The Department of Energy is considering tearing down Hanford's K Reactors that stand on the banks of the Columbia River rather than sealing them up for 75 years.

If the plan goes forward, it could lead to tearing down eight of the nine plutonium production reactors along the river instead of leaving them "cocooned." Only B Reactor, which is expected to be preserved as a museum, would remain standing.

Demolishing the reactors now instead of waiting 75 years to dispose of them could "save a ton of money" in long-term costs, said Dave Brockman, manager of the DOE Hanford Richland Operations Office.

"We have got to get rid of them sometime," he said. In 75 years, the cleanup project would have to be remobilized for the cocooned reactors, new workers hired and trained, and a landfill for radioactive waste in central Hanford reopened for the waste.

Demolishing the reactors also would improve the view along the Columbia Reach, the last free-flowing, non-tidal stretch of the Columbia River. Now boaters on the reach and visitors to the Hanford Reach National Monument north of the Columbia River look over at hulking gray monoliths of old reactors, even as DOE works to complete most cleanup of Hanford along the river by 2015.

For now, DOE and its new contractor CH2M Hill Plateau Remediation Co. are investigating demolishing just the K East and K West Reactors.

"It's a concept -- one we're very seriously looking at," Brockman said. "It has merit."

Work is continuing in the meantime to cocoon N Reactor.

In 1993, DOE decided to cocoon the reactors that no longer were needed to produce plutonium for the nation's nuclear weapons program. To date, five of the reactors have been torn down to little more than their radioactive cores, been reroofed and had openings sealed up. Costs have varied along with conditions of the reactor, with cocooning D Reactor costing about $13 million and H Reactor about $24 million.

Cocooning originally was planned because it reduces maintenance and surveillance costs -- reactors are entered and checked every five years -- and allows radiation to decay over 75 years to present less of a hazard to workers.

Although a future generation might make its own decision on the cocooned reactors, the plan on the books calls for leaving the 8,000-ton graphite cores of the cocooned reactors intact and hauling them five to 10 miles to burial grounds in central Hanford.

A crawler such as the one used to move space shuttles would be rolled into a hole dug beneath the reactors and then would haul the cores away on roads built to withstand the cores' weight.

DOE and CH2M Hill started considering demolishing the K Reactors rather than cocooning them as they prepare to start cleaning up contaminated soil at the reactors, including soil contaminated by the leak-prone K East Basin.

The K West Basin is being used to hold radioactive sludge from both basins in underwater containers until it can be treated for disposal. But the K East Basin has had much of its below-ground walls demolished and CH2M Hill is ahead of schedule to meet a legal deadline of having the basin removed by July 31, said John Lehew, president of CH2M Hill Plateau Remediation Co.

It's also on schedule to start removing contaminated soil beneath the leak-prone K East Basin by an August deadline.

However, removing the contaminated soil with the reactor still standing would require some major work to stabilize the reactor. One place the reactor leaked water is at a construction joint where concrete was poured to build the fuel discharge chute for dropping fuel from the reactor to the cooling basin.

Worker safety is one reason DOE decided to cocoon the reactors 16 years ago. But as cleanup has progressed at Hanford, work has been done successfully with waste so radioactively hot that it has to be handled with remotely operated equipment.

"We've got a contractor on board with a lot of experience in cleanup," Brockman said.

CH2M Hill has done a design and mockups for a system to decommission the graphite core of the Piles I Reactor in the United Kingdom, although the decommissioning work has not been funded. It worked on the project with one of its subcontractors at Hanford, S.A.Robotics, which also holds a contract for decommissioning the Brookhaven Graphite Research Reactor in New York.

Work to decommission the K East Reactor could be done with money from the American Recovery and Reinvestment Act, under a plan CH2M Hill will submit in early June. Now CH2M Hill is working with S.A.Robotics on the initial planning phases of the project, which includes evaluating the radioactivity of the reactor's core and irradiated material.

"Looking at the initial data for the material we're dealing with, I don't see any show-stoppers," Lehew said.

The work plan could call for building a frame to support remotely operated equipment. Then a hole might need to be cut in the concrete and metal shielding to allow access to the core.

A decision would need to be made about whether the core, which was assembled from graphite blocks, would be cut into pieces or broken up and how large the pieces should be. The pieces would be lifted out and possibly grouted inside boxes and sent to the Environmental Restoration Disposal Facility in central Hanford.

"It's a good opportunity to get the whole 100-K Area done and look at some longer-term cost savings," Lehew said.

It might be possible to remove the graphite core of K East by late 2011 or 2012, according to preliminary estimates.

The Environmental Protection Agency, the regulator at the K Reactors, is enthusiastic about the project because of the increased ability to remove contaminated soil near the reactors and even underneath them and prevent the contamination from reaching the ground water and then the Columbia River.

"I'm very supportive of looking at demolition earlier rather than later," said Rod Lobos, EPA engineer.