Cesium waste

Mellini M, Weiss Z, RiederM, Drabek M (1996) Cs-ferriannite as a possible host for waste cesium Crystal stracture and synthesis. Eur J Mineral 8 1265-1271... 

The properties of hydrated titanium dioxide as an ion-exchange (qv) medium have been widely studied (51—55). Separations include those of alkaH and alkaline-earth metals, zinc, copper, cobalt, cesium, strontium, and barium. The use of hydrated titanium dioxide to separate uranium from seawater and also for the treatment of radioactive wastes from nuclear-reactor installations has been proposed (56). 

Zirconium phosphate [13772-29-7] also absorbs cesium and other radioactive-decay daughter products, and has been proposed as part of permanent disposal systems for nuclear fuel waste processing. 

It has been suggested that cesium may be useflil in the fixation of radioactive waste in a cesium-based glass and in detoxification procedures for fugitive Cs emissions, such as at Chernobyl, Ukraine. 

Cesium isotopes can be recovered from fission products by digestion in nitric acid, and after filtration of waste the radioactive cesium phosphotungstate is precipitated using phosphotungstic acid. This technique can be used to prepare radioactive cesium metal or compounds. Various processes for removal of Cs isotopes from radioactive waste have been developed including solvent extraction using macrocycHc polyethers (62) or crown ethers (63) and coprecipitation with sodium tetraphenylboron (64). 

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. 

FIGURE 17.29 Containers of high-level waste products, including cesium-137 and strontium-90, glow under a protective layer of water. If the canisters were unshielded, the radiation that they emit would be great enough to cause death within about 4 s. 

Behrens, E. A., Sylvester, P., Clearfield, A., Assessment of a Sodium Monotitanate and Pharmacosiderite-Type Ion Exchangers for Strontium and Cesium Removal from DOE Waste Simulants, Environ. Sci. Technol. 32, 101-107 (1998). 

Cadwell, L.L., R.G. Schreckhise, and R.E. Fitzner. 1979. Cesium-137 in coots (Fulica americana) on Hanford waste ponds contribution to population dose and offsite transport estimates. Pages 485-491 in Low-Level Radioactive Waste Management Proceedings of Health Physics Society. Twelfth Midyear Topical Symposium. February 11-15, 1979, Williamsburg, VA. 

Another application for adsorption of metal impurities is in the nuclear power industry. Radioactive cesium is one of the compounds that is difficult to remove from radioactive waste. This is because ordinary resins and zeolites do not effectively adsorb radioactive cesium. In 1997, lONSlV lE-911 crystalline silicotitan-ate (CST) ion exchangers were developed and effectively used to clean up radioactive wastes in the Melton Valley tanks at Oak Ridge [268, 269], CST was discovered [270] by researchers at Sandia National Laboratories and Texas A M University, with commercial manufacture carried out by UOP. 

Cesium hydroxide is used as electrolyte in alkahne storage batteries. Other apphcations of this compound involve catalytic use in polymerization of cyclic siloxane and treatment of hazardous wastes. 

Process pH, sodium, calcium, and nitrate concentrations, plugging of the ion exchange column, lot variance, and the presence of binders can affect process efficiency. lonsiv IE-911 does not remove anionic radioactive ions such as technetium. The resins are designed for one-time use and must be replaced when loaded. The waste acceptance criteria at the resin disposal facility may limit the loading of the CST resin. Size constraints of the cesium removal system (CRS) may limit system flow rates. 

UOP molecular sieves (UOP) has developed the lonsiv family of ion exchange resins for the extraction of radionuclides from wastewater. lonsiv TIE-96 is composed of a titanium-coated zeolite (Ti-zeolite) and is used to separate plutonium, strontium, and cesium from alkaline supernatant and sludge wash solutions. The technology was developed by Pacific Northwest Laboratory (PNL) for use at the West Valley, New York, nuclear waste facility. The technology is commercially available. 

Researchers claim that lonsiv TIE-96 can remove 99.9% of the plutonium, strontium, and cesium from waste solutions, allowing for wastes to be divided into separate low-level and high-level radioactive waste streams, where they can be safely and efficiently processed for disposal. 

Sediments in the Mississippi River were accidentally contaminated with a low-level radioactive waste material that leaked from a nuclear power plant on the river. Pore water concentrations of radioactive compounds were measured following the spill and found to be 10 g/m over a 2-mm depth. The water contamination was 30% radioactive cesium ( Cs), with a half-life of 30 years, and 70% radioactive cobalt ( °Co), with a half-life of 6 years. Objections by the local residents are preventing clean-up efforts because some professor at the local state university convinced them that dredging the sediments and placing them in a disposal facility downstream would expose the residents to still more radioactivity. The state has decided that the sediments should be capped with 10 cm of clay and needs a quick estimate of the diffusion of radioactive material through the clay cap (Figure E2.8.1). If the drinking water limit (10 g/m ) is reached at mid-depth in the cap, the state will increase its thickness. Will this occur ... 

Blasius, E., Nilles, K.-H., The removal of cesium from medium-active waste solutions. 1. Evaluation of crown ethers and special crown-ether adducts in the solvent extraction of cesium, Radiochim Acta, 35,173-182,1984. 

Haverlock, T. J., Bonnesen, F. V., Sachleben, R. A., Moyer, B. A., Applicability of a calixarene-crown compound for the removal of cesium from alkaline tank waste, Radiochim Acta, 76,103-108,1997. 

Tsuda, T., Hussey, G. L., Luo, H. M., Dai, S., Recovery of cesium extracted from simulated tank waste with an ionic liquid Water and oxygen effects, /. Electrochem. Soc., 153, D171-D176, 2006. 

Aloy, A. S., Iskhakova, O. A., Koltsova, T. I. Trofimenko, A. V. 1998. Glass waste form performance for disposal of the cesium and strontium concentrate resulting from the partitioning of HLW. Materials Research Society Symposium Proceedings, 506, 901-906. 

Lambregts, M. J. Frank, S. M. 2002. Preliminary studies of the disposition of cesium in glass-bonded sodalite waste form. Materials Research Society Symposium Proceedings, 713, 373-380. 

Kksson, S. E. 1983, The immobilisation of cesium in synroc hollandite. Radioactive Waste Management and the Nuclear Fuel Cycle, 4, 53-72. 

The leach rates seen here can be compared to those from a similar test on simulated waste glass of the same composition. The leach rates for cesium and strontium from the fully radioactive Rlass were the same as the leach rates of the simulated glass. Although both tests were done on bulk glass samples, they differed in configuration. The fully radioactive samples were disks cm (height) x 3.5 cm (diameter)], and the... 

The release rate was determined for 10 radioisotopes from fully radioactive waste glasses in deionized water for a period of 1.75 years. For cesium and strontium, good agreement exists between the leach rates for simulated and fully radioactive glass of the same composition. 

The counting techniques described in this paper are also readily applicable to studies of "hot radioactive waste (z.e.j radioactive waste from reprocessed nuclear fuel). With this type of material, the cesium can be analyzed as 30-y (662-keV y), the RE as 13-y Eu (964-keV and 1408-keV y), strontium as 28-y Sr (after chemical separation and beta counting), and the actinides by group separation and alpha counting. 

For the nuclides studied (rubidium, cesium, strontium, bariun silver, cadmium, cerium, promethium, europium, and gadolinium) the distribution coefficients generally vary from about 10 ml/gm at solution-phase concentrations on the order of 10 mg-atom/ml to 10 and greater at concentrations on the order of 10 and less. These results are encouraging with regard to the sediment being able to provide a barrier to migration of nuclides away from a waste form and also appear to be reasonably consistent with related data for similar oceanic sediments and related clay minerals found within the continental United States. 

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... 

FIGURE 17.29 Containers of high-level waste products, including cesium-137 and strontium-90, glow under a protective layer of water. 

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