Test Loop and Florence, page-15

Zog, you are correct saying that excitation of the fundamental vibrational mode of UF6 is much more efficient than exciting an overtone or combination mode (indeed, the absorption cross section of v3 is 10,000 higher than 3v3). The downside is that it requires extremely complex and expensive photons. Generating the exact wavelength of 16um (actually 15.xxxx um) is known by only a handful of folks, and of course classified. All sorts of complexities involved with this wavelength, fortunately the Silex folks understand this and MG did communicate to me a while back that most of the technology barriers have been overcome. The CRISLA process is certainly less efficient, but the lasers are much more simplified: no reprate issues, no amplifiers, no multiplexing and no wavelength convertors required - overall high MTBF and low MTTR. QCL's does not have sufficient peak power for laser enrichment, let alone working at 16um.

Silex did not adopt the South African HeliKon vortex process. The vortex process is a variant of centrifuge technology, and has nothing to do with laser enrichment & harvesting. In normal centrifuges, you have tall centrifuges spinning at mind-blowing speeds. In the old South African enrichment process (Z plant), the walls were stationary but the UF6 gas was forced into a vortex motion using pumps ("Mamba" to push the gas and "Cheetah" to pull the gas). In this vortex motion the isotopes would separate and 235UF6 would be skimmed off the center of the vortex nozzles. The laser enrichment (MLIS) program were supposed to replace this aging (and expensive!) vortex technology, but the joint venture with France's COGEMA came to an end in Nov 1997 and further MLIS research was terminated. With apartheid over, embargoes against South Africa was lifted and they could buy their nuclear fuel internationally to fuel its one and only nuclear plant - Koeberg.