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Development of Radio-Active Waste Decontamination Process by Using Atmospheric Pressure Plasma and Its Safety Analysis.

常压等离子体放射性废物净化工艺开发及其安全性分析。

基本信息

批准号：
13558060
负责人：
SUZUKI Masaaki
金额：
$ 8.64万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

项目摘要

In this project, we have studied the following two subjects, which is required to make the plasma decontamination process, which we have suggested, practicable. (1)To demonstrate the plasma decontamination process by using practical atmospheric pressure plasma. (2)To develop the process safety assessment method and to assess its process safety.In the former subject, we generated the atmospheric-pressure non-equilibrium plasma by using rare gases and CF_4/O_2 mixture and we carried out some experiments of removal of cobalt oxide film stained on the stainless steel plate surface. The atmospheric -pressure non-equilibrium plasma generated here had two operation modes, atmospheric pressure glow discharge and dielectric burner discharge, depending on its discharge conditions. The decontamination characteristics under each mode and various conditions were made clear. In the case of Mel CF_4/O_2 gas mixture plasma the fluorination reaction proceeds sufficiently at 180-200 degree C and almost of cobalt oxide was converted into its fluoride within 5 minutes. The fluoride could be flush out easily by water and it could indicate the possibility of practical use of this process.In the latter subject, we made modeling of processes of fine particle generation and its growth, adding to the evaporation of metal, which takes place in the plasma process. And also we developed the numerical calculation code to simulate a series of process which appears in the plasma process. By using this code we calculated the characteristics of fine particles generated in the plasma process. By adding to its code a collecting process by various air filter, furthermore, we completed a series of the process for the estimation process estimate the amount of fine particles which were released into the environment without collecting. Consequently, we could develop a method to obtain information fo safety assessment of the plasma decontamination technique.

在这个项目中，我们研究了以下两个主题，这是使我们建议的等离子体去污过程可行所需的。(1)To用实际的大气压等离子体演示了等离子体去污过程。(2)To在前一课题中，我们利用稀有气体和CF_4/O_2混合气体产生大气压非平衡等离子体，并进行了去除不锈钢板表面钴氧化膜的实验。根据放电条件的不同，产生的大气压非平衡等离子体有大气压辉光放电和介质燃烧器放电两种工作模式。明确了各模式下不同条件下的去污特性。在MeI CF_4/O_2混合气体等离子体中，在180-200 ℃下，钴的氧化反应充分进行，在5分钟内，几乎所有的钴氧化物都转化为氟化物。在后一个课题中，我们对等离子体过程中发生的细颗粒的生成和生长过程进行了模拟，并加入了金属的蒸发过程。并编制了数值计算程序，对等离子体过程中出现的一系列过程进行了模拟。利用该程序计算了等离子体过程中产生的细颗粒的特性。通过在其代码中添加各种空气过滤器的收集过程，我们还完成了一系列用于估算过程的过程，估算未经收集而释放到环境中的细颗粒物的量。因此，我们可以开发一种方法来获得信息的安全评估等离子体去污技术。