A model to predict indoor concentrations and internal radiation doses of radioactive aerosols from nuclear accidents

Spread of radiation contaminations can be affected by several factors. Some of these factors were considered in previous articles. Those studies were based on some Computational Fluid Dynamic (CFD) schemes and gave good results for describing deposition and penetration of aerosol particles. In this paper, those CFD schemes are applied to set a model that can be used to calculate the indoor concentrations of the radioactive aerosols that release from nuclear accidents. The one of the Fukushima nuclear power plant (NPP) that took place in 2011 is taken as an example. Furthermore, the internal radiation doses caused by the intake of the radioactive aerosols are estimated. Considering in particular the radionuclide C137s, due to its very long half-life, the internal doses are calculated for the lungs and some of the surrounding vital organs. The radiation transport throughout the body is simulated by codes of the Monte-Carlo N-Particle simulation software, version 5 (MCNP5), with exploiting the human body representation by the phantom of the Oak Ridge National Laboratory-Medical Internal Radiation Dose (ORNL-MIRD). The results show a large spread of the radiation contaminations from outdoors to indoors, and that the whole-body annual dose from C137s is more than tenfold higher than the annual dose limit set by the International Commission on Radiological Protection (ICRP).