Unit 1 of the South Texas Project nuclear complex went offline in an unplanned outage at about 11:25 p.m. Central on Jan. 26, according to an event report filed with the Nuclear Regulatory Commission (NRC).
“This event was not significant to the health and safety of the public based on all safety systems performed as designed,” according to the report. Unit 2 was not affected and continued to run at full power.
“At 2325 [CST] on 01/26/2016, Unit 1 was manually tripped due to loss of Feedwater on ‘C’ S/G [Steam Generator]. The loss of Feedwater was a result of a failure on ‘C’ S/G Main Feedwater Regulating Valve that caused the valve to travel closed with no Operator action. Auxiliary Feedwater and Feedwater Isolation actuated as designed,” according to the report filed with NRC.
The South Texas Project, located in Matagorda County, Texas, includes two pressurized water reactors (PWRs) that together have a generating capacity of about 2,700 MW.
The South Texas Project is operated by STP Nuclear Operating Co. STP is owned jointly by NRG Energy (NYSE:NRG), CPS Energy and Austin Energy. Owners are seeking to keep their nuclear options open by pursuing new nuclear reactor licenses through NRC.