The Department of Energy and Fluor Hanford have begun to drain water from Hanford's leak-prone and radioactively contaminated K East Basin.

"It's been a long time coming," said Nick Ceto, Hanford program manager for the Environmental Protection Agency, the regulator on the project. "It's unfortunate it has taken so long."

Before the water could be drained, workers had to remove 1,100 tons of irradiated nuclear fuel and 42 cubic yards of radioactive sludge from the basin.

That work took more than six years, and because of delays in removing sludge DOE has missed a legally binding deadline under the Tri-Party Agreement to have the basin demolished by March 31 of last year and soil excavation started a month later.

Draining of the water from the basin, which started this week, marks the last part of the cleanup of the K East Basin that is expected to be technically challenging because of radioactive material.

"This is the culmination, the endgame of the basin life," said Bob Wilkinson, Fluor vice president of deactivation and decommissioning.

Once water is out of the basin, work will proceed to a more traditional industrial demolition to remove the building above the basin, making way for removal of the in-ground basin.

Workers are pumping about 1 million gallons of water out of the basin into 5,000-gallon tanker trucks. The water will be taken to the Effluent Treatment Facility in central Hanford in about 200 trips. The last trip is expected to be completed in early March unless bad weather causes delays.

It's the same way water was removed from the basin to adjust water level when the pool was used to cool irradiated fuel from 1955 to 1971, the years the K East Reactor was producing plutonium for the nation's nuclear weapons program.

As water is removed now, spray nozzles installed in the basin will apply fixative to bond residual radioactive contamination to the walls. The first application of fixative is expected to be applied next week, with spraying done each time the water level drops about 4 feet and then a final application.

Because the water acts as a radiation shield, all work is being done by remote operations outside the basin to protect workers.

The basin next will be backfilled with sand mixed with a thin slurry of grout to make it easier to pour into the basin. That should harden within a few days into a stiff sand that provides both a radiation shield and a surface to work on as the above-ground portion of the building is torn down starting in late summer.

The building should be down in September and work then will begin to tear out the walls and then the floor of the basin. The debris will be packaged with the sand filling the basin.

That clears the way for work to begin on the problem beneath the basin: Soil that was contaminated by past leaks. The contamination poses a risk to the Columbia River just 400 yards away.

"We know the K East Basin has leaked contaminated water several times, primarily in the 1970s," said Tom Teynor, DOE federal project director, in a statement. "We want to eliminate the potential for any future leaks and get to the contaminated ground beneath as soon as possible."