The nuclear sector has a very real need for the capability to accurately identify potentially hazardous substances from a distance, thereby limiting exposure and hazard to human operators. IS-Instruments has been working in the nuclear decommissioning sector since 2018, when it partnered with i3D robotics to develop Callisto, a system combining advanced stereo camera technology to provide a 3D map of the scene and Raman spectroscopy to identify the chemical composition of target substances within that scene.
ISI has also collaborated with Jacobs to develop a spectrometer capable of making Raman measurements within a radioactive environment.
Raman spectroscopy is a proven technique for identifying radioactive substances and is capable of detecting alpha emitters, including low-energy gamma emitters, even when large quantities of other high-energy gamma emitters are present. However, the instruments cannot usually operate effectively in a radiative environment and therefore, cannot be placed in proximity to the target substance. This has so far limited its use in the nuclear sector.
That may all change now with the development of a new class of spatial heterodyne Raman spectrometer system developed in a collaboration between Jacobs and ISI.
The Raman probe can be mounted on a range of platforms, such as a robotic arm or a remotely operated vehicle (ROV) deployed into the area, and stationed at a distance of up to three meters from the target sample. Power and communication are fed through an umbilical cord and used to manoeuvre the platform, whilst a shielded fibre is used to feed the Raman signal back to the spectrometer located outside of the field of radioactivity. This keeps the majority of sensitive, expensive, and complex sensing equipment outside the danger zone, reducing costs and waste. The probe itself was designed from the outset with deployment into radiative environments in mind, and therefore its profile has been constructed with this in mind and from materials that are relatively easy to decontaminate.
IS-Instruments provides expert knowledge in the field of LIDAR, and initially, this technology was used to position the probe at the required distance from the sample. However, owing to repeatability issues, this was later replaced with a stereo vision system provided by i3D robotics, industry leaders in stereo vision technology.
This project is the result of what was initially an Innovate UK-funded Game Changers’ competition supported by FIS360. The system was further developed and incorporated into a wider decommissioning platform during Jacobs’ participation in the UK Integrated Innovation for Nuclear Decommissioning (IIND) competition, which was supported by Innovate UK, the Nuclear Decommissioning Authority and Sellafield Ltd.
This stage of the project has progressed from Technology Readiness Level 3 (TRL3) to TRL8 and has been tested in a representative environment. An expert panel of assessors determined that the Raman technology is of ‘high maturity’ and has demonstrated the requirement for high-quality in-cell characterisation in decommissioning planning and operations. The full system is scheduled for deployment during the decommissioning of an active separation cell on the Sellafield site, and the Raman technology will be one of the first to be implemented.
Read more from these two articles in the Nuclear Engineering International online magazine: Jacobs deploys Raman spectroscopy to identify radioactive contamination and Raman spectroscopy – nuclearized.
