Experiment and analysis on melting of the UO2/ZrO2 mixtures using a cold crucible

Korea Atomic Energy Research Institute (KAERI) has been carrying the fuel-coolant interaction (FCI) experiments called the Test for Real cOrium Interaction with water (TROI) program using the reactor material. As a part of the program, the melting and release method of oxide materials with high melting points has been studied. The melting experiment of UO2/ZrO2 mixture (w/o 8:2) is carried out using the cold crucible melting method. About 10 kg melt is obtained from the melting experiments and was successfully applied to FCI experiments. The heat transferred to the induction coil, the cold crucible and melt is calculated using operating parameters of R. F generator. Also, the superheat of melt is predicted from heat balance analysis between the heat input, which is transferred to the cold crucible and melt, and the heat loss, which is removed through the cooling water from the crucible and the radiation from the melt surface. The melt is superheated over 500K in maximum from the calculation result. Meanwhile, when the two-color pyrometer is used for the temperature measurement, the emissivity ratio has to be set but depends on the surrounding conditions. In the UO2/ZrO2 test, the emissivity ratio of the pyrometer is guessed about 1.18