| 摘要 |
<p>PURPOSE:To decrease the repair and exchange of devices and to simplify processes by drying a plutonium nitrate soln. and uranyl nitrate soln. by a vacuum freeze drying method to obtain the residual matter contg. nitrate. CONSTITUTION:The Pu soln. and U soln. 1 refined and recovered in a solvent extraction stage of a retreatment plant, etc., are straightly frozen in a freezing stage 2. The frozen matter is then sent to a sublimation stage 3 and is heated under a vacuum. The water and nitric acid sublimate and are condensed in a condenser 5. The condensate is separated to a condensed liquid 11 consists of the water, nitric acid, etc., and the residual matter consisting of plutonium nitrate salt and uranyl nitrate soln. which do not sublimate. The residual matter 4 is sent to a heating and denitrifying stage 6 where the residual matter is thickened by heating and is denitrified to obtain the denitrified matter 7. The off-gas generated at this time is made into the condensed liquid 8. The denitrified boyd 7 is sent to a roasting and reducing stage 9 where the denitrified matter is roasted in the air and is reduced in a gaseous mixture composed of hydrogen and nitrogen to adjust the power properties. A product 10 consisting of an Pu oxide and U oxide is thus obtd.</p> |
