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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 47815 | 8 April 2012 09:01:00 | Other Unspec Reqmnt | Offsite Notification of Noise Associated with Plant Shutdown | Notified Van Buren County Sheriff of atmospheric steam dump valve usage for cooldown of Palisades Nuclear Plant for start of refueling outage. The licensee will notify the NRC Resident Inspector. | ||
| ENS 47523 | 14 December 2011 20:10:00 | Other Unspec Reqmnt 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Manual Reactor Trip Due to Loss of Both Main Feedpumps | The reactor was manually tripped at 1510 EST on 12/14/11 due to loss of both main feedpumps. Both feedpumps tripped on low suction pressure due to an apparent unplanned opening of the 'A' main feedpump recirculation valve. The cause of the main feedpump recirculation valve opening has not been determined. All full length control rods fully inserted. Auxiliary feed pump P-8A automatically started at 1511 EST on steam generator level as designed (10CFR50.72(b)(3)(iv)(A)). The turbine bypass valve is in service maintaining reactor coolant system temperature (by directing steam flow to the main condenser). The plant is stable in mode 3 (and the reactor trip was considered uncomplicated). The Van Buren County Sherriff was notified (per other plant requirements) concerning use of the atmospheric steam dump causing excessive noise in the vicinity of the plant (immediately following the plant trip). The plant electric power is in the normal shutdown configuration. There was no primary to secondary leakage. A press release is planned for the local media. The licensee notified the NRC Resident Inspector. | Steam Generator Reactor Coolant System Control Rod | |
| ENS 42514 | 19 April 2006 21:50:00 | Other Unspec Reqmnt | Radiation Reading in Containment Read 100 Times Above Normal Levels | At 0225 hrs on April 19, 2006, a container storing in-core instrument pieces rose to the surface of the flooded reactor cavity under its own bouyancy, causing unexpected high radiation readings in the general vicinity of the reactor cavity for a few seconds before the container returned to the bottom of the reactor cavity. Emergency Action Level RU2.2 was promptly reviewed, and it was determined that the threshold for an unusual event was not exceeded, because the area radiation monitors rose by a factor of approximately 100 versus the EAL setpoint of 1000 over normal levels. Subsequently, at 1750 hrs, during post event investigation, it was discovered that dose rates indicated by an electronic dosimeter worn by an individual in the area at the time of the event may have exceeded the EAL setpoint of 1000 times the normal radiation levels for that area of containment for a few seconds. The total exposure received by the individual was less than 50 millirem. Therefore, this event is being reported in accordance with NUREG 1022, Revision 2, Section 3, "Discussion." as a potential event discovered after-the fact. The licensee notified the NRC Resident Inspector, and Al Svilpe, Emergency Management Office in Van Buren County, MI. There is also expected to be some media attention from this incident. |