Subject nuclear fuel cycle

The coordination chemistries of the elements considered in this chapter have already been the subject of detailed discussion in earlier sections of these volumes. Consequently, it is the purpose of this chapter to review, in general terms, the nuclear fuel cycle, the production of metal radionuclides and subsequently their incorporation into radiopharmaceutical formulations. Within this framework, specific aspects of coordination chemistry which are relevant to the application in question will be considered. 

In the first level of the hierarchy, radioactive waste that arises from operations of the nuclear fuel cycle (i.e., from processing of uranium or thorium ores and production of nuclear fuel, any uses of nuclear reactors, and subsequent utilization of radioactive material used or produced in reactors) is distinguished from radioactive waste that arises from any other source or practice. The latter type of waste is referred to as NARM (naturally occurring and accelerator-produced radioactive material), which includes any radioactive material produced in an accelerator and NORM [naturally occurring radioactive material not subject to regulation under the Atomic Energy Act (AEA)]. 

The mutual separation of actinide elements and the selective isolation of useful actinides from fission products are indispensable for the nuclear fuel cycle and have become important subjects of investigation for the development of advanced nuclear fuel reprocessing and TRU (TRans Uranium elements) waste management [1], A variety of research concerning the separation chemistry of actinides has so far been accumulated [2]. There are, however, only a few theoretical studies on actinides in solution[3-5]. Schreckenbach et a), discussed the stability of uranyl (VI) tetrahydroxide [UO,(OH) ] [3] and Spencer and co-workers calculated the optimized structures of some uranyl and plutonyl hydrates [AcO, nH,0 (Ac = U, Pu and n = 4,5,6)] [4],... 

One important point to consider if ILs are to be used in the nuclear fuel cycle is their stability against radiation. Allen et al. have subjected imidazolium ILs to a, (1, and y radiation and studied their stability vs irradiation type and dose [266], These preliminary results suggest that IL stability is similar to that of benzene, but much higher than that of mixtures of tributylphosphate and kerosine under similar irradiation conditions. That is, imidazolium ILs are rather radiation resistant and no significant decomposition was reported. 

In March, 1997, the fourth workshop was held in Amarillo, Texas, with the broadened topic of nuclear materials safety management. This subject was considered in the context of the entire nuclear fuel cycle. The focus was on the non-reactor segments with emphasis on the disposition of weapons plutonium from disassembled nuclear warheads. It was recognized that an accident in either country could considerably delay and possibly disrupt the efforts to disposition fissile weapons... 

At the final stage, where disposal must proceed, there are two basic approaches. Firstly to contain the waste or pollutant, immobilized in a controlled manner. The pollutant is then localized and release is subject to the lifetime of the containment barriers, under the storage conditions used. This is relatively straightforward where the lifetime of the hazard is short but a major consideration in the longer term, where containment must perform adequately for many hundred and thousands of years. The management of radioactive waste from the nuclear fuel cycle is perhaps the most appropriate example here of the latter. ... 

Nuclear proliferation indicates the spread of nuclear knowledge and technology that, though initially may be for the use of nuclear energy for peaceful purposes, can eventually enable many nations, even those of the Third World, to build their own nuclear weapons. The INFCE report dwelt mainly on this subject, but perhaps, in conclusion, the most sensitive points regarding the proliferation of the nuclear fuel cycle should be examined here. 

The field of propulsion deals with the means by which aircraft, missiles, and spacecraft are propelled toward their destinations. Subjects of development include propellers and rotors driven by internal combustion engines or jet engines, rockets powered by solid- or liquid-fueled engines, spacecraft powered by ion engines, solar sails or nuclear reactors, and matter-antimatter engines. Propulsion system metrics include thrust, power, cycle efficiency, propulsion efficiency, specific impulse, and thrust-specific fuel consumption. Advances in this field have enabled hiunanity to travel across the world in a few hours, visit space and the Moon, and send probes to distant planets. 

A.505. An analysis shall be provided which shows that the fuel elements can withstand the thermal conditions to which they are subjected throughout their normal operational life cycle. This life cycle should comprise not only nuclear applications in the reactor core but also periods of storage, handling and transport. 

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