Release Process of Fission Xenon Produced by β-Decay of Precursor Iodine in Natural Graphite at 1, 000°C

FUKUDA Takeshi, OMORI Shunzo, YAMAGISHI Shigeru

doi:10.3327/jnst.10.242

In order to study the release process of fission xenon produced by decay of the precursor iodine in natural graphite powder, post-irradiation experiments were carried out at 1, 000°C soon after 20min irradiation with UO₂ powder. In an experiment with interruption (2hr heating-10 day cooling-10hr heating), it was found that the decay of ¹³³I to ¹³³Xe caused a fraction of the ¹³³Xe produced to be released rapidly, while the remaining fraction was released gradually. This was followed by a continuous heating experiment, during which the release rates of ¹³³Xe, ¹³⁵Xe and ¹³⁵mXe were measured, and in which production and release of xenon occurred simultaneously in a manner similar to conditions prevailing under actual irradiation experiments. The rates of nuclide release were explained by assuming the same release probability for each xenon nuclide as that for ¹³³Xe in the first experiment. The origin of the initial rapid release by decay of iodine to xenon was considered mainly to be the change of chemical interaction between the defects and the atoms trapped therein. The release behavior of xenon after its production was explained by assuming that the activation energies for the release from the defects were lowered by about 10kcal/mol by the decay.

Release Process of Fission Xenon Produced by β-Decay of Precursor Iodine in Natural Graphite at 1, 000°C

Search this article

Description

Journal

Keywords

Details 詳細情報について

Export

Report a problem