tions. The incorporation of such cations causes a pronounced change in their distribution between the liquid and solid phases and weakens the bonds between isotopes and formation rock. Now preparation of the formation is as equally important. To reduce the possibility of chemical interaction between the waste and the formation, the waste is first flushed with acid solutions. This operation removes the principal minerals likely to become involved in exchange reactions and the soluble rock particles, thereby creating a porous zone capable of accommodating the waste. In this case the required acidity of the flushing solution is established experimentally, while the required amount of radial dispersion is determined using the formula:R = Qt 2 mn R is the waste dispersion radius (metres)Q is the flow rate (m/day)t is the solution pumping time (days)m is the effective thickness of the formation (metres)n is the effective porosity of the formation (%)In this concept, the storage and processing are minimized. There is no surface storage of wastes required. The permanent binding of radioactive wastes in rock matrix gives assurance of its permanent elimination in the environment. This is a method of disposal safe from the effects of earthquakes, floods or sabotages. With the development of new ion exchangers and the advances made in ion technology, the field of application of these materials in waste treatment continues to grow. Decontamination factors achieved in ion exchange treatment of waste solutions vary with the type and composition of the waste stream, the radionuclides in the solution and the type of exchanger. Waste solution to be processed by ion exchange should have a low suspended solids concentration, less than 4ppm, since this material will interfere with the process by coating the exchanger surface. Generally the waste solutions should contain less than 2500mg/l total solids. Most of the dissolved solids would be ioni...
