Characterization of the irradiation facilities SINCA and SIRCA of the TRIGA Mark III reactor using the code MCNPX

The commitment of changing fuels of high enrichment for fuels of low enrichment in the TRIGA Mark III reactor of the Nuclear Center of Mexico generates the necessity to know the distribution of the spectrum of the neutrons flux in the irradiation facilities like they are: the Pneumatic System of Capsules Irradiation and the Rotational System of Capsules Irradiation. Is very important for the experiments design as well as for the reactor safety to know the profiles of the neutrons flux and the spectrum that these maintain with the mixed core with which operates, to effect of conserving the same characteristics when the reactor core will be operated with fuel of low enrichment totally. Also, knowing the profiles of the neutrons flux, the reactor operators can optimize the irradiation conditions of the processed samples and likewise the users can select the irradiation positions more adaptable to their necessities. This work present the characterization of the neutron flux in the irradiation facilities SINCA and SIFCA, calculated with the code MCNPX. (Author)