An inspection of three unplanned shutdowns, or “trips,” of nuclear reactor Unit 3 at Florida Power & Light’s Turkey Point nuclear power plant in Homestead has uncovered six issues of very low safety significance.
An inexperienced plant crew and FPL’s failure to make design changes to account for higher permitted power levels contributed to the Aug. 20 outage, according to the U.S. Nuclear Regulatory Commission.
The NRC inspection report issued last week revealed that an onsite inspection took place from Aug. 31 to Sept. 4, followed by an offsite inspection from Sept. 5 through the end of October.
The NRC’s inspection team was composed of two senior resident inspectors, a senior reactor analyst, an operator licensing examiner, two reactor inspectors and a safety culture-qualified inspector, according to agency’s Senior Public Affairs Officer Roger Hannah.
“The team thoroughly reviewed each trip and completed more than 60 interviews of plant staff,” Hannah told the Free Press. “The team determined that the operator’s actions to stabilize the plant following the trips were acceptable, but the inspectors did identify six findings of very low safety significance, including five Green non-cited violations and one Green inspection finding.”
The Green color code indicate issues of safety issues of very low significance.
The inspection finding relates to the Aug. 20 incident and could be factored into NRC actions if there are future violations in the same or similar areas.
The first trip, manually initiated by plant operators, occurred on Aug. 17 from approximately 91% power in response to rising steam generator water levels that approached the automatic turbine trip set point.
The second, on Aug. 19, was automatically initiated by the plant’s reactor protector system when an instrument sensed a high neutron flux condition and occurred during reactor startup.
The third trip, manually initiated by plant operators, occurred on Aug. 20 from approximately 34% power in response to the loss of the single operating 3B steam generator feed-water pump.
FPL spokesman Peter Robbins maintains there was no safety risk to employees or South Florida residents.
“While Turkey Point experienced three unplanned reactor shutdowns in August of this year, there was never any impact to the safety of our employees or the public. In all three cases, the reactor was shut down as designed and all systems responded normally. There was never an emergency at the power plant, nor was there any impact to the safety of our employees or the public,” he said.
The Aug. 20 shutdown was attributed to the licensee’s failure to implement adequate design change controls associated with the 2012 Unit 3 extended power up-rate modification, according to the federal agency’s report.
NRC granted FPL an increase in both Unit 3 and 4’s core power level from 2300 megawatts thermal to 2644 MWt, representing a net increase in licensed core thermal power of approximately 15% including a 13% power up-rate.
“There were missed opportunities specific to the plant operators that day and shortfalls in their performance, which ultimately led to the automatic reactor trip ,” the report says.
The NRC team determined that the inexperience of the plant crew working that day was one of the “contributing factors to the human performance errors,” but overall they found that the trips had very low safety significance.
“The NRC will follow up on these issues through a focused sample by the resident inspectors as well as adding an operations inspector to the team for a previously-scheduled NRC problem identification and resolution inspection at the plant this spring,” Hannah said.
Meanwhile, the company said it has learned from the situation.
“We have taken this situation seriously,” Robbins said. “Because nothing we do is more important than the safe operation of our plant, we have already begun taking steps to address the NRC’s feedback as part of the regulatory process. We will use the learnings from this situation to help us get even better.”