Abstract
The article analyses the designs and fuel cycles of thorium nuclear reactors being developed in leading producing countries. Special attention is paid to molten salt reactors (MSR), advanced heavy water reactors (AHWR), high-temperature systems (HTR), and subcritical accelerator-driven systems (ADS). The physicochemical properties of thorium and its behaviour in different types of cores are reviewed. A comparative analysis with uranium fuel is carried out, and the advantages and limitations of the thorium cycle in terms of energy efficiency, radiation safety, and reproduction of fissile isotopes are disclosed. The main design approaches to the integration of thorium into existing and prospective reactor plants, including solid-fuel, liquid-salt and hybrid systems, are described. Possible coolants and external neutron sources as well as spent fuel reprocessing requirements are discussed. On the basis of review and experimental data, recommendations on further directions of scientific and technical research and international co-operation in the field of thorium energy are formulated.