Work carried out under the Radiolytic Oxidation Contract from 1986-1989 is reported. The effects of alpha- and gamma-irradiation on the chemistries of plutonium, neptunium and technetium, under conditions representative of the near fields of intermediate and high level waste repositories, are investigated. Gamma-radiolysis of Np(IV) results in oxidation in solutions below pH 12. Solutions of Tc(VII) are reduced to Tc(IV) by gamma-irradiation in contact with blast furnace slag/ordinary Portland cement under an inert atmosphere, but not when in contact with pulverised fuel ash/ordinary Portland cement. Tc(IV) is shown to be susceptible to oxidation by the products of the alpha-radiolysis of water. Mathematical models of the behaviour of plutonium and neptunium during gamma-radiolysis indicate that oxidation to Pu(VI) is possible at dose rates typical of those expected for HLW. Simulations at ILW dose rates indicate some effect upon the speciation of neptunium. Laboratory studies of the gamma-irradiation of Np(IV) in bentonite-equilibrated water have also been modelled.
Bibliographic Reference: EUR 13670 EN (1991) 110 pp., FS, ECU 10
ISBN: ISBN 92-826-3216-4
Record Number: 199111617 / Last updated on: 1994-12-02
Original language: en
Available languages: en