Trace level estimation of thorium in dissolver solution by neutron activation analysis

摘要

Thorium fuel rods In the form of oxide (19 fuel rod cluster) were Irradiated in KAPP-1 for 508 days full power. These were discharged on 11~(th) Feb. 1997. Burn up was calculated based on the history of the irradiation using different codes. The total number of fissions per ton of thorium is required for the evaluation of the average flux seen by the fuel. The thorium concentration in the dissolver solution is required for the calculations. A method based on the neutron activation has been developed for the estimation of thorium at ppm level in the dissolver solution without any prior separation of thorium. ~(233)Pa produced by neutron activation of thorium in the sample is assayed by gamma ray spectrometry