Lab Works To Make Nuclear 'Gunk' Environmentally Safe

The university's Diagnostic Instrumentation and Analysis Laboratory currently is working with more than $25 million in U.S. Energy Department grants. The research involves new technologies that can reduce environmental threats from both high- and low-level wastes.

"DOE has spent well over $1 billion on the development of new technology for nuclear waste cleanup," said lab director John Plodinec. "Very few of the technologies are actually being used because the right link has not been made between developers and the ultimate users."

He said DIAL--Mississippi State's longest and largest continuous research project--is focusing on the development of technologies involving an electric arc capable of reaching 15,000 degrees Fahrenheit. Known as the plasma torch, it can turn virtually any material, including nuclear waste, into glass.

DIAL researchers also have found new ways to monitor pressure inside drums storing low-level nuclear wastes.

Virtually all high-level nuclear waste in the U.S. comes from the production of Cold War nuclear weapons. "The most dangerous portion of the high-level nuclear waste is in the form of aqueous slurries, commonly referred to as 'gunk' because of their appearance," Plodinec said.

At present, the gunk is stored in large steel tanks in the states of South Carolina, New York and Washington.

Plodinec said DIAL researchers are aiding in the cleanup effort at all three high-level waste sites, as well as at other facilities with low-level radioactive waste.

Low-level waste ranges from the spent fuel rods of nuclear reactors to the protective clothing used by nuclear facility workers. Most is stored in sealed 55-gallon drums.

Plodinec said tank and drum storage continue to be acceptable methods of dealing with nuclear waste, even though more effective solutions have been developed in recent years.

He said DIAL's research is geared to practical applications of new technologies that help storage facilities reduce environmental risks. Projects involving the tremendous heat of a plasma torch are finding effective ways to turn nuclear waste into glass.

Then, there are the problems of pressures that build in drums storing low-level wastes. The most immediate danger here is to personnel handling the barrels.

"As the sealed material breaks down, pressure builds up and creates the possibility of an explosion if the drum is damaged or opened without care," Plodinec explained.

He said researchers Daniel Costley and Mark Henderson have developed a "drum thunker" to test the pressure inside a drum while it is still sealed. The non-intrusive device senses the amount pressure in a drum, which is read with the help of a laptop computer equipped with a soundcard and microphone.

The 'thunker' also can be used to test storage containers in non- nuclear facilities. For instance, DIAL scientists recently tested the device at Lockheed Martin Energy Systems in Paducah, Ky., where some 55-gallon drums of waste material were found to be under pressure.

"The information provided by the tests will enable Lockheed Martin personnel to plan for safer handling of their storage drums," Plodinec said.