[Radioepidemiological studies in the nuclear industry of China]

The results of retrospective-cohort radioepidemiological studies on workers of mines and plants governed by China National Nuclear Corporation was reported. The total number was 40,122 persons and 575,411 person-years. The accumulated personal dose in workers of reactor, nuclear fuel reprocessing plants and research units was 57 mSv on the average. For fuel element fabrication and diffusion plants, it was about 5 mSv. Mortality of cancers, especially the non-cancerous diseases was not higher but lower than the controlled group and national values, showing the so-called health worker effect. 31,786 off springs of workers in the nuclear plants were examined. There were no significant difference in the incidence of hereditary-congenital diseases among exposed and controlled groups. The results mentioned above provide the direct medical evidences of the safety of nuclear industry in China. Owing to the high concentration of radon in the uranium prospective and mining tunnels in early years, the average cumulative exposure to radon progeny was about 80 WLM for miners who had the history of working underground. The relative risk of lung cancer was about 2. The excess relative risk per WLM was similar to the value reported abroad.