A wide variety of materials can become contaminated by radionuclides, eitherfrom aterrorist attack or an industrial or nuclear accident. The final dispositionof these materials depends,in large part, on the effectiveness of decontamination measures. This studyreports on investigationsinto the decontamination of a selection of building materials. The aim hasbeen to find an effective,easy-to-use and inexpensive decontamination system for radionuclides of cesiumand cobalt,considering both the chemical and physical nature of these potentialcontaminants. The basicmethod investigated was surface washing, due to its ease and simplicity. Inthe present study, a basicdecontamination formulation was modified by adding isotope-specificsequestering agents, toenhance the removal of cesium(I) and cobalt(II) from such constructionmaterials as concrete,marble, aluminum and painted steel. Spiking solutions contained 134Cs or 60Co,which were preparedby neutron activation in the SLOWPOKE-2 nuclear reactor facility at the RoyalMilitary College ofCanada. Gamma spectroscopy was used to determine the decontaminationefficiency. The resultsshowed that the addition of sequestering agents generally improved theradiologicaldecontamination. Although the washing of both cesium and cobalt from non-porous materials, suchas aluminum and painted steel, achieved a 90-95% removal, the decontaminationof concrete andmarble was more challenging, due to the porous nature of the materials.Nevertheless, the removalefficiency from six-year-old concrete increased from 10 % to approximately 50% for cobalt(II), andfrom 18 % to 55 % for cesium(I), with the use of isotope binding agents, asopposed to a simplewater wash.Keywords: decontamination, radionuclides, sequestering agents, gamma-spectroscopy
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