Study On Technical Method Of Restoration Of Radioactive Contaminated Site In Uranium Mine

The demand of uranium source in our country has significantly increased due to the advancement of the nuclear power which highlights the optimized direction of the energy source. However, the environment damage caused by the exploitation of uranium has been the hindrance of its utilization, rendering pollution admiration of the uranium mine crucial for the sustainable development of nuclear power. The in-situ contaminated remediation technology of the uranium mine is emphasized in this paper.After sufficient investigation of the documents, summary was proposed in the aspects of the degree of the uranium mine contaminated sites, the research status of the remediation technology and nuclide migration, etc in this paper.Investigation was performed via sampling analysis method for the soil from uranium mine contaminated sites. The result demonstrates that concentration of the radionuclide in the contaminated sites is at least one order of magnitude higher than that in uncontaminated sites, which may continuously get increased due to the solid enrichment effect. Those sites suffering from this aforementioned problem include the mine lot, waste rock yard as well as the farmlands in their downstream, the ground of the water treatment plant and the farmlands around the drainage channel of the tailing pond.The soil in the uranium mine gets contaminated majorly by means of the solid waste, water and gas, etc. In the respect of the solid waste, the soil was contaminated by the radionuclide by directly contacting with the solid waste such as waste mineral from the waste rock yard, sludge from the water treatment plant and the gauge from the tailing pond. On the other hand, the outer drainage from the waste rock yard, opencast mining and underground mining, dipping water and leaching water from the solid waste and the waste water from the water treatment plant also post threat to the soil. Dust fall functionalizing by means of relocation diffusion and sedimentation the gaseous contamination source which comprises the radon and its derivatives from the opencast mining and underground mining, mine dust from the process of rock drilling, blasting, ore drawing and the dust fall from the process of the loading and unloading of the mineral as well as its transportation.The radionuclide in the perpendicular direction mainly centralizes in the surface of the ground, with several cases of 50 cm. Due to the retardation interaction between the clay and radionuclide, the pollutants caused by the mining concentrate in the clay layer. The discrepancy of the radionuclide migration depth between the paddy field in the downstream of the tailings pond and the dry land in the downstream of the mining area is assigned to the different solid structures of them which is relatively closed for paddy field whose surface is constructed by clay with rather small Soil grade. The clay layer works as a natural barrier for the uranium mine contamination which effectively hinders a further migration of the radionuclide into the ground. 50 cm should be regarded as a standard soil remediation depth set up by the fact that the clay layer is 50 cm deep in this area.The migration of three radionuclides is simulated in this paper.The section concentration of U gets enhanced with time elapsing which will migrate through the clay layer into the lower powder soil after 50 years; the clay layer in the vadose zone is of vital importance in the retardant process of the radionuclide migration; after migrating enough time, U will eventually reach the phreatic layer, causing groundwater pollution. The section concentration of Th also gets enhanced as time goes on, which however, cannot penetrate through the clay layer within 100 years. The retardation effect of the clay layer in the vadose zone to Th is much stronger than that to U which indicates a smaller threat to the groundwater of Th that will accumulate within the clay layer. The increasing trend of Ra with time passing in not as distinctive and won’t migrate through the clay layer or contact with the Groundwater aquifer, which tends to centralize in the surface of the vadose zone. Manifested by the result of the simulation, 50 cm can work as the Solution control standard during the remediation of the uranium mine contaminated sites explored less than 50 years, for the reason that there is no contamination below 50 cm or the concentration of the concentration of the radionuclide far below the standard. Furthermore, no further migration of the pollutants in the surface of the ground will occur with the pollutant source extinguished in the above 50 cm ground.Analytic hierarchy process(AHP) is employed in this paper which concludes the remediation technologies of the contaminated sites in turns as soil washing, heap leaching decontamination, high gradient separation, in situ curing glass through constructing judgment matrix and calculation. In the meanwhile, the advantage of the chemical method compared with the physical methods is also distinctively manifested. Perfectly Consistent with reality. Soil washing method is an efficient way in the remediation of uranium contaminated sites that demands extensive prompt.