CERN’s Future Circular Collider: tunnelling scale and risks explained for engineers
Reviewed by Tom Sullivan

First reported on Tunnelling Journal – News
30 Second Briefing
CERN Council has declared the CHF15bn Future Circular Collider technically feasible, clearing a major hurdle for a 90.7km circumference tunnel with access shafts between 180m and 400m deep across eight surface sites, seven in France and one in Switzerland. The feasibility review drew on around 1,500 experts from 162 institutes in 38 countries, with no technical “showstoppers” identified so far. Recommendations under the European Strategy for Particle Physics will be finalised by May 2026, with a construction decision expected around 2028, signalling a potential decade-scale tunnelling and underground works programme.
Technical Brief
- Feasibility review followed a dedicated CERN Council meeting held on 6–7 November 2025.
- Multiple governance layers were involved: subordinate bodies, independent expert committees, and Scientific Policy and Finance Committees.
- Around 1,500 specialists from 162 institutes in 38 countries contributed to the FCC Feasibility Study.
- ESPP update process is community-driven, with a dedicated recommendation meeting scheduled for December 2025 in Ascona.
- Council approval of updated European Strategy for Particle Physics is targeted for May 2026.
- Feasibility Study report is explicitly framed as decision support for CERN Member States, not a pre-approval.
- Council statement links FCC delivery to maintaining CERN’s leadership role in particle physics and technology.
Our Take
Among the 163 Infrastructure stories in our database, very few involve underground works on the scale of the FCC’s 90.7 km tunnel with 180–400 m shafts, so this will likely set reference prices and methodologies for future deep tunnel tenders in Switzerland and France.
The concentration of seven of the eight FCC surface sites in France suggests French planning, utilities and transport interfaces will dominate early enabling works, with Swiss authorities more focused on cross-border governance and high-level environmental approvals.
With 162 institutes from 38 countries tied into the FCC Feasibility Study, contractors bidding around 2028 can expect unusually stringent and internationally benchmarked requirements on ground investigation, settlement control and vibration isolation compared with typical regional infrastructure schemes.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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