Process for separating radionuclides from spent nuclear fuel named 2005 Outstanding Engineering Achievement

Project leader Monica Regalbuto and technician Mark Clark work on the UREX+ process in the hot cell.

The Chemical Engineering Division's UREX+ separations process for separating key radionuclides from commercial spent nuclear fuel has been named by the Illinois Engineering Council as a 2005 Outstanding Engineering Achievement.

Commercial spent nuclear fuel comprises the major part of high-level radioactive waste generated in the United States. With current projections for the growth of nuclear energy, it is possible that the accumulating inventory of spent nuclear fuel could exceed the capacity of the planned Yucca Mountain repository at some time in the future. If we are to avoid the need for a second repository, we must find a way to reduce the heat load and volume of wastes that must be emplaced in Yucca Mountain.

Transuranic elements (plutonium, neptunium, americium and curium) make up only about 1-2% of the waste in spent nuclear fuel, but pose the greatest hazard. UREX+ is a family of aqueous processes that can be tailored to meet the requirements for full recycle and destruction of these elements by fissioning in advanced reactors. The UREX+ processes use specifically designed solvent extraction steps to separate (1) uranium, (2) technetium, (3) cesium and strontium, and (4) the transuranic elements from the other fission products present in spent fuel. Depending upon national policy decisions, the transuranics can be separated further to facilitate their incorporation in recycle fuels. Such advanced chemical partitioning methods will lead to a reduction in the amount of waste storage capacity required, to only about one one-hundredth that of the capacity needed under today's "once-through" fuel cycle, thereby contributing greatly to the development of a sustainable nuclear energy system for the United States.

Argonne is leading the development of UREX+, working with Oak Ridge and Idaho national laboratories. Argonne has successfully demonstrated the process in hot cells and glove boxes and is preparing for scale-up demonstration.

The Illinois Engineering Council, founded in 1938, represents more than 20 engineering societies throughout the state as an advocate on matters of education, registration and public policy. Each year, outstanding engineering projects completed in Illinois are recognized by the Council for demonstrating inter-disciplinary engineering accomplishments and creativity as well as social benefit.

Argonne's work on UREX+ is funded by the U.S. Department of Energy's Advanced Fuel Cycle Initiative.