Comparative cost analysis of direct disposal versus pyro-processing with DUPIC in Korea

There are 20 nuclear reactors operating in Korea and four more are under construction. The spent nuclear fuel and radioactive wastes will be accumulated and an effective management must be introduced. In Korea, pyro-processing and Direct Use of spent PWR fuel In CANDU (DUPIC) are drawing attentions of many researchers and policy makers. However, cost comparison studies of each or both options against the direct disposal have not been adequately conducted. Therefore, the purpose of this study is to compare the fuel cycle strategy in cost terms. Based on mass balance of the Heavy Metal, cost of each process in the fuel cycle was considered. It was found that the pyro-processing-only cannot win against the direct disposal, but it can be compensated by adding DUPIC. Pyro-processing with DUPIC was cheaper by 925 M$ than the direct disposal. Further time-considered analysis will supplement this work with reasonable basis.     

Trapping characteristics of volatile ruthenium oxides by Y<Subscript>2</Subscript>O<Subscript>3</Subscript> filter

Yttria filter has been suggested as a trapping agent for gaseous oxides of ruthenium volatilized during DUPIC fuel fabrication process. Experiments were performed to evaluate the trapping characteristics of gaseous ruthenium oxides by yttria ceramic foam filters in the two-zone furnace under air condition. Yttria filter is expected to offer stable material in which the volatility of the ruthenium can be effectively trapped because of its incorporation into a lattice of high stability over 900 ‡C under air condition. The XRF result of ruthenium trapped on an yttria filter under air condition showed that concentrations of ruthenium on the back and the front faces of the filter decreased linearly with increasing superficial air velocity, and the back face concentration of filter was lower than the front face concentration by about 30-45%. The TGA result of ruthenium trapped on an yttria filter indicates that there is weight loss of 5.8 wt% up to 1,400 ‡C, which is believed to be due to the fact that the thermally stable Y₂Ru₂O₇ phase was formed on an yttria filter.