[en] The thorium-uranium fuel cycle has several advantages that make it attractive. Some of these beneficial properties are of particular interest now as they help alleviate current concerns. The Th-U cycle has neutronic advantages when utilized in thermal or epithermal reactors. Some of these reactors enjoy extraordinary safety qualities. The combination of these traits suggest that now is an appropriate time to deploy and begin exploiting the Th-U fuel cycle

[en] The medium term world energy and environment countermeasures for 2020-2070 are not yet clearly established. The forecast of energy situation hereafter, its problems and the measures for solution are considered. World trend is removing borders, and the north-south problems are increasing the importance. The rational and clear idea with the support of concrete technology is required. The demand of energy will increase enormously at the annual rate of 2.3%. The world energy situation was forecast considering the increase of population, and it will be 115 TW at the end of the next century. The present status, problems and the countermeasures in nuclear fission energy technology are explained. The countermeasures should be based on three principles, namely Th-U-233 cycle, the utilization of molten fluoride fuel medium and the separation of molten salt breeders and molten salt reactors. Accelerator molten salt breeders, small molten salt reactors, the nuclear fuel cycle and the annihilation process for radioactive wastes are reported. The perspective that the nuclear energy system, in which the reactor safety, the measures to wastes and others are improved by the spallation-fission symbiont using thorium molten salt as the working medium, can be constructed is shown. (K.I.)

[en] To reply the huge world energy/ecological demand in the next century, a simple and rational Th energy system has been proposed, which is acceptable in public not only solving all issues relating with safety, nuclear-proliferation and -terrorism, radio-waste and breeding fuel-cycle, but also not requiring any big R and D cost and time. (author)

[en] This paper reports the results of nine structural lattices obtained through the WIMS-TRACA computer program. This work was performed by request of the managers of the WLU/IAEA project, for the extension of the first stage. These benchmark lattices include regular arrays with heavy water and data of the thorium cycle. Besides K_∞ and K_eff (employing the experimental buckling to account for the leakages) spectrum index and ratio at reaction rates are also determined for comparison with the experimental values. The input data for each lattice, are given in the appendix to help exploring possible differences in the results. (author). 4 refs, 1 fig, 11 tabs

[en] Aiming at building up the scientific and technical foundation for the development of the thorium fuel cycle, we carried out a cooperative fundamental study on this cycle as a promising energy source in and after the next century by the support of Grant-in-Aid for Scientific Research by the Ministry of Education, Science and Culture of Japanese Government from April 1988 to March 1993. In this cooperative research program, the following subjects were assigned: (1) Nuclear data for the thorium fuel cycle, (2) Design study of Th/U-233 fuelled reactors, (3) Critical experiments of these reactors and their analyses, (4)Preliminary works for fusion-fission hybrids with thorium, (5) Thorium fuel development; new thorium fuels and thorium fuel irradiation, (6) Molten salt technology, (7) thorium fuel reprocessing, and (8) Radiation safety for the thorium fuel cycle. Important results of this cooperative study from (1) to (3) are briefly reviewed. (Author)

[en] The talk concentrated on the Uranium Institute views with regards to the uranium supply and demand issue. The Institute has calculated that by 2010 there would be an apparent gap of some 27200 t of uranium between the assumed production of currently existing mines and the probable needs of world reactors, including those coming on streams in the interim. The effect on the uranium market of the Russian high enriched uranium is also discussed. It is pointed out that the breakthrough in nuclear disarmament could be use by the industry to demonstrate that nuclear weapon material can be redeployed for the benefit of all using to generate environmentally benign electricity. 4 refs

[en] In this article the cost of reprocessing spent nuclear fuels is examined in the light of the improvement in the world political situation and consequent reduction in the need for plutonium for nuclear weapons. The greater availability of uranium and more efficient use of it is discussed. Detailed consideration is given to the cost of recycling fuel for Light-water, AGR and Magnox reactors. (U.K.)

[en] The fact that the research, development and utilization of nuclear energy in Japan is strictly limited to peaceful purposes is stressed by making reference to Japan's Atomic Energy Basic Law and the legal framework. One of the basic policies of the Atomic Energy Commission (AEC) and of the Japanese Government from the beginning has been to recycle and fully utilize plutonium, since this material is a very precious energy source for Japan. Another policy of the AEC and the Government is that international safeguards and the State System of Accounting and Control (SSAC) of nuclear materials should be fully and strictly enforced. The nuclear share of total electricity generation and the total amount of nuclear materials, as well as the number of facilities under safeguards, are discussed. Japan's national safeguards system is explained with reference to the role of the Nuclear Material Control Center, which is responsible for conducting destructive and non-destructive assays, among other tasks. A description is given of typical safeguards techniques and research and development activities, including those which are being conducted currently on reprocessing plants. The paper also discusses the co-operative relationship with the IAEA in the field of safeguards and inspection activities, and research and development work designed to contribute to more efficient and more effective safeguards. In this connection, reference is made to various extra-budgetary contributions made by the Japanese Government. The Government is prepared to contribute to the effort of the IAEA in streamlining the safeguards system to cope with the growing safeguards requirements and to overcome financial constraints. (author). 2 figs, 2 tabs

[en] This paper is a status on the Plutonium recycle in FBR (Fast Breeder Reactor) system which is the solution to the dilemma of saving the global environment under the increasing world energy demand. This paper presents a status and the perspectives of the FBR and its fuel cycle development. (TEC). 8 figs., 13 refs

[en] The use of lead-bismuth and lead as reactor coolant of ultra long life fast reactor was studied to improve reactor physics characteristics, especially to reduce coolant void coefficient while maintaining small excess reactivity during burnup. The reactors were medium sized (900 MWt), and their life time was 40 years without refueling or fuel shuffling. The reactors with uranium cycle, combined uranium-thorium cycle, and thorium cycle were considered. And the use of neutron absorbing material in the central region to reduce coolant void coefficient was also considered. As the result, several designs with excess reactivity no more than 0.2 %Δk or 0.3 %Δk during burnup and negative coolant void coefficient over all burnup period were obtained. Thermal hydraulic calculations for these reactors were also carried out. (author)