Neutron beam tubes will be used to supply those instruments which are located in the reactor building around the core. By tangential arrangement of the tubes in relation to the core axis, direct view from the instrument back to the core is avoided. As a result, contamination by fast neutrons and gammas as an outcome of the fission process is significantly reduced.

Each beam tube is designed to deliver two neutron beams with typical cross sections of 120mm x 80mm. With an angle of 8° between these beams, two instruments can be placed at the beam exit without geometrical constraints. The spectrum of neutrons delivered by these tubes is determined by the characteristic source temperature in front of the nose, which will be thermal in respect of D₂O (300K), cold in respect of tubes facing the cold D₂ source, or hot in respect of the graphite source (2900K). The beam tubes are made out of aluminium alloys to minimize neutron losses from passage through the walls. For safety reasons, all guide tubes are filled with Helium gas.

One large beam tube facing the cold source will deliver neutrons to the large guide hall outside the reactor building - the so-called neutron guide hall. This tube will deliver six guided neutron beams horizontally spread within a fan of about 15° around the main axis. To avoid losses in beam intensity, these beams are guided within rectangular glass tubes - these neutron guides were, in fact, invented at the FRM resp. the Atomic Egg.

Neutrons are totally reflected from the very flat surfaces of many materials, as these surfaces constitute barriers in terms of critical potential energy from which they are reflected. Due to the weakness of these potentials (some neV), only a small cone (less than 1° for thermal neutrons) can be guided without loss in these neutron guides - however this fairly small cone meets the beam requirements of many instruments in an ideal way.