Radioepidemiological studies on the occupational exposure of workers in nuclear industry of China

The results of retrospective-cohort radioepidemiological studies on the workers exposed to occupational radiation in the uranium and nuclear plants and uranium mines governed by China National Nuclear Corporation is reported. Period of follow-up is 1971 ∼ 1985, total number of observation 40122, person years of follow-up 575411. The per caput dose of external radiation in workers of reactor, nuclear fuel reprocessing plants and research units was 57 mSv. For fuel element fabrication and gaseous diffusion plants, it was less than 5 mSv and about 3/4 of which came from the committed effective dose of internal radiation. SMR of total death and cancer death was generally less than 1.0 in exposure group of nuclear plants. There was no evidence of increment of the risk of radiogenic cancer. 31786 offsprings of workers in nuclear plants were subjected to the study on hereditary effects. The results was also negative. The only exception was uranium mines. Owing to the high concentration of radon before the 1960's, the average cumulative exposure of radon daughters of uranium miner was about 80 WLM, relative risk of miner lung cancer was about 2.0. the absolute risk coefficient was about 1/10 to 1/3 of the results of Western countries because of the low baseline rate of lung cancer in China. The excess relative risk coefficient was similar to the value presented by other countries. Radon contamination and increment of miner lung cancer encountered prominently in some non-uranium mines in China