At the 1986 Chernobyl nuclear accident, there was a very large release of radioactivity in a few minutes, followed by a slowly declining release rate over several months. The total release is estimated to have been about 5×10<sup>7</sup>curies The winds carried the released materials all the way to Sweden, from which the first reports came that there had been a nuclear accident in the USSR.

For the purposes of this problem assume that there was an instantaneous release of 10<sup>7</sup>curies of radioactive gases (and fine particles, which are assumed to remain in the atmosphere and not settle out). Then estimate the maximum ground level concentration of radioactive gases (curies/m<sup>3</sup>) when the radioactive cloud from the accident got to Sweden. Make the following assumptions: (1) Ignore decay of the radioactive gases (i.e., assume their half-lives were infinite). (2) Assume the distance between Chernobyl and Sweden is 1000 km. (3) Assume that the wind speed was 3 m/s and the stability class C. (4) Assume that the mixing height was 2000 m. (5) Assume that mlXmg in the x direction(up and down the direction of the wind) has the same intensity as miXing in the y(crosswind)direction.

时间:2023-09-24 14:55:08

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