Note: Plasma optical emission spectroscopy for water vapor quantification and detection during vacuum drying process

Abstract

A methodology involving plasma optical emission spectroscopy driven by a direct current (dc) plasma source is developed to quantify water vapor concentration in a gaseous stream. The experimental setup consists of a dc driven low-pressure plasma cell in which the emission from the plasma discharge is measured by using an optical emission spectrometer. The emission from Hα at 656.2 nm—the first transition in the Balmer series, was found to be the most sensitive to the water vapor concentration in the gas stream. Consistent linear trends of the emission signals with respect to variation in concentration of water are observed for multiple combinations of operating parameters. This method has been applied to a vacuum drying process of a mock nuclear fuel assembly to quantify the concentration of water vapor during the drying process.

Aluminum-clad Spent Nuclear Fuel Engineering Scale Drying Experiment Design

“…This instrument involves a direct current (DC) driven plasma discharge and optical emission spectroscopy (OES) for detecting as well as quantifying water vapor in a flowing gas stream under both trace and high-water vapor loading conditions. For the quantification of water content, a system has been calibrated for gas mixtures of helium and water vapor (Tahiyat, 2018). The OES system is connected to the chamber via a 0.25" (0.635 cm) stainless steel tube and Swagelok connection from one of the 2.75" CF ports on the upper section of the chamber.…”