Effective Doses of Employees at the Former Uranium Processing Plant MAPE Mydlovary, Czechoslovakia

Results are presented of a survey of almost 1000 dosimetric records of employees at the former uranium processing plant MAPE Mydlovary. Located ~20 km to the north-west of České Budějovice in South Bohemia, it was the place where most of the uranium ore mined in Czechoslovakia in the years from 1962 to 1991 was processed. The records refer to incorporation of short-lived radon progeny and long-lived radionuclides as well as external gamma exposure. The average annual doses calculated from the recorded data were 2.7 ± 1.4, 5.0 ± 3.1 and 1.7 ± 0.9 mSv from these three sources, respectively. Thus, the relative contributions of these components to the effective dose were 29 ± 6, 53 ± 14 and 18 ± 13% , respectively. This is different from the findings in an earlier study for the exposure of uranium miners, where the overall doses were similar, but over 50% was contributed by short-lived radon progeny. No legal limits applicable at the time were exceeded, as the inclusion of long-lived radionuclides in the dose calculations was not yet obligatory.