This International Standard presents the general methodology governing the design of neutron radiation protection shielding and the choice of neutron radiation protection shielding materials. This International Standard is applicable to facilities and operations where neutron sources are located and used, and where workers are occupationally exposed. These operations and facilities vary considerably in design and purpose. These facilities and operations include, but are not limited to: - nuclear power plants; - research reactors; - particle accelerators and neutron generators; - fusion research facilities; - transportation packaging for radioactive materials operations; - medical treatment and research facilities and applications; - industrial applications such as use of devices for measuring and detecting moisture and density level; - space applications; - calibration facilities; - radiographic installations; - nuclear fuel cycle installations (reprocessing plants, plutonium solution handling facilities, shielded cells, waste storage, etc.). The criteria for the design of neutron shielding and the choice of shielding materials contained in this International Standard should be applied to the design of neutron radiation protection shielding systems in such facilities.