Measurements of Radioactivity Distributions in Several Woods Sampled in Fukushima prefecture

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K00552
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Risk sciences of radiation and chemicals
• Research Institution: 防衛大学校(総合教育学群、人文社会科学群、応用科学群、電気情報学群及びシステム工学群)
• Principal Investigator: Takada Masashi 防衛大学校(総合教育学群、人文社会科学群、応用科学群、電気情報学群及びシステム工学群), 応用科学群, 教授 (50291109)
• Research Collaborator: Suzuki Yojyu 森林総合研究所 ; Kimura Fumihiro 防衛大学校
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 放射性セシウム / 放射線計測 / 木材 / 放射能分布

Outline of Final Research Achievements

Radioactivity distributions of cross-sectional wood sampled in Fukushima prefecture were measured using imaging plates. Measurement results of konara oak show that radioactivity in sapwood is higher than that in heartwood, and it is dependent on heights from the ground. From radioactivity measurements of Japanese red pine and ceder sampled in forests over 0.5 micro-Sv/h dose rates, it is found that these radioactivities were quite small. In the Japanese red pine, the radioactivities between the heartwood and the sapwood are similar; while in the Japanese ceder the radioactivity in the heartwood is higher than the sapwood. Because of quite small amount of the radioactivity, we have to consider natural radioisotopes, like potassium-40 and carbon-14 to analyze radioactivity in woods.

Free Research Field

放射線計測

Academic Significance and Societal Importance of the Research Achievements

住宅建材として利用されているアカマツやスギについて樹木内部の放射能分布について計測調査した結果，毎時0.5マイクロシーベルトを上回る森林から伐採された木材サンプルにもかかわらず，樹木内部の放射能汚染はかなり低いことが分かった．樹種より放射能汚染の仕方（部位）が異なることも明らかになった．