Krypton and Xenon Radionuclides Monitoring in the Northwest Region of Russia

Abstract

Monitoring of Xe and Kr radionuclides was conducted from August 2006 to 30 July 2008 within the framework of ISTC Project #2133. Cherepovets City in Vologda Province and St. Petersburg were chosen as monitoring locations. Kr-Xe concentrate samples were obtained as a result of processing of several thousand m 3 of atmospheric air. New results of 85 Kr monitoring show, that for last 15 years, the 85 Kr volumetric activity in the atmospheric air of the northwest region of Russia has increased approximately 50% and has achieved a level of 1.5 Bq/m 3 . This value correlates well with similar data for Western Europe and Japan. The xenon fraction (80-160 cm 3 under STP) is adsorbed on charcoal in the ampoule, which is measured in the well of HPGe gamma detector. Minimum detectable concentration (MDC) of 133 Xe for this technique is 0.008 mBq/m 3 , and it is the most sensitive method used today. The 133 Xe concentration in the atmospheric air of Cherepovets City varied in the monitoring period ranging from 0.09 to 2.5 mBq/m 3 . During the period of March 2007-30 July 2008, 133 Xe activity concentration in the atmospheric air of St. Petersburg changed from background values (0.2-0.3 mBq/m 3 ) to 185 mBq/m 3 and for approximately 20% of the samples 135 Xe was also measured with the 135 Xe/ 133 Xe activity ratio varied within the range of 0.03-3.5. -nuclides background in the air of St.-Petersburg, noble gas radionuclides release from nuclear power plants, high sensitivity methods of measuring Xe radionuclides.

Monitoring of Kr and Xe isotopes in air using liquid oxygen

“…In St. Petersburg located at a distance of 80 km from the Leningrad NPP, the 133 Xe activity level is considerably higher than in Cherepovets, where we also performed monitoring of Kr and Xe radionuclides [6]. In contrast to Cherepovets, in St. Petersburg in some cases we detected two Xe radionuclides: 133 Xe and 135 Xe, with their ratio varying in a wide range, suggesting the effect of other objects apart from Leningrad NPP.…”