NEUTRON-FLUX DENSITY PROFILING DURING IRIDIUM IRRADIATION

Using the perturbation method, the dependence of the specific activity of Ir-192 on the variation of neutron flux density is investigated. I t has been shown that sensitivity of the specific activity of Ir-192 v alue at a given irradiation time depends on the time-point of neutron flux perturbation, being greater if perturbation is introduced at the end of the irradiation cycle. Practical realisation of a proposed sche me will allow an increase in Ir-192, specific activity together with s avings in reactor fuel, due to the lower level of reactor power at the beginning of the cycle. (C) 1997 Elsevier Science Ltd. All rights res erved.