A New Wiping Device for Detecting Removable Contamination

Abstract

A new wiping device for detecting removable contamination was developed. A cylindrical plastic scintillator (PS) is applied to a roller device. A wiping material wraps around the cylindrical PS roller, and then the roller is used for wiping to detect removable contamination (PS method). After contamination on the floor is wiped off using the roller, the wrapped PS is removed from the roller and placed in a glass vial for use in a liquid scintillation counter (LSC). The vial is measured by LSC without liquid scintillation cocktail. When the PS method was used by wrapping with NUC-Wipe™, the wiping efficiencies, except for the measurement efficiencies, were almost 15% for H and 40% for C. Also a repositionable tape (Double Stick Tape™) could be used for wiping material. The device has three main advantages: 1) Though the wiping efficiency is not very high when using the PS method, the variability observed is lower than that for hand wiping; 2) even when it is contaminated with nuclides whose maximum beta ray energies (Emax) are very close, for example C (Emax; 156 keV) and S (Emax; 167 keV), the contaminated radioisotopes are identified with their spectra by using PS; and 3) the PS method is environmentally friendly, as post-processing time is vastly shortened because it does not use a liquid scintillator. Some issues that were previously considered unavoidable in the wiping method were improved using a plastic scintillator as a roller.