Actinide transmutation

For many years it has been recognized that it is theoretically possible to transmute some of the long lived actinides in spent nuclear fuel into shorter lived products, thereby reducing the potential waste disposal hazard. To this end some actinide burners have been designed but 

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Coy, F.B. 2002. Developing computer models for the UREX solvent extraction process and performing a sensitivity analysis of variables used for optimizing flowsheets for actinide transmutation. Thesis. The University of Texas at Austin. 

Hermann, O.W. and Westfall, R.M. (1995) ORIGEN-S Scale System Module to Calculate Fuel Depletion, Actinide Transmutation, Fission Product Buildup and Decay, and Association Source Terms,... 

O. W. Hermann and R. M. Westfall, ORIGEN-S A SCALE System Module to Calculate Fuel-Depletion, Actinide Transmutation, Fission Product Buildup and Decay, and Associated Radiation Source Terms, Sect. F7 of SCALE A Modular Code System for Performing Standardized Computer Analyses for Licensing Evaluation, NUREG/CR-0200, Rev. 5 (ORNL/NUREG/CSD-2/R5), Vols. 1, 2 and 3 (draft November 1993). Available from Radiation Shielding Information Center as CCC-545. 

In the current structure of nuclear power, light water reactors (LWRs) are predominant over a small number of heavy water reactors (HWRs), and even smaller number of fast breeder reactors (FBRs). However, an increase of FBR share can be predicted for the future, taking into account their unique properties. First of all, there is the capability of nuclear fuel breeding by involving into the fuel cycle. Secondly, there is the fast reactor s flexibility permitting its use as plutonium incinerators and minor actinides transmutation. Thus, unless new sources of energy are found, the development of nuclear power will be necessarily based on fast breeder reactors. 

Plutonium Utilization md Long-lived Minor Actinides Transmutation... 

Finally, in order to respond to issues raised during licensing it is necessary to have a well balanced assessment of the reactor concept using sodium coolant compared to other coolants and to review the basis for taking the earlier decisions in the light of the current changed priorities concerning plutonium production, minor actinide transmutation and inspectability. 

The investigation of safety and more particularly of severe accident conditions is important for accelerator driven systems (ADS). Subcritical ADS could be of particular interest for the actinide transmutation from the safety point of view, because fast reactors with Neptunium, Americium and Curium have a much smaller fraction of delayed neutron emitters (compared to the common fuels and U), a small Doppler effect and possibly a positive coolant void coefficient. This poses a particular problem of control since the fraction of delayed neutrons is essential for the operation of a nuclear reactor in the critical state. In addition, the IRC presented in the past a review of accelerator-driven sub-critical systems with emphasis on safety related power transients followed by a survey of thorium specific problems of chemistry, metallurgy, fuel fabrication and proliferation resistance. 

Switzerland Within the framework of the CAPRA project, the fuel option for amplified plutonium consumption is being studied. In the area of materials for actinide transmutation, the following tasks has been completed in 1994 (1) preparatory experiments and solubility tests for (Ui, PUJ O2 (0.25 < x < 0.65 and for (Uj., PU,J N (0.25 < x< 0.75), as possible materials for the efficient fission of plutonium in a fast neutron flux (2) fabrication of pure PuN-microspheres for ceramic-metal fuel (3) design calculations for sphere-pac segments, based on the idea of a ceramic-metal fiiel (4) material preparation of (U, Zr) N and pelletization tests of TiN and (U, Zr)N for the irradiation experiment in the reactor PHENIX (5) experimental preparations of (Ce,U) O2, (Ce,U,Pu)02 and (Ce, PU)02 for the CAPRA core with lower Pu content, and (6) cleaning of americium from waste streams of the plutonium separation equipment (extraction chromatography). 

C. L. Cockey, T. Wu, A. J. Lipps, and R. N. Hill, Higher Actinide Transmutation in the ALMR, Proceedings of Global 93, Future Nuclear Systems Fuel Cycles and Waste Disposal Options, Seattle, WA, September, 1993. 

OnG.J. Allan s paper on "Disposal Concepts and IHsposalAltematives"r L vi idbeStxcssed that underground disposd was both feasible and cal and that concepts such as actinide transmutation do not eliminate the need for facilities for disposal of waste with long lived activity. There was nothing contentious. 

As a second step in the Chinese fast reactor technology development effort, a 600 MW(e) China prototype fast reactor (CPFR) is presently under consideration. The role of minor actinide transmutation is also being evaluated taking as reference for the CPFR. 

Kochetkov, A.L., Tsykunov, A.G., Scientific Research Program on Actinide Transmutation by Use of Fast Reactors, in Proc. IAEA Spec. Meeting, Obninsk, 1992, IAEA-TECDOC-693, 1993. 

The diluent pins and subassemblies provide potential sites for minor actinide transmutation. 

Ernest O. Lawrence, inventor of the cyclotron) This member of the 5f transition elements (actinide series) was discovered in March 1961 by A. Ghiorso, T. Sikkeland, A.E. Larsh, and R.M. Latimer. A 3-Mg californium target, consisting of a mixture of isotopes of mass number 249, 250, 251, and 252, was bombarded with either lOB or IIB. The electrically charged transmutation nuclei recoiled with an atmosphere of helium and were collected on a thin copper conveyor tape which was then moved to place collected atoms in front of a series of solid-state detectors. The isotope of element 103 produced in this way decayed by emitting an 8.6 MeV alpha particle with a half-life of 8 s. 

Each of the elements has a number of isotopes (2,4), all radioactive and some of which can be obtained in isotopicaHy pure form. More than 200 in number and mosdy synthetic in origin, they are produced by neutron or charged-particle induced transmutations (2,4). The known radioactive isotopes are distributed among the 15 elements approximately as follows actinium and thorium, 25 each protactinium, 20 uranium, neptunium, plutonium, americium, curium, californium, einsteinium, and fermium, 15 each herkelium, mendelevium, nobehum, and lawrencium, 10 each. There is frequently a need for values to be assigned for the atomic weights of the actinide elements. Any precise experimental work would require a value for the isotope or isotopic mixture being used, but where there is a purely formal demand for atomic weights, mass numbers that are chosen on the basis of half-life and availabiUty have customarily been used. A Hst of these is provided in Table 1. 

Potential fusion appHcations other than electricity production have received some study. For example, radiation and high temperature heat from a fusion reactor could be used to produce hydrogen by the electrolysis or radiolysis of water, which could be employed in the synthesis of portable chemical fuels for transportation or industrial use. The transmutation of radioactive actinide wastes from fission reactors may also be feasible. This idea would utilize the neutrons from a fusion reactor to convert hazardous isotopes into more benign and easier-to-handle species. The practicaUty of these concepts requires further analysis. 

Adloff JP, Roessler K (1991) Recoil and transmutation effects in the migration behavior of actinides. Radiochim Acta 52/53 269-274... 

In the year 2000, 15% of the world s electric power was produced by 433 nuclear power reactors 169 located in Europe, 120 in the United States, and 90 in the Far East. These reactors consumed 6,400 tons of fresh enriched uranium that was obtained through the production of 35,000 tons of pure natural uranium in 23 different nations the main purification step was solvent extraction. In the reactors, the nuclear transmutation process yielded fission products and actinides (about 1000 tons of Pu) equivalent to the amount of uranium consumed, and heat that powered steam-driven turbines to produce 2,400 TWh of electricity in 2000. 

Actinide and Fission Products Partitioning and Transmutation 1999. Proceedings of the Vth International Information Exchange Meeting, Mol, Belgium, 25-27 November 1998, OECD, EUR 18898 EN. 

Baestle, L. H., Wakabayashi, T. Sakurai, S. 1999. Status and assessment report on actinide and fission product partitioning and transmutation, an OECD Nuclear Energy Agency review. In Proceedings of the International Conference on Future Nuclear Systems Global 99 Nuclear Technology - Bridging the Millenia , Jackson Hole, CD-ROM. 

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