Study On The Rapid Assessment Of Internal Dosimetry In Nuclear Emergency

In nuclear emergency, radionuclides released into environment can enter the body through various ways, such as inhalation, ingestion et al, and give internal radiation, threaten the health of the body. Dose assessment on internal radiation is the basis for radiation hazard assessment, and is an important part of medical response to nuclear emergency. In order to assess the internal radiation dose rapidly in medical response to nuclear emergency, a series of studies were carried out in this thesis. The main results are as following:Firstly, a radionuclide parameter database was estabilished on internal contamination in nuclear emergency. The possible nuclear emergencies were classified as nuclear facility related events, nuclear explosions and radioactive dispersion devices (RDD). Then, the radionuclide composition discharged from different nuclear emergencies and the radionuclide parameters were achieved based on the publications of IAEA, UNSCEAR, ICRP and other relevant organizations, the monitoring data in nuclear weapon tests and nuclear events, and some other relevant research literatures. The database on internal contamination for nuclear incidents was developed by using MS Visual Studio 2005 C# and MS Access programming language. The database was very convenient for searching radionuclides discharged from different nuclear emergencies and the radionuclide parameter data, such as physical decay paramaters, absorption and metabolism in the body et al, which would be helpful to the monitoring and assessment of internal contamination in nuclear emergencies.Secondly, environmental monitor is necessary and firstly carried out in all nuclear emergency monitors if there would be radionuclides discharged to the environmental. The monitor data are usually the fastest gotten data for dosimetry assessment. Therefore, this thesis analyzed the features and contents of environmental radioactive monitoring in nuclear emergency, and given the important radionuclides corresponding to different intake pathways for nuclear facility relevant events. According to the purposes and needs of internal dose estimation in nuclear emergency, the rapid dose estimation models, parameters and software were established for the public intake radionuclide from inhalation, food ingestion and water ingestion pathways. Furthermore, this thesis has analyzed the influences, such as indoor and outdoor occupation, food processing et al, on the dose estimation and given the recommended correction factors. For different intake pathways and radionuclides, the special organs/tissues radiation weighted absorbed dose can be calculated for different committed time, such as 1 week,1 month,1 year and whole lifetime (50 years for adults, to 70 years for child). The software is the most comprehensive, more practical software currently for dose estimation according to the emergency environmental monitoring in the whole nation.Finally, it was summarized possible radioactive sources, common sources activities, important exposure pathways and dose estimation methods for RDD explosion attacks. Then, a special Gaussian puff atmospheric dispersion model and parameters were established for RDD explosion attacks. By using the models, the distribution of instantaneous radioactivity concentration and of effective dosimetry with time were simulated for 9 radionuclides, such as 241Am,60Co et al, under the same parameter settings. From the results of the simulation, it was concluded that took 241 Am and 60Co as the hypothetical sources for internal and external exposure, respectively, if the sources of RDD explosion are unknown.