The €20bn ($21.9bn) International Thermonuclear Experimental Reactor (Iter) nuclear fusion project is at a critical moment and facing “technical and regulatory difficulties” as executives work to finalise a new schedule and key targets, Fusion for Energy (F4E) director Marc Lachaise told the budget committee of the European Parliament.

Lachaise said the project is experiencing “some further delays” which are temporarily affecting the full implementation of the current budget earmarked for F4E, the organisation administering Europe’s contribution to Iter.

Responding to questions from MEPs about a budget forecast for 2025-2027, Lachaise said that before a new schedule is agreed by the Iter Council, which oversees the project, it is impossible to accurately forecast figures.