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[en] It is shown by some examples how chemistry allowed the production of materials required by nuclear industry (graphite, zirconium, uranium, sodium, isotopes, TBP, glass for radioactive wastes, corrosion resistant alloys). Conversely these materials have now applications in various fields: microelectronics, medicine..
[fr]On montre par quelques exemples comment la chimie a pu creer les materiaux dont l'industrie nucleaire avait besoin (graphite, zirconium, uranium, sodium, isotopes, TBP, verres pour enrober les dechets, alliage anticorrosion...). Reciproquement ces materiaux trouvent des applications dans des domaines tres varies: microelectronique, biomedical...
[en] Some applications of radionuclides, by-products of research reactors, are recalled. Then the importance of chemistry in the exploitation of fluid circuits of different types of nuclear reactors are examined. These examples and chemical problems to solve for fusion reactor studies are used to justify the need for chemistry training to take nuclear industry into account
[fr]On rappelle d'abord quelques-unes des applications des sous-produits du fonctionnement des reacteurs de recherche que sont les radioelements artificiels. On examine ensuite, le role du chimiste dans l'exploitation des circuits de fluides des reacteurs nucleaires des differentes filieres et meme dans la conception de certaines d'entre elles. Les exemples cites, completes par des indications sur la place qu'il faut donner, a la resolution des problemes chimiques dans l'etude de reacteurs qui mettraient en oeuvre la fusion nucleaire, seront utilises pour justifier des propositions de sujets de reflexion pour le debat sur un enseignement de la chimie tenant compte de la place de celle-ci dans les industries nucleaires
[en] New extractants for lanthanides, actinides, alcohols, iron, ash, etc. were studied in the Separations Science program. Topics studied in the Fuel Cycle Chemistry program included Np and Pu photochemistry, Raman studies of actinides, solvent extraction of Ru, Tc, and Re by TBP, and Mo- and Zr-containing precipitates in high-level waste and fuel reprocessing solutions. Chemical Engineering research included development of a continuous annular chromatograh, granular electrofiltration for removing small particles, high-temperature slagging for extracting copper, CH4 purification, and sedimentation. Recovery of alumina from fly ash by dissolution was studied. Thermodynamics and compatibility of Th and U carbides with clad alloys were studied. It was found that yttrium sorbents can remove tritium from lithium
[en] The purpose of this paper is first briefly to review the basic chemistry underlying the processes used on an industrial scale for the manufacture of fuel elements for thermal nuclear power reactors and then to consider in more detail the chemistry involved in the reprocessing of this fuel after irradiation, paying particular attention to developments which have been made to allow the newer enriched oxide fuels to be processed. Section headings are: nuclear fuel manufacture (U metal fuel; UO2 ceramic fuel); nuclear fuel reprocessing; irradiated fuel dissolution; solvent extraction chemistry (chemistry and kinetics of Pu reduction; the behaviour of Np and Tc); treatment of highly active raffinates (evaporation and storage of highly active liquors; highly active waste vitrification; thermal decomposition of wastes). (U.K.)
[en] The development of radiochemical techniques for rapidly separating fission products for yield measurements will be discussed. Some results of the measurements will be presented and compared with results from other types of yield measurements and with systematic trends in the yields deduced from empirical models
[en] Radioactive atoms formed in nuclear reactions provide excellent tracer species for investigations of chemical reaction mechanisms, including both hot and moderated thermal reactions. The addition of thermal 38Cl to haloolefins (e.g. CH2=CHBr) is only weakly anti-Markownikoff (Reaction at the less-substituted carbon to form CH238ClCHBr), but isomerization of the initial radicals is frequently observed. Thermal 18F atom addition to the C2 carbon of substituted propenes (RCH2CH=CH2) creates excited radicals which decompose to form CH2=CH18F + RCH2. The rate constant for radical decomposition decreases with increasing R for olefins from propene to heptene, but not when R contains a heavy atom such as (CH2=CHCH2)3Sn or (CH2=CHCH2)3Ge which is believed to block intramolecular energy transfer. Decomposition has been observed with the addition of thermal T atoms to metal-allyls, in apparent disagreement with comparable experiments with thermal H atoms. Energetic substitution reactions have been observed for 3H, 18F and 38Cl with many gaseous organic compounds; some of these substitution reactions can also take place with thermal atoms
[en] New states in the positive parity yrast bands of 74Se and 77Kr have been observed with the reactions 52Cr(28Si,α2p)74Se and 52Cr (28Si,2pn)77Kr at 98 MeV. The target consisted of approximately 1 mg/cm2 natural chromium (84% 52Cr abundance) evaporated on a thick lead backing. The new states extend the known level scheme of 74Se up to Iπ = (22+) and most of the transitions in the other previously reported bands have been seen. For the states Iπ ≥ 6+ the spectrum shows a relatively constant moment of inertia parameter (h2/2Θ) = 27.8 ± 0.5 keV. Excited positive parity states up to spin (41/2) have been observed in 77Kr. ΔI = 1 transitions have been identified throughout the positive parity band. The energies, mixing ratios and B(M1) transition rates for these transitions alternate in size as the spin increases. A cranked shell model analysis was performed along with Strutinsky-Bogolyubov cranking calculations. The observed decrease in the signature splitting of the νg9/2 band has been attributed to a band crossing due to an aligning pair of g9/2 protons. Prolate quadrupole deformations of β2 = 0.34 for the ground band and β2 = 0.26 for the first excited band are predicted. This band crossing is associated with a shape change caused by the polarization effect of aligned quasiparticles