YAKIMA, Wash. (AP) — Federal officials are closely monitoring the investigation into a leak at a nuclear waste treatment plant in Britain — a plant managed by the same company that was initially hired to design, build and operate a similar plant at the Hanford nuclear reservation in south-central Washington.

Officials with the U.S. Department of Energy, which manages the Hanford site, do not believe the leak will have any effect on the design of Hanford's waste treatment plant.

However, they continue to monitor Britain's investigation into how the leak occurred — and went undiscovered for months — to learn from any mistakes that may have been made there, said John Eschenberg, project manager for the Energy Department's Office of River Protection.

"The bottom line for me is that there's no real corollary between that plant's design and our plant's design,'' Eschenberg said this week. "But we're not going to blow it off and say their plant is so different from ours. That would be foolish.''

The leak at the Sellafield nuclear site in Britain — an estimated 22,000 gallons of liquid nuclear waste — was discovered April 19. An investigation by the British firm that manages the site, British Nuclear Group, determined the leak had gone undetected for three months.

The leak was limited to a sealed room, and no radiation was released, said Carla Hages, spokeswoman for BNG America.

British Nuclear Group, formerly British Nuclear Fuels, is the parent company of BNG America, formerly BNFL Inc., which won the original contract to design, build and operate the waste treatment plant at the Hanford site.

The Energy Department fired BNFL in 2000 after the company's construction cost estimate ballooned from $6.9 billion to $15.2 billion.

Portions of the original design by BNFL have been continued by the new contractor, including the concept of sealed rooms around waste tanks, but the design of the piping and the tanks is very different, Eschenberg said.

Metal fatigue has been blamed for the pipe leak in Britain.

"If, in fact, they identify any engineering shortcomings, we'll make sure we can take advantage of those as they might apply to our design here,'' Eschenberg said.

"My focus is on the lessons learned from an operational standpoint, and then going forward, on what they learn as they clean the cell.''

The Hanford plant will use a process called vitrification to turn highly radioactive waste into glass logs for permanent disposal in a nuclear waste repository. The waste, about 53 million gallons, is stored in 177 aging underground tanks less than 10 miles from the Columbia River.

The plant is being designed as it is being built.

Earlier this week, The Associated Press learned that Congress had requested an investigation into the plant. The review is likely to center on its skyrocketing cost, which was estimated at $4.35 billion before the contract was awarded to Bechtel National in 2000.

Already, the cost has grown more than 30 percent — to $5.8 billion — and is expected to rise even further as the Energy Department evaluates seismic concerns in light of a new seismic review released earlier this year.

The Energy Department announced Tuesday it was halting construction on parts of the plant most affected by seismic concerns.

For 40 years, the Hanford reservation made plutonium for the nation's nuclear weapons arsenal. Today, work there centers on a $50 billion to $60 billion cleanup, to be finished by 2035.