CSIC is working in collaboration with Industry Partner CERN and Arup engineers to identify suitable remote monitoring technologies to help maintain tunnels and other infrastructure at the European Organisation for Nuclear Research, in Switzerland, which are showing some signs of movement at certain sections.
The radioactive environment inside the tunnels makes several conventional monitoring technologies unsuitable for long-term monitoring as the radiation affects their performance.
CERN has a variety of tunnels with a total length of approximately 80km. A 27km ring tunnel, constructed in the 1980s, houses the Large Hadron Collider (LHC), the world’s largest and most powerful particle accelerator. Access at many sections of the tunnels is limited due to the radioactive environment making maintenance difficult. With certain tunnel sections showing some signs of movement, long-term monitoring is essential, but effective maintenance requires a better understanding of the long-term behaviour of the tunnels.
CSIC is monitoring critical sections of the tunnels and underground caverns using distributed fibre optic sensing, 3D laser scanning and computer vision technology.
CSIC’s monitoring delivers a long-term commitment to providing continuous data about the structural health of the CERN tunnels. CSIC’s technologies are robust enough to survive the extremely demanding environmental conditions and present minimal maintenance costs. The ability to offer spatially continuous data builds confidence about the current and future condition of the underground structures.
To date, two tunnel sections and an underground cavern have been instrumented and are being monitored with CSIC technologies. This project will continue until late 2017 and the CSIC team is training CERN engineers to ensure the monitoring and maintenance programme can continue autonomously. Six Arup and CERN engineers attended a two-day CSIC course on fibre optic sensing in Cambridge in December 2014, followed by on-site training at CERN in February 2015.
Impact and benefits
• the installed sensors provide long-term sensing data of CERN assets and create a database of infrastructure behavioural patterns. This will be coupled with engineering analysis of long-term performance of CERN tunnels conducted by CSIC researchers
• CERN will know if its assets can survive under extreme radiation conditions during the operation of the experiments
• CSIC’s fibre optic technologies offer a cost-effective solution as there is minimal maintenance cost of the fibres and a comparatively low operative cost of the fibre optic analysers
• civil engineers will be able to better understand the long-term behaviour of tunnels and underground structures over their entire life history and additionally investigate how these structures respond to radioactivity