per 10 CFR 50.72(b)(3)(iv)(A). This update revises the wording as follows: The feedwater isolation valve was manually closed. After receipt of the high-high level trip signal, 21, 23, and 24 feedwater isolation valves automatically closed. This is also reportable under 10 CFR 50.72(b)(3)(iv)(A). The licensee notified the NRC Resident Inspector. Notified R1DO (Conte). |
| ENS 42749 | 2 August 2006 04:49:00 | On August 2, 2006 at approximately 0006 hours, the Emergency Planning Department determined that all of the 156 sirens in the Indian Point Energy Center, Emergency Planning Zone were unavailable due to, an inability to activate the sirens through the computer operating system. In accordance with the Indian Point reporting criteria, the loss of 16 or more sirens that cannot be returned to service in one hour, constitutes a major loss of the offsite notification capability that requires an 8-hour non-emergency notification in accordance with 10CFR 50.72(b)(3)(xiii). The Emergency Plan has route alerting and public radio announcement available as necessary to notify the public in lieu of the non-operational sirens. The condition was recorded in the IPEC Corrective Action Program as CR# 1P2-2006-04625 and actions have been initiated to investigate and correct the condition. Troubleshooting continues. The cause of failure is still unknown at this time. The licensee notified the NRC Resident Inspector, state, and local agencies of this event.
Update to the initial notification provided at 0449 hours on August 2, 2006, regarding the inability to activate the 156 sirens of the Indian Point Entergy Center (IPEC) offsite Emergency Notification System (ENS) through its computer operating system. The capability to activate the IPEC ENS was returned to service at 0635 hours. The total time the ENS sirens were unavailable was approximately 6 1/2 hours. During the event, route alerting and public radio announcement was available as necessary to notify the public. Troubleshooting identified two problems; a hardware problem with drive failures, and a problem with the computer system where the Oracle database control file synchronism failed. These failures resulted in the inability of the ENS computer system to connect to the Oracle database which prevented ENS from being activated. The computer drives were replaced and operating system data file error corrected. Troubleshooting is continuing to identify the cause. The IPEC Corrective Action Program recorded the event as CR-IP2-2006-04625 and will identify any additional corrective actions to prevent recurrence. The licensee notified the NRC Resident Inspector, state, and local agencies of this event. Notified R1 DO (P. Finney), DRP (N. Mamish) and OPA (D. McIntyre). |