典型NORM企业液态流出物源项补充调查及所致公众剂量评估方法的应用-辐射防护与环境保护专业论文.docxVIP

PAGE PAGE VI ABSTRACT Additional Survey for Liquid Effluent Discharged from Typical NORM Companys and Application of New Assessment Method for Public Effective Dose The national environment protecting department has made an across the board investigation on concomitant radioactive contaminant, in this work they have investigated the production of NORM across the country and its distribution in each province, and figured out the company whose total quantity of radioactive element like U, Ra-226, Th-232 yielded by rubbish is beyond 1000Bq/kg, 500Bq/kg and the total output of its rubbish. Due to the limitation of time, they havent tested the radionuclides activity concentration in the effluents outlet by those company, however, these data are essential to the assessment of the public effective dose of radioactive element in effluents. 9 typical companys have been choosen from NORM companys across the nation, after sampling the effluents discharged, element such as U-238、Th-232、Ra-226、Ra- 228、Po-210 and Pb-210 have been tested. As those samples are environmental sample, the concentration of radioactive element is relatively low, it can hardly be tested by instrument directly, so the samples were concentrated by coprecipitation beforehand. Large acreage α grid-ionization chamber was used to determine U-238、Th-232、Ra- 226 in amples, and HPGe anti-Compton detector was used to test Ra-228, while Po-20 and Pb-210 were tested in Nuclear industry Geosciences Academe. The currently used dose evaluation model for radiological environmental impact assessment in our country is mainly derived from the dose evaluation model used for nuclear industry radiological environmental impact assessment during the past 30 years, it required detail information on hydrologic geology, population and diet. However, in our country, the total number of NORM companys that match investigation condition is about 1400, it is a fomidable task in terms of the collection of information alone. In orde