Deposition of 236U from atmospheric nuclear testing in Washington state (USA) and the Pechora region (Russian Arctic)

236U and 239,240Pu ratios from soils around an Australian nuclear weapons test site

“…This may again reflect different behaviour of U and Pu in the soil and/or that the surface soil at these sites has been disturbed. The total 236 U inventory of 6 Â 10 13 atoms/m 2 at site T008 is by far the largest of all the sites, and well above the only other inventory levels reported to date for global fallout in Australia (0.08 Â 10 13 atoms/m 2 , Srncik et al, 2014) and in the Northern Hemisphere (0.8e3.0 Â 10 13 atoms/m 2 , Ketterer et al, 2013). Sites T001-T007 have inventories that are much closer to that reported by Srncik et al (2014) (but typically greater by factors of 2e10), and lower than those reported for the Northern Hemisphere.…”

“…As noted above, this is a consequence of the fallout plutonium being derived from material dispersed by the safety trials. There is considerable variability across the other sites; however the values are typical of those, reported to date, for global fallout (Sakaguchi et al, 2009;Srncik et al, 2011;Ketterer et al, 2013;Srncik et al, 2014). A possible explanation for this variability is the presence of micron-size plutoniumbearing particles in the soil matrix, which is well documented at Maralinga (Long et al, 2004), and which lead to some anomalies in the plutonium results .…”

He stripping for AMS of 236U and other actinides using a 3 MV tandem accelerator

“…236 U/U from natural production by cosmic rays is expected to be quite low [4], and has escaped detection so far, but the ratios derived from radiogenic production in high grade ores are within the capabilities of suitable AMS instruments [5,6]. The most recent environmental applications evolved around the discovery of 236 U from global fall-out [7,8], with a strong focus on oceanography [9][10][11], but also first soil science studies [12,13] and first measurements in ice cores have been published recently [14].…”

Analysis of 236U and plutonium isotopes, 239,240Pu, on the 1 MV AMS system at the Centro Nacional de Aceleradores, as a potential tool in oceanography

“…In this context, a potential complementary approach would be the study of the 236 U/ 239 Pu ratio. A very reliable range for the global fallout 236 U/ 239 Pu ratio of 0.19-0.23 has been obtained from the study of soil cores from different areas of the Northern Hemisphere, far from local actinides sources other than global fallout [5,15,16]. These ratios were deduced using the integrated inventories of 239 Pu and 236 U along the cores, due to the matrix-dependent profiles of both radionuclides.…”