Application of computer modeling for forecasting of radionuclides migration in soil (CEMEPE 09)

Second International Conference on Environmental Management, Engineering, Planning and Economics (CEMEPE 09) & SECOTOX Conference, Greece, June 21 to 26, 2009.

Abstract

An outlook of various methods of computer modeling application for the analysis and forecasting of radionuclides migration in the soil is being discussed. The focus is that further progress in this field is expected due to the development of universal program facilities integrating analytical models, expert and information systems, data bases, geographic information systems (GIS), etc. In this respect an approach of combined methods of physical-mathematical modeling and expert systems application along with supplementary fuzzy logic instruments in subject domain is being considered.

A new mathematical model of radionuclides transport in near-surface soil layer under non-isothermal conditions is being proposed in this paper. The given model takes into account the soil moisture content change effecting the solute transport and sorption owing to evaporation processes and recondensation of water vapor. Moreover numerical investigations of solute transport in aeration zone under rainfalls infiltration and moisture evaporation from soil surface have been implemented.

The article also covers the possibility of hybrid expert systems (HES) application for solving contaminants migration in the soil. Special structure of HES including models hybridization is being proposed. It includes both expert system for pre- and post data processing and artificial neural networks as solving mechanism (neuronet’s model). To increase system flexibility and prediction accuracy, it is recommended to use one copy of ANN for each migration substance. The proposed approach allows to upgrade (to perform posterior training) the expert system during its running without losing previous training results.

On the basis of given methods and models a new software has been developed. It splits into several modules that include mathematical model, HES, GIS-instruments and data base for storing necessary information (maps, various experimental data, calculating results etc.). For modules’ software implementation dynamic replaceable plug-ins technology has been used.

Keywords: mathematical modeling; hybrid expert systems; radionuclides transport; contaminants migration; soil physics.