Model "PROLOG" for Countermeasures Efficacy Assessment and its Calculation Algorithm Verification on the Base of the Chazhma Bay Accident Data

Methodical approaches used in the computational model “PROLOG” are given in the paper. This model is intended for assessing radiological situations and an efficiency of counter measures after short term radioactive releases. Basic local Gaussian dispersion algorithm is supplemented with modules for assessing a plume rise, dry deposition velocities, effect of buildings and complex terrain, etc. The modules provide a compromise between simplicity, shortage of initial data and adequacy of the model in case of real accident. Approaches to assess the dose and countermeasure efficiency are presented as well. Plume rise, complex terrain and contaminant polydispersity modeling approaches were tested on the basis of comparison of calculation and experimental results for dose rate and Co-60 surface contamination measured after the Chazhma bay accident in 1985.