Limiting occupational exposure due to plutonium inhalation intake

The article presents analysis of weaknesses of limits on occupational exposure to plutonium. Features of doses formation in prime organs of plutonium deposition due to chronic inhalation of the radionuclide as oxide and nitrate salt are considered. Calculated annual excess risk from inhalation of plutonium-containing substances shows that valid safety standards do not ensure proper level of radiation protection of nuclear industry workers. The limit of committed effective dose received during 50-years, accepted in Russian Radiation Safety Standards (RSS-99/2009) as the standard, cannot be used as the basic value for calculation of annual excess risk, because it does not take into account true levels of internal exposure due to specific mechanism of plutonium metabolism. The article suggests approaches to limiting occupational exposure of workers and setting limits on plutonium intake in dependence of the annual equivalent, accumulated doses in prime organs of the radionuclide deposition.