标题：Determination of Radionuclides Produced by Neutrons in Heavily Exposed Workers of the JCO Criticality Accident in Tokai-mura for Estimating an Individual's Neutron Fluence
其他标题：Determination of Radionuclides Produced by Neutrons in Heavily Exposed Workers of the JCO Criticality Accident in Tokai-mura for Estimating an Individual's Neutron Fluence
摘要：In the Tokai-mura criticality accident, three workers were heavily exposed. Biological materials, such as blood, urine, vomit and hair, were collected from the workers and analyzed for radioactivities, produced by the neutron irradiation. Activation products, such as 24 Na, 42 K and 82 Br, were found in these materials by gamma-ray spectrometry. The radionuclide of the highest activity observed in biological materials was 24 Na, e.g. the concentrations of this nuclide in the blood samples from the three patients at the accident time were 169, 92 and 23 Bq/ml, respectively. The concentrations of stable sodium in the same samples were determined by ICP-AES to obtain specific activities of 24 Na (concentration ratio between the produced 24 Na and stable 23 Na), which are essential for estimating the neutron fluences and radiation doses. The specific activities of 24 Na obtained for the three patients through the blood analysis were 8.2×10 4 , 4.3 ×10 4 and 1.2×10 4 Bq 24 Na/g 23 Na. Based on these values, individual's neutron fluences were estimated to be 5.7×10 11 , 3.0×10 11 and 0.85×10 11 cm -2 , respectively.
