Evaluating the surface protection and decontamination efficiency of DeconGel 1101 toward Cs-137 spilled on biological, salt-covered, rusty, wet and solid painted surfaces
This thesis presents an approach to develop innovative methods for decontamination and surface protection applicable to naval nuclear ships and potentially, personnel, replacing antiquated techniques. To accomplish this goal, two products manufactured by CBI Polymers, LLC., DeconGel™ 1101 (1101) and a shampoo, DeconGel™ 'prototype' (prototype), were tested. The prototype was specially developed for personal decontamination. In vitro studies with dry shaved pigskin, analogous to human skin, showed similar decontamination efficiencies for both 1101 and prototype gels. After two applications, uptake of Cs with 1101 was 43.2%, while the prototype removed 49.7% of contamination. Decontamination parameters for Cs-137 with 1101 gel were measured for four different solid surfaces of common naval paints. Decontamination efficiency for these surfaces ranged from 81.9% to 99.8% after three applications of the gel. Paint surfaces that exhibited the most stability and highest decontamination efficiencies were composed of insoluble silicon alkyd resins followed by slightly less stable copolymer epoxies and finally, an unstable safflower alkyd. Uptake of Cs-137 by 1101 was affected by changes in the gel binding capacity when competing homogeneously spread and dried impurities common on naval surfaces altered it. One impurity, sodium chloride representing seawater, showed 95.6% uptake of Cs-137 by one application of 1101 gel in the presence of 8.6E-4 g/cm² NaCl, but decreased to 80.7% when the surface concentration increased to 8.6E-2 g/cm² NaCl. Another impurity ferric chloride representing rust, showed 99% uptake of Cs-137 by one application of 1101 gel in the presence of 1.2E-2 g/cm² FeCl₃, but decreased to 62.7% when the surface concentration increased to 0.15 g/cm² FeCl₃. DeconGel™ 1101 was 99.1% efficient at removing contamination from a wet surface, and 99.4% effective at protecting surfaces from contamination suspended in water; both simulating wet spill conditions. DeconGel™ 1101 is an inexpensive, versatile and easy to use product. Results reported in this thesis can be used for development of improved decontamination procedures.