| 摘要 |
PURPOSE:To decrease the release of gaseous fission products and to relieve the mechanical interaction of pellets and cladding pipes as well as to reduce the production cost of the pellets by adding and mixing Cr2O3 at a specific weight ratio to and with raw material powder and molding the mixture. CONSTITUTION:After the Cr2O3 is added and mixed at 0.1-0.3wt.% to and with the raw material powder for the UO2 fuel pellets, the mixture is prepd. into roughly molded slag. This roughly molded slag is ground and pelletized and a lubricant is added to the resultant pellet powder; thereafter, the powder is molded to the pellets. The pellets are sintered for 10-20hr at <=1,600 deg.C in humidifying and drying gaseous H2. The Cr2O3 changes to the oxide of a lower order and releases the excess oxygen according to this method and, therefore, the oxygen potential in the pellets increases and the sintering of the pellets is accelerated. The chromium precipitated at the grain boundaries and the chromium oxide of the lower order decrease the activation energy on the surface of the crystal grains to facilitate the growth of the crystal grains. |
