Neutron flux in the context of Neutron scattering

A breeding blanket is a device used in nuclear engineering to transmute quantities of an element, using the neutron flux from a fission reactor or fusion reactor. In the fission context, breeding blankets have been used since the 1950s in breeder reactors, to manufacture fission fuel from fertile material. In the fusion context, they have been conceptualized for the manufacture of tritium from lithium-6. In both scenarios, neutron radiation is converted into thermal energy in the blanket, leading it to require its own cooling system.

The Advanced Test Reactor (ATR) is a research reactor at the Idaho National Laboratory, located east of Arco, Idaho. This reactor was designed and is used to test nuclear fuels and materials to be used in power plants, naval propulsion, research and advanced reactors. It can operate at a maximum thermal power of 250 MW and has a "Four Leaf Clover" core design (similar to the Camunian rose) that allows for a variety of testing locations. The unique design allows for different neutron flux (number of neutrons impacting one square centimeter every second) conditions in various locations. Six of the test locations allow an experiment to be isolated from the primary cooling system, providing its own environment for temperature, pressure, flow and chemistry, replicating the physical environment while accelerating the nuclear conditions.

The ATR is a pressurized light water reactor (LWR), using water as both coolant and moderator. The core is surrounded by a beryllium neutron reflector to concentrate neutrons on experiments, and houses multiple experiment positions as well. It operates at low temperature and pressure 71 °C (160 °F) and up to 2.69 MPa water pressure. The ATR reactor vessel is solid stainless steel, 35 feet (11 m) tall by 12 feet (3.7 m) across. The core is approximately 4 feet (1.2 m) tall by 4 feet (1.2 m) across.