| Overview of the Long-Term Experience of the Scientific as well as Technological Research in the Field of Molten Salt Reactors (MSR) Miloslav Hron1; 1, Praha, Czech Republic; PAPER: 161/Molten/Regular (Oral) SCHEDULED: 18:15/Thu. 24 Oct. 2019/Ambrosia A (77/RF) ABSTRACT: The principal ideas will first be reminded. Then, the basic scientific research steps will be clarified in the very beginning of the first nuclear era, in the repetition of this effort in the so-called renaissance of this scientific region, in the frame of global collaboration, and also in the national research area in the Czech Republic (former Czechoslovakia). The first stage is the period from the 1940s up to the 1960s, when this field of research was mostly performed in the USA, namely in the Oak Ridge National Laboratory [1]. The second stage is the period from the 1960s up to the 1980s, when higher activity in this field started during that time in the Soviet Union. The Soviet Union was closely collaborating with Czechoslovakia, namely in the field of spent nuclear fuel reprocessing. The developed regeneration process was based on the fluorination of uranium and plutonium by elementary fluorine to volatile hexafluoride. This process has been developed to fit the level of the demonstration laboratory equipment, where mechanically disintegrated spent fuel in powder form is converted, by fluorination, to UF<sub>6</sub> and PuF<sub>6</sub>. Volatile and non-volatile fission products are separated by fluorination or by distillation of UF<sub>6</sub>. The whole technological line is operated in the hot chamber with a remote control. The capacity of the entire technological equipment is 1-2 kg of heavy metal / day. The fluorinator of the flamboyant type, including the entire device, is made by nickel, resp. by MoNel metal. The condensers, separation columns, and distillation are provided with control elements, valves, flow meters, and pressure gauges. This allows remote control directly from the control panel. The principle of technology and the entire procedure, including the operational experience, are applicable to reprocessing of spent fuel from reactors operating in the thorium-uranium fuel cycle. This activity was stopped after the Chernobyl accident and started again in the 1990s when a renaissance of this effort started in the US Los Alamos National Laboratory, in the frame of the so called ADTT (Accelerator Driven Transmutation Technology) [2]. The scientific and technological research of this concept based on MSR systems was performed in the frame of a close collaboration of the scientific capacity of the USA, Russian Federation, and the Czech Republic. Since the beginning of the 2000s, it was incorporated in the global activity of the development of the nuclear reactors of the 4<sup>th</sup> generation [3] and the preparation of the entrance in the second nuclear era. References: [1] A. Weinberg, E. Wigner: "The Physical theory of Neutron Chain Reactorsa", The University of Chicago Press (1958). [2] C. D. BOWMAN, "Accelerator-Driven Systems for Nuclear Waste Transmutation," Annual Review of Nuclear and Particle Science, 48, 505-556 (December 1998). [3] U.S. DEPARTMENT OF ENERGY, A Technology Roadmap for Generation IV Nuclear Energy Systems, Nuclear Energy Advisory Committee and the Generation IV International Forum (2002). |
