MANUFACTURING METHOD OF NUCLEAR FUEL SINTERED BODY

摘要

PROBLEM TO BE SOLVED: To stably provide a large grain size sintered body when manufacturing a nuclear fuel sintered body by sintering in two stages in an oxidizing atmosphere and a reducing atmosphere at a comparatively low temperature. SOLUTION: Powder with 25-45 wt.% triuranium octoxide mixed in uranium dioxide raw material powder or mixed powder mixed with uranium oxide so that a final O/U of a mixture is equivalent to the powder is used as a raw material, at least a high temperature side is 1200-1100 deg.C and a low temperature side is <=1080 deg.C during a sintering period in the oxidizing atmosphere, and the raw material is subjected to a temperature rise to the high temperature side and a temperature drop to the low temperature side at least one time each in between the high temperature side and the low temperature side. It is desirable that a temperature difference between high temperature and low temperature is 50 deg.C.