Behavior of cesium in municipal solid waste incineration

Kazuyuki Oshita; Hiroshi Aoki; Satoshi Fukutani; Kenji Shiota; Takashi Fujimori; Masaki Takaoka

doi:10.1016/j.jenvrad.2015.01.019

Behavior of cesium in municipal solid waste incineration

J Environ Radioact. 2015 May:143:1-6. doi: 10.1016/j.jenvrad.2015.01.019. Epub 2015 Feb 17.

Authors

Kazuyuki Oshita¹, Hiroshi Aoki², Satoshi Fukutani³, Kenji Shiota², Takashi Fujimori⁴, Masaki Takaoka⁴

Affiliations

¹ Graduate School of Global Environmental Studies, Kyoto University, Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto 615-8540, Japan; Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto 615-8540, Japan; Department of Chemical Engineering, KU Leuven, Jan De Nayerlaan 5, 2860 Sint-Katelijne-Waver, Belgium. Electronic address: oshita@epsehost.env.kyoto-u.ac.jp.
² Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto 615-8540, Japan.
³ Research Reactor Institute, Kyoto University, Kumatori, Sennangun, Osaka 590-0494, Japan.
⁴ Graduate School of Global Environmental Studies, Kyoto University, Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto 615-8540, Japan; Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto 615-8540, Japan.

PMID: 25697082
DOI: 10.1016/j.jenvrad.2015.01.019

Abstract

As a result of the Fukushima Daiichi Nuclear Power Plant accident on March 11, 2011 in Japan radioactive nuclides, primarily (134)Cs and (137)Cs were released, contaminating municipal solid waste and sewage sludge in the area. Although stabilizing the waste and reducing its volume is an important issue differing from Chernobyl nuclear power plant accident, secondary emission of radioactive nuclides as a result of any intermediate remediation process is of concern. Unfortunately, there is little research on the behavior of radioactive nuclides during waste treatment. This study focuses on waste incineration in an effort to clarify the behavior of radioactive nuclides, specifically, refuse-derived fuel (RDF) with added (133)Cs (stable nuclide) or (134)Cs (radioactive nuclide) was incinerated in laboratory- and pilot-scale experiments. Next, thermogravimetric (TG) and differential thermal analysis (DTA) of stable Cs compounds, as well as an X-ray absorption fine structure (XAFS) analysis of Cs concentrated in the ashes were performed to validate the behavior and chemical forms of Cs during the combustion. Our results showed that at higher temperatures and at larger equivalence ratios, (133)Cs was distributed to the bottom ash at lower concentration, and the influence of the equivalence ratio was more significant at lower temperatures. (134)Cs behaved in a similar fashion as (133)Cs. We found through TG-DTA and XAFS analysis that a portion of Cs in RDF vaporizes and is transferred to fly ash where it exists as CsCl in the MSW incinerator. We conclude that Cs-contaminated municipal solid wastes could be incinerated at high temperatures resulting in a small amount of fly ash with a high concentration of radioactive Cs, and a bottom ash with low concentrations.

Keywords: Cesium; Equivalence ratio; Incineration; Municipal solid waste; Radioactive nuclides.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Biofuels / analysis*
Cesium / analysis*
Cesium Radioisotopes / analysis*
Coal Ash / analysis*
Differential Thermal Analysis
Incineration*
Solid Waste / analysis*
Thermogravimetry

Substances

Biofuels
Cesium Radioisotopes
Coal Ash
Solid Waste
Cesium