Using 244Pu/239Pu to pinpoint 240Pu/239Pu signatures of locally derived reactor material in the terrestrial environment

Accelerator mass spectrometry measurements of trace plutonium were conducted on soil samples from a relatively undisturbed site in the United Kingdom. Average isotopic ratios were measured across 15 samples for [Formula: see text]Pu/[Formula: see text]Pu and across 13 samples for [Formula: see text]Pu/[Formula: see text]Pu, yielding values of [Formula: see text] and [Formula: see text], respectively. The latter is noted to be lower than the global background. A balance equation was employed to determine the local [Formula: see text]Pu contribution at ([Formula: see text])%. Revisiting this in terms of [Formula: see text]Pu suggests a [Formula: see text]Pu/[Formula: see text]Pu ratio of [Formula: see text] for the local contribution. Whilst inconsistent with materials associated with the Windscale and Chernobyl accidents, this ratio aligns with prior [Formula: see text]Pu/[Formula: see text]Pu measurements of spent Magnox fuel.