| As the application of nuclear industry and nuclear energy technology,Nuclear waste is increasing year by year.The pressure of safe disposal of radioactive waste will be more and more serious.Our country has also carried out a large number of research work on the location of the repository and the relevant research The migration behavior of radionuclides in nuclear waste is a critical issue that must be focused on in the geological treatment of nuclear waste.At present,most researchers consider the surface water or groundwater as the medium.They studied on the migration behavior of radionuclides in the geological environment from the viewpoint of hydrodynamics and hydrogeology.But radionuclide migration in geological environment is a complex process.Especially,To the high activity and high heat release of high level radioactive waste.It is formed by the complex field of a temperature field and radiation field.Therefore,It is necessary to study the migration of radionuclides in geological environment from more perspectives.In this paper,the terrestrial air flow is the carrier of nuclide migration.The fact that the ore bodies in the concealed ore bodies can migrate to the surface in the form of nanometer metal particles can be transferred by the geo-gas flow.Experimental study was carried on the migration behavior of radionuclides in the geological environment.To provide basic data support for environmental impact and safety assessment of geological disposal of radioactive waste from a new perspective.In this paper,the neutron activation material is used to simulate nuclear waste.Based on the model of the geo-gas migration column.Using two kinds of radioactive detection methods such as a means of detection gamma ray spectrum and alpha energy spectrum.The action of the downward migration of the radionuclides in the bottom of the column model is investigated.On the basis of the above work,the stable oxides of Sr,La,Ce and natural U ores were selected as 4 kinds of radionuclides in nuclear waste.7 models of gas migration in soil column were designed and manufactured.Through the simulation experiment,the near field transfer of four representative substances in the simulated nuclear waste was studied.Based on the collection of natural gas from deep buried uranium deposits,the migration of U,Th,Sr and under the action of geo-gas is studied.The major accomplishments are as follows:?1?The feasibility study carried out with radionuclide migration of geo-gas,Using the neutron activated trace elements as simulated nuclear waste.Building a column model,through gamma spectrometry and alpha spectrometry these radioactive detection method.Maded a detection of the model of the underlying column radionuclide the behavior of updraft vertical migration.It is proved that the model of geo-gas flow in the laboratory can be used to simulate the migration of radionuclides by geo-gas.?2?Experimental study on the upwelling and migration of the geo-gas by 7 models of the geo-gas column It is proved that the migration ability of the four elements in the geo-gas is Sr,Ce,La,U.The solidification treatment of nuclear waste can effectively reduce the emission of radioactive substances by geo-gas;The model of the soil cover layer reduces more than half the amount of radioactive material.The results show that the soil has good retention ability to the radioactive material which is transported by air current.?3?Based on the information of radionuclide migration in the soil column model.The migration rate of four nuclides in the short term?180d?was calculated by using the migration rate formula of the migration model.The amount of migration is between a few and a few hundred nanogram every day?4?In the acquisition of the geo-gas information Guangdong uranium mine in Jiangxi Xiangshan uranium deposit.The migration of nuclides is related to the burial depth,the size and content of aggregates?the size of uranium ore bodies?.Due to the reasons the increase of geothermal energy and the pressure difference,there is a greater power of nuclide migration in the deeper nuclide aggregates.larger aggregates and more content of migration near the surface.The coverd more denser,the greater the ability to block the migration of the nuclide.?5?Natural analogue experiment on the far field migration induced by the effect of geo-gas over the deep buried uranium ore body,It is confirmed that the geo-gas can carry radioactive material with a depth of more than 850 m to the surface.and accumulate in the soil.Rough calculation of Soil U concentration of JXC line in Xiangshan uranium deposit was made.the U in the buried uranium ore body of 850 m is transported to the surface soil after being transported to the surface soil.Increased the concentration of uranium in soil by 1.96 * 10-6g/g. |
PDF Full Text Request