Originally created 11/20/00

Stable storage

Operation began at the $2.4 billion Defense Waste Processing Facility at Savannah River Site in March 1996 after 13 years of construction and testing. By 2025, the facility's job will be done.

Construction on the facility, which converts on-site high-level liquid nuclear waste into solid glass log canisters, began in 1983.

Dean Campbell, a spokesman for Westinghouse Savannah River Co., said the extended time period to get the facility running was necessary.

"We never waited for funding. It was continual. But it took a while because you build and you test and you build and you test. This is a mammoth facility," Mr. Campbell said.

He said DWPF operated in "shakedown mode" in the first year.

"It's the first of its kind in the country, and we had to get all the bugs out," Mr. Campbell said.

Some difficulties that arose within the first few years of operation included the wearing down of gears on a canister turntable, a failed cooling coil, a broken water pipe, problems with software and even a lightning strike. Each problem caused a temporary shutdown of the facility.

More recently, Mr. Campbell said, the facility has been "working wonderfully."

The high-level radioactive liquid processed at the facility is a byproduct of years of weapons production at the site. The waste is stored in 51 tanks at SRS, with two already closed and filled with a cement-like product to prevent leakage into the environment.

By 2025, the processing of the 34 million gallons of waste in the 49 remaining tanks should be complete, and the tanks will be closed by 2028. Until then, it will cost more than $140 million per year to operate the facility.

Mr. Campbell said the facility is paid $25,000 for every canister made, and on average 200 canisters are completed each year. But the facility's commitment to the Department of Energy, beginning this year, is to produce 500 canisters every two years.

"There are what we call performance-based incentives across the site. If we don't do that, we have to pay back $40,000 for every one we don't get," Mr. Campbell said.

There are three layers of waste in the tanks. The bottom layer, called sludge, is chemically treated to remove aluminum and transported to the facility through a mile-long underground pipeline.

The waste is mixed with a sand-like glass and sent to the plant's ceramic melter. The mixture is heated and poured, in a thin stream, into stainless steel canisters to cool and harden. The canisters are welded shut and inserted with a plug.

The canisters are 10 feet tall and weigh about 5,000 pounds each.

The other two layers of waste must be treated before being processed into glass at DWPF.

The top liquid layer of waste must be concentrated by the site's three evaporators, one of which is being repaired and is scheduled to reopen early next year. Mr. Campbell said the shutdown has not caused a problem.

"One of the evaporators just opened and started processing this summer. It does the work of the other two combined," he said.

The middle layer of waste, which comprises the highest volume, is a salt mixture of high and low radioactive materials. The In-Tank Precipitation Facility, a plant designed in 1985 at SRS to treat the salt layer before sending the highly radioactive portion to the Defense Waste Processing Facility, was deemed a $500 million failure in January 1998.

"There is a team across the country working on that. They are looking at several technologies that could do the job," Mr. Campbell said.

Ed Lyman, scientific director of the Nuclear Control Institute, said Westinghouse had been advised to have backup options if the ITP failed. Mr. Lyman called their approach "foolish and shortsighted."

"The problem is that right now there is waste at the site that can't be run through the plant," Mr. Lyman said, "And now they're stuck with a plant (ITP) that went over budget."

Mr. Lyman said the ITP Facility used one chemical to separate the highly radioactive materials to send to the Defense Waste Processing Facility, but the result was a build-up of benzene that is potentially explosive.

He said an alternative method is to use ion exchange resins that selectively remove certain constituents such as cesium, a soluble radioactive material in the salt mixture. But he said Westinghouse "simply didn't consider alternatives at the time."

Mr. Campbell said there is enough sludge to run DWPF for eight to 10 more years without a facility to process the "salt cake" layer. He expects, however, that by then there will be an alternative to the ITP Facility.

The waste yet to be processed will come only from SRS, according to Mr. Campbell.

"There are other vitrification plants in France, Japan and Belgium, but each is specifically designed for the waste you have," he said.

Tammy Reynolds, operations manager at DWPF, said the workers inside the plant are well trained to handle the waste. She said operators and mechanics go through a training and qualification process before they set foot in the building.

"A lot of safety controls are in place from pouring the glass into canisters to the storage buildings," Ms. Reynolds said, "If you look at the big picture, we're turning liquid into glass, which is a more suitable form. We're helping put the environment in a more safe condition."

She said the facility has proven that its technology does work.

"We are constantly looking for areas to improve production rates. We have equipment failures, but nothing out of the ordinary," Ms. Reynolds said.

"When we do have problems, we make that a priority," she said.

The final stop for the glass log canisters is the on-site storage facility that will be full by 2006. Ms. Reynolds said there are plans to build a new glass waste storage building.

Ultimately, the glass canisters will be moved to an underground storage area. Mr. Campbell said Yucca Mountain in Nevada is a site that has been discussed, but no decision has been made.

"Until then, the waste is safely stored here," Mr. Campbell said.


Canisters produced at DWPF for each fiscal year (Oct. 1-Sept. 30)

Fiscal year (Oct. 1-Sept. 30)/Canisters produced

* 1996/64






* six months of operation

Reach Jennifer Bishop at (706) 823-3217.


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