LAUSR

Calculation codes for radioisotopes production using multi-group formalism and experimental neutron flux require a prior calculation of the self-shielding of resonances. These calculations yield multigroup cross sections for which the neutron flux depressions at the resonance energies in the fuel medium have been adequately taken into account. For this objective, a fast, accurate and flexible approach allowing the prediction of radioisotope activities generated in irradiated targets has been developed. This approach is constituted by interconnected computer modules to calculate the radioisotope activities produced. In our study we took as applications the irradiation of TeO2 and MoO3 targets in the central thimble of the Moroccan Triga Mark II research reactor at 2 MWth power. This computerized modular system was qualified by experimental 131I production tests. The 131I activities determined from both calculation and experiments were comparable. In addition to the calculation precision, this computerized modular system allows a large reduction of a computation time in estimating the source term at any time of the irradiation and processing phases.