Nuclear chemistry thorium reactor

This is a radioactive element. It occurs in minute traces in barium and thorium minerals, but it can be produced by irradiation of bismuth in a nuclear reactor. (The study of its chemistry presents great difficulty because of its intense a radiation). 

The chemistry of the early actinide metals has been most extensively studied for many reasons. Chief among these is the availability of materials for study. Thorium and uranium obtained from ores as described above have been available for chemical investigations for well over 100 years. In fact, all early actinide elements may be found in nature, although only thorium, protactinium, and uranium are present in sufficient quantities to justify extraction. The remaining early actinide elements, neptunium and plutonium, are produced in large quantities in nuclear reactors. 

The investigation of safety and more particularly of severe accident conditions is important for accelerator driven systems (ADS). Subcritical ADS could be of particular interest for the actinide transmutation from the safety point of view, because fast reactors with Neptunium, Americium and Curium have a much smaller fraction of delayed neutron emitters (compared to the common fuels and U), a small Doppler effect and possibly a positive coolant void coefficient. This poses a particular problem of control since the fraction of delayed neutrons is essential for the operation of a nuclear reactor in the critical state. In addition, the IRC presented in the past a review of accelerator-driven sub-critical systems with emphasis on safety related power transients followed by a survey of thorium specific problems of chemistry, metallurgy, fuel fabrication and proliferation resistance. 

Thorium was recently the focus of an environmental problem on extracting rare earths from ores, such as mon-azite. Actually thorium can be utilised for nuclear fertile material, thus the electrochemical process is one of the promising techniques of separation from rare earth elements. One of the systematic studies on the chemistry of the compounds containing thorium was the development of molten salt reactors [1]. To investigate the relationship between the electrochemical behaviour and physico-chemical properties of thorium is important for process design, but structural information of the related materials is still limited [2], Thus, EXAFS analysis of molten thorium fluoride in mono- and divalent cationic fluoride mixtures was systematically carried out to elucidate the variation in local structure of thorium cation in various melts. 

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