Analysis of plutonium isotope ratios including 238Pu/239Pu in individual U–Pu mixed oxide particles by means of a combination of alpha spectrometry and ICP-MS

Publication date: 1 April 2017
Source:Talanta, Volume 165
Author(s): Fumitaka Esaka, Kenichiro Yasuda, Daisuke Suzuki, Yutaka Miyamoto, Masaaki Magara
Isotope ratio analysis of individual uranium–plutonium (U–Pu) mixed oxide particles contained within environmental samples taken from nuclear facilities is proving to be increasingly important in the field of nuclear safeguards. However, isobaric interferences, such as ²³⁸U with ²³⁸Pu and ²⁴¹Am with ²⁴¹Pu, make it difficult to determine plutonium isotope ratios in mass spectrometric measurements. In the present study, the isotope ratios of ²³⁸Pu/²³⁹Pu, ²⁴⁰Pu/²³⁹Pu, ²⁴¹Pu/²³⁹Pu, and ²⁴²Pu/²³⁹Pu were measured for individual Pu and U–Pu mixed oxide particles by a combination of alpha spectrometry and inductively coupled plasma mass spectrometry (ICP-MS). As a consequence, we were able to determine the ²⁴⁰Pu/²³⁹Pu, ²⁴¹Pu/²³⁹Pu, and ²⁴²Pu/²³⁹Pu isotope ratios with ICP-MS after particle dissolution and chemical separation of plutonium with UTEVA resins. Furthermore, ²³⁸Pu/²³⁹Pu isotope ratios were able to be calculated by using both the ²³⁸Pu/(²³⁹Pu+²⁴⁰Pu) activity ratios that had been measured through alpha spectrometry and the ²⁴⁰Pu/²³⁹Pu isotope ratios determined through ICP-MS. Therefore, the combined use of alpha spectrometry and ICP-MS is useful in determining plutonium isotope ratios, including ²³⁸Pu/²³⁹Pu, in individual U–Pu mixed oxide particles.

Graphical abstract

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