Nuclear Techniques ›› 2016, Vol. 39 ›› Issue (1): 10401-010401.doi: 10.11889/j.0253-3219.2016.hjs.39.010401

• NUCLEAR ELECTRONICS AND INSTRUMENTATION • Previous Articles     Next Articles

Influence of air pumping flow rate on the continuous measurement of open-loop radon exhalation rate

LIU Chang1, SHAN Jian1, YUAN Jiulin2, ZHONG Shili1, XIAO Detao1, LIU Xiaoxiang1, LIU Yan1   

  1. 1 Institute of Nuclear Science and Technology, University of South China, Hengyang 421001, China;
    2 Nuclear and Radiation Safety Monitoring Center of Shandong Province, Jinan 250117, China
  • Received:2015-09-18 Revised:2015-12-12 Online:2016-01-10 Published:2016-01-14
  • Supported by:

    Supported by National Natural Science Foundation of China (No.11375083)

Abstract:

Background: The research on radon exhalation rate mainly focuses on the influence factors of radon exhalation rate on the media surface, while research is still lacking with respect to equilibrium radon concentrations in radon cover sets, gas flow rate and other factors affecting the measurement accuracy of radon exhalation rate. Purpose: This study aimed to explore the relationship of the open-loop air-bleed rate, equilibrium radon concentrations and radon exhalation rate through theoretical calculations and actual measurements. Methods: MATLAB was used to simulate the variations of radon concentrations with time at different air-bleed rates during the open-loop measurement of radon exhalation rate in radon cover sets. The results were further proven by experiments. Results: In the case of constant parameters in radon cover sets in the measurement of radon exhalation rate, the equilibrium concentrations of radon decreased with the increase of air-bleed rates, and the time to reach the equilibrium concentrations was also shortened. The decrease of equilibrium concentrations of radon minimized the effect of the leakage and counter diffusion. The increase of air-bleed rates shortened the time for radon concentrations to reach equilibrium with better inlet gas uniformity in the radon cover sets. Conclusion: Reasonable parameters were obtained in this experiment with 1.94-3.0 L·min-1 for air-bleed rates, 299 cm2 for basal area and 1.79×10-3 m3 for the volume of radon cover sets.

Key words: Radon exhalation rate, Open-loop measurement, Air pumping flow rate, Equilibration time, Equilibrium radon concentration

CLC Number: 

  • O571.3