Assessment of intake of an actinide-bearing dust formed from the pond storage of spent magnox fuel

The biokinetics of ^238+239Pu, ²⁴¹Am, ¹⁴⁴Ce and ¹³⁷Cs, present in a source of airborne contamination that can be inhaled as a consequence of the pond storage of irradiated magnox fuels, have been examined after their deposition in the rat lung and predictions made of their behaviour in humans. The results show that the most toxic radionuclides present are the actinides; the transfer rates of the actinides to blood are between those calculated for compounds assigned to inhalation classes W and Y by the International Commission on Radiological Protection; intakes of the aerosol in amounts less than the annual limit on intake could be assessed from external measurements of ¹⁴⁴Ce in the lungs or ¹³⁷Cs in the whole body.