Major Research and Development Programs
Laboratory for Zero-Carbon Energy has put following theme as the main research goal 'Release and utilization of energy combined in molecules, atoms and nuclei'.
Generation of energy is essentially brought by the change of the states of molecules, atoms and nuclei. Produced materials such as fission products should be released not to burden to the environment, while the generated energy, i. e., heat, should be transformed into useful forms like electricity, chemical energy and so on. Our mission is to keep consistency between the effective and safe generation/transformation of the energy, and the conversion of newly produced materials into useful resources or harmless materials. For this purpose, we have proposed six research programs as follows.
Frontier Research on Dispersion-Type Nuclear Energy System
Since nuclear energy systems involve highly sophisticated technologies, it was a reasonable or unavoidable choice to take the target of large-size reactors, which can satisfy the conditions of safety and economy, as seen in the past development activities of LWRs. So far FBRs with MOX fuels and sodium coolant have been following also this route. However recent global environmental issues have drawn the attention to the small dispersion-type energy sources which may improve total energy efficiency with less environmental burden. The concept of the dispersion-type energy system is completely opposite to the conventional direction of nuclear energy system, which has been regarded as typically large, centralized energy system. In order to explore the new frontier of nuclear energy, The Research Laboratory for Nuclear Reactors has initiated a new research program of Dispersion-type Nuclear Energy Systems.
Safety and Control of Nuclear Fusion System
The tokamak, which is the most promising confinement scheme for nuclear fusion reactors, has been studied world-widely. Since the D-T break-even condition has been achieved in magnetically confined plasmas, it is a matter requiring immediate attention to develop a nuclear fusion technology, in particular, the safety and control of nuclear fusion systems. One of the gravest issues concerning the safety is that it becomes difficult to predict the plasma behavior because of the increasing energy of hot plasmas. Thus we focus the following subjects;
- Generation of very strong magnetic fields with multi-helical force balanced coils.
- Control and avoidance of high energy plasma disruptions
- Development of materials which withstand plasma disruptions
- Design of a fusion safety research reactor.
Utilization of Nuclear Energy with High Efficiency
Energy in the 21 century is intimately related with drastic increase of population, energy resources, global environment, industrial/domestic wastes. We must secure stable and economic utilization techniques of energy to overcome these problems.
- Efficient energy system with public acceptance
- Direct conversion of heat to electricity with high efficiency
- High energy utilization of degraded heat by chemical heat pump
- Decomposition and reclamation of harmful industrial waste
- Direct generation of electricity from nuclear fission energy
Safety Research of Nuclear Energy System
The nuclear energy systems based on fission or fusion reactors, in future should provide the stable and high-quality energy supply without any anxiety of the safety of the system and accumulating radioactive materials in the systems. To establish the ways to this goal of the nuclear energy systems, the comprehensive studies have been conducted in the research fields of the advanced nuclear (fission, fusion and accelerator-driven) reactor systems and the advanced nuclear fuel cycles, as follows.
- Development of safety philosophy for future nuclear energy system
- Development of nuclear system concepts harmonizes with global environment and human society
- Study on nuclear (fission, fusion, accelerator-driven ) reactors to transmute TRU and FP with inherent safety characteristics
- Development of nuclear data base for TRU and FP transmutation
- Study on advanced nuclear fuel cycles harmonized with global environment
Development of Nuclear Frontiers by Accelerators
We consider nuclear engineering as "comprehensive technology making good use of nuclear reactions and particle beams", and aim at developing its frontiers through a variety of studies with particle beams from accelerators and R&D of intense-beam accelerators. Practically, we make a variety of basic and elemental studies with the aim of performing the following major subjects:
- Studies on nuclear transmutation of transuranic elements and long-lived fission products,
- Studies on interaction between heavy-ion beams and plasma,
- Studies on environment with ion beams,
- Development of accelerator technology.
Self-consistent Nuclear Energy System(SCNES)
An ultimate goal of the nuclear energy research and development is to establish a way to harmonize nuclear energy systems with the global environment as well as human society. The concept of self-consistent nuclear energy system(SCNES) has been proposed to attain this ultimate goal in coming centuries. The SCNES is defined as a system which meets simultaneously the following four requirements: 1) energy generation with high efficiency, 2) fuel production in pursuit of inexhaustible energy source, 3) burning of radionuclide aiming at the "zero release" of radioactive materials from the overall system,and 4) inherent safety. The SCNES will help us, once materialized, to resolve not only the energy issue but also the environmental and population problems. In this context, we are investigating the feasibility of such a nuclear system and related phenomenology. Also we try to identify the concept of the system on which we will confirm its feasibility from the engineering point of view and then propose a detailed constituents of the system.