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课题，这是使我们建议的等离子体净化工艺切实可行所必需的。 (1)利用实际常压等离子体演示等离子体去污过程。 (2)建立工艺安全评估方法并评估其工艺安全性。在上一课题中,我们利用稀有气体和CF_4/O_2混合物产生常压非平衡等离子体,并进行了去除常压非平衡等离子体的实验。不锈钢板表面沾有氧化钴膜。这里产生的大气压非平衡等离子体根据其放电条件有两种工作模式：大气压辉光放电和介质燃烧器放电。明确了各模式、各种条件下的去污特点。在Mel CF_4/O_2混合气体等离子体的情况下，氟化反应在180-200℃下充分进行，并且几乎所有的氧化钴在5分钟内转化为其氟化物。氟化物可以很容易地被水冲洗掉，这表明该过程具有实际应用的可能性。在后一个主题中，我们对细颗粒的生成及其生长过程进行了建模，并添加了发生金属蒸发的过程。在等离子工艺中。我们还开发了数值计算代码来模拟等离子体过程中出现的一系列过程。通过使用此代码，我们计算了等离子体过程中产生的细颗粒的特征。此外，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估算过程，用于估算释放到环境中的细颗粒物的数量而不进行收集。因此，我们可以开发一种方法来获取等离子体净化技术安全评估的信息。