Neutrons at the ILL are delivered by its reactor.
Refurbished between 1993 and 1995, thereactor produces the most intense continuous neutron flux in the world in the moderator region: 1.5x1015 neutrons per second per cm2, with a thermal power of 58.3 MW.
The reactor operates continuously for a 50-day period ("cycle"), followed by a shutdown to change the fuel element. One longer shutdown is planned every year to enable maintenance work to be carried out. Normally there are 4 cycles in a year, providing 200 days for science.