コロンビア川の堆積物におけるハンフォード製プルトニウム
まとめ
コロンビア川の堆積物には,同位体比でプラトニウムが含まれており,地球規模の降下物と地元の源の両方を示しています. ハンフォード原子炉からのプルトニウム-239は,沈殿物の汚染に大きく寄与する.
科学分野:
- 環境科学 環境科学
- 核化学 核化学は,核化学である.
- 放射線学的評価について
背景:
- コロンビア川の沈殿物は,環境汚染物質のシンクです.
- プルトニウムイソトープは,地球規模の放射性降下物と地元の核活動の両方から発生します.
- プルトニウム源を理解することは,環境修復とリスク評価において極めて重要です.
研究 の 目的:
- コロンビア川の堆積物におけるプルトニウムイソトープの源を調べるために.
- プルトニウム汚染に対する過去の原子力炉の操作の寄与を定量化するために.
- 川の環境における地球規模の降下物と地方的なプルトニウム源を区別する.
主な方法:
- 堆積物サンプルにおけるプルトニウムイソトープ (Pu-240,Pu-242,Pu-239) の質量スペクトロメトリ分析.
- 測定された同位体比と既知の地球規模の降下物値の比較.
- 原子炉産プルトニウムの貢献を推定するためのモデリング.
主要な成果:
- プルトニウム-240とプルトニウム-242の比率は,地球規模の降下物パターンと一致しています.
- プルトニウム-240とプルトニウム-239の比率は,地球規模の降下物から著しく逸脱し,追加の源を示しています.
- マクナリー貯水池の堆積物中のプルトニウムの20~25%は,ハンフォード原子炉の稼働に由来すると推定されている.
結論:
- コロンビア川の堆積物には,グローバル・フォールアウトとハンフォード・サイトの原子炉からの混合プルトニウムシグネチャーが見られる.
- ハンフォードからの原子炉の排水はネプチウム239を供給し,それはプルトニウム239に崩壊し,沈殿物を汚染した.
- 地元の核活動は,下流の堆積物におけるプルトニウム汚染の重要で定量化可能な源である.
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