Conversion coefficients from 24Na specific activity to effective dose in criticality accidents

New conversion coefficients relating 24Na specific activity in the human body induced by neutron exposure to the corresponding effective dose are presented to estimate public exposure in criticality accidents. The coefficients were calculated using state-of-the-art mesh-type phantoms developed by the International Commission on Radiological Protection (ICRP) and the Particle and Heavy Ion Transport code System code. Calculations were performed for all irradiation geometries defined by the ICRP, with monoenergetic neutrons ranging from thermal energies to 20 MeV. These newly derived coefficients enable a more accurate assessment of neutron radiation exposure to the general public in criticality accidents.