Oct. 26, 2011
Scientists and engineers at Catholic University's Vitreous State Laboratory (VSL) have completed the first, $1.2 million phase of a major project to demonstrate the capture and recycling of an especially dangerous radioactive element in the cleanup of millions of gallons of nuclear waste.
The process will keep the highly volatile radioactive element technetium, a product of nuclear reactions, from escaping when nuclear waste is treated for disposal.
Technetium often is the "most significant" environmental risk associated with such wastes, explains VSL Director Ian Pegg.
The technetium recycling is part of a process that will be used at a $12.2 billion U.S. Department of Energy (DOE) nuclear waste processing plant being constructed at Hanford, Wash. The facility will convert "legacy" nuclear waste - leftover from the manufacture of atomic bombs during World War II and the Cold War - into stable glass that can be disposed of safely.
Since 1996, the DOE has awarded the Catholic University lab more than $80 million for research and development support for the nuclear waste treatment program at Hanford .
The Hanford glass-making system was designed with complex gas cleaning systems to remove technetium from the exhaust that's produced by the high temperatures - and recycle it back into the glass melter. The intent is for "essentially all" of the technetium to be forced into the highly stable and leach-resistant glass, says Pegg. However, this technetium "recycle" concept had never been demonstrated - until now.
In April, VSL received funding to test the approach - but on a tight schedule. The first set of tests had to be complete by Sept. 30, the end of the federal fiscal year. VSL performed detailed process modeling to support the design and operation of a complex new test system that was installed in the basement of Hannan Hall, the building that houses VSL on the University's campus. In June, at the Hanford site, Pegg presented the modeling results and testing plans to a DOE review panel, which approved the project.
VSL then completed the design, procured and installed equipment, developed control software and operating procedures, trained operators, and performed debugging tests - all by mid-August in a "truly Herculean effort," says Pegg.
With the new test system in place, VSL conducted four round-the-clock weeklong tests with various Hanford waste compositions by the September deadline. So far the results appear to be good news for the new Hanford treatment facility. According to Pegg, the tests indicate that less than about 0.03 percent of the technetium should escape from the recycle loop, and most of that will be captured elsewhere in the process.
Completing such a complex project in a short six months is "pretty remarkable," says Brad Bowan, senior vice president for engineered systems and technology projects at Energy Solutions , an international nuclear waste processing and disposal company. Energy Solutions and VSL are longtime partners on the Hanford plant work as well as many other nuclear waste projects.
To celebrate the successful test of the technetium recycling system, Energy Solutions hosted a luncheon for VSL's scientists and engineers at the Edward J. Pryzbyla University Center on Oct. 20.
Building on the recent success, VSL is gearing up for the next phase of testing on the new recycling system in the coming months.
Currently, there are 53 million gallons of radioactive "legacy" waste being stored in 177 aging underground tanks across 586 square miles at Hanford. The DOE plant there is scheduled to open and start converting the nuclear waste into glass in 2019.
Catholic University's Vitreous State Laboratory (VSL) is a leading research center for the studies of materials in their vitreous - or glass - state. At VSL, 100 Ph.D. scientists and engineers develop applications in such areas as nuclear environmental protection, fiber optics, biophysics, and nanotechnology. Established in 1968, VSL operates on grants and private contracts totaling on average $7 million a year. In the area of nuclear technology, VSL experts have developed processes to transform highly radioactive nuclear waste into stable glass that can be disposed of safely. Those technologies are in use at nuclear facilities in the United States, Japan, and Great Britain.
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