Multi-technique characterization of a nuclear bomb particle from the Palomares accident

A January 1966 accident dispersed Pu and other nuclear bomb materials in the vicinity of Palomares, a village in southeastern Spain. Radioactive particles were identified in a soil sample collected in 1998 and analytical results obtained from one of the isolated particles are presented here. Isolation of the particle was performed using gamma-ray spectrometry and imaging plates. Scanning electron microscopy with X-ray microanalysis revealed the presence of U and Pu as well as Pb and Fe in the particle of ∼ 10μm diameter. Radioisotopes of U, Pu, and Am were quantified using radiometric methods, inductively coupled plasma mass spectrometry and secondary ion mass spectrometry. The elevated 235U/238U atom ratio indicates enriched U, and the Pu atom ratios are consistent with weapons-grade material. This work demonstrates that the analysis of individual particles provides information not available through bulk sample analysis