Study on Main Radionuclides of Liquid Waste in Containment Under Severe Accident Available to Purchase

After the Fukushima accident, the disposal of radioactive liquid waste has received great attention. The analysis of nuclide activity in the liquid waste of the containment after a severe accident is the prerequisite for the treatment of the liquid waste. Based on the source and reduction mechanism of radionuclides in the liquid waste of the containment after the severe accident, the composition change of nuclides in the liquid waste was studied. The results showed that during the release stage of nuclides from core to containment, the activity of each group nuclides in the liquid waste gradually increased. Then the activity of each group nuclides gradually decreased with time except for the lanthanum group nuclides. The total iodine activity decreased the fastest, and the total activity of the cesium group decreased the slowest. At the beginning of the accident, iodine was the main nuclide in the liquid waste, followed by cesium group. The percentage of cesium group in the total activity decreased first and then increased, while that of other groups first increased and then decreased. ¹³⁴Cs, ¹³⁷Cs, ⁸⁹Sr, ⁹⁰Sr, ¹²⁷Te^m, ¹⁰⁶Ru, ⁹⁰Y, ¹⁴⁴Ce, ²⁴¹Pu decayed very slowly, which were the important components of the radioactive liquid waste.