Hui-Jun Won

Metal Surface Decontamination by the PFC Solution

PFC (perfluorocarbon) spray decontamination equipment was fabricated and its decontamination behavior was investigated. Europium oxide powder was mixed with the isotope solution which contains Co-60 and Cs-137. The different shape of metal specimens artificially contaminated with europium oxide powder was used as the surrogate contaminants. Before and after the application of the PFC spray decontamination method, the radioactivity of the metal specimens was measured by MCA. The decontamination factors were in the range from 9.6 to 62.4. The spent PFC solution was recycled by distillation. Before and after distillation, the turbidity of PFC solution was also measured. From the test results, it was found that more than 98% of the PFC solution could be recycled by a distillation.Copyright

TRIGA Soil Decontamination by Electrokinetic Method

The experiment for removing cesium and cobalt from the contaminated soil around the TRIGA reactor in Korea using the electrokinetic method were conducted. To increase removal efficiency by the electrokinetic method, a device to restrain the pH increase in the soil column was suggested. An acetate buffer solution (CH3 COONa+CH3 COOH) was injected into the soil column and acetic acid periodically was injected into the cathode reservoir to restrain any pH increase. Many 137 Cs and 60 Co were transferred by electromigration rather than electroomosis during the intial remediation period, and no precipitate was formed in the soil column. 25% of cesium radioactivity in the soil column was removed after 10 days, while 94% of cobalt radioactivity was removed. Furthermore, the remaining radioactive concentrations predicted by the developed numerical model were similar to those obtained by experiment.Copyright