Plutonium cerium

Tucker, P.A., D.A. Etter and J.M. Gebhardt, 1967, Phase equilibria in the ternary system plutonium-cerium-iron, in Plutonium, 1965, London, pp. 392-404. 

The crystal structures of Hf 2 (OH) 2 (S0O 3 (H2O) i, (14) and Ce2(0H)2(S0i,)3 (H20)it (14) also have been determined and found to be isomorphous to the zirconium compound. The cell constants for this series of four isomorphous compounds reflect the effect of the ionic radii on the dimensions of the unit cell. The values for these cell constants are in Table II. Thus, the cell constants for the zirconium and hafnium compounds are nearly identical and smaller than the cell constants for the cerium and plutonium compounds which are also nearly identical. This trend is exactly that followed by the ionic radii of these elements. 

The explanation appears to be related to current work on mixed-valent cerium compounds. Plutonium-americium alloys also show this behavior. Considerations based upon the plutonium atomic volume in the solids show the greatest promise of explaining this irregularity. 

They are centered on the elements manganese, cerium, and plutonium. There is much theoretical work underway on all of these elements. The only inadequacy in the experimental side is that there remains a tremendous shortage of even fundamental data on plutonium metallic compounds. The reasons for the shortage are known to all plutonium scientists, but there is also no doubt that there is still a lot of science to be done. 

Erdal, B.R. Aguilar, R.D. Bayhurst, B.P. Daniels, W.R. Duffy, C.J. Lawrence, F.O. Maestas, S. Oliver, P.Q. Wolfsberg, K. "Sorption-Desorption Studies on Granite. I. Initial Studies of Strontium, Technetium, Cesium, Barium, Cerium, Europium, Uranium, Plutonium, and Americium", in "Proceedings of the Task 4 Waste Isolation Safety Assessment Program Second Contractor Information Meeting", Vol. II, Report PNL-SA-7352, Battelle Pacific Northwest Laboratory, 1978, pp. 7-67. 

Complete dissolution of plutonium residues, especially high temperature calcined plutonium dioxide contained in residues such as incinerator ash, continues to cause problems, despite continued research since the Manhattan Project (9). Methods to improve the Rocky Flats system include the use of additives (e.g., cerium) and electrochemistry, other solvents (HCl-SnCl2) as well as high-temperature fusion methods (10). High pressure dissolution, HF preleaching, fluorination, and other methods are being investigated. 

A kind of summary of the similarities which, albeit with some uncertainties, may be evidenced between the single lanthanide and actinide metals is reported, according to Ferro et al. (2001a) in Fig. 5.13. According to this scheme the alloying behaviour of plutonium could be simulated by cerium whereas a set of similarities may especially be considered between the block of elements from praseodymium to samarium with those from americium to californium. 

Tricyclopentadienyluranium tetrahydroalmninate, 3688 N. /V.4-Trilithioanilinc. 2180 Triphenylmethylpotassium, 3781 Tris(cyclopentadienyl)cerium, 3683 Tris(cyclopentadienyl)plutonium, 3 684 Tris(cyclopentadienyl)uranium, 3685... 

Calcium, 3922 Cerium, 3961 Chromium, 4222 Cobalt, 4199 Europium, 4292 Hafnium, 4599 Iridium, 4643 Iron, 4388 Lead, 4882 Manganese, 4700 Nickel, 4820 Palladium, 4885 Platinum, 4887 Plutonium, 4888 Rhodium, 4892 Rubidium, 4889 Strontium, 4913 Tantalum, 4914 Technetium, 4915 Thorium, 4917 Titanium, 4919 Tungsten, 4925 Uranium, 4923 Vanadium, 4924 Zinc, 4927 Zirconium, 4928... 

In 1942, the Mallinckrodt Chemical Company adapted a diethylether extraction process to purify tons of uranium for the U.S. Manhattan Project [2] later, after an explosion, the process was switched to less volatile extractants. For simultaneous large-scale recovery of the plutonium in the spent fuel elements from the production reactors at Hanford, United States, methyl isobutyl ketone (MIBK) was originally chosen as extractant/solvent in the so-called Redox solvent extraction process. In the British Windscale plant, now Sellafield, another extractant/solvent, dibutylcarbitol (DBC or Butex), was preferred for reprocessing spent nuclear reactor fuels. These early extractants have now been replaced by tributylphosphate [TBP], diluted in an aliphatic hydrocarbon or mixture of such hydrocarbons, following the discovery of Warf [9] in 1945 that TBP separates tetravalent cerium from... 

The oxysulphides of lanthanum, cerium and plutonium are found to be iso-structmral with the hexagonal sesquioxides of the lanthanides (63). In these oxysulphides, the central metal atom is seven coordinated and has four oxygens and three sulphur atoms as nearest neighbours (Table 3). 

Misch metal, an alloy of cerium with other lanthanides is a pyrophoric substance and is used to make gas lighters and ignition devices. Some other applications of the metal or its alloys are in solid state devices rocket propellant compositions as getter in vacuum tubes and as a diluent for plutonium in nuclear fuel. 

In several respects, this ranking is not unexpected low charge, high mobility ions like Ca and Sr2+ should leach more easily than the rare earth and actinide elements. Although plutonium and cerium have similar properties as pure oxides, Plutonium was found to have a higher release rate than Cerium or Curium. Obviously, much more work is needed to understand these differences than was possible with this study. 

The coordination geometry in anhydrous Th(CF3COCHCOMe)4 is a 1111 ( )4-422) antiprism 74 the structure of the monohydrate has been discussed earlier (p. 1144). Th[CF3COCHCO(2-C4H3S)]4 is isostructural with the cerium(IV), uranium(IV) and plutonium(IV) analogues. The coordination polyhedron is a distorted dodecahedron in which the four ligands span the two perpendicular trapezoids of the dodecahedron.75 In the complexes M(n-C3F7COCHCOBut)4, the thorium(IV), uranium(IV) and neptunium(IV) compounds are isomorphous, but the plutonium compound is not. 

In an analysis of the hazards of the alpha emitters from reactor operations it has been pointed out (25) that the most significant and hazardous species are plutonium, americium, curium, and neptunium. Plutonium is as hazardous as such fission products as ruthenium-106, cesium-137, cerium-144, and promethium-147, depending on the kind of fuel, the power of the reactor, the storage time of the waste, and whether it is released to the atmosphere or to water. If strontium-90 is removed... 

A mixture of well-known extractants, di-(2-ethylhexyl)phosphoric acid (HDEHP) and CMPO, in n-paraffin was used for the study of combined extraction of different actinides (americium, plutonium, and uranium) and lanthanides (cerium and europium) and their separation from fission products (cesium, strontium, ruthenium, and zirconium).54 Combined extraction of MAs and lanthanides was studied together with group separation of MAs from lanthanides by selective stripping with a solution of diethylenetriaminepentaacetic acid (DTPA), formic acid, and hydrazine hydrate. This solution strips only MAs, leaving lanthanides in the organic phase. Subsequently, the lanthanides are stripped using a mixture of DTPA and sodium carbonate. 

A decrease in the decontamination performance of uranium and plutonium for fission products (mainly ruthenium, zirconium, cerium, and niobium)... 

Tris(bromomethyl)ethanol, 1916 Tris(cyclopentadienyl)cerium, 3676 Tris(cyclopentadienyl)plutonium, 3677 Tris(cyclopentadienyl)uranium, 3678 Tris(2,3-diaminobutane)nickel(II) nitrate, 3583 Tris(l,2-diaminoethane)chromium(III) perchlorate, 2615 Tris(l,2-diaminoethane)cobalt(III) nitrate, 2618 Tris(l,2-diammoethane)ruthenium(III) perchlorate, 2617 Tris(difluoroamino)fluoromethane, 0363 Tris(dimethylamino)antimony, 2594... 

Aluminium, 0048 Antimony, 4901 Barium, 0200 Beryllium, 0220 Bismuth, 0226 Cadmium, 3943 Caesium, 4248 Calcium, 3916 Cerium, 3955 Chromium, 4216 Cobalt, 4193 Copper, 4261 Europium, 4286 Gallium, 4400 Germanium, 4406 Gold, 0110 Hafnium, 4594 Indium, 3579 Iridium, 4638 Lanthanum, 4672 Lead, 4876 Lithium, 4675 Magnesium, 4685 Manganese, 4695 Mercury, 4595 Molybdenum, 4707 Neodymium, 4813 Nickel, 4814 Niobium, 4811 Osmium, 4867 Palladium, 4879 Platinum, 4881 Plutonium, 4882 Potassium, 4640 Praseodymium, 4880 Rhenium, 4884 Rhodium, 4886 Rubidium, 4883 Ruthenium, 4888... 

Tris(2,4-pentanedionato)molybdenum(III), 3683 Tris(cyclopentadienyl)cerium, 3676 Tris(cyclopentadienyl)plutonium, 3677 Tris(cyclopentadienyl)uranium, 3678... 

Finally, the column is flushed with three volumes of 0.8 M HC1 to remove sorbed impurities, such as zirconium and plutonium. More precisely, the LiCl eluent solutions are adjusted to within 0.05 M of the desired concentration and are acidified to 0.10 + 0.05 M HC1 hydroxylamine hydrochloride is added (to a concentration of 0.1 M) as a reducing agent for any tetravalent cerium sorbed on the resin and methyl alcohol is added (to a concentration of 2.5% by volume) to suppress the rate of radiolytic destruction of HC1 and the corresponding generation of radiolytic gases (8) Typically, the eluents are added to the feed tank in small portions and pumped to the column thus, the eluents also serve to flush the feed system. The eluent flow rate is 1 L/h and the superficial column velocity is 140 iim/s. 

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