Summary on Research Activities in the Plutonium Field Japan

The studies concerning spent fuel reprocessing, reactor physics on plutonium recycling and fabrication of plutonium fuels have been carried out. In the reprocessing test, natural uranium spent fuel from the research reactor (JRR-3) was processed by purex type process and about 180 grams of plutonium were separated, during the course of the test done in March to August 1968. The first stage experimental studies concerning plutonium use for thermal reactors using light water moderated critical assembly (TCA) have been carried out. The pellets fabrication by co-precipitation method and by powder mechanical blending method were studied. Sol-gel processing to obtain coarse end dense particles suitable for vibratory compaction has been carried out. The studies on thermal conductivity of vibratory compacted fuels, temperature distribution in fuel rods, etc., have been carried out.