CALCULATION AND JUSTIFICATION OF BIOLOGICAL PROTECTION FOR HOT CELLS WITH REPROCESSED-[sup.99]Mo VOLUME ENLARGEMENT AT KARPOV RESEARCH INSTITUTE OF PHYSICAL CHEMISTRY

Medical radionuclides irradiated in hot cells emanate from targets irradiated in a reactor. Limitations associated with the maximum dose rate do not allow more than eight targets to be processes simultaneously, which increases the processing time and reduces the number of targeted radionuclides produced. The possibilities of processing a larger number of targets in hot cells or shortening their hold-up time after irradiation in a WWR-Ts reactor are analyzed. A computational model of an irradiated target was formulated. The computational results for targets made it possible to enumerate and estimate the radiation level of the radionuclides making the main contribution in the gamma source. The dose rate was calculated for processing of eight and 10 targets with hold-up time 20 h and eight targets with 10 h hold-up. The calculations showed that the dose rate under the considered cases does not exceed the maximum admissible value. The calculations are compared with experiment.