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Modelling the external radiation exposure from the Chernobyl fallout using data from the Swedish municipality measurement system

Jönsson, Mattias LU ; Tondel, Martin; Isaksson, Mats LU ; Finck, Robert LU ; Wålinder, Robert; Mamour, Afrah and Rääf, Christopher LU (2017) In Journal of Environmental Radioactivity 178-179. p.16-27
Abstract

In connection with the Chernobyl fallout and the subsequent deposition of radionuclides in Sweden, Swedish municipalities launched a measurement program to monitor the external radiation exposure. This program encompasses measurements of the ambient dose equivalent rate 1 m above ground at selected locations, and repeats those measurements at the same locations at 7-month intervals. Measurement data compiled from the seven locations with the highest deposition were combined with data from aerial surveys since May 1986 of ground deposition of (137)Cs, high-resolution gamma spectrometry performed at four locations in May 1986, and measurements from fixed continuous air gamma rate monitoring stations from 28 April to 15 May 1986. Based on... (More)

In connection with the Chernobyl fallout and the subsequent deposition of radionuclides in Sweden, Swedish municipalities launched a measurement program to monitor the external radiation exposure. This program encompasses measurements of the ambient dose equivalent rate 1 m above ground at selected locations, and repeats those measurements at the same locations at 7-month intervals. Measurement data compiled from the seven locations with the highest deposition were combined with data from aerial surveys since May 1986 of ground deposition of (137)Cs, high-resolution gamma spectrometry performed at four locations in May 1986, and measurements from fixed continuous air gamma rate monitoring stations from 28 April to 15 May 1986. Based on these datasets, a model of the time pattern of the external dose rate in terms of ambient dose equivalent rate from the Chernobyl fallout was developed. The decrease in the ambient dose equivalent rate could, on average, be described by a four-component exponential decay function with effective half-times of 6.8 ± 0.3 d, 104 ± 26 d, 1.0 ± 0.02 y and 5.5 ± 0.09 y, respectively. The predominant contributions to the external dose rate in the first month were from short-lived fission products superseded by (134)Cs and then (137)Cs. Integrated over 70 y and using extrapolation of the curve fits, our model predicts that (137)Cs contributes about 60% and (134)Cs contributes about 30% of the external effective dose at these seven locations. The projected time-integrated 70 y external effective dose to an unshielded person from all nuclides per unit total activity deposition of (137)Cs is estimated to be 0.29 ± 0.0.08 mSv/(kBq m(-2)). These results are in agreement with those found in Chernobyl contaminated Russian forest areas, and emphasize the usefulness of maintaining a long-term and regular measurement program in contaminated areas.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Environmental Radioactivity
volume
178-179
pages
12 pages
publisher
Elsevier
external identifiers
  • scopus:85023629835
  • wos:000415769000002
ISSN
1879-1700
DOI
10.1016/j.jenvrad.2017.07.003
language
English
LU publication?
yes
id
496d7019-8537-4504-b9de-5d202eddcd7a
date added to LUP
2017-08-29 11:22:55
date last changed
2018-01-16 13:23:44
@article{496d7019-8537-4504-b9de-5d202eddcd7a,
  abstract     = {<p>In connection with the Chernobyl fallout and the subsequent deposition of radionuclides in Sweden, Swedish municipalities launched a measurement program to monitor the external radiation exposure. This program encompasses measurements of the ambient dose equivalent rate 1 m above ground at selected locations, and repeats those measurements at the same locations at 7-month intervals. Measurement data compiled from the seven locations with the highest deposition were combined with data from aerial surveys since May 1986 of ground deposition of (137)Cs, high-resolution gamma spectrometry performed at four locations in May 1986, and measurements from fixed continuous air gamma rate monitoring stations from 28 April to 15 May 1986. Based on these datasets, a model of the time pattern of the external dose rate in terms of ambient dose equivalent rate from the Chernobyl fallout was developed. The decrease in the ambient dose equivalent rate could, on average, be described by a four-component exponential decay function with effective half-times of 6.8 ± 0.3 d, 104 ± 26 d, 1.0 ± 0.02 y and 5.5 ± 0.09 y, respectively. The predominant contributions to the external dose rate in the first month were from short-lived fission products superseded by (134)Cs and then (137)Cs. Integrated over 70 y and using extrapolation of the curve fits, our model predicts that (137)Cs contributes about 60% and (134)Cs contributes about 30% of the external effective dose at these seven locations. The projected time-integrated 70 y external effective dose to an unshielded person from all nuclides per unit total activity deposition of (137)Cs is estimated to be 0.29 ± 0.0.08 mSv/(kBq m(-2)). These results are in agreement with those found in Chernobyl contaminated Russian forest areas, and emphasize the usefulness of maintaining a long-term and regular measurement program in contaminated areas.</p>},
  author       = {Jönsson, Mattias and Tondel, Martin and Isaksson, Mats and Finck, Robert and Wålinder, Robert and Mamour, Afrah and Rääf, Christopher},
  issn         = {1879-1700},
  language     = {eng},
  pages        = {16--27},
  publisher    = {Elsevier},
  series       = {Journal of Environmental Radioactivity},
  title        = {Modelling the external radiation exposure from the Chernobyl fallout using data from the Swedish municipality measurement system},
  url          = {http://dx.doi.org/10.1016/j.jenvrad.2017.07.003},
  volume       = {178-179},
  year         = {2017},
}