In Different Pressure An Experimental Study On Migration Of Radon

Radon, as one kind of radioactive gas in environment, can easily be absorbed by human body. If the human body has long been ionizing radiation exposure to the radon and its daughter, it will induce lung cancer, leukemia and respiratory and other diseases. The migration study of Radon in the air is the foundation theory problems of radon measurement and protection. Basing on experiment, this thesis uses the method of active carbon accumulated measuring radon to study the migration regularity of radon gas in different gas pressure, and establish one-dimensional, 3-d migration equations of the radon in the air.The three groups of comparative experiments are as following to explore the inherent migration law of radon in the air:1.The paper measures the concentration distributions of radon in airtight vertical glass tube under the same cumulative time, temperature, humidity and different pressure in vacuum (respectively for -0.06MPa, -0.05MPa, -0.04MPa, atmospheric conditions).2.The paper measures the concentration distributions of radon in airtight horizontal,vertical glass tube under the same pressure(for -0.06MPa vacuum), temperature, humidity and different cumulative times.3.Basing on the migration equations of radon gas in the air and the concentration distribution of radon under different gas pressure, the paper estimates the average speed of radon gas under different pressures.Through series experiments, following conclusions can be obtained: the migration velocity of radon in the air is related with the air pressure: with greater air pressure, the conveyance speed is faster. Especially at low-pressure state the downward migration is more apparent. Through the comparison of measurement results of radon in vertical direction and a horizontal direction, the migration ability of radon in the vertical height is far larger than that in the horizontal direction whatever the pressure is. The average speed of radon in different pressures cases are estimated as follows: the upward migration average speed under atmospheric environment is 1.02×10^-6m/s, the downward migration average speed is 2.08×10^-6m/s; The upward migration average speed under -0.06MPa vacuum environment is 0.91×10^-6m/s, the downward migration average speed is 2.77×10^-6m/s. As is consistent with the practical measurement result.