Year
2019
Abstract
At INMM 2017 Goldston et al. (1) presented a concept for a non-invasive, non-spoofable, thermal mass-flow meter for use in unattended monitoring of gas-centrifuge enrichment plants. It is based on nearby surface heating and cooling of a pipe carrying UF6 gas, and the determination of the power required to maintain a specified temperature gradient along the pipe. This concept is currently undergoing experimental testing and analysis at the Los Alamos National Laboratory, to be reported at INMM 2019. We will present a simplified, flexible time-dependent analysis tool based on the Dittus-Boelter correlation for heat flow between pipe walls and turbulent gas flow. Initial time-independent analytic results show good agreement with more complete ANSYS CFX studies, but greatly decreased computational requirements. This tool will allow efficient optimization of the feedback algorithm to sustain the specified temperature gradient, including optimization of the time-response and sensitivity of the system. It will also allow determination of the resistance of the system to spoofing through heating or cooling of the UF6 gas relative to the pipe, in advance of its entry into the measurement section. Time dependent changes in environmental conditions can be analyzed as well. Comparisons with more complete analysis and experimental results will be presented.