METHOD FOR REMOVING RADIOACTIVE CESIUM AND SEPARATION ACCELERATOR-CONTAINING SLURRY

• Main Authors: ICHIKAWA SEIGO, HAMA TOSHIO, ITO TAKAYASU, NISHIZAKI YOSHIHIKO, TAKAHASHI TOSHIYUKI, FUKUSHI SEIJI
• Format: Patent
• Language: English; Japanese
• Published: 12.08.2016
• Subjects: DECONTAMINATION ARRANGEMENTS THEREFOR; NUCLEAR ENGINEERING; NUCLEAR PHYSICS; PHYSICS; PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULARRADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL

PROBLEM TO BE SOLVED: To provide a method for removing radioactive cesium, for which a temperature of heat processing for separating radioactive cesium from waste can be sufficiently lowered, and capable of satisfactory attaining a high radioactive cesium removal ratio and volume reduction of radioactive cesium contaminants at the same time.SOLUTION: The removal method according to the present invention includes a mixing step of mixing radioactive cesium-contaminated waste with a separation accelerator to obtain a processing object, a heating step of heating the processing object to volatilize the radioactive cesium contained in the processing object, and a washing step of water washing the processing object after the heating step to allow the radioactive cesium remaining in the processing object to elute. The separation accelerator is prepared by using two or more types of chlorides and contains a mixture or a double salt with a melting point of 700°C or lower. The separation accelerator further contains a calcium source. In the mixing step, slurry containing the separation accelerator and water is mixed with the waste to obtain the processing object.SELECTED DRAWING: Figure 18 【課題】廃棄物から放射性セシウムを分離するための加熱処理の温度を十分に低くできるとともに、放射性セシウムの高い除去率と放射性セシウム汚染物の減容化を十分に両立できる放射性セシウムの除去方法を提供する。【解決手段】本発明の除去方法は、放射性セシウムで汚染された廃棄物と分離促進剤とを混合して処理対象物を得る混合工程と、処理対象物を加熱することによって処理対象物に含まれる放射性セシウムを揮発させる加熱工程と、加熱工程後、処理対象物を水洗することによって処理対象物に残存する放射性セシウムを溶出させる水洗工程とを備える。分離促進剤は２種類以上の塩化物を用いて調製され且つ融点が７００℃以下である混合物又は複塩を含み且つカルシウム源を更に含み、混合工程において、分離促進剤と水とを含むスラリーと廃棄物とを混合することによって処理対象物を得る。【選択図】図１８