Experiments were undertaken on the incorporation in plastics-polyethylene in particular-of radioactive spent ion exchange resins produced in nuclear power plants. The resulting polyethylene products burdened with radioactive resin were tested to ascertain the properties considered important for radioactive waste management. T h e items chosen for testing were mechanical strength, leachability of radionuclide and radiation resistance. Polyethylene products burdened with 50% of resin were found t o possess an impact strength of lOkg.cm/cm and a compressive strength of 300kg/cm2, which values do not indicate any appreciable decrease in mechanical strength compared with polyethylene unburdened with resin. The leaching rate of I3?Cs from the resinburdened polyethylene product was very small-only 0.1% leached out in one year. In respect of decomposition by radiation, the amount of gases evolving upon absorbing a dose of lo9 rad was 10 mZ/g. The effect of radiation on the mechanical strength was also studied.It is concluded from above results that solidification of radioactive spent ion exchange resin by incorporation in plastics is one of the best methods devised so far for treating spent resins.

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Pu and Am were recovered from the deposit in a synthetic acid digestion solution.After being leached out from the deposit with water, they were separated from the resultant solution by Ca-oxalate coprecipitation. The alpha radioactivity in the solution was reduced from about 4 mCUL to 0.1 pCi/L by the technique. The precipitate obtained was dissolved in 7 M nitric acid solution, from which Pu-Am were separated by the use of anion and cation exchange resin columns, respectively.The coprecipitation technique was also utilized for the concentration of A m in the emuent of the anion column prior to its separation by a cation column. The overall recovery efficiencies of Pu and Am were about 80 and 85%, respectively.

A polyethylene solidification process of the low-and intermediate-level radioactive wastes generated from nuclear power facilities has already been developed. However, the density of polyethylene solidified filtersludge and spent ion-exchange resin is less than the value of 1.2, which is considered to be necessary for a waste solid to be dumped into sea. This lack of the density may cause these polyethylene solidified wastes to float on the sea surface and carry the radioactivity to the human environment, when the sealed waste containers happen to be damaged for some reasons.In this study, a trial is made to prepare polyethylene products having the higher density, and the products was adjusted to have the density of higher values than 1.2 by mixing about 32-33 76 of cupper slag. These polyethylene products showed the monoaxial compressive strength of above 150 kg/cm2 and the good stability in deionized water for immersion period of 500 days. T h e volume reduction factor of these heavier polyethylene products to which cupper slag was added also becomes smaller, but it shows still twice a s large a s that of the cement-and asphalt-solidified wastes.