摘要
Interest in thorium stems mainly from the fact that it is expected to have a substantial increase in uranium prices. So, advanced fuel cycles which increase the reserves of nuclear materials are interesting, particularly, the use of thorium is to produce the fissile isotope ^233U. Thorium is three to five times more abundant than uranium in the earth＇s crust. Additionally, thoria produces less radiotoxicity than the UO2, because it produces fewer amounts of actinides. ThO2 has higher corrosion resistance, besides being chemically stable, and the burning of Pu in a reactor based in thorium also decreases the inventories of Pu from the current fuel cycles. There are some ongoing projects in the world, taking into consideration the proposed goals for Generation IV reactors, namely： sustainability, economics, safety and reliability, proliferation resistance and physical protection. Some developments on the use of thorium in reactors are underway, with the support of the IAEA （International Atomic Energy Agency） and some govern like molten salt reactor. In this paper, we discuss the future importance of thorium, particularly for Brazil, which has large mineral reserves of this strategic element, the characteristics of the molten salt reactor and the experience of the IPEN （Instituto de Pesquisas Energ6ticas e Nucleares） in the purification of thorium compounds.
