In the statistical analyses of the data on occupational radiation exposure at JPDR, statistical features were obtained as follows.
(1) The individual doses followed log-normal distribution.
(2) In the distribution of doses from one job in controlled area, the logarithm of the mean (μ) depended on the exposure rate (r(mR/h)), and the σ correlated to the nature of the job and normally distributed. These relations were as follows.
μ=0.48ln r-0.24, σ=1.2±0.58
(3) For the data containing different groups, the distribution of doses showed a polygonal line on the log-normal probability paper.
(4) Under the dose limitation, the distribution of the doses showed asymptotic curve along the limit on the log-normal probability paper.
