CORTLANDT, NY — Indian Point Unit 3 was re-connected to the grid and began generating electricity at about 9 a.m. Wednesday. Unit 3 automatically shut down Feb. 16.
The shutdown was due to loss of power to the excitation system in the main electrical generator, located on the non-nuclear side of the plant, said Entergy spokeswoman Vera Carley. The excitation system produces a magnetic field that is needed in order for electricity to be produced by the generator. Engineers determined the excitation system’s power supply failed and automatically shut down, which as designed caused the plant to shut down. The power supply failure was corrected by installing an upgraded component, which we believe will result in better reliability of the excitation system.
The Nuclear Regulatory Commission’s resident inspectors assigned to Indian Point on a full-time basis closely followed Entergy’s efforts to resolve the problems involving the main generator exciter, said spokesman Neil Sheehan.
“Even though the turbine-generator is on the “non-nuclear” side of the plant, we were interested in the resolution of issues involving it because such problems can unnecessarily challenge operators and lead to unplanned shutdowns,” he said. “We found that the work to identify the cause of the exciter problem was thorough and detailed. We did not have any immediate safety concerns regarding the restart of the plant.
“The restart of the plant was also monitored by our inspectors.”
Indian Point Unit 2 continues to operate at full power.
Indian Point is scheduled to cease power generation by 2022.