Yvonne Zipp of the Kalamazoo Gazette reported this afternoon on MLive:
A piece of metal from a broken impeller blade has lodged in the reactor vessel at Palisades Nuclear Power Plant. Workers discovered the issue during the nuclear power plant’s scheduled refueling and maintenance shutdown, which began Jan. 19.
The metal is 5 inches by 12 inches long, said Lindsay Rose, spokeswoman for Entergy Corp., which owns Palisades. The piece is wedged into the reactor vessel between the vessel wall and the flow skirt, inside the vessel.
What should be done about the broken blade? According to Energy, nothing:
Efforts to remove the metal have proved unsuccessful. At this point, Entergy plans to leave it in place, saying it does not pose a safety risk.
“We took steps to remove it. We’ve thoroughly analyzed it and we’ve determined that, based on the location of where it is, it’s not going to have any impact on safe operations. We do not believe it is going to move from its location,” Rose said. “It has not compromised safe operations and it is not expected to.”
The Nuclear Regulatory Commission might allow Palisades to continue to operate with the piece of metal in place. According to the MLive article:
The NRC will have the final say on whether the metal represents a safety-significant issue, (NRC senior public affairs officer Viktoria) Mitlyng said.
“If they propose to leave the metal in the reactor core, they have to provide analysis and justify to the NRC that leaving that in there would not have an impact on the safe operation of the reactor,” she said.
David Lochbaum, director of the nuclear safety project at the Union of Concerned Scientists, said that similar situations have taken place at other nuclear plants, sometimes with safety consequences:
…in 1992, the Connecticut Yankee nuclear plant experienced more serious damage when workers removed the thermal shield, a metal plate that was designed to act as insulation but was found to be unnecessary. When cutting through the plate, the workers created metal slivers and flakes that were not fully removed before the reactor started, Lochbaum said.
“It damaged the metal fuel rods either by direct impact or by lodging against some of the framework holding the fuel rods. Water flowing past vibrated the debris against the fuel rods, wearing it away. Workers had to shut down the reactor and inspected each and every fuel rod for signs of damage — replacing the damaged fuel,” he said.