The reactor will be equipped with four secondary sources, shifting the thermal neutron energy spectrum in the D₂O moderator into different energy regions:

• A fission spectrum of neutrons in the MeV range is provided by a uranium plate(²³⁵U enriched to 93%) close to the nose of a beam tube. This geometry avoids neutron moderation in water to a high extent and delivers a fast neutron flux of 2x10⁹cm^-2s^-1 at the exit of this beam tube.
• A hot neutron spectrum from 100meV to 1eV emerges from a block of graphite (20cm diameter, 30cm high), being heated by the gamma radiation of the core to a maximum temperature of about 2900K.
• A cold neutron spectrum peaked around 5meV is supplied by a liquid D₂ moderator (20 litres sphere with re-entrant hole) at a distance of 40cm from the core axis and at a temperature of about 25K. The cooling power of 5kW is supplied by an He refrigerator.
• A source of ultra-cold neutrons with energies below 10μeV will be provided by a solid D₂ or a superfluid He source. The optimum source and design concept is still under investigation.