A Practical fabrication method for the advanced heterogeneous fuel with magnesia containing minor actinides

Miwa, Shuhei  ; Osaka, Masahiko  

The fabrication tests of the advanced heterogeneous fuel with MgO were carried out for the purpose of establishing a practical fabrication method. The advanced heterogeneous fuel consists of spheres (diameter of above 100 m) of a minor actinides oxide and MgO inert matrix (macro-dispersed type fuel). The macro-dispersed type fuel pellets having a high density above 90 %T.D. were successfully fabricated. In addition, they showed a homogeneous dispersion of near spherical host phase granules. These were attained by optimization of the fabrication process and conditions; i.e. a preliminary heat treatment of raw powders of host phase, adjustment of pressure at granulation process, deployment of a spray-dry process for MgO sphere preparation and sintering in the He atmosphere. From these results, a practical fabrication method for the MgO-based macro-dispersed type fuel based on a simple powder metallurgical technique was established.