Chemical Reprocessing of Nuclear Fuel

Abstract

This-NOTICE rhl» report wu prepared » in account of work iponiored by the United Sum Government. Neither tot United SMn nor the United Statn Atomic Energy .ommlwion, nor any of their employed, nor «ny of neir conlractora, eubconlrtctori, or their employees, naket any warranty, expreu or implied, or auumn .ny •fal liability or retponiibility for the accuracy, comileicntu or uiefulneu of any information, appuatui, woduci or proceaa diicloied, or repreienn that tu me wuld not infringe privately owned riiiilj. Don E. FergusonOak Ridge National LaboratoryOak Ridge, Tennessee 3783O ABSTRACT paper describes the status of the present nuclear fuel reprocessing industry and comments on trends for the future. It also discusses the developmental work aud plans for reprocessing of future reactor fuels. Improved technology is being applied not only to the main process but also to the containment of radioactive effluents., The Purex process is almost universally used for making the separations. For the lightvater reactor (LWR) fuels, the chop-leach head-end has become the preferred method. For hightemperature, gas-cooled reactors (HTGRs), burning of the graphite fuel matrix appears to be the favored head-end step. This burning procedure presents a unique off-gas treatment problem which appears to be near solution. Certain differences inherent in liquid-metal fast breeder reactor £T»TODT:) fuel" tasLkr the™ reore difficult + o recess. lv-».o ~f their hi^h contest of valuc'-lc ^.lutonium, a factor of 10 higher than that of light-water reactor fuel, there is a large economic incentive for processing at shorter decay times. This, coupled with the fact that IMFBR fuels will operate at higher power densities, 150 vs 35 kW/kg for LWR fuel, and to burnups of the order of 100,000 MHd/metric ton, creates a serious heating problem in handling the fuel. These same factors iixrease the amounts of volatile fission products, such as iodine, xenon, krypton, and tritium, which must be handled and contained in the plant. A comprehensive development program is being carried out in the United States of America to solve these and other problems associated with the processing of spent LMFBR fuels. Methods are being developed for the deactivation and removal of sodium. Handling techniques to provide reliable cooling of the spent fuel elements are also being developed. In the head-end, the fuel is chopped and the volatile fission products are removed by a new process, called voloxidation, which involves oxidation at U50°C. Dissolution and feed preparation for the high-plutonium-content, high-burnup fuel are also being studied. Other countries, notably France, Germany, and the USSR, have similar programs under way. In addition, France and the USSR are developing fluoride volatility processes for LMFBR fuels.ENT4S-U NLIMIT£D.