Another busy weekend for the nation’s nuclear power plants, with a fire, flooding, three reactor scrams and a fuel melting scare. We start in Kansas:
1. On Friday afternoon, operators of the research reactor at Kansas State University declared an Unusual Event, after receiving indications that fuel in the 25 megawatt facility might be melting. Initial indicators were that the concentration of radioactive iodine was 80 times the expected concentration. A second sampling showed no excess radiation. A third sample showed high concentrations of cesium, but no excess iodine. Operators of the reactor now say that the samples were probably the results of a miscalibrated monitor, and that the high readings “were probably due to the proximity of the radioactive sample handling table to the sampling location.”
2. On Saturday morning, the Nine Mile Point nuclear plant in New York declared an Unusual Event for Unit 1 due to a fire in an electrical panel. It took almost half an hour for the fire to be extinguished and for the Unusual Event to be terminated.
3. On Saturday afternoon, the Browns Ferry nuclear station in Alabama lost all primary and secondary power to the Meteorolgical Monitoring station that serves the station’s three reactors. It took two and a half hours to restore power to the monitoring equipment. All three reactors continued to operate at 100 per cent power during the incident.
4. Early Sunday morning, operators making rounds discovered a leak in a steam pipe in the Unit 3 reactor at Peach Bottom in Pennsylvania. As a result of the leak, the reactor’s High Pressure Coolant Injection (HPCI) system was declared inoperable. The steam pipe was isolated and, three and a half hours later, the HPCI was repaired and back in operation.
5. Also Sunday morning, Fort Calhoun in Nebraska, which is in shutdown due to flooding, had a further problem when the AquaDam, an inflatable rubber flood barrier, failed. This resulted in the starting of two emergency diesel generators serving the Unit 1 reactor. Fort Calhoun remains under a Notice of Unusual Event due to flood waters. The plant also reported a petroleum discharge to the Missouri River.
6. On Sunday evening, operators of the Wolf Creek nuclear plant manually scrammed the Unit 1 reactor following the failure of one of the reactor’s main feedwater pumps and a drop in steam generator levels. Operators were attempting to restart the reactor following a refueling outage when the failures occurred.
7. Later Sunday evening, the Unit 1 reactor at Sequoyah nuclear in Tennessee suffered an automatic reactor shutdown following a turbine trip. During the shutdown, three of the valves in the reactor’s steam dump system did not close as expected. Operators were forced to use the atmospheric relief valves to remove decay heat from the reactor.
8. Finally, on Sunday evening, a coolant pump in the Unit 2 reactor failed at the Salem nuclear plant in New Jersey, resulting in an automatic reactor shutdown.
I hate Mondays….