Originally created 09/18/02

Site gets closer to salt solution



AIKEN - A Tuesday decision by the Department of Energy lays the groundwork for processing one of Savannah River Site's most problematic legacy waste components: radioactive salts.

The department awarded two $10 million contracts for the conceptual design of the Salt Waste Processing Facility, its first step toward being commissioned.

The facility is to be connected with the Defense Waste Processing Facility, which began closing out the site's 38 million-gallon-waste tanks in 1996.

"(Salt processing) is essential to meet federal and regulatory commitments for high-level waste treatment and ultimate closure of tanks," said Julie Peterson, an Energy Department spokeswoman.

Waste in the tanks separates into water, salt and sludge.

The water is a small portion of the content and is mostly low-level radioactive waste. It is mixed with grout and buried at the site's Saltstone facility.

Sludge is the most radioactive of the waste. It is turned into glass form and encased in metal canisters in a process called vitrification.

It is being stored temporarily at the defense waste facility until a permanent underground repository is opened.

The roughly 34 million gallons of salt remaining is more difficult to process because it is a mix of low- and high-level waste.

The most fiscally efficient method of disposal is to separate the two.

Otherwise, according to Westinghouse Savannah River Co. spokesman Dean Campbell, "You would make 20 times more canisters and have to build several more Defense Waste Processing Facilities. You're talking tens of billions of dollars if you do that."

Because the cesium is chemically bound to the lower-level waste, new solvent extraction technology will have to be used.

A previous method of extraction called in-tank precipitation was abandoned at SRS as an expensive failure.

Parson Infrastructure & Technology Group Inc of Pasadena, Calif., and Foster Wheeler USA Corp. of Clinton, N.J., were awarded the design contracts Tuesday.

They will have 12-15 months to complete their design work, then DOE will select a contractor to finalize blueprints and construct the facility.

Reach Eric Williamson at (803) 279-6895 or eric.williamson@augustachronicle.com.