Some things from this morning’s Nuclear Regulatory Event Reports:
1. Yesterday afternoon, while attempting to restart the Unit 2 reactors, operators at the Hatch nuclear power plant in Georgia noticed that one of the Intermediate Range Monitors (IRM) was spiking. They bypassed the monitor, but the second IRM also showed fluctuations in readings. Operators then scrammed the reactor. Cause of the problem is under investigation.
2. Operators at Nine Mile Point in New York determined that both channels of the Unit 2 Reactor Water Cleanup System were declared inoperable. The problem was repaired within an hour, but it was reported as “an event or condition that could have prevented fulfillment of a safety function.”
3. During a maintenance walkthrough yesterday morning, an employee at the Dresden nuclear power plant in Illinois “inadvertently opened the bus potential fuse drawer for Unit 2 Safety Related Bus 23.” The mistake caused a safety system for both Units 2 and 3 to become inoperable. Although the duration of the accident — approximately seven seconds — limited the possibility for a related accident, the event demonstrates a point that has been raised by oppenents of nuclear plant expansions like South Texas and Comanche Peak: colocation of nuclear plants increases the chance that an incident at one reactor will have a safety impact on the additional units. The clearest example is the cascade of events at Fukushima following the earthquake, when major problems with one unit prevented operators from dealing with problems with other reactors at the plant.
4. Yesterday afternoon, technicians at the Susquehanna nuclear plant in Pennsylvania replaced a router at the facility’s Emergency Operations Facility (EOF). The work caused “a temporary outage of network devices such as personal computers, telephones, printers, routers, switches, alarm panels, and wireless communications.” Restoration of the router took eight hours. Both reactors at the facility continued to operate at full power during the outage.