RADCAL-III mod.N: Calculation of radioactive concentrations in air and at ground level of urban areas located at mesoscale distance (subclass α) from a nuclear plant hit by severe accident - phase 1

This report describes the activities performed in the frame of LP1, Objective B, task B2, theme 2 of PAR-2014. The Ministry of Economic Development (MiSE), through the B.3.1. Program agreement with ENEA, have funded two project lines in the field of nuclear energy. The first one is aimed at maintaining and, where applicable, to increase the growth of a system of scientific expertise dedicated to safety, security and sustainability of nuclear power, in order to be ready for independent safety assessments in the case of emergencies caused by severe accidents in NPPs located near the Italian border. RADCAL-III mod. N is a code under development and validation, characterized by innovative models, to calculate radioactive concentrations in urban areas and surrounding open country, taking account of natural and artificial obstacles in the short field, different architectural layouts, and different local meteorological conditions. The work performed during phase-I is concluded. The modular structure and all models are ready for phase-II, during which the calculation of radioactive concentrations and comparisons with other codes for validation purposes will be carried out. Phase 2 will begin from the first year of the next three-year national plan.