Direct-use nuclear material is essential for building nuclear weapons. The diversion or theft of such material can enable terrorists or countries to build nuclear weapons without investing in expensive nuclear technologies and facilities. One way of deterring and detecting theft is by instituting nuclear material control systems on a national level and at facilities handling direct-use material. “Direct-use nuclear material” consists of highly enriched uranium (HEU) and plutonium that is relatively easy to handle because it has not been exposed to radiation or has been separated from highly radioactive materials. Direct-use material presents a high proliferation risk because it can be used to manufacture a nuclear weapon without further enrichment or irradiation in a reactor. According to the International Atomic Energy Agency, approximately 25 kilograms of HEU or 8 kilograms of plutonium is needed to manufacture a nuclear explosive, although the Department of Energy (DOE) suggests the amounts needed to build a weapon may be smaller. Many types of nuclear facilities routinely handle, process, or store direct-use material. Besides nuclear weapon production facilities, direct-use material can also be found at research reactors, reactor fuel fabrication facilities, uranium enrichment plants, spent fuel reprocessing facilities, and nuclear material storage sites. Most civilian nuclear power facilities are of less concern because they use low-enriched or natural uranium as fuel, which would require additional enrichment before the fuel would be suitable for nuclear weapons. While these reactors produce plutonium in spent reactor fuel, such fuel is dangerous to handle because it is highly radioactive. Spent reactor fuel also requires reprocessing before it is suitable for nuclear weapons. Nuclear materials are controlled to prevent and detect their theft. Nuclear material can be stolen or diverted by (1) outside individuals or groups, such as terrorists attempting to break in and steal nuclear material; (2) inside individuals or groups, such as one or more employees that have access to nuclear material; and (3) combinations of insiders and outsiders. A nuclear material control system consists of three overlapping components—material protection, material control, and material accounting. Together they compose a set of procedures, personnel, and equipment that address both insider and outsider threats. Material protection systems are designed to limit access to nuclear material by outside individuals and prevent the unauthorized removal of material from a facility by inside individuals. Nuclear facilities protect their material by (1) installing fences with sensors and television cameras to delay, detect, and assess unauthorized intrusions; (2) posting armed guards at entry and exit points; (3) establishing a protective response force that can react to unauthorized intrusions; and (4) installing nuclear material monitors to detect attempts to remove material from a facility. Nuclear facilities also assess the reliability of personnel with access to nuclear material by conducting background checks and continuously monitoring their behavior. Material control systems contain, monitor, and establish custody over nuclear material. Nuclear facilities control material by (1) storing material in containers and vaults equipped with seals that can indicate when tampering may have occurred, (2) controlling access to and exit from nuclear material areas using badge and personnel identification equipment, and (3) establishing procedures to closely monitor nuclear materials. Nuclear facilities also designate custodians to be responsible for nuclear material in their possession. Material accounting systems maintain information on the quantity of nuclear materials within specified areas and on transfers in and out of those areas. They employ periodic inventories to count and measure nuclear material by element and isotopic content. Nuclear facilities use the inventory and transfer data to establish nuclear material balances, which track materials on hand and the flow of material within a specified area. The material balances are closed periodically by reconciling physical inventory with recorded inventories, correcting errors, calculating inventory differences and evaluating their statistical differences, and performing trend analysis to detect protracted theft of nuclear material. Nuclear facilities in the United States are capable of updating material accounting data within 24-hour periods. Some U.S. facilities with more modern nuclear accounting systems are capable of updating material accounting data within 4 hours. In addition to facility systems, the United States and most other countries have established national material protection, control, and accounting (MPC&A) systems. These systems include regulations governing procedures for nuclear material protection control and accounting, inspection requirements to ensure that the systems are implemented properly, and tracking systems to provide information on the location and disposition of nuclear material nationally. In the United States, the Nuclear Regulatory Commission and DOE have promulgated regulations on controlling nuclear material. The United States is pursuing two different, but complementary strategies to achieve its goals of rapidly improving nuclear material controls over direct-use material in the newly independent states (NIS). Under the Cooperative Threat Reduction (CTR) program,the U.S. Department of Defense (DOD) entered into agreements with the governments of Russia, Ukraine, and Kazakstan in 1993 to rapidly improve nuclear material controls over civilian nuclear material and develop national MPC&A systems in these countries. On June 23, 1995, DOD entered into an agreement with the Ministry of Defense in Belarus to improve controls over its civilian nuclear material. DOE implements the programs under these agreements. As a complementing strategy, DOE initiated a program in April 1994 of MPC&A cooperation with Russia’s nuclear institutes, operating facilities, and enterprises. This initiative, known as the lab-to-lab program, brings U.S. and Russian laboratory personnel directly together to work cooperatively on implementing MPC&A upgrades at Russian nuclear facilities. The purpose of the lab-to-lab program is to rapidly improve MPC&A at civilian, naval nuclear, and nuclear weapons-related facilities handling direct-use material in Russia. The program is jointly funded by DOE and the CTR program. Our objectives were to (1) review the nature and extent of problems with controlling nuclear materials in the NIS; (2) determine the status and future prospects of U.S. efforts to help strengthen controls over direct-use nuclear material in Russia, Ukraine, Kazakstan, and Belarus; and (3) assess plans for consolidating these efforts in DOE. While seven NIS inherited direct-use nuclear material, we focused on the four countries that have been the primary recipients of U.S. assistance—Russia, Ukraine, Kazakstan, and Belarus. The scope of our review included direct-use nuclear material controlled by civilian authorities in the NIS and direct-use material used for naval nuclear propulsion purposes. We did not review the protection, control, and accounting systems used for nuclear weapons in the possession of the Ministry of Defense in Russia. U.S. officials believe there to be relatively better controls over weapons in the custody of the Ministry of Defense than over material outside of weapons. We also did not include in our review the upgrades at four sites funded by DOE that were not part of the lab-to-lab program. We recently issued a report that addressed the safety of facilities in the NIS. To meet our objectives, we reviewed U.S. assessments of the nature and extent of nuclear material control problems in the NIS; pertinent program documents, including agreements between DOD and the Russian Ministry of Atomic Energy (MINATOM), the Ukrainian State Committee on Nuclear and Radiation Safety, the Ministry of Defense of Kazakstan, the Ministry of Defense of Belarus, and between DOE and Gosatomnadzor (GAN); program plans; trip reports; quarterly progress reviews and State Department cables; and program budget, obligation, and expenditure data for the CTR-sponsored government-to-government program and for DOE’s lab-to-lab program. We also discussed with DOE plans to consolidate U.S. MPC&A assistance in DOE. We interviewed officials from DOD, DOE, the Department of State, the Nuclear Regulatory Commission, the National Laboratories (including Los Alamos, Sandia, and Lawrence Livermore), the Pacific Northwest Laboratory, the National Security Council, and the National Academy of Sciences. We also interviewed nonproliferation specialists from the Monterey Institute of International Studies. In Russia, we interviewed officials from MINATOM, Gosatomnadzor (the Russian nuclear regulatory agency), the Kurchatov Institute, the Institute of Physics and Power Engineering, the Elektrostal Machine Building Plant, the MINATOM nuclear weapons laboratories Arzamas-16 and Chelyabinsk-70, and the Kazakstan Atomic Energy Agency. In addition, we toured facilities at the Kurchatov Institute and the Institute of Physics and Power Engineering, located in the Russian Federation, to obtain information on current MPC&A systems implemented at these facilities. We visited sites in Russia that have been the recipients of U.S. assistance efforts, including the Elektrostal Machine Building Plant, the Kurchatov Institute, and the Institute of Physics and Power Engineering. We also witnessed the demonstration of a model MPC&A system at Arzamas-16. Our review was conducted between November 1994 and January 1996 in accordance with generally accepted government auditing standards. With the dissolution of the Soviet Union, Russia and six other NIS inherited hundreds of tons of direct-use nuclear material. Much of this material is thought to be located at 80 to 100 civilian, naval nuclear, and nuclear weapons-related facilities, mostly in Russia. However, U.S. and NIS officials do not know the exact amounts and locations of this material. Much of it is highly attractive to theft because it is relatively safe to handle and is not in weapons. U.S. officials are concerned that social and economic changes in the NIS have increased the threat of theft and diversion of nuclear material, and with the breakdown of Soviet-era MPC&A systems, the NIS may not be as able to counter the increased threat.