A voltage problem on an electrical panel led to the Perry nuclear power plant in North Perry, OH, to unexpectedly shut itself down Friday.
There were no injuries and no radiation releases, said plant owner FirstEnergy Nuclear Operating Co. The shutdown, or “scram” occurred at 8:47 a.m., said spokeswoman Jennifer Young, as the control rods automatically inserted into the nuclear core.
“All systems responded as designed for a smooth shutdown, and the plant remains safe at 0 percent power,” Young said.
An engineering team’s preliminary investigation released early this afternoon determined that a voltage problem in one of the electrical panels supplying power to the pumps that keep the reactor supplied with fresh, purified water and the fuel rods submerged led to the automatic shutdown.
Another problem in that same power supply circuitry caused the reactor to shut itself down Oct. 20.
During a routine maintenance procedure early in the morning on that day, engineers switched the electrical circuits to the pumps — and the second circuit failed to switch on, instantly leading the reactor to shut itself down.
Engineers traced the power failure in that incident to an electrical circuit card in a power inverter, a kind of transformer that switches the direct current produced by the plant’s generator to alternating current that powers the pumps. The company restarted the reactor on Oct. 27.
Friday’s problems, though in the same electrical system, are not identical, Young said.