Plutonium Estimation

Abstract

A probabilistic model that incorporates the nature of radioactive contamination of a nuclear weapons site has been proposed by Wise and Kabaila (1989).The interest has focussed on regions of significant contamination that have resulted from local fallout from nuclear weapons tests and from explosive fragmentation of plutonium in safety trials. Plutonium here refers to a mixture of three isotopes of plutonium with mass numbers 239,240 and 241. These are initially formed in a nuclear reactor and they may be detected when freshly deposited on the soil surface but are difficult to be detected when the isotopes begin migrating through the soil surface. Several techniques exist for determining the concentrations of plutonium in soil. The Australian Radiation Laboratory has done a number of radiological surveys of nuclear explosions which the United Kingdom Atomic Weapons Research Establishment conducted between 1953 and 1963 at the Monte Bello Islands, Mu and the Maralinga test range in Australia. The model developed by Wise and Kabaila involves direct sampling of the soil and indirect observation of emitted radium using the NaI detector.