DECONTAMINATION PROCEDURE FOR NUCLEAR REACTOR UNITS AND REACTOR VESSELS Russian patent published in 1998 - IPC

FIELD: decontamination and reconditioning of nuclear reactors. SUBSTANCE: reactor vessel or unit is placed in air-tight chamber and interior of the latter is connected to vacuum installation. Internal volume of vessel or unit is reduced by introducing flexible tank whose interior is filled with compressed medium to press it to vessel walls with clearance provided between this tank and vessel wall. Three-dimensional gauze electrode is placed in this clearance. Vessel wall and electrode are connected to current supply poles and chemically active working medium of mixture of acids with soluble-wall gas-filled balls introduced into it is supplied to vessel-to-electrode clearance. As radionuclides are accumulated in working medium, part of this medium is conveyed by means of flocculates for separation, enrichment, and recovery; volume and concentration of working medium is recovered by introducing new portion of working medium. Process is continued until desired maximum permissible concentrations of radioactive materials are obtained in portion of conveyed working medium. EFFECT: improved recovery of reactor vessels and units for their reuse. 7 dwg