Radioactive particles released from various nuclear sources

Abstract

Abstract. Radionuclides released to the environment may be present in different physico-chemical forms, ranging from ionic species to colloids, particles and fragments. Following releases during nuclear events such as nuclear weapon tests or use of depleted uranium munitions, and from nuclear accidents associated with explosions or fires, radionuclides such as uranium and plutonium are predominantly present as particles, mainly fuel particles. Similarly, radioactive particles are present in effluents from reprocessing facilities, and radioactive particles are observed in sediments in the close vicinity of radioactive waste dumped at sea. Thus, releases of radioactive particles occur far more often than earlier anticipated.Soils and sediments can act as a sink for colloids, particles and fragments, while contaminated soils and sediments may also act as a potential diffuse source, depending on particle characteristics and processes influencing particle weathering and remobilisation of associated radionuclides. To assess long-term impact from radioactive particle contamination, information on the source term is essential, i.e. activity concentrations and isotopic ratios as well as the particle size distribution, crystallographic structures and oxidation states influencing particle weathering rates and the subsequent mobilisation and biological uptake of associated radionuclides. The activity concentrations and the isotopic ratios will be source dependant, while particle characteristics will also reflect the release scenario, dispersion processes and deposition conditions. The present paper will summarise information on various nuclear sources summarise having released radioactive particles in the past.

“Hot” and active particles in alluvial soils and sediments of the Yenisei river: Radioisotope composition

“…Particles are also released in authorized and nonauthorized discharges from reprocessing plants and associated radioactive wastes. Therefore, releases of radioactive particles have occurred more frequently than perhaps usually anticipated [1][2][3].…”

Radioactive particles in dose assessments

“…This session considered the problems that the 'hot particles' present including development of an appropriate sampling strategy; transport processes and pathways. Further information on the sources and methods of characterisation of radioactive particles has been reported by Salbu and Lind (2005). However, to date there has been little consideration of the problems associated in the assessment of potential doses which could be received from such particles.…”