Distribution and settling behavior of americium-241 in the tropical East Pacific

Kinoshita, Norikazu*; Nagaoka, Mika; Nakanishi, Takashi*

Science of the Total Environment, 753, p.142087_1 - 142087_10, 2021/01

https://doi.org/10.1016/j.scitotenv.2020.142087

The distribution of the anthropogenic radionuclide americium-241 (Am), a decay product of Pu discharged from atmospheric tests of nuclear weapons, was investigated to resolve its horizontal and vertical migration in the Tropical East Pacific. We analyzed Am concentrations in seawater samples collected in 2003. On comparing the Am concentrations with the previously determined concentrations of Pu in the same samples, the vertical profiles of Am were found to be similar to those of Pu. At some stations, the maximum concentration of Am occurred 100-200 m deeper than that of Pu. The Am/Pu ratios in the North Pacific and South Pacific were comparable to one another, and were typical of the ratio for the Pacific. The Am distribution was influenced by the water mass at depths below 400 m. The Am data support the view there is a current flowing at depths of 400-3000 m from the North Pacific through the equator to the South Pacific. In addition, the Am vertical profile was explained by using a box model that considers the decay of Pu and adsorption and scavenging by suspended particles. The different depths for the maximum concentrations of Am and Pu observed at some stations were well explained by the model and by the distribution of CaCO particles. The residence time of Am in the Pacific was also estimated by using the model.

Measurements of americium isotopes by activation method at KURRI-Linac

Nakamura, Shoji; Terada, Kazushi; Takahashi, Yoshiyuki*; Sano, Tadafumi*; Hori, Junichi*

KURRI Progress Report 2015, P. 69, 2016/08

http://www.rri.kyoto-u.ac.jp/PUB/report/PR/ProgRep2015/PR2015.pdf#page=78

Neutron capture cross section measurements has been conducted for Minor Actinides (MAs) under the research project entitled by "Research and development for Accuracy Improvement of neutron nuclear data on Minor ACtinides (AIMAC)". The present work selected two americium isotopes, Am and Am, were selected, and measurements were carried out by an activation method with neutron sources at KURRI-Linac. It was found that the neutron flux at the target positon was of the order of 10 (n/cms). The reaction rates of Am and Am were obtained by - and -ray measurements of the irradiated Am samples.

Evaluation of Neutron Nuclear Data for Am and Am

Kikuchi, Yasuyuki

JAERI-M 82-096, 103 Pages, 1982/08

JAERI-M-82-096.pdf:3.17MB

no abstracts in English

Absolute measurements of the disintegration rates of americium-241 sources by using semiconductor detectors

; Hiroyuki Tamura*; Yoshifumi Sakurai*

Journal of Nuclear Science and Technology, 1(3), p.101 - 107, 1964/00

https://doi.org/10.3327/jnst.1.101

no abstracts in English