A physical protection system is the integration of people, procedures, and equipment used to protect assets or facilities against theft, sabotage, or other malicious human attacks. The PPS functions are detection, delay and response. As Defined by the IAEA, Nuclear security is: The Prevention and Detection of, and Response to, theft sabotage unauthorized access illegal transfer theft , Sabotage , Unauthorized access, Illegal transfer or other malicious acts involving nuclear material, other radioactive substances or their associated other radioactive substances or their associated facilities. These objectives can be achieved with equipment, methods and human behavior that we can trust. The objectives of the nuclear security and physical protection system is to protect nuclear facility or nuclear material against threats and terrorist. The equipment is not sufficient it must be completed with nuclear security and nuclear security culture to achieve these objectives. The PPS and nuclear security can achieve the protection of nuclear facility and nuclear material if they complete each other’s and fill the gaps.