BRATTLEBORO — Neglected maintenance on the brakes on a Vermont Yankee refueling floor crane failed in May as it was holding a cask full of spent nuclear fuel because Entergy Nuclear failed to correct ongoing problems with the crane, a recently released inspection report from the Nuclear Regulatory Commission stated.

The crane has accumulated seven problems in more than three years, a result of "Entergy's failure to take timely and appropriate corrective action," the special inspection report stated.

"As a result, the brakes failed to function during the movement of a spent fuel storage cask," on May 12, the report stated.

In addition to the neglected maintenance of the crane's brakes, Entergy reported that it had also violated federal regulations when it removed mechanical safety stops on the crane on June 10 while spent fuel was being moved, according to reports on file with the NRC.

Federal regulations "requires crane travel limit mechanical stops to be installed during cask handling operations to prohibit movement of the cask over irradiated fuel," according to the report.

At the time of both incidents, Entergy Nuclear was moving high-level radioactive waste into a steel and concrete "dry cask," and had moved the cask out of the spent fuel pool," according to a report filed by Entergy Nuclear on July 31.

The two incidents come as Vermont Yankee starts using its dry-cask storage facility. The plant ran out of storage inside the reactor building this year, and it would have been forced to shut down without the new facility, which was built just north of the plant.

The company said its own inspectors discovered the missing mechanical stops on June 10, Entergy Nuclear spokesman Rob Williams said.

He said Entergy Nuclear procedure was in conflict with federal regulations, since the Entergy procedure allowed the supervisor on the floor to remove the stops.

He said the problem was reported to the NRC within the 60-day time limit. He said the NRC was notified verbally on June 10.

"Subsequently, VY determined … that the stops were removed and reinstalled (and) did not comply with the requirements of the TS (technical specifications,)" the company wrote to the NRC.

Despite the missing safety equipment, the company said there were no personnel or public safety implications.

Williams said that five casks were filled with old irradiated fuel, and that the procedure, which started on May 12, was completed on July 29.

The NRC, in an Aug. 5 inspection report on the original May 12 incident, said the crane brake problem only warranted a "green" finding, the lowest level finding, since it didn't result in any direct safety problem.

The crane operator had put on the brakes to stop the cask while it was 4 inches above the floor, but the cask sunk slowly to the floor instead.

The NRC report said the brakes failed because of faulty relays.

Raymond Shadis, senior technical advisor for the nuclear watchdog group New England Coalition, said the crane brake failure, and the missing stops, were cause for worry.

"They were in violation of their tech specs," he said. "Those stops are there to provide a margin of safety and they eliminated one of the safety steps."

Shadis also noted that an Entergy top-level official had reassured the public immediately after the May 12 incident that there were mechanical stops in place to keep the crane from dropping the cask back into the fuel pool, on top of the radioactive fuel.

If the cask had slipped into the pool it could have crushed the spent fuel assemblies, or even punctured the bottom of the fuel pool, he said.

He noted that Entergy had sat on the information for two months before notifying the NRC formally on July 31.

"It's typical of the way they handle uncomfortable information," he said.

The company blamed the problem on "inadequate procedures."

The federal inspectors said the crane that was involved in the May 12 incident had had a total of seven problems in recent years, and that Entergy had failed to follow through on corrective measures it had promised to do.

"The inspectors determined that Entergy failed to take appropriate corrective actions when system performance goals were not met, prior to moving spent fuel," according to the NRC report.

The Aug. 5 inspection report did not make mention of the second problem with the crane.

The supplemental report from Entergy Nuclear had been filed on July 31.

Entergy Nuclear safety assurance director John Dreyfuss, in statements to the press in May, said the fully loaded concrete-and-steel cask could not have ended up in the spent fuel pool because there were mechanical controls in place to keep it from doing that.

Williams said the safety stops were in place on May 12.

Both NRC spokesman Neil Sheehan and Stephen Wark, spokesman for the Vermont Department of Public Service, said Thursday they didn't have enough information about the problem but would have more information today.

Contact Susan Smallheer at susan.smallheer@rutlandherald.com.