This was an eventful week for US nuclear plants. Five plants tripped or scrammed. Here’s a summary.
On Sunday:
Perry shutdown due to a TS violation: unidentified leakage in the drywell from the reactor recirculation loop A pump discharge valve vent line.
Fitzpatrick notified the NRC of a scram due to lowering intake level, which led to an unexpected residual transfer that resulted in the loss of the non-vital busses, loss of all circulating water pumps, and a manual closure of the MSIVs.
On Monday:
Millstone experienced an automatic reactor trip after the ‘B’ reactor coolant pump (RCP) tripped offline.
Calvert Cliffs (Unit 1) was manually tripped from 10 percent power due to elevated condenser sodium levels.
Read more about these by clicking this link:
http://www.nrc.gov/reading-rm/doc-collections/event-status/event/2016/20160125en.html
On Tuesday, South Texas (Unit 1) was manually tripped due to loss of feedwater on the ‘C’ steam generator (S/G) because of a failure on the ‘C’ S/G main feedwater regulating valve that caused the valve to travel closed without operator action. Read more about that by clicking this link:
http://www.nrc.gov/reading-rm/doc-collections/event-status/event/2016/20160128en.html
All of these events were reported through the NRC’s daily event notification report, accessible by clicking here:
http://www.nrc.gov/reading-rm/doc-collections/event-status/event/2016/