Investigation of Radioxenon Probability Density Functions at IMS Radionuclide Stations Using a Monte Carlo Method for Background Estimation

Abstract The International Monitoring System, the primary means of verification of the Comprehensive Nuclear-Test-Ban Treaty, monitors the planet for any sign of a nuclear explosion. Regarding the International Monitoring System radionuclide stations, it is known that radioxenon released from nuclear facilities such as medical isotope production facilities and nuclear power plants influences the stations. For the purposes of monitoring nuclear explosions, it is important to better understand the radioxenon background based on these nuclear facilities. The probability density functions of background activity concentration at IMS radionuclide stations are estimated using a Monte Carlo method based on emissions from known nuclear facilities and source receptor sensitivity data. This paper describes two case studies of radioxenon detections at radionuclide stations applying the developed approach. This method could be one of several prospective approaches to predict the activity concentrations of isotopes of radioxenon at radionuclide stations in Comprehensive Nuclear Test-Ban Treaty Organization’s (CTBTO’s) prototype xenon background estimation tool software. It can also be used in characterization of CTBT-relevant nuclear events for expert technical analysis. Plain Language Summary Civil nuclear power stations and medical isotope production facilities release radioisotopes of xenon during their normal operations. These emissions would make it harder to detect xenon produced from any nuclear weapon test that might occur. A method is described that starts with information about civil releases and produces a statistical description of the concentrations of isotopes measured at stations designed to detect nuclear tests. This information makes it possible to enhance nuclear explosion detection performance.