0

Full Content is available to subscribers

Subscribe/Learn More  >

Distribution of Radioactive Cesium in Trees and Effect of Decontamination of Forest Contaminated by the Fukushima Nuclear Accident

[+] Author Affiliations
K. Iijima, H. Funaki, T. Tokizawa, S. Nakayama

Japan Atomic Energy Agency, Fukushima, Japan

Paper No. ICEM2013-96113, pp. V002T04A004; 6 pages
doi:10.1115/ICEM2013-96113
From:
  • ASME 2013 15th International Conference on Environmental Remediation and Radioactive Waste Management
  • Volume 2: Facility Decontamination and Decommissioning; Environmental Remediation; Environmental Management/Public Involvement/Crosscutting Issues/Global Partnering
  • Brussels, Belgium, September 8–12, 2013
  • Conference Sponsors: Nuclear Engineering Division, Environmental Engineering Division
  • ISBN: 978-0-7918-5602-4
  • Copyright © 2013 by ASME

abstract

In decontamination pilot projects conducted by Japan Atomic Energy Agency (JAEA), many different techniques were tested to determine their applicability to remediate areas evacuated after the Fukushima Daiichi nuclear accident following the Great Tohoku earthquake and tsunami of March 11, 2011. In addition to buildings, roads and farmland, the forest adjacent to living areas was one of the main decontamination targets.

The projects evaluated the radioactive contamination of trees and the effectiveness of decontaminating a highly contaminated evergreen forest. This forest was located 1.3 km southwest of the Fukushima Daiichi Nuclear Power Plant and is dominated by Japanese cedar trees and fir trees.

As the first step, three Japanese cedar trees and three fir trees were cut down and the distributions of radioactive cesium (Cs) were measured in each. The total concentrations of 134Cs and 137Cs in the leaves and branches were about 1 MBq/kg for both cedar and fir trees, and were appreciably higher than in the bark for cedar. The concentrations in the outer part of the trunks (under the bark) were lower, on the order of 10 kBq/kg, and those in the core of the trunks were lower than 1 kBq/kg for both kinds of trees. The observation that the Cs concentrations are higher in the outer part of trees, is compatible with the assumption that radio-Cs was mostly adsorbed on the surface of trees and partly penetrated into the trunks through the bark.

Evolution of air dose rates in a 100 × 60 m pasture adjacent to the forest was monitored during decontamination of the forest and of the pasture itself. The dose rates in the pasture decreased drastically after stripping contaminated topsoil from the pasture and decreased slightly more after stripping contaminated topsoil of the forest floor and pruning the trees. Cutting down and removing 84 trees in the outermost area (10-m width) of the forest also slightly decreased these dose rates. After decontamination, the residual dose rates around the highly contaminated forest were mostly attributed to radioactive Cs existing in or on trees and topsoil in the untouched forest beyond the decontaminated area.

Copyright © 2013 by ASME

Figures

Tables

Interactive Graphics

Video

Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In