On the remote monitoring of gaseous uranium hexafluoride in the lower atmosphere using lidar

• This paper proposes a new method for DIAL detection of the location of UF6 leakage in the lower troposphere.
• This paper uses Raman lidar as a supplement to identify HF as a probe for real-time detection of UF6.
• The system can be used during normal operation or deployed in response to accidental releases from an enrichment plant.
• The system combines DIAL and Raman lidar; thus, it is contactless and can be widely used in the enrichment plant.

Uranium hexafluoride (UF6), a major material for uranium enrichment, is highly toxic and can have adverse effects on the environment and human health if it escapes into the atmosphere. This paper proposes a contactless enhanced remote-sensing system for spatial and temporal detection of gaseous UF6 in the atmosphere and visualization of the leakage location. The system is composed of a combination of differential absorption lidar (DIAL) and Raman lidar for the simultaneous detection of gaseous UF6 and HF. The DIAL provides information on the UF6 concentration using a frequency-quadrupled Nd:YAG laser at 266 nm for the off-wavelength and a Nd:YAG-pumped Coumarin 450 dye laser using a Littrow grating mounting operating in the frequency-doubled mode at 245 nm for the on-wavelength. The Raman scattering of molecular HF at a wavelength of 297.3 nm (with a Raman frequency shift of 3959 cm−1) is a versatile technique used to identify the HF as a probe for real-time detection of the toxic UF6 leakage location. Combining the simultaneous measurements of UF6 and HF allows for a reduction of the uncertainty and an increase in the sensitivity of remote sensing of UF6.