The Study On AMS Measurement Of ¹²⁹I In The Nuclear Power Plant Gaseous Effluent

129I is an important radioactive nuclear fission products,high yield, long life of 107 years. With the continuous expansion of nuclear energy application timing and size, the number of human 129I nuclear activities accounted for the vast majority of 129I in nature. Iodine is an essential trace element of the human body, the monitoring of radioactive iodine is an important part of nuclear power plant environment must be monitored. Since 129I almost proportional to the time accumulated, so by periodically measuring gaseous samples of nuclear facilities, very small leak can make a diagnosis.129I generated by the decay of -β to 129Xe, release 39.6keV of y-rays, since the long half-life can not be accurately quantified by radioactivity measurement. Accelerator Mass Spectrometry (AMS) by direct measurement of the number of nuclear and isotope abundance ratio nuclides achieve high sensitivity measurements of radionuclide, and is not affected by the length of life of radionuclide.129Xe is the 129I’s only stable isobaric, can not be formed in the ion source of the negative leads, so AMS in the measurements of 129I,129I nuclear power plant effluent gas content detection in extreme advantage.Collect atmospheric particulate matter, first made into the form of AgI samples need to be added in the production process of iodine carrier, and the carrier will interfere with the measurement of 129Ⅰ. This paper improves the AMS measurement sample preparation process consists of atmospheric particles of iodine, by reducing the amount of iodine added to the carrier to reduce the background 129Ⅰ, improve measurement accuracy. And studied the accelerator mass spectrometry method 129Ⅰ atmosphere samples. Gaseous effluent of a domestic nuclear power plant and the surrounding atmosphere contains 129Ⅰ were measured and found that the number 129Ⅰ only nuclear power plant emissions than the surrounding environment, content is the same order or an order of magnitude, approaching the background level of emissions.129Ⅰ content in the atmosphere is far higher than 131Ⅰ, has obvious advantages in health monitoring for nuclear power plants. And found that the content of 129Ⅰ atmosphere increases the distance from the discharge port is reduced, and the trend is obvious.