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

概要

論文の詳細を見る
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.
日本放射線影響学会の論文