NRC says tritium program working

NRC says tritium program working

Apr 21 - McClatchy-Tribune Regional News - Bob Audette Brattleboro Reformer, Vt.

Engineers and technicians at Vermont Yankee nuclear power plant found the source of a leak of tritiated water in 49 days, much quicker than at other plants with similar leaks, said John White, the chief of Nuclear Regulatory Commission's Region 1 plant support branch.

Entergy made "A major effort with plenty of resources" to find and stop the leak, said White, who was in Brattleboro Monday as part of a public workshop and hearing to discuss the leak.

At other nuclear power plants, it has taken months, and in Indian Point's case years, to find the source of tritium leaks, said White.

White said the reason the leak at Yankee and its source were discovered so quickly was because of the industry's groundwater initiative.

Though the source was found, exactly why the pair of steam trap pipes leaked into a trench 15 feet below ground and tritiated water seeped into the environment through a gap in concrete surrounding an off-gas pipe won't be known until Entergy turns in to the NRC what is called a "root causes analysis," said White.

Water leaked through the gap because the system's sump was clogged with cement dust and the water pooled up in the pipe trench, high enough to reach the gap and to leak out.

If the drain had not been clogged, the two leaking pipes might have been found sooner, said White, because plant operators would have been alerted that the sump pump was turning on a regular basis. In

that case, the tritiated water probably would never have leaked out and the gap in the concrete would not have been discovered.

Two years prior to the leak, Yankee installed three monitoring wells as part of an industry wide initiative to detect tritium leaks. In those two years, no tritiated water was found in those test wells, said Jim Noggle, Region I's senior health physicist.

But in a review of Yankee's compliance with the groundwater initiative, the NRC found that the plant had not met the timelines outlined in the voluntary program, he said. Where Yankee was not up to snuff was in determining how to detect leaking pipes in a "process way," said Noggle.

A common thread for all tritium leaks has been that they usually originate from pipes that are hard, or impossible, to monitor visually, said White.

That issue is one the NRC is addressing in a task force established to review tritium leaks and the NRC's conclusions about the dangers of tritium, said Charles Casto, deputy regional administrator for Region IV.

"We are looking at what we've done and if there is anything we can do to strengthen our program," he said.

The NRC's tritium task force will also be meeting with health professionals "To validate what we've been saying with regard to the health effect or to tell us where we're not on target," said Casto.

The task force's report is due on May 15.

Darrell Roberts, deputy director of the NRC's Region 1, said the NRC's self review is all part of its internal process to assimilate operating experience into a knowledge database.

Because of that, he said, "We as a regulator know much more about nuclear power plants than we did 10, 20 or 30 years ago."

Not only will the NRC issue an operating experience report about the Yankee tritium leak to all nuclear power plants in the country, said White, Entergy will issue a "lessons learned" report to the 10 other nuclear power plants in its fleet.

The NRC's notice will reccomend that all power plant operators review how they maintain and surveil below-grade pipes such as those that turned out to be the source of the leak at Yankee, said White.

Bob Audette can be reached at raudette@reformer.com, or at 802-254-2311, ext. 273.