| Description |
viii, 132 leaves : illustrations ; 29 cm |
| Summary |
"The recent advent of nuclear energy has opened an era of almost unlimited power and countless problems. A problem of extreme importance is the recovery of unburned nuclear fuel and the claiming of transmutation products, such as Pu²³⁹ and U²³³, from the irradiated fuel elements. The chemical processing must also separate the fission products from the fissionable material if the fuel is to be used again. At present, the irradiated fuel elements are stored for 90 to 120 days to allow the intense short half-life activity to decay. After "cooling down", the nuclear fuels are separated from the fission products and the inert components of the reactor element by solvent extraction. The fuel elements are usually dissolved in nitric acid and the resulting solution is fed into the midsection of an extraction column where it is contacted with an immiscible organic solvent. The solvent selectively extracts the uranium and plutonium from the acid aqueous phase. A "salting agent” is added to the top of the column, removing the last trace of fission products from the organic phase. The aqueous phase is now composed of the fission products and large amounts of inert material, such as nitric acid, aluminum nitrate, and the dissolved cladding. The aqueous solution must be processed to remove the valuable radioelements and prepare the active waste for disposal in an acceptable manner. The waste solutions are concentrated, usually by evaporation, and stored permanently in underground steel tanks. Since the storage facilities are limited, a method must be developed for permanent disposal of fission products. A very promising method of treating the radioactive waste is the use of ion exchange membranes in electrodialysis. Electrodialysis units can remove the nitric acid from the aqueous waste containing the fission products and inert components. Only after the major portion of the acid and inert salts have been removed from the solution is the fixation of the fission products on clay material effective for ultimate disposal. The purpose of this investigation was to determine if radioisotopes could be separated in a pure form by electrodialysis. The behavior of the radiocolloidal nature of selected radioisotopes was also studied. The ultimate aim of the investigation was the economic recovery of selected radioelements In a pure form. The removal of the long half-life radioisotopes also aids in the preparation of the waste for ultimate disposal. The isotopes studied were cerium-144, cesium-137, and zirconium-95 in equilibrium with their daughter products, praseodymium-144, barium-137, and niobium-95 respectively"--Introduction, leaves 1-2. |
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