WILMINGTON, NC-A closely guarded technology developed in Australia for separation of isotopes by laser excitation (SILEX) appears to have cleared enough of the technological, economic, and political hurdles in the field of nuclear fuel enrichment to attract the attention of General Electric’s nuclear business (GE; Wilmington, NC). GE has signed an exclusive agreement with Silex Systems (New South Wales, Australia) to license the technology and develop the company’s next-generation low-enriched uranium manufacturing process in the United States.
Natural uranium contains 99.3% uranium-238 (U238). To increase the remaining 0.7% concentration of uranium-235 (U235) to that required of reactor fuel, the isotopes must be separated. Nearly identical electronic and chemical properties of the two isotopes render chemical processing difficult and inefficient, however, so conventional methods separation methods rely on small differences in the masses of the different isotopes.
Laser-based isotope separation holds out the potential of becoming the third generation uranium enrichment process, following first generation gas diffusion and second generation gas centrifuge-two mechanical technologies with relatively high cost structures. Laser isotope separation can be used for numerous materials, such as ytterbium, silicon, zirconium and carbon, but the GE-Silex deal focuses on the global uranium enrichment market, currently worth approximately $5 billion annually, according to Silex Systems. Silex Systems expects the growing market to increase over the medium term as the energy policies of many countries begin to respond to the threat of global climate change and to pursue sustainable energy policies.
The SILEX process consists of a uranium hexafluoride molecules (UF6) vaporization process, a separation system and withdrawl system. The UF6 is mixed with a carrier gas, cooled to a low temperature and is fed to a separator system. The U235 component is selectively excited with a pulsed laser operating in the 16-mm infrared spectral region. This excitation results in a separation of the two isotopic forms into an enriched product and a U238-rich tails stream, both of which are mechanically removed into a collection system.
The GE-Silex agreement provides for a phased approach to the commercialization of the SILEX technology-construction of a test loop, pilot plant, and a full-scale commercial enrichment facility. These operations would be built at GE’s site in Wilmington or another suitable location in the United States. In addition to funding the technology development program, GE has agreed to make $55 million in total payments to Silex at key points in the processes of government approval, testing, and construction. GE has also agreed to pay royalties to Silex up to a maximum of 12% upon deployment and use of the technology. -HJB