Remotely Monitoring Uranium-Enrichment Plants with Detection of Gaseous Uranium Hexafluoride and HF Using Lidar

Abstract

A sudden release of UF 6 inside a building or to the atmosphere could conceivably cause undesirable health effects to workers and the public in general, mainly associated with the exposure to hydrolysis products HF and UO 2 F 2. Although the hydrolysis reaction of UF 6 is fast, after escaping of UF 6 into the atmosphere, besides HF and UO 2 F 2 ,U F 6 may also be found in the atmosphere. This chapter proposes a real-time technique to provide information to technical personnel and facility operators on the atmospheric release of UF 6 to ensure that the workers, the public, and the environment are adequately protected. The system comprises a combined differential absorption lidar (DIAL) and Raman lidar to detect gaseous UF 6 and HF, simultaneously. The DIAL provides information on UF 6 concentration using a frequency-quadrupled Nd:YAG laser at 266 nm as the off-wavelength and a Nd:-YAG-pumped Coumarin 450 dye laser using a Littrow grating mounting operating in the frequency doubled at 245 nm as the on-wavelength. Recording Raman scattering of molecular HF at wavelength of 297.3 nm (with Raman frequency shift of 3959 cm À1) is a versatile technique to identify HF as a probe for real-time detection and localization of UF 6 leaks.