The Simulation Study Of Uranium Migration In The Groundwater Of A Nuclear Waste Disposal Site

The study of radionuclide migration is the important part of saftey evaluation of nuclear waste disposal sites.The research of radionuclide migration mainly have following aspects: The first is laboratory simulation ;The second is field test ;The third is the investigation of radionuclide migration in view of nuclear accident , and the last one is computer simulation which development quickly these years. The laboratory simulation has an important position in the study of radionuclide migration . After all, the simulation of laboratory conditions have great disparity with the actual field conditions , and so do the datas got from these two ways. So it is more and more popular to research the radionuclide migration in the field sites . These years , with the development of the computer , the simulation of nuclide migration with computer is much more populer. At present , the form and content of simulations with computer are simplicity . However , view on the trend of development , the research of simulation will be one of the important ways .The paper chooses a nuclear waste disposal No.1 site as research object. Based on geological survey data , to clear how the nuclear waste to pollute the groundwater in any case of leakage after the landfill operating . The thesis uses the multi-component reactive transport code PHREEQC-Ⅱfrom USGS (United States Geological Survey) to model and forecast the conditions after the uranium enterd into the groundwater .The study of this paper have two aspects below :⑴Using the multi-component reactive code PHREEQC-Ⅱto get the principal elemental form in the groundwater and spring water of the nuclear waste disposal site The main form of uranium pollutants are made a detailed analysis calculation. The results show that the pH value have a great impact on the uranium form of the solution . and also the uranium existent forms of the solution are very different . ⑵Using the fuction of 1D transport of PHREEQC-Ⅱto get the concentration distribution of uranium after enter into the aquifer . Different with the most traditional simulation ,this thesis not only analyse the distribution of uranium as a continuous source, but also as a instantaneous source . Then compared these two conditions . Based on the conclusion of the model , the paper also analysis the impact of various factors in the role of simulation .