Separation of isotopes by laser excitation
[2] Slight variations in operating parameters, equipment arrangements, lasers and their capabilities, may exist from one SILEX-type process to the next (and be called by a different name), but the physical separation concept remains the same if condensation repression is utilized, especially when compared to that used by AVLIS or MLIS.
Princeton physicist Ryan Snyder has suggested that this process may lead to the further proliferation of nuclear weapons by providing a new and increasingly accessible technological pathway[2][3] and undetectable signatures (small area footprint and high energy efficiency).
After initial euphoria, laser isotope separation research was mostly abandoned during the 1990s, mainly because it still required extensive and uncertain R&D work, while centrifuges had reached technological maturity.
The U.S. Nuclear Regulatory Commission (NRC) approved a license amendment allowing GLE to operate the Test Loop.
Also in 2008, Cameco Corporation, Canada, the world's largest uranium producer, joined GE and Hitachi as a part owner of GLE.
[13][14] In 2016, the United States Department of Energy agreed to sell about 300,000 tonnes of depleted uranium hexafluoride to GLE for re-enrichment (from 0.35 to 0.7 % 235U) using the SILEX process over 40 years at a proposed Paducah, Kentucky Laser Enrichment Facility.
To allow for selective excitation, the UF6, diluted about 100 fold by a carrier gas (which can be argon or nitrogen), is cooled to about 80 K by adiabatic expansion through a nozzle into vacuum.
With SILEX, the pressure and nozzle diameter are chosen large enough to provide a sufficient number of collisions immediately after the nozzle, to allow for formation of clusters (UF6•G) with the carrier gas G. (UF6•UF6 clusters are practically not formed due to the much lower density of UF6 compared to G.) If 235UF6 is selectively excited at 628.3 cm−1, then this molecule does not aggregate with G, whereas the nonexcited heavier 238UF6 does.
Due to their higher thermal velocity, the free molecules leave the axis of the molecular beam faster than the clusters.
That is, SILEX uses a separation nozzle, modified by a laser and profiting from selective repression of cluster formation ("condensation").
[9] The attractiveness is even enhanced by the claims of GLE that a SILEX plant is faster and cheaper to build, and consumes considerably less energy.
[1][23] In June 2001, the U.S. Department of Energy classified "certain privately generated information concerning an innovative isotope separation process for enriching uranium".
Under the Atomic Energy Act, all information not specifically declassified is classified as Restricted Data, whether it is privately or publicly held.
The female protagonist Sophie Walsh states that the technology will be smaller, less energy-intensive, and more difficult to control once it is a viable alternative to current methods of enrichment.
