STATUS OF RESEARCH AND DEVELOPMENT OF FABRICATING LARGE-SIZE HIGH-LEVEL WASTE PELLET BY HOT PRESS

摘要

This study investigated the hot-pressing behavior ofthe mixed powder of sodium nitrate and cerium oxide asthe simulated material of calcined high-level waste. Weobtained a 1.0-cm-diameter pellet having fillingpercentage of nearly 100% by pressing near the meltingpoint of the nitrate. Subsequently, the non-radioactivesimulated high-level waste that contains 19 elements werepressed. At a 250 °C temperature, which is near themelting point of some nitrates in the simulated high-levelwaste, we also obtained the 1.0-cm-diameter pellet with afilling percentage of 95% at a 1.0-kN load while pressing.This result made it possible to obtain a pellet larger thanthe desired diameter. As this was a trial test with theobjective of enlarging the diameter, we successfullyobtained a pellet having a diameter of 3.0 cm with afilling fraction above 90%.