title: 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.
abstract: 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 24Na, -K and 82Br, were found in these materials by gamma-ray spectrometry. The radionuclide of the highest activity observed in biological materials was 24Na, 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 24Na (concentration ratio between the produced 24Na and stable 23Na), which are essential for estimating the neutron fluences and radiation doses. The specific activities of 24Na obtained for the three patients through the blood analysis were 8.2 x 10(4),4.3 x 10(4) and 1.2 x 10(4) Bq24Na/g23Na. Based on these values, individual's neutron fluences were estimated to be 5.7 x 10(11), 3.0 x 10(-1) and 0.85 x 10(11) cm(-2), respectively.
authors.affiliation: National institute of Radiological Sciences, Chiba, Japan. y_murama@nirs.go.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Muramatsu
authors.forename: Y
authors.initials: Y
authors.lastname: Noda
authors.forename: H
authors.initials: H
authors.lastname: Yonehara
authors.forename: N
authors.initials: N
authors.lastname: Ishigure
authors.forename: S
authors.initials: S
authors.lastname: Yoshida
authors.forename: M
authors.initials: M
authors.lastname: Yukawa
authors.forename: K
authors.initials: K
authors.lastname: Tagami
authors.forename: T
authors.initials: T
authors.lastname: Ban-Nai
authors.forename: S
authors.initials: S
authors.lastname: Uchida
authors.forename: T
authors.initials: T
authors.lastname: Hirama
authors.forename: M
authors.initials: M
authors.lastname: Akashi
authors.forename: Y
authors.initials: Y
authors.lastname: Nakamura
mesh_terms: D000328:Adult; D005214:Fast Neutrons / Q000009:adverse effects*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D009501:Neutron Activation Analysis; D009784:Occupational Diseases / Q000209:etiology; D016273:Occupational Exposure; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000209:etiology; D018788:Radioactive Hazard Release; D011868:Radioisotopes / Q000009:adverse effects* / Q000032:analysis*; D012979:Sodium Radioisotopes / Q000009:adverse effects / Q000032:analysis
chemical_list: D011868:Radioisotopes; D012979:Sodium Radioisotopes