Each nuclear power generating station has comprehensive design features to limit the exposure of the public to radioactive material. These design features include fission-product barriers that limit the mobility of radioactive material; shielding systems that absorb the direct radiation from radioactive material; control systems that maintain the energy released from the reactor in balance with the energy dissipation capability of the station and that maintain the release of low-level radioactive effluents within established limits; and safety systems which detect abnormal conditions and act to perform a protective function that prevents or limits the escape of radioactive material. The requirements set forth in this document are directed toward developing the design basis for safety systems and safety supporting systems. The requirements consider the integrated response of the nuclear reactor, the structures, the fluid systems, the mechanical equipment, the instrumentation systems, and the electrical systems of the station, to events that are related to the mobility of radioactive material.