A new report is recommending three of Hanford's oldest buildings that once were used to hold irradiated nuclear fuel be torn down and the soil beneath them be dug up.

That's the most protective and costly cleanup plan studied in a engineering evaluation of cleanup of the 212-N, 212-P and 212-R buildings that was prepared for the Department of Energy.

DOE, the Environmental Protection Agency and the Washington State Department of Ecology have been taking comments on the proposal before a decision is made on how the buildings should be cleaned up.

If the plan preferred in the study is selected, work would begin before the end of the year.

It will be another step toward shrinking the contaminated area of the Hanford nuclear reservation to the central 75 square miles by 2015, said Geoff Tyree, a DOE spokesman. The buildings are in a shrub steppe area called the 200 North Area, just north of the 200 West and East areas in central Hanford that will take decades longer to clean up.

The buildings were used as early as 1945 as part of Hanford's original system for handling fuel irradiated in Hanford reactors to produce plutonium for the nation's nuclear weapons program.

In Hanford's earliest days, irradiated fuel, called lags, was stored in pools attached to reactors for short periods that could range from several hours to a day. Then the fuel rods were loaded into shielded rail cask cars and taken to the lag storage buildings.

The rods were stored in the 200 North Area buildings for anywhere from a few weeks to as long as 50 days to allow the isotopes to decay. Then the fuel was taken to either T Plant or B Plant to have the plutonium chemically separated out.

But by the early years of the Cold War, the Atomic Energy Commission had decided fuel should be stored for 90 to 125 days before chemical processing to allow radiation to decay and to reduce the emission of iodine 131 and other radioactive isotopes during processing. Those emissions could be carried by the wind off the Hanford site, potentially harming people who lived downwind.

Hanford officials also wanted to save transportation costs to the 212 buildings and reduce radiation exposure to workers during the transfer.

As a result, in 1951 the buildings were closed and irradiated fuel was stored only in the pools attached to reactors.

After a fire and explosion on Hanford's 308 Building in 1965, the 212-N building was used to store large pieces of equipment that had been contaminated. The equipment remained there in crates until it was removed in 2007 and disposed of as radiological waste.

The 212-R building also was used to store crates of contaminated equipment, but waste was later consolidated in the 212-N building and some waste from 212-R was disposed of as industrial waste. The 212-P building was used for storage of PCB waste, which also has been removed.

In addition, some of the waste sites associated with the buildings have been cleaned up. During the years the buildings were used to store fuel, water was routinely added to the storage basins and water was discharged to areas called "cribs" for soil filtration.

In 2007 DOE sampled four waste sites that received water from the facilities and the two that were found to have contamination were cleaned up the same year. Three waste sites still must be checked.

The buildings are left with radiological contamination that includes uranium, plutonium and strontium. The majority is likely in residues encrusted in the basins, piping and ventilation system ductwork, according to the engineering evaluation.

The buildings are one-story, steel-frame structures with concrete block walls and pre-cast concrete walls. They include highbay areas for a rail transfer car with a crane used to unload the fuel casks.

Inspections in 1998 and 2000 found some of the concrete blocks had cracked and wooden doors and the roof were in poor repair.

Keeping the buildings under continued surveillance and maintenance until disposition in 2035 would cost $1.68 million, according to the study. But that also would increase the likelihood of a radiological release.

Tearing down just the above-ground structures and leaving the basins and underlying soil would cost $3.41 million, the study said.

The study's favored alternative, tearing down the facilities, including the basins, and digging up about 3.3 feet of soil beneath each basin would cost $6.16 million. That alternative would provide the greatest long-term protection and reduction of contaminants, the study found. It's unknown whether there is contamination in the soil or how much, but large plumes of contamination under the basins are not expected to be found.

The study is posted at www.hanford.gov under the Hanford Events Calendar in January. Comments may be submitted to Margo Voogd, DOE Richland Operations Office, P.O. Box 551, A6-38, Richland, 99352.