The Effects Of The Collection Of Radon Cover Parameters On Radon Exhalation Rate Measurement

Indoor radon pollution and the problems of radon exhalation rate have been given attention by people. The “third national natural radiation exposure and control conference” pointed out that some cities of indoor radon concentration showed a rising trend, what’s more, a part of these cities rising trend is obvious. In the report of The United Nations atomic radiation effect scientific committee(UNSCEAR) in 2000, on the basis of summarizing the research results it pointed out, to the normal background regions of the world, the average annual effective dose of radon and its progeny was 1.3m Sv, which accounts for adults caused by ionizing radiation sources 54.2% of the annual effective dose 2.4m Sv. Indoor radon radiation on people of radon is to 90% of the total amount of people.Along with the research of radon harming to human body health, the research of radon control is obtaining more and more attention by people. The measuring of the radon exhalation rate quickly and accurately is a prerequisite for radon control. In addition, the parameters of collection of radon cover have a vital for measuring quickly and accurately. In this paper, study the influence of electrostatic collection radon exhalation rate measurement in the parameters of collection of radon cover. The main research content has the following five aspects:1) To analysis and calculation influence of the radon exhalation rate measurement results basing on different parameters of collection of radon cover.2) In view of different ways of opening of collection of radon cover, we carried out the corresponding simulation analysis for the movement of the wind by using FLUENT software.3) By using the method of double chamber balance, we analyzed and researched the influence of radon emanation measurement results from difference change of the parameters of sampling method and sampling flow rate.4) In view of different ways and number of the opening hole, study the regular of the measured results by double room open loop balance method.5) We acquired the collection of radon parameters affect the conclusion of the result of the radon exhalation rate measurement, which provide collection of radon cover choice basis for researching the fast an accurate method of the radon exhalation rate measurement.Through the theoretical calculation of the collection of radon parameters influence on radon emanation measurement and related experimental research, we found that the movement of the wind in the collection of radon the more tend to be homogenization, the data of measuring radon exhalation rate is more close to the real value eventually. Though the method of double chamber balance and electrostatic collection, we can get the radon exhalation rate quickly and accurately. Generally the accurate radon exhalation rate can be got after 30 minutes. We can improve the accuracy of measuring radon exhalation rate by changing the collection of radon parameters and airflow rate. A large number of experiments showed that the radon cover should be the type of small size and large bottom area, and the volume should be less than 4500 ml. Suction flow rate should be less than 1L?min-1 at the time of measurement. When the radon exhalation rate on the surface of the medium is small, suction flow rate should be small appropriately. Radon exhalation rate is also slightly different at different times of the day.