TY - BOOK

T1 - Multi-element ultra-trace detection of radionuclides in environmental samples

AU - van Eerten, Darcy

PY - 2024/6/11

Y1 - 2024/6/11

N2 - A ‘hot particle’ is a microscopic fragment deriving from nuclear material. The detection of these particles is in some cases the first marker of the release of nuclear material. Its history is contained in its isotopic composition, characteristic of its origin and interaction with the environment. This work focuses on environmental samples derived from the accident sites in Chornobyl and Fukushima, studied through resonant ionisation mass spectrometry, RIMS. The principle of RIMS relies on the universality of atomic structure to selectively analyse isotope ratios in a target element. This work discusses the design and operation of different instruments. Individual hot particles were analysed in the SIRIUS RIMS instrument at the Institute for Radiation Protection and Radioecology (IRS) in Hannover, Germany. A comparison study was done on eight Chornobyl Exclusion Zone (CEZ) particles with the LION at Lawrence Livermore National Laboratory (LLNL) in Livermore, USA. Comparable results across instruments show a range of burnup dependent isotope ratios for U and Pu and Cs, characteristic of RBMK-type reactors. Isotopic analysis therefore provides vital information about sample origin and degradation. In most mass spectrometric techniques without laser ionisation, the removal of isobaric interference requires chemical pre-treatment, thereby destroying the sample. This limits their application for isotopic analysis, necessitating a focus on one or two elements only, as allowed by small sample size. The versatility offered by multi-element RIMS makes it uniquely suited to the study of individual hot particles. In this work, isotope ratio analysis has been expanded to the actinides U, Pu, Np, and Am, and the fission products Rb, Sr, Zr, Cs and Ba. Isotope ratio analysis is interpreted in the contexts of nuclear forensics, radioecology, and reactor physics. A collection of samples can be grouped by analysing the time-dependent Sr, show how flux changes the U, Pu, and Cs composition across a reactor, and show through Ba that Cs has been lost to the environment.

AB - A ‘hot particle’ is a microscopic fragment deriving from nuclear material. The detection of these particles is in some cases the first marker of the release of nuclear material. Its history is contained in its isotopic composition, characteristic of its origin and interaction with the environment. This work focuses on environmental samples derived from the accident sites in Chornobyl and Fukushima, studied through resonant ionisation mass spectrometry, RIMS. The principle of RIMS relies on the universality of atomic structure to selectively analyse isotope ratios in a target element. This work discusses the design and operation of different instruments. Individual hot particles were analysed in the SIRIUS RIMS instrument at the Institute for Radiation Protection and Radioecology (IRS) in Hannover, Germany. A comparison study was done on eight Chornobyl Exclusion Zone (CEZ) particles with the LION at Lawrence Livermore National Laboratory (LLNL) in Livermore, USA. Comparable results across instruments show a range of burnup dependent isotope ratios for U and Pu and Cs, characteristic of RBMK-type reactors. Isotopic analysis therefore provides vital information about sample origin and degradation. In most mass spectrometric techniques without laser ionisation, the removal of isobaric interference requires chemical pre-treatment, thereby destroying the sample. This limits their application for isotopic analysis, necessitating a focus on one or two elements only, as allowed by small sample size. The versatility offered by multi-element RIMS makes it uniquely suited to the study of individual hot particles. In this work, isotope ratio analysis has been expanded to the actinides U, Pu, Np, and Am, and the fission products Rb, Sr, Zr, Cs and Ba. Isotope ratio analysis is interpreted in the contexts of nuclear forensics, radioecology, and reactor physics. A collection of samples can be grouped by analysing the time-dependent Sr, show how flux changes the U, Pu, and Cs composition across a reactor, and show through Ba that Cs has been lost to the environment.

U2 - 10.15488/17441

DO - 10.15488/17441

M3 - Doctoral thesis

CY - Hannover

ER -