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Direct radiolysis of extractants for separation of elements in radioactive liquid waste

Research Project

Project/Area Number 18K05001
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 31010:Nuclear engineering-related
Research InstitutionJapan Atomic Energy Agency

Principal Investigator

Kumagai Yuta  国立研究開発法人日本原子力研究開発機構, 原子力科学研究部門 原子力科学研究所 原子力基礎工学研究センター, 研究副主幹 (70455294)

Project Period (FY) 2018-04-01 – 2021-03-31
Project Status Completed (Fiscal Year 2020)
Budget Amount *help
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2020: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2019: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2018: ¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000)
Keywords放射線分解 / 抽出剤 / 直接過程 / 分解生成物 / 直接効果 / ジグリコールアミド
Outline of Final Research Achievements

We have studied radiolysis of extracting agents used for separation of actinide elements, N,N,N',N'-tetraoctyl-diglycolamide (TODGA) and N,N,N',N',N'',N''-hexaoctyl-nitrilotriacetamide (HONTA). In order to understand the radiation-induced degradation, we performed irradiation experiments of these extractants. The results exhibited that irradiation of pure TODGA and of TODGA solution in n-dodecane formed a similar intermediate state on a timescale of nano-seconds. This was similarly observed in the radiolysis of HONTA. These results indicate that direct ionization/excitation of the extractant molecule and the reaction of dodecane radicals generated identical radicals or excited states. Consistently, product analysis of irradiated extractants detected radiolytic products that suggest selective bond cleavages in DGA or NTA structures. The mechanism of the selective bond cleavages is expected to be the reactions at the early stage of radiolysis proceeding in a few nanoseconds.

Academic Significance and Societal Importance of the Research Achievements

放射性核種の分離は原子力のエネルギー利用で生じる放射性廃棄物の処理・処分に不可欠なプロセスである。多量の放射能を扱うため、この分離プロセスを進める上では、安全に関する潜在的なリスクを事前に十分に検証しておくことが求められる。放射線分解による溶媒劣化もプロセスの安全に影響する要因であり、この影響を評価するためには分解反応のメカニズムに関する理解が必要である。本研究で得られた知見は、抽出溶媒の放射線分解過程を把握し、その影響を予測するための基礎であり、放射性核種分離の安全性を高めていくことに貢献する。

Report

(4 results)
  • 2020 Annual Research Report   Final Research Report ( PDF )
  • 2019 Research-status Report
  • 2018 Research-status Report
  • Research Products

    (5 results)

All 2021 2019 2018 Other

All Int'l Joint Research (1 results) Journal Article (1 results) (of which Int'l Joint Research: 1 results,  Peer Reviewed: 1 results) Presentation (3 results) (of which Int'l Joint Research: 3 results,  Invited: 2 results)

  • [Int'l Joint Research] Idaho National Laboratory/Calfornia State University Long Beach/Brookhaven National Lboratory(米国)

    • Related Report
      2020 Annual Research Report
  • [Journal Article] Radiation-induced effects on the extraction properties of hexa-n-octylnitrilo-triacetamide (HONTA) complexes of americium and europium2021

    • Author(s)
      Toigawa Tomohiro、Peterman Dean R.、Meeker David S.、Grimes Travis S.、Zalupski Peter R.、Mezyk Stephen P.、Cook Andrew R.、Yamashita Shinichi、Kumagai Yuta、Matsumura Tatsuro、Horne Gregory P.
    • Journal Title

      Physical Chemistry Chemical Physics

      Volume: 23 Issue: 2 Pages: 1343-1351

    • DOI

      10.1039/d0cp05720g

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed / Int'l Joint Research
  • [Presentation] Radiolytic degradation of an extractant for actinides; HONTA -a comparative study of direct and indirect radiolysis processes.2019

    • Author(s)
      Y. Kumagai, T. Toigawa, S. Yamashita, T. Matsumura
    • Organizer
      Miller Conference 2019
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research
  • [Presentation] Radiation energy transfer simulation toward extraction solvent in minor actinide separation process.2019

    • Author(s)
      T. Toigawa, Y. Tsubata, T. Kai, T. Furuta, Y. Kumagai, T. Matsumura
    • Organizer
      Miller Conference 2019
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] Degradation of 2-Chlorophenol by gamma-Radiolysis in Zeolite-Water Mixture Containing Bromide or Nitrate Ion2018

    • Author(s)
      Yuta Kumagai, Atsushi Kimura, Mitsumasa Taguchi, Masayuki Watanabe
    • Organizer
      The 7th Asia-Pacific Symposium on Radiation Chemistry
    • Related Report
      2018 Research-status Report
    • Int'l Joint Research / Invited

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Published: 2018-04-23   Modified: 2022-01-27  

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