Chemical vapor deposition and isotope separation

Journal Article · Sat Jan 01 04:00:00 EST 1977 · J. Electrochem. Soc.; (United States)

DOI:https://doi.org/10.1149/1.2133229· OSTI ID:7121785

Severin, P J ^[1]; Lydtin, H

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1. Philips Research Labs., Eindhoven, Netherlands

Because chemical vapor deposition (CVD) is based on diffusion, isotope separation should take place if the process is in the diffusion-limited range. The enrichment in a horizontal reactor as used for silicon epitaxy is calculated including thermal diffusion effects. It is found that whereas the deposition rate decreases exponentially along the reactor with characteristic length ..lambda.., the isotope enrichment decreases linearly over the length from maximum to zero at x = ..lambda... The maximum value depends in a complex way on the masses and concentrations of the gas to be separated and the second gas, present as a reaction component or carrier gas. The requirements for efficient CVD isotope enrichment, which include fast mixing, a high deposition rate, and high enrichment ratio can be satisfied better by a liquid-source CVD system. An experimental arrangement is described and discussed in terms of heat transfer by film boiling. Experiments with carbon deposition from C/sub 12/H/sub 26/ have shown a /sup 12/C//sup 13/C enrichment ratio up to0.8%, whereas ..delta..M/2M = 0.3%. This effect is attributable to mass and thermal diffusion, selective evaporation, spray fractionation by drops acting as microultracentrifuges, and geometry effects. The possibility of achieving uranium isotope separation with a CVD process has been considered theoretically. Thermodynamically possible reactions are specified by which liquid UF/sub 6/ is transformed into solid UF/sub 3/, UF/sub 4/, and UF/sub 5/. In principle CVD can also be used as a collector mechanism with laser-induced isotope enrichment.

• OSTI ID: 7121785
• Journal Information: J. Electrochem. Soc.; (United States), Journal Name: J. Electrochem. Soc.; (United States) Vol. 124:1; ISSN JESOA
• Country of Publication: United States
• Language: English

Related Subjects

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400703 -- Radiochemistry & Nuclear Chemistry-- Radioisotope Production
ACTINIDE COMPOUNDS
ACTINIDE ISOTOPES
ALKANES
CARBON 12
CARBON 13
CARBON ISOTOPES
CHEMICAL COATING
CHEMICAL REACTIONS
CHEMICAL VAPOR DEPOSITION
DEPOSITION
DIMENSIONS
ENERGY TRANSFER
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FLUIDS
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HEAT TRANSFER
HYDROCARBONS
ISOTOPE SEPARATION
ISOTOPES
LASER ISOTOPE SEPARATION
LENGTH
LIGHT NUCLEI
LIQUIDS
NUCLEI
ORGANIC COMPOUNDS
SEPARATION PROCESSES
STABLE ISOTOPES
SURFACE COATING
URANIUM COMPOUNDS
URANIUM FLUORIDES
URANIUM HEXAFLUORIDE
URANIUM ISOTOPES