Nuclear isotope separation

S. ViUani, Isotope Separation, American Nuclear Society, La Grange Park, lU., 1976. 

The high cost of isotope separation has limited, the use of separated isotopes in nuclear reactors to specific cases where substitutes that do not involve separated isotopes are not available. The most important example is that of uranium-235 [15117-96-17, the most abundant naturally occurring... 

Uranium oxide [1344-57-6] from mills is converted into uranium hexafluoride [7783-81-5] FJF, for use in gaseous diffusion isotope separation plants (see Diffusion separation methods). The wastes from these operations are only slightly radioactive. Both uranium-235 and uranium-238 have long half-Hves, 7.08 x 10 and 4.46 x 10 yr, respectively. Uranium enriched to around 3 wt % is shipped to a reactor fuel fabrication plant (see Nuclear REACTORS, NUCLEAR FUEL reserves). There conversion to uranium dioxide is foUowed by peUet formation, sintering, and placement in tubes to form fuel rods. The rods are put in bundles to form fuel assembHes. Despite active recycling (qv), some low activity wastes are produced. 

Atomic- Vapor Laser Isotope-Separation. Although the technology has been around since the 1970s, laser isotope separation has only recently matured to the point of industrialization. In particular, laser isotope separation for the production of fuel and moderators for nuclear power generation is on the threshold of pilot-plant demonstrations in several countries. In the atomic vapor laser isotope-separation (AVLIS) process, vibrationaHy cooled U metal atoms are selectively ionized by means of a high power (1—2 kW) tunable copper vapor or dye laser operated at high (kHz) repetition rates (51,59,60). 

H2—HD and Ar— Ar binary gas mixtures have been measured (34,35). A vortex tube has been used for isotope separation (36), and for the separation of gases in nuclear rocket or ramjet engines. 

K. Cohen, The Theory of Isotope Separation as Applied to the Targe-Scale Production oflJ-235 Nad. Nuclear Energy Ser. Div. Ill, Vol. IB, McGraw-HiU Book Co., New York, 1951, Chapt. 6. 

A. S. Berman, A Theory of Isotope Separation in a Tong Countercurrent Gas Centrifuge Rept. K-1536, Union Carbide Corp., Nuclear Div., 1962. 

G. F. Mailing and E. Von H.a]le,Merocfnamic Isotope Separation Processes for Cranium Enrichment Process Requirement, paper presented at the Symposium on New Advances ia Isotope Separation, Div. of Nuclear Chemistry and Technology, American Chemical Society, San Francisco, Calif., Aug. 1976 CCC-ND Report K/OM-2872, Oak Ridge Gaseous Diffusion Plant, Oak Ridge, Term., Oct. 7, 1976. 

Proceedings of the International Conference on Cranium Isotope Separation, London, Mar. 5—7, 1975, British Nuclear Energy Society, 1975. 

The licensing process consists of two steps construction and operating license that must be completed before fuel loading. Licensing covers radiological safety, environmental protection, and antitru,st considerations. Activities not defined as production or utilization of special nuclear material (SNM), use simple one-step. Materials Licenses, for the possession of radioactive materials. Examples are uranium mills, solution recovery plants, UO fabrication plants, interim spent fuel storage, and isotopic separation plants. 

Other reasons for investigating plutonium photochemistry in the mid-seventies included the widely known uranyl photochemistry and the similarities of the actinyl species, the exciting possibilities of isotope separation or enrichment, the potential for chemical separation or interference in separation processes for nuclear fuel reprocessing, the possible photoredox effects on plutonium in the environment, and the desire to expand the fundamental knowledge of plutonium chemistry. 

The use of micelles or similar aggregates in isotopic separations on the basis of nuclear spins is an especially interesting example of the way in which colloidal aggregates can keep reactive intermediates in close proximity (Turro and Kraeutler, 1980 Gould et al., 1984b Herve et al., 1984). 

In 1929 Lawrence invented the cyclotron, which instrument played (and still plays) an important role in nuclear physics. That work led directly to the award of the Nobel Prize in Physics for 1939, just one of his many honors. During World War II E. O. Lawrence made vital contributions to the development of the atomic bomb holding several high-level appointments in the Manhattan Project. He played an influential role in the decision to develop and later employ electromagnetic methods for uranium isotope separation (Calutrons) during the early 1940s. (Photo credit http //wikipedia.org, public domain)... 

The extraction of deuterium from natural water feed forms an excellent case study of the application of large scale distillation and exchange distillation to isotope separation. The principal historical demand for deuterium has been as heavy water, D20, for use in certain nuclear reactors. Deuterium is an excellent neutron moderator, and more importantly, it has a low absorption cross section for slow neutrons. Therefore a reactor moderated and cooled with D20 can be fueled with natural uranium thus avoiding the problems of uranium isotope enrichment. This was the... 

Charpin, J. and P. Rigny. 1990. Inorganic membranes for separative techniques From uranium isotope separation to non-nuclear fields. Proc. 1st Inti Corf. Inorganic Membranes, 3-6 July, 1-16, Montpellier. 

Molecular modelling of transition metal complexes (TMC), reproducing characteristic features of their stereochemistry and electronic structure, is in high demand in relation with studies and development of various processes of complex formation with an accent on ion extraction, ion exchange, isotope separation, neutralization of nuclear waste, and also when studying structure and reactivity of metal-containing enzymes. Solving these techno-... 

Other uses of lasers include eye surgery on detached retinas, spot welding, holography, isotope separation, accurate determination of the moon s orbit by reflection of laser light off a reflector placed on the moon s surface, and laser-guided bombs and missiles. Possible future uses include terrestrial and extraterrestrial communication, applications to computers, and production of the high temperatures needed for controlled nuclear-fusion reactions. 

This isotope, 239Pu, was shown to have a cross section for thermal neutron-induced fission that exceeded that of 235U, a property that made it important for nuclear weapons, considering that it could be prepared by chemical separation as compared to isotopic separation that was necessary for 235U. 

The alkoxides of actinides are rarely studied except the derivatives of uranium and thorium, as interest in the alkoxides of these 2 elements has increased by the hope to use them in the isotope-separation processes. The study of uranium alkoxides was initiated by groups led by Gilman and Bradley in the 1950s. The major part of this work is still carried out at the Nuclear Research Center at Los Alamos in the United States by the group of Sattelberger et al. [1671]. The detailed data on alkoxides ofuranium is provided in a number of... 

Prior to about 1955 much of the nuclear information was obtained from application of atomic physics. The nuclear spin, nuclear magnetic and electric moments and changes in mean-squared charge radii are derived from measurement of the atomic hyperfine structure (hfs) and Isotope Shift (IS) and are obtained in a nuclear model independent way. With the development of the tunable dye laser and its use with the online isotope separator this field has been rejuvenated. The scheme of collinear laser/fast-beam spectroscopy [KAU76] promised to be useful for a wide variety of elements, thus UNISOR began in 1980 to develop this type of facility. The present paper describes some of the first results from the UNISOR laser facility. 

Isolde is known throughout the world as the on-line isotope separator at the 600 MeV synchrocyclotron at CERE, Geneva. Work has been going on there since 1967 on many topics includino nuclear physics, solid state, atomic physics, etc. There have been great improvements made over the years but it became clear that the physics output could only be increased if there were to be an expansion of the facility. It was decided to build a second on-line separator to be used alternately with the existing Isolde, thus doubling the potential. The new separator is under construction, called Isolde 3, and is scheduled for first operation next year. 

Undoubtedly the Chalk River ISOL will be used, as others are, in the identification and spectroscopy of exotic nuclei. The nuclear chart in figure 5 illustrates the scope for such studies. However, the extreme purity of isotopes separated by our ISOL has been essential in the past to precision studies of the weak interaction, in one case the lifetimes of superallowed 0+ 0+ transitions [K.OS83], in another 8-v-a triple correlation coefficients in the decay of 2( Na [CLI83] both yielded measurements of the weak vector coupling constant. These types of measurements will be extended to other nuclei, since they exploit the best qualities of the accelerator and separator. 

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