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Journal Articles

Hydrogen release reaction from sodium hydride with different sample quantities

Doi, Daisuke

Proceedings of 29th International Conference on Nuclear Engineering (ICONE 29) (Internet), 7 Pages, 2022/08

https://doi.org/10.1115/ICONE29-91847

Journal Articles

Kinetic and Fourier transform infrared studies on the thermal decomposition of sodium hydride

Kawaguchi, Munemichi

Journal of Physical Chemistry C, 125(22), p.11813 - 11819, 2021/06

https://doi.org/10.1021/acs.jpcc.1c00538

Times Cited Count：2 Percentile：14(Chemistry, Physical)

Isothermal and constant heating thermogravimetry-differential thermal analysis (TG-DTA) and Fourier transform infrared spectrometer (FTIR) measurements have been performed for pre- and post-fired sodium hydride (NaH) in the temperature range of 500-700 K, respectively. Temperature dependence of NaH thermal decomposition rates obtained by the isothermal TGs showed an inflection point at around 620 K, which was caused by two kinds of hydrogen states (rapid diffusing and immobile hydrogen). In the FTIR spectra for the NaH and sodium (Na), the specific signals were observed at around 873.4, 1010.4, 1049.5 and 1125.7 cm $^{-1}$ , and the integrated values of FTIR signals for post-fired NaH at below 550K and at above 698 K were comparable to those for pre-fired NaH and Na, respectively. Those for post-fired NaH at 602-667 K were the intermediate values of the pre-fired NaH and Na, which denoted that the Na-Na bonds haven't grown sufficiently and the hydrogen coexisted in metallic Na. In order to predict the practical kinetics of NaH thermal decomposition reaction, we suggested the simple kinetics model which assumed two kinds of rapidly diffusing and immobile hydrogen states. The simulation results revealed the inflection point in temperature dependence of the thermal decomposition rates accordingly because the transition from immobile hydrogen to rapid diffusing hydrogen crosses over at around 620 K.

JAEA Reports

Investigation of release behavior of volatile ruthenium species from thermal decomposition of ruthenium nitrosylnitrate

Abe, Hitoshi; Masaki, Tomoo; Amano, Yuki; Uchiyama, Gunzo

JAEA-Research 2014-022, 12 Pages, 2014/11

JAEA-Research-2014-022.pdf:1.03MB

To contribute safety evaluation of boiling and drying accident of high active liquid waste (HALW) in fuel reprocessing plant, release behavior of Ru, which was considered as an important nuclide for evaluating public dose from the volatile viewpoint, has been investigated. It has been reported that release of Ru becomes conspicuously after HALW is dried up. In this work, to grasp the release behavior of Ru, release ratio of Ru with thermal decomposition of Ru nitrate, which would be in the dried HALW, was measured and release rate constant of Ru from the nitrate was estimated. It was found that the calculation result of release rate of Ru from the nitrate with rise of temperature by using the constant could well simulate the result acquired from the beaker-scale experiment.

Journal Articles

Decomposition behavior of PCDD/F isomers in incinerator gases under electron-beam irradiation

Hirota, Koichi; Kojima, Takuji

Bulletin of the Chemical Society of Japan, 78(9), p.1685 - 1690, 2005/09

https://doi.org/10.1246/bcsj.78.1685

Times Cited Count：7 Percentile：31.75(Chemistry, Multidisciplinary)

Decomposition behavior under electron-beam irradiation was examined for polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) isomers in incinerator gases. Significant decomposition was obtained for all PCDD isomers over the investigated absorbed doses, which was resulted from oxidation reactions with OH radicals yielded by electron-beam irradiation. In the case of PCDFs, specific isomers having symmetrical structures such as 1, 2, 8, 9-, 2, 3, 7, 8-, and 3, 4, 6, 7-TeCDFs were yielded through the dechlorination of PeCDF isomers. Thermal electrons probably played a role in the dechlorination of PeCDF isomers.

Journal Articles