Characterization of uranium and plutonium containing particles originating from the nuclear weapons accident in Thule, Greenland, 1968

To improve long-term radioecological impact assessment for the contaminated ecosystem of Bylot Sound, Greenland, U and Pu containing particles have been characterized with respect to particle size, elemental distribution, morphology and oxidation states. Based on scanning electron microscopy with XRMA, particles ranging from about 20 to 40 μm were isolated. XRMA and μ-XRF mapping demonstrated that U and Pu were homogeneously distributed throughout the particles, indicating that U and Pu have been fused. Furthermore, μ-XANES showed that U and Pu in the particles were present as mixed oxides. U was found to be in oxidation state IV whereas Pu apparently is a mixture of Pu(III) and Pu(IV). As previous assessments are based on PuO2 only, revisions should be made, taking Pu(III) into account.