| Popis: |
After the lead-bismuth coolant flows through the core area of the lead-bismuth fast reactor and is irradiated by neutrons, the radionuclide Polonium-210 will be produced. Polonium-210 has a half-life of 138 days and releases alpha particles during decay. With certain volatility, Polonium-210 will pose a potential threat to the environment. Therefore, Polonium-210 is one of the key contents of radiation environmental impact assessment of lead-bismuth reactor. The calculation model of Polonium-210 is established according to the metabolic mechanism of Polonium-210 in the coolant. According to the Polonium-210 calculation model, the generation, decay and migration laws of Polonium-210 in the whole life were analyzed, and the influence of extraction rate on the saturation of Polonium-210 was calculated. The results show that, taking a 20MWth lead-bismuth reactor as an example, in the case of no extraction, Polonium-210 reaches saturation in the fifth year of reactor operation, with a saturation activity of 3.15E + 15Bq. With an extraction efficiency of 90%, Polonium-210 will reach saturation on the 60th day after the reactor starts operating, with a saturation activity of 3.83E + 10Bq. The calculation results can provide a reference for the research on the distribution of Polonium-210 in the coolant. |
