A detection efficiency calibration method of radioactive iodine activated carbon sampling filter box
A technology of detection efficiency and radioactive iodine, applied in the field of gaseous effluent monitoring of nuclear power plants, can solve problems such as errors
Active Publication Date: 2021-08-17
CHINA INST FOR RADIATION PROTECTION +1
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One disadvantage of this method is that a large number of experiments need to be done in the early stage to obtain the fitting formula. Another disadvantage is that the measurement errors of these influencing parameters will not be transferred to the final measurement error. Neglected influence parameters, fitting formula method will bring immeasurable error
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[0022] The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.
[0023] Utilize the surface source detection efficiency measured by laboratory calibration to vary with the depth of the surface source in the sampling filter box and according to the experimentally measured detector full-energy peak counts when the sampling filter box is placed in the forward and reverse directions, the method designed in the present invention The exponential decline distribution parameter of iodine in the sampling filter box and the detection efficiency of the detector to iodine can be obtained simply and quickly, and the value of the method can be traced to the national measurement standard.
[0024] Step 1: Prepare a standard surface source certified by a first-level national metrology institution. This source is a multi-gamma nuclide mixed source and can cover the energy of 365keV gamma rays mainly emitted by I-131.
[0025] Step ...
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The invention relates to a method for calibrating the detection efficiency of radioactive iodine activated carbon sampling filter boxes. According to the adsorption law of iodine in the sampling filter box, a standard surface source calibration detector is used to detect different depths of the sampling filter box, and then the sampling filter box is The detection efficiency of the detector for the iodine adsorbed in the sampling filter box can be obtained by placing it in the forward and reverse directions and measuring once. The invention can provide technical support for accurately and reliably measuring the activity concentration of radioactive iodine in places involving gaseous radioactive iodine monitoring such as nuclear power plants. The present invention utilizes the variation curve of surface source detection efficiency measured by laboratory calibration with the depth of surface source in the sampling filter box and the detector all-energy peak count when the sampling filter box is placed in the forward and reverse directions measured according to the experiment. The present invention designs The method can simply and quickly obtain the exponentially decreasing distribution parameters of iodine in the sampling filter box and the detection efficiency of the detector for iodine, and the value of the method can be traced to the national measurement standard.
Description
technical field [0001] The invention specifically relates to a detection efficiency calibration method of a traceable radioactive iodine activated carbon sampling filter box, and belongs to the technical field of nuclear power plant gaseous effluent monitoring. Background technique [0002] Radioactive iodine is produced during the daily operation of nuclear power plants. In order to protect the life and health rights of staff and the public, nuclear power plants must monitor the concentration of radioactive iodine activity in the gaseous effluent to ensure that it does not exceed the threshold specified by the national standard. The main forms of iodine in the gaseous effluent are gaseous element iodine and methyl iodide. Generally, activated carbon filter boxes impregnated with certain reagents are used to absorb and collect these iodine, and the activity is measured by NaI(Tl) detectors. The measured flow value can be used to calculate the activity concentration of radioa...
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IPC IPC(8): G01T7/00
CPCG01T7/005
Inventor 陈立唐智辉王勇韦应靖黄亚雯冯梅李强杨慧梅牛蒙青
Owner CHINA INST FOR RADIATION PROTECTION