10.109. An extensive program of safeguards has been established in the United States to prevent the theft of “special nuclear material” defined as plutonium, uranium-233, or uranium enriched in uranium-235, and partic­ularly of “strategic” special nuclear material, consisting of plutonium, ura­nium-233, or uranium enriched to more than 20 percent in an amount equivalent to more than 5 kg of uranium-235. The importance of the latter lies in the fact that it could be used for the illicit production of a nuclear explosive. The safeguard regulations apply to all stages of the fuel cycle, including fuel fabrication, power generation, fuel reprocessing, storage, and transportation. Broadly speaking, however, two situations are consid­ered: material at fixed sites and material during transportation.

10.110. At fixed sites, special nuclear material must be held within a “protected area” with multiple physical barriers. Access to the area is controlled and unauthorized entry is prevented by monitoring systems with alarms. Continuously operating communication systems provide contact with local law-enforcement authorities.

10.111. During transportation, special nuclear material is probably more vulnerable to diversion than at any other time. All shipments, which may be by road or rail, must be accompanied by armed guards, and regular communication must be maintained with the shipper of the material. Trans­portation of special nuclear material could be minimized if nuclear reactors, fuel fabrication plants, and spent-fuel reprocessing facilities were in close proximity. However, single fuel fabrication and reprocessing plants would meet the requirements of more reactors than are likely to be constructed in a particular area. Consequently, even under the best conditions, some transportation of special nuclear material could not be avoided.

10.112. Additional protection against the diversion of special nuclear material is provided by a comprehensive program of internal material con­trol and accounting. This program is designed to detect any loss and to take timely action should such a loss occur. In the United States, the Nuclear Regulatory Commission operates an inspection and enforcement program which includes supervision of material control and accounting. Although the overall costs of the safeguards program are substantial, they are expected to increase the cost of nuclear power by no more than a few percent.

10.113. The International Atomic Energy Agency (IAEA) conducts a broad safeguards program to enforce adherence to the Treaty of the Non­proliferation of Nuclear Weapons (NPT) which has been signed by over 100 nations. An inspection program features accountancy, containment, and surveillance. Material accountancy utilizes various sophisticated in­struments to assay the amount of fissile material present to supplement ordinary “bookkeeping.” “Containment” includes various measures such as locks and seals to assure that material has not been tampered with between inspections. By “surveillance” is meant an inspection program to keep track of material flows.