Burn-Up Determination of Irradiated Uranium Oxide by Means of Direct gamma Spectrometry and by Radiochemical Method

摘要

The burn-up of thermal neutrons irradiated U sub 3 O sub 8 (natural uranium) samples has been determined by using both direct gamma spectrometry and radiochemical methods and the results obtained were compared. The fission products exp 144 Ce, exp 103 Ru, exp 106 Ru, exp 137 Cs and exp 95 Zr were chosen as burn-up monitors. In order to isolate the radioisotopes chosen as monitors, a radiochemical separation procedure has been established, in which the solvent extraction technique was used to separate cerium, cesium and ruthenium one from the other and all of them from uranium. The separation between zirconium and niobium and of both elements from the other radioisotopes and uranium was accomplished by means of adsorption on a silica-gel column, followed by selective elution of zirconium and of niobium. When use was made of the direct gamma-ray spectrometry method, the radioactivity of each nuclide of interest was measured in presence of all others. For this purpose use was made of gamma-ray spectrometry and of a Ge-Li detector. Comparison of burn-up values obtained by both methods was made by means of Student's t test, and this showed that the results obtained in each case are statistically equal. (ERA citation 07:047509)