| In the past decades, the application of nuclear technology in China, especially the development of the use of nuclear energy development is very rapid. From the use of Qinshan first-stage nuclear power plant in1991to11existing nuclear power plants’ commercial operation such as Zhejiang Qinshan nuclear power plant, Guangdong Daya Bay Nuclear Power Station, Tianwan Nuclear Power Plant, Yangjiang Nuclear Power Station and so on and the other12nuclear power plants under construction, China’s nuclear power technology has achieved a greater leap in quality and quantity. In accordance with national nuclear power development plan, nuclear power capacity will reach150million kilowatts by2035(adjustment programs reach200million kilowatts in2030) in China, which means the number of radiation workers and the public around the plant will substantially increase, in the mean while the potential nuclear security risks will increase significantly. For nuclear safety and nuclear accident, monitoring radioactivity in environmental of relevant units and personnel is particularly important. With the reference to the method which has been used to measure gross radioactivity level in water, a suitable method for measuring and screening the radioactivity level in large quantities of urine samples was established. The gross alpha and beta radioactivity levels of131normal adults’ urine samples were measured and the relationships between gender and age with radioactivity level were also analyzed.The experimental method is:the collected samples were acidized for anticorrosive processing, and evaporating and concentrating131cases of normal adult urine samples for pretreatment. Measuring samples after pretreatment by low background measuring instrument, then calculating and analysing experimental data. Through constantly exploring got the optimal condition of experiment is:the volume of urine sample is200mL, turned to nitric acid salinization, ashed at300℃,2h, and measuring1000min. To get a more stable result, the urine residues were put aside for24h before measured. The gross alpha radioactivity in urine of healthy adults is between0～1.65Bq/Land gross beta radioactivity in urine of healthy adults is between9.40～53.41Bq/L, and the difference of radioactivity level in urine among different gender and age is not big.The results show that the method of measuring the gross alpha and beta radioactivity in urine by applying the evaporation concentration and low background measurement method is relatively simple and can satisfy the need of large-scale sample. And this method provide a pathway for measuring the internal exposure level of nuclear workers in daily screening, as well as the data of the radioactivity level in urine of normal adults which measured in this paper provides a baseline reference for decorporation effect of radioactive nuclide in nuclear accident emergency. |
