Nuclear Techniques ›› 2020, Vol. 43 ›› Issue (4): 40501-040501.doi: 10.11889/j.0253-3219.2020.hjs.43.040501

• NUCLEAR PHYSICS, INTERDISCIPLINARY RESEARCH • Previous Articles     Next Articles

Thermal plasma decontamination of graphite surface

Mingqiang SI1,2,Jingjing ZHANG1,2,Jinqiu REN1,2,Chunhai LU1,2()   

  1. 1.Sichuan Key Laboratory of Applied Nuclear Techniques in Geosciences, Chengdu University of Technology, Chengdu 610059
    2.State Environmental Protection Key Laboratory of Synergistic Control and Joint Remediation for Soil and Water Pollution, Chengdu University of Technology, Chengdu 610059
  • Received:2019-09-23 Revised:2019-11-28 Online:2020-04-15 Published:2020-04-20
  • Contact: Chunhai LU E-mail:luchhi@126.com
  • About author:SI Mingqiang, male, born in 1995, graduated from North China University of Water Resources and Electric Power in 2017, master student
  • Supported by:
    Sichuan Department of Education Key Research Projects(13ZA0067);Science and Technology Research Project of Chengdu University of Technology(KR1115);China Spallation Neutron Source Project(C-T-03-04-14);China Power Investment Project(YDT-YF-2016-04)

Abstract: Background

During the operation of nuclear facilities, a large amount of radioactive waste is produced, most of the radioactive pollutants in decommissioning are surface contamination. Decontamination can effectively remove radioactive contamination and reduce the difficulty of subsequent waste disposal. Conventional physical decontamination and chemical decontamination are time-consuming and expensive whilst little attention has been paid to study of effective but low-cost thermal plasma decontamination.

Purpose

This study aims to investigate thermal plasma decontamination of surface contaminated graphite, and explore factors related to decontamination ability of thermal plasma.

Methods

Graphite samples contaminated with heavy metal cadmium were taken and prepared as two kinds of samples, i.e., drop-on sample and soaking sample. Decontamination was performed using a thermal plasma device. Decontamination efficiency at different output current and action time were recorded. On the basis of hot plasma dry decontamination, the feasibility and regularity of wet decontamination were also investigated and compared.

Results

Experimental results of hot plasma dry decontamination show that the drip-on sample has a higher decontamination rate and a lower peel thickness compared with soaking sample. When the output current is 60 A and the decontamination time is 100 s, the decontamination rates of drip-on and soaking samples are 92% and 65%, respectively, while the stripping thicknesses are 48 and 117 microns, respectively. Under the same conditions, the wet decontamination has a better decontamination rate than the dry decontamination.

Conclusions

The decontamination ability of hot plasma is basically proportional to the output current and decontamination time, and wet decontamination can greatly improve its decontamination ability, which is a promising decontamination method.

Key words: Thermal plasma, Graphite, Surface decontamination, Stripping

CLC Number: 

  • TL941+.39