RADIOLYTIC DECOMPOSITION AND CORROSION OF A HEAVY-WATER BLANKET FOR ACCELERATOR DRIVEN TRANSMUTATION - MODELING AND EXPERIMENTAL TESTS

The concept of a chemical-engineering complex and its operation stabil ity is described for a radioactive-waste separation and transmutation plant. In the framework of the plant, this chemical complex runs in a closed cycle with a nuclear transmutation reactor driven by a 1 GeV-10 0 mA class accelerator. Heavy water provides circulation of materials to be transmuted in the reactor blanket and transports the irradiated suspension to and from the chemical-engineering complex for reprocessi ng and further disposal of transmutation products. Modeling and experi mental tests of radiolytic decomposition and corrosion were made in or der to evaluate the operation stability of the desired separation and transmutation cycle. Preliminary calculations were made for some metho ds to suppress gas evolution from water (deuterium) solutions with tho rium and transuranium nuclides or from suspensions of their oxides at a pressure of 10 MPa, a temperature of 285 degrees C and radiation dos es up to 5 x 10(7) Gy. The results were checked experimentally. Also t he change in size of the suspended particles during irradiation was me asured. Additionally, corrosion rates of zirconium alloy tubes were es timated from experiments under the same conditions. (C) 1998 Elsevier Science B.V. All rights reserved.