Operators at Oak Ridge National Laboratory’s High Flux Isotope Reactor manually shut down the 85-megawatt research reactor last Wednesday after a large 36-inch valve “closed a bit too much.”
According to Tim Powers, ORNL’s research reactors chief, the incident occurred while new operators were undergoing training last week. He said the shift supervisor made the “conservative decision” to shut down the reactor. It was the second unplanned shutdown at the reactor in the past month.
“All shutdown procedures performed well, and we restarted the reactor today and achieved 100 percent power at approximately 1:20 p.m,” Powers said.
Over the past several days, lab workers completely inspected the valve in question, along with valve actuators, and tested the instrument loop that’s associated with controlling the valve, Powers said via email. “We also operated the valve many times under normal plant conditions,” he said.
Powers said the plan is to operate the reactor until Thursday or Friday, completing the fuel cycle, and then carry out maintenance activities and refueling before restarting the High Flux Isotope Reactor on July 21.
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