Design concepts for construction of cold neutron source

The cold neutron source (CNS) is a facility installed near the core to increase the cold neutron flux. The moderator material is limited from the reason of cross sections and build up of radiation damage, and in practice, the combustible hydrogen or deuterium is used in research reactors. Therefore we need to compromise and optimize between safety and a gain factor of cold neutron flux. We discuss generally how to draw up and promote the CNS construction project, considering safety-standard which is now admitted in many CNS facilities. Design concepts concerning neutronics calculation, commission procedures and material inspections are also discussed. (author)