Age determination of plutonium using inductively coupled plasma mass spectrometry

Abstract

The age of plutonium is defined as the time since the last separation of the plutonium isotopes from their daughter nuclides. In this paper, a method for age determination based on analysis of 241 Pu/ 241 Am and 240 Pu/ 236 Pu using ICP-SFMS is described. Separation of Pu and Am was performed using a solid phase extraction procedure including UTEVA, TEVA, TRU and Ln-resins. The procedure provided separation factors adequate for this purpose. Age determinations were performed on two plutonium reference solutions from the Institute for Reference Materials and Measurements, IRMM081 ( 239 Pu) and IRMM083 ( 240 Pu), on sediment from the Marshall Islands (reference material IAEA367) and on soil from the Trinity test site (Trinitite). The measured ages based on the 241 Am/ 241 Pu ratio corresponded well with the time since the last parent-daughter separations of all the materials. The ages derived from the 236 U/ 240 Pu ratio were in agreement for the IRMM materials, but for IAEA367 the determination of 236 U was interfered by tailing from 238 U, and for Trinitite the determined age was biased due to formation of 236 U in the detonation of the "Gadget".

Nuclear Forensic Science: Analysis of Nuclear Material Out of Regulatory Control

“…If concordant model ages are determined with multiple radiochronometers, then the model age may be interpreted as the production age of the material with a high degree of confidence. Concordant model ages are observed in many uranium and plutonium reference materials that are commonly analyzed for validation of analytical methods (Wallenius & Mayer 2000, Nygren et al 2007, Shinonaga et al 2009, Eppich et al 2013, Sturm et al 2014). However, reference materials are produced with great care in controlled environments; real world samples produced in industrial facilities may not necessarily be expected to exhibit such ideal behavior.…”

240Pu/239Pu mass ratio in environmental samples in Finland

“…ICP-MS (inductively coupled plasma-mass spectrometry) is a complementary method for alpha spectrometry in identifying the origin of the Pu in environmental samples since, in contrast to alpha spectrometry, the amounts of 239 Pu and 240 Pu can be determined separately (Nygren et al, 2003(Nygren et al, , 2007. The analysis is rapid, compared with radiometric methods, and the detection limit of ICP-MS for Pu isotopes is as good as or even lower than that of alpha spectrometry, depending on the type of mass spectrometer used and the half-life of the nuclide to be measured.…”

Isotope ratio analysis of actinides, fission products, and geolocators by high-efficiency multi-collector thermal ionization mass spectrometry

“…In the nuclear forensic context, isotopic composition [1,2,4,[68][69][70][71][72][73][74][75][76][77] is of primary concern, in addition to the determination of physical parameters (including roughness, microstructure, geometry) [2][3][4][78][79][80], chemical structure (e.g., mineralogical structure, metallurgical information, oxidation states) [81][82][83], impurity and analyte content [2,3,77,78,[84][85][86][87], geolocation signatures (e.g., host rock, climate) [3,[88][89][90][91], or age since last chemical treatment [3,90,[92][93][94][95][96]. Isotope ratio analysis can be particularly useful in revealing the origin and history of nuclear materials.…”