Distributions of annual doses to some UK radiation workers

The authors present an analysis of doses to workers for whom radiation dose records were kept by the National Radiological Protection Board (NRPB) for the whole of the calendar year 1986, a total of 9400 individuals. The mean annual doses were low. Even the occupational group with the highest exposure (industrial radiographers) recorded an average annual dose of only 1.1 mSv. The variation of mean dose with age and sex is discussed. It was found that the distribution of annual doses deviated significantly from log-normality. There are indications that mean doses and the proportion of individuals exceeding 15 mSv in a year are falling with time. However, it is impossible to exclude the possibility that the first trend arises, at least in part, from an increase in the number of individuals who record little or no dose.