Isotope Exchange Reaction between U-235 Enriched Uranium Pentafluoride Particles and Natural Uranium Hexafluoride Gas.

• ONOE Jun

  The Institute of Physical and Chemical Research (RIKEN)

• KUGA Yoshikazu

  The Institute of Physical and Chemical Research (RIKEN)

• ISOMURA Shohei

  The Institute of Physical and Chemical Research (RIKEN)

• TAKEUCHI Kazuo

  The Institute of Physical and Chemical Research (RIKEN)

Abstract

Molecular laser isotope separation (MLIS) is an attractive technique for ²³⁵U enrichment from natural uranium hexafluoride (UF₆). In MLIS at RIKEN, the v3 vibrational mode (628 cm^-1) of supercooled ²³⁵UF₆ in natural UF₆/Ar mixture is selectively excited and successively dissociated with a multi-frequency para-H₂ Raman laser to produce nonvolatile ²³⁵U pentafluoride (²³⁵UF₅). The ²³⁵UF₅ molecules thus formed are immediately aggregated to form particles. These ²³⁵U enriched UF₅ particles are collected on an impactor plate, and they are easily separated from the reactant gas⁽¹⁾⁽²⁾. <BR>Grigore'v et al.⁽³⁾ have recently reported on an isotope exchange reaction between ²³⁵UF₆ and ²³⁵UF₆ that reduced the isotope ratio of the enriched UF₅ particles as shown in the following equation : <BR>²³⁵UF₅(solid)+²³⁵UF₆(gas) →←<BR>²³⁵UF₆(gas)+²³⁸UF₅(solid).( 1 )<BR>Consequently, the apparent separation factor of MLIS decreased. According to their report, this exchange process (Eq. ( 1 )) progressed at two rates : a fast process due to the exchange reaction between the outermost layer of the enriched UF₅ particles and the UF₆ gas, and a slow process due to the exchange reaction between underlying layers of the UF₅ particles and the gas. From fitting a calculated result to experimental data, they obtained an exchange reaction probability of 1.1×10^-9, and a participation probability of the underlying layer in this exchange reaction of 0.6. However, the agreement of their calculated result with experimental data by a numerical method alone does not verify their reaction model. The analytical solution of this exchange reaction, if it can be obtained, is preferable, since then the model can be verified by a dimensionless plot, deduced directly from the analytical solution, of the experimental results. <BR>Assuming Eq. ( 1 ) is a bimolecular-type, reversible, first-order reaction, we present in this note a kinetical analysis of our experimental data obtained using 7% ²³⁵U enriched UF₅ particles and natural UF₆ gas.

Journal

• Journal of Nuclear Science and Technology

  Journal of Nuclear Science and Technology 28 (8), 777-779, 1991

  Atomic Energy Society of Japan

Keywords

• molecular laser isotope separation
• isotope exchange reaction
• uranium pentafluoride
• uranium hexafluoride
• isotope ratio
• separation factor
• exchange reaction probability

Details

• CRID: 1390282679071997696
• NII Article ID: 130000826415
• DOI: 10.3327/jnst.28.777
• COI: 1:CAS:528:DyaK3MXls1ymt7s%3D
• ISSN: 18811248
• ISSN: 00223131
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed