Times Argus Online
BRATTLEBORO — Inspectors from the Nuclear Regulatory Commission have stopped Entergy Nuclear from making changes in the electrical controls of the heavy-duty crane that handles high-level radioactive fuel at the Vermont Yankee reactor.
The next-to-last quarterly safety inspection at Vermont Yankee has turned up three low-level safety violations, including a plan by Entergy to change the crane’s electrical controls.
NRC spokesman Neil Sheehan said the change should have required NRC approval. But he said the NRC discovered the changes before they could be put into place.
“It was never implemented,” said Martin Cohn, Entergy spokesman. He said Entergy Nuclear engineers had tried to “improve the original design,” but the changes did not meet NRC approval. Instead, NRC suggested other improvements, Cohn said, and those were put into place.
“We re-modified it. It was a change to the design that we thought didn’t merit review. We thought we were improving it,” he said.
The NRC said the change would have compromised the “independence of the redundant upper travel limits” of the crane.
The crane had been the source of a serious problem in May 2008 when the brakes on the crane didn’t function properly and it almost dropped a load of high-level radioactive waste during the first removal of the waste from the spent fuel pool into a cask for air-cooled storage outside of the plant.
According to reports at the time, the brakes on the crane did not respond properly because its electrical relays were “out of adjustment.” The cask came within 1½ inches of the floor, when the operator wanted it to stop four inches above the floor.
Sheehan said the current issue was of “very low safety significance.”
“This is based on the fact that the crane was not operated over the spent fuel pool, nor was there an actual load drop,” Sheehan wrote in an email.
“In this case, Entergy implemented the change to the crane control system that removed redundancy, increasing the likelihood of occurrence of a malfunction that could result in damage to spent fuel. But it did so without seeking a license amendment for the modification,” he added.
He said the change would have resulted in “more than a minimal increase in the likelihood of occurrence of a malfunction of a system, structure or component important to safety.”
Christopher Recchia, commissioner of the Department of Public Service, said the three safety problems, even if they were of low significance, were more proof that it was good Vermont Yankee was shutting down in less than two months.
“We just want to get to the end of December,” he said. “I am concerned when these things happen, and this is fundamentally why we want the plant to close,” he said. “It’s just another indication it needs to just close.”
via Entergy cited for proposed crane changes: Times Argus Online [link expired].