Research programme on the conditioning of nuclear power waste

Main parts of this programme have included the use of zeolites and titanates to improve reactor waste treatment, the fractionation of high level reprocessing waste by extraction, and a study of liquid partition chromotographic technique for the removal of impurities from reactor cooling circuits. Preparation of large crystal zeolites has been continued and refined. For titanate production new routes are tried to produce material of a form suitable for use in a sorption process. The possibility of lithium-7 recovery from spent PWR resins in the elution process is under study. Final products from different routes of heat treatment of loaded zeolites and titanates are characterized and compared. In parallell to this work a full-scale system is under study including transport, system design, integrated process flowsheets and cost estimates. The aim is to have basis early in 1982 to decide on the merits of a plant at the planned repository for low and medium level waste (SFR), to be commissioned around 1990. In the high level waste fractionation project, a demonstration of the developed process has been performed on a fission product solution from the reprocessing of low burn-up fuel. Disregarding some equipment malfunction the design goal of better than 99.99 % actinide removal from the high level waste waste solution was reached. The basic chemistry of the process seems to be quite tolerant against reasonable flow rate deviations in the extraction cycles. Also the concluding sorption step on mordenite-titanate worked quite well. The small scale experiments on liquid partition chromatographic techniques have included studies of the capacity of various carrier materials treated with NH4 DEHP or Aliquat-336 to sorb radioactive impurities from reactor water, both in the laboratory and at the Ringhals-1 BWR. (author)