Automatic continuous measurement system for separation extraction and content of 85Kr gas in air

Abstract

The invention discloses an automatic continuous measurement system for separation extraction and content of 85Kr gas in air. The whole system is vacuumized through a vacuum device, air sample gas is introduced into a water removal device to remove water and carbon dioxide, and then enters a first activated carbon low-temperature cold trap soaked in liquid nitrogen through a first mass flow meter at a proper flow rate; after the sample is distilled for a certain time, the first activated carbon cold trap is heated through a temperature control device, further concentration and preliminary enrichment are completed, the first activated carbon low-temperature cold trap is heated, the helium carrier gas device carries krypton gas and other gas in the first activated carbon low-temperature cold trap through helium gas to enter a gas chromatography device for first chromatography, krypton gas returns and is guided into a second activated carbon low-temperature cold trap for secondary chromatography when going out of a peak, the krypton gas is purified by a gas suction and degassing device and then is conveyed to a collecting container, the collecting container is transferred to an ATTA measuring system to measure the content of 85Kr in the sample, and continuous separation and extraction of the 85Kr gas in the air and automatic continuous measurement of the content are achieved.

Description

technical field [0001] The present invention relates to the air 85 Kr content monitoring technical field, especially relate to a kind of air 85 Automatic continuous measurement system for Kr gas separation, extraction and content. Background technique [0002] radioactive isotopes in the atmosphere 85 The release of Kr mainly comes from the cutting and dissolution process of reprocessing spent fuel rods in nuclear fuel plants. in the atmosphere 85 The monitoring of Kr content is of great significance in environmental protection. [0003] 85 The isotopic abundance of Kr is extremely low and cannot be detected by conventional mass spectrometry. Currently commonly used 85 Kr has gamma spectrum measurement and beta spectrum measurement. [0004] Gamma spectrum measurement is simple and fast, but limited by the device background and low detection efficiency, the detection limit is as high as 34000Bq / m 3 , much higher than the air 85 Abundance of Kr. [0005] β spectrum...

AI Technical Summary

Problems solved by technology

The detection limit of LLC and LSC is low, but limited by half-life and radiation background, a large amount of sample is required (10 ~ 20m 3 ) and the measurement time is relatively long (a few days to a week), and it has high requirements on the ambient radiation background and gas purity

[0006] Due to the impossibility of continuous air 85 Kr gas separation and extraction, the current measurement methods have not shown quasi-continuous monitoring of air 85 The possibility of Kr content greatly limits the 85 Application of Kr in Environmental Monitoring

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