Chelating scintillation fibers for measurements of Cs-137

Solid scintillating fibers, coated with a dual-mechanism bifunctional polym er shown to bind Cs(I) in alkaline solutions, were developed for measuremen t of Cs-137. The effect of the epoxy-polymer coating thickness on attenuati on of the signal from Cs-137 was evaluated. After optimal coating condition s were determined, both scintillation fiber and resin functions were retain ed, producing stable field-ready fibers. Temporal studies were performed to examine:the kinetics of Cs-137 uptake into the resin. Calibration curves o f the fiber response were generated by beta-emission from solutions of Cs-1 37 dissolved in 1 M sodium hydroxide. The plots exhibited a linear response over a range of 4-3200 nCi/mL (3.4 x 10(-10)-2.7 x 10(-7) M Cs-137), with a limit of detection of 3.65 nCi/mL (similar to 42 parts per trillion Cs-13 7). The distribution coeffcient of Cs was determined to be 490 +/- 50 mL/g from these measurements. Selectivity studies of the resin were performed in the presence of 100 fold excess of Sr(II), Al(III), and nonradioactive Cs( I), Linear calibration plots were obtained in the presence of these potenti al interferences, but at a reduced sensitivity. The fibers were also used t o evaluate the Cs-137 content of a mock tank waste sample to show the poten tial of the fibers in complicated matrixes.