99 Mo is an essential isotope in nuclear medicine, but the nuclear reactors used for their production reaching their end of life, problems of supply arise and new methods of production need to be considered. Here we study the possibility of using gamma and neutron irradiation of Mo nanoparticles (NPs) in suspension and use the separation of the isotopes escaping the nanoparticle by primary recoil to evaluate the efficiency of the process for 99 Mo production. Molecular Dynamics simulations with empirical potential of Ackland and Thetford were used to obtain information about the 99 Mo escape yield from the NPs and the resulting sputtering depending on NPs sizes and recoil energy. Results show that the best yield is obtained for 5 nm NPs irradiated with gamma particles. These results are used to guide accelerator irradiation experiments led in parallel in order to evaluate the possibility of using accelerators instead of nuclear reactors for the production of 99 Mo.