Originally created 08/08/06

Process aids waste disposal



AIKEN - Officials at Savannah River Site announced Monday the development of a process that removes radioactive materials from liquid waste.

The process uses centrifugal contactors, special equipment that was installed as part of the new Modular Caustic Side Solvent Extraction Unit process, to remove radioactive materials from liquid salt waste now stored at SRS.

"This process has never, ever been done before on radioactive waste," said Brent Gifford, the unit project owner.

He said that the $80 million project will process tank waste and "put it in a state that's safe for long-term storage or disposal."

Radioactive liquid waste was generated at SRS as a by-product of nuclear materials processing. About 36 million gallons of that waste is stored in 49 underground tanks at SRS.

"Ultimately, we want to empty or close all those large tanks," Mr. Gifford said.

The project, which is scheduled to begin in September 2007, is an interim process that will run until full-scale operations begin in 2011 with the construction of a Salt Waste Processing Facility at SRS, he said.

Centrifugal contactors have been used at the site's chemical separations facilities for years, officials said, but the modified technology will allow radioactive material to be removed from liquid waste for the first time.

The salt waste is a radioactive solution that crystallizes and becomes similar to salt, Mr. Gifford said.

The equipment divides salt solutions into two waste streams, he said.

He said the salt waste from heavy solids will be sent to the Defense Waste Processing Facility at SRS and encapsulated in glass.

"That's a small percentage of our overall waste," Mr. Gifford said.

The other stream contains a low-level salt waste solution that will be sent to the site's Saltstone Disposal Facility and mixed with a grout solution for permanent storage, he said.

The equipment has been tested off the site, but the process will begin at SRS next year, said Mr. Gifford.

"All of our testing has confirmed that, yes, it will indeed work just like we anticipated," he said.

The interim process will provide experience that can be applied to the operation of the permanent Salt Waste Processing Facility, and it will create tank space while that facility is under construction, Mr. Gifford said.

Reach Betsy Gilliland at (803) 648-1395, ext. 113, or betsy.gilliland@augustachronicle.com.

WHAT'S NEXT:

The new Modular Caustic Side Solvent Extraction Unit project is scheduled to begin in September 2007, and full-scale operations at a Salt Waste Processing Facility at Savannah River Site will begin in 2011.