Reactor overview

ILL night large

Under its dome, the ILL operates the world’s most intense continuous neutron source: the High-Flux Reactor (HFR, known officially as Installation Nucléaire de Base n° 67), a nuclear research reactor designed to provide very intense neutron beams. The reactor operates 24 hours a day in cycles of approximately 60 days, delivering three cycles per year. Its core consists of a single fuel element of enriched uranium (almost 10 kg) cooled by heavy water (thermal power 58 megawatts).
Neutrons are produced by the fission of uranium nuclei. They can reach speeds of 20,000 km/second and must be slowed down (or moderated) for use in research. The ILL reactor comprises different sources that allow scientists to select different energy ranges.
The High-Flux Reactor has a modular structure that allows virtually all of its components to be replaced and upgraded. The replacement of the reactor vessel in 1995 has extended the technical life of the HFR until around 2060.

Contact

Email: reacteur@ill.eu

Recent news

Vue ILL
May 25, 2025 Green light to extend ILL operations until 2033
The ILL has just received a firm commitment from its Associate countries, France, the UK and Germany, to continue operation until 2033. “We have been working very hard to secure a unanimous commitment from all three Associate countries and are delighted with the decision,” says ILL Director, Ken Andersen, “The ILL is now in a position to plan scientific operation until the end of 2033.”
France Germany Press releases Reactor Operation United Kingdom
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