There are over 1,000 different nuclear facilities worldwide, including nuclear power plants, research reactors and fuel cycle facilities. With considerable amounts of nuclear and radioactive material in transit and in storage, improved physical protection is an essential preventive measure against acts of theft and sabotage. Physical protection requires a mixture of security devices, radiation detectors, cameras, procedures for guards and fences. The IAEA's Office of Nuclear Security operates an International Physical Protection Advisory Service (IPPAS), which helps states to identify ways to strengthen the protection of nuclear materials and facilities. At the request of a state, the IAEA assembles a team of international experts to assess the country's physical protection system, compare it with international best practices and make recommendations for improvements. In January and February 2012 an IPPAS mission was conducted at various nuclear facilities in the Netherlands. Khammar Mrabit, the Director of the IAEA's Office of Nuclear Security discusses the purpose and goals of an IPPAS mission.