Experiments for airborne dispersion ratio of radionuclides during plasma arc cutting were carried out in a contamination control enclosure, using stored radioactive metal wastes arising from the decommissioning activities of Japan Power Demonstration Reactor, which was a boiling water type reactor. Neutron induced-activated piping and surface contaminated piping were segmented into pieces using air plasma arc cutting, using a current power was 100A. In addition, similar experiments for contaminated piping of the Advanced Thermal Reactor, Fugen were carried out. As a result, dispersion ratios for activated piping were 0.2 to 0.7% of Co-60 and 0.4% of Ni-63 under the condition with a covered cap on the head. And those for surface contaminated piping were from 18 to 23%. In addition, those for vertically segmented piping which simulated flat plate were from 34 to 43%. There was no difference of dispersion ratios between stainless steel and carbon steel base materials. All values obtained were smaller than the Handbook recommended value of 70% for contaminated materials. Filtering collection efficiencies of the coarse dust filter were approximately 40% for activated piping and approximately 55 to 80% for surface contaminated piping. However there was no effect for collection of aerosols smaller than 1 μm. Size distribution analysis indicated a greater concentration of radionuclides in particles smaller than 0.1μm when compared with larger particles. In addition, there was a tendency that the Ni-63 was concentrated to the particles smaller than 0.3 μm compared with the Co-60. The results support data obtained in the previous studies using non-radioactive materials.
- Nuclear Engineering Division and Environmental Engineering Division
Plasma Arc Cutting Experiments Using Radioactive Materials for Evaluation of Airborne Dispersion Ratio
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Shimada, T, Takamura, A, Kamiya, A, Sukegawa, T, & Tanaka, T. "Plasma Arc Cutting Experiments Using Radioactive Materials for Evaluation of Airborne Dispersion Ratio." Proceedings of the ASME 2009 12th International Conference on Environmental Remediation and Radioactive Waste Management. ASME 2009 12th International Conference on Environmental Remediation and Radioactive Waste Management, Volume 2. Liverpool, UK. October 11–15, 2009. pp. 381-388. ASME. https://doi.org/10.1115/ICEM2009-16106
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