Detection of 192Ir in ground level air in Ursvik 20 September 2004 with Quarterly report on measurements in ground level air in Sweden

Authors:

  • Söderström Catharina
  • Arntsing Rune
  • Jansson Peter
  • Lindh Karin
  • Wilhelmsen Katarina

Publish date: 2005-01-01

Report number: FOI-R--1691--SE

Pages: 12

Written in: English

Abstract

The radioisotope 192Ir was found in the filter from Ursvik, Monday 20 September 2004. There were no indications of 192Ir in filters from any of the other national stations during that period. The measured activity concentration of 192Ir was about 50 µBq/m3, corresponding to a total collected activity of 2.36 Bq of 192Ir in the filter. The source of the release was the Studsvik Nuclear AB production site about 80 km south of Ursvik and the preliminary estimation of released activity was 58 kBq. Locally performed measurements and dispersion calculations show that the released amount of 192Ir was in the order of 1 GBq. This is in agreement both with the measurements at the filter station in Ursvik, and with the dispersion calculations performed by FOI. Filtering of ground level air is performed weekly at six different locations in Sweden: Kiruna, Umeå, Gävle, Ursvik, Visby and Ljungbyhed. The filters are pressed and the contents of different radionuclides are measured by gamma spectroscopy. Precipitation is also collected at four of the stations: Kiruna, Gävle, Ursvik and Ljungbyhed, the samples are ashed and the contents of radionuclides are measured. The levels of Be-7 and Cs-137 in air and precipitation are presented for the different stations. Other antropogenic radionuclides detected, if any are also presented.

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