Methodology for the nuclear design validation of an alternate emergency management centre (CAGE)

The establishment of a centre (called alternate emergency management centre - CAGE) in each nuclear power plant to manage safely a nuclear emergency is a post-Fukushima measure. Living conditions of the CAGE occupants in the event of a severe accident imply that TEDE must be < 50 mSv and the equivalent dose to the thyroid must be < 500 mSv within 30 days following the accident. The total dose must be optimized by varying parameters such as CAGE location, flow filtering need for recirculation, thicknesses and compositions of the walls, etc. The study of weather conditions as part of the data of the site will determine the relative concentrations of radionuclides in the air using ARCON96. The activity in the air is characterized depending on the source and release sequence specified in NUREG1465 by RADTRAD code, which provides results of the inner cloud source term contribution. Known activities, energy spectra are inferred using ORIGEN-S, which are used as input for the models of the outer cloud, filters and containment generated with MCNP5. After applying the methodology defined in this article, the CAGE design has been validated through several iterations to comply dose constraints