Simulation of natural radiation environments on shallow gas hydrates for investigation of the history

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K06983
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Earth system and resources engineering
• Research Institution: Kobe University
• Principal Investigator: Tani Atsushi 神戸大学, 人間発達環境学研究科, 准教授 (10335333)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: メタンハイドレート / 非在来型天然ガス / 放射線 / 被曝線量 / シミュレーション

Outline of Final Research Achievements

A simulation program, assuming the growth model of natural gas hydrate, was developed to evaluate the radiation dose inside the sample, based on a large different penetration depth from the surface of the sample in natural radiation like alpha, beta, and gamma rays. We clarified two points; (1) the total radiation dose was greatly depending on the position of the sample and the growth model and (2) the growth model of natural gas hydrate could be discussed by selecting at least three points for age estimation. In addition, we developed a device for collecting sample fragments from natural gas hydrate samples for age estimation, and improved the evaluation method for the fragments.

Free Research Field

地球惑星物質学

Academic Significance and Societal Importance of the Research Achievements

自然放射線環境からの被曝線量シミュレーションから，未分解で結晶性の良いメタンハイドレート試料を成長方向に複数個に分割して分析を進めることで，メタンハイドレートの成長モデルを制約することができることを示した．メタンハイドレートの生成史を考慮することで，時間とともにメタンハイドレートが変化することを考慮した資源量評価への道筋をつけることができた．