[en] This paper reviews sub group B's 11 tasks, commenting upon each and noting what work remains to be done and the procedure adopted for completing it. The majority of the tasks have been completed and it was decided that further consideration of their assessment of proliferation resistance, institutional and safeguards questions and the economic assessment of reprocessing be carried out jointly with sub group A. It was also agreed that all further meetings of sub group B should take place jointly with sub group A

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[en] The problems in five major areas of nuclear fuel cycle are generally discussed. The first part reviews the demand and supply of uranium. The author conjectures that the uranium resources should not be a major problem as long as the option of fast reactors will be available by about 1990. Recent polytical trends in major uranium-producing and nonproducing countries are also reviewed. The second part treats the enrichment process. Diffusion and centrifuge processes are mainly discussed, and economical comparison is made. The third part discusses the problems plutonium utilization. The experiences of BNFL in manufacturing mixed plutonium/uranium oxide fuel are briefly described. The utilization of plutonium for thermal reactors is also discussed in connection with the timing of full scale introduction of fast reactors. In the fourth part, the author briefly reviews the activities of NBFL in the transport of irradiated fuel. The problems of transport by road, rail and sea are discussed. Some recommendations for the future transport ships and casks are given. The final area is the reprocessing of fuel. New technical problems which will be encountered in reprocessing oxide fuel are discussed together with the problems associated with the regulatory standards. (Aoki, K.)

[en] The processing of LWR fuels in recent years has run into difficulties due to the adaptation of the Purex process to these fuels with a high irradiation rate. This has led to development of new technological techniques. High-capacity plants should, in the future, limit their discharge of liquid and gaseous effluents to values comparable to those of nuclear electric stations. Investment costs necessary for processing the effluents and for temporary storage of the wastes are part of the total cost of these plants. However, the investments remain within acceptable limits. The 1500-ton/year plant presented is an example of what can be done in the 1980's

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[en] Enriched uranium metal fuel irradiated in the Dounreay Fast Reactor has been reprocessed and refabricated in plants specifically designed for the purpose in the U.K. since 1961. Efficient and reliable fuel recycle is essential to the development of a plutonium based fast reactor system and the importance of establishing at an early stage fast reactor fuel reprocessing has been reinforced by current world difficulties in reprocessing high burn-up thermal reactor oxide fuel. In consequence, the U.K. has decided to reprocess irradiated fuel from the 250 MW(E) Prototype Fast Reactor as an integral part of the fast reactor development programme. Flowsheet and equipment development work for the small scale fully active demonstration plant have been carried out over the past 5 years and the plant will be commissioned and ready for active operation during 1977. In parallel, a comprehensive waste management system has been developed and installed. Based on this development work and the information which will arise from active operation of the plant a parallel development programme has been initiated to provide the basis for the design of a large scale fast reactor fuel reprocessing plant to come into operation in the late 1980s to support the projected U.K. fast reactor installation programme. The paper identifies the important differences between fast reactor and thermal reactor fuel reprocessing technologies and describes some of the development work carried out in these areas for the small scale P.F.R. fuel reprocessing operation. In addition, the development programme in aid of the design of a larger scale fast reactor fuel reprocessing plant is outlined and the current design philosophy is discussed

[en] BOREXINO is a large-scale liquid scintillator detector for solar neutrinos with a low expected event rate, therefore requiring an extremely low radioactive background. In this paper we present a method, which makes it possible to measure the surface and bulk activities of ²²⁶Ra in thin nylon foils for use in BOREXINO at unprecedented concentration levels, as low as 0.5 μBq/m² and 10 μBq/kg, respectively. It is based on high-sensitivity ²²²Rn emanation detection, taking advantage of the fact that the permeability of nylon for radon is strongly enhanced in the presence of water. A mathematical diffusion model is outlined to distinguish the surface and bulk activity of ²²⁶Ra from the ²²²Rn emanation rates of dry and wet film. The experimental method is described in connection with screening measurements of nylon foils of different origin. One foil could be identified with a low ²²⁶Ra contamination (corresponding to ∼10^-12 g/g ²³⁸U-equivalent) for application in BOREXINO. This film will be used for the construction of a liquid scintillator containment vessel as the central part of the BOREXINO solar neutrino detector

[en] Development of a novel In-loaded scintillator for a next generation low energy solar neutrino detector that would be based on neutrino interactions with ¹¹⁵In is reported. In particular, β-diketone complexes added to organic scintillating solvents are investigated. Details of the chemical synthesis and unique purification steps for specific indium-β-diketonates is described so as to achieve the main properties needed for such an experiment: optical transparency, chemical stability and high solubility in a scintillator solvent. Together with suitably adjusted fluors, notable light yields are possible. (author)