The United States has long sought, via its domestic laws as well as foreign policies, to ensure that ostensibly peaceful nuclear commerce does not aid nuclear weapons programs. Mechanisms and instruments such as the nuclear Nonproliferation Treaty (NPT), International Atomic Energy Agency (IAEA) safeguards, the Nuclear Suppliers Group (NSG), and economic sanctions all continue to play a role in stemming nuclear weapons proliferation. The restrictions contained in U.S. law governing nuclear cooperation with other countries comprise another tool for preventing proliferation. However, Congress has become increasingly concerned that, with the growing international interest in nuclear power, U.S. laws and policies may need to be changed in order to prevent further nuclear proliferation. This report begins with a brief overview of the global nuclear power industry, including the possessors of enrichment and reprocessing technology. It then describes the state of the U.S. nuclear industry, particularly its dependence on both international trade and foreign suppliers. The report then reviews the multilateral nuclear nonproliferation mechanisms. It concludes with a detailed summary of U.S. nuclear cooperation agreements, the primary mechanism by which the United States both promotes U.S. nuclear commerce and ensures that such commerce does not contribute to clandestine nuclear weapons programs. The report also includes appendices that provide additional details. The United States has long engaged in civil nuclear commerce with other countries, buying and selling nuclear fuel, reactors, and related components. Perhaps the most significant congressional action to regulate such commerce was the Nuclear Nonproliferation Act of 1978 ( P.L. 95-242 ), which amended the Atomic Energy Act of 1954 (AEA) and imposed additional restrictions on U.S. nuclear commerce designed to ensure that transfers of nuclear energy technology would not contribute to the proliferation of nuclear weapons. In the 113 th Congress, Members have introduced several bills that would add to the nonproliferation criteria and strengthen congressional oversight of bilateral nuclear cooperation under Section 123 of the AEA, as amended ( P.L. 95-242 ; 42 U.S.C. §2153 et seq.) (hereinafter "123 agreements"). During the past decade, Members of Congress have become increasingly concerned that, with an increased global interest in nuclear power, additional countries may obtain domestic enrichment or reprocessing technology, the most sensitive components of the nuclear fuel cycle. Uranium enrichment can produce low-enriched uranium for use as fuel in nuclear reactors, but can also produce highly enriched uranium, which can be used as both reactor fuel and as fissile material in nuclear weapons. By reprocessing spent nuclear reactor fuel, a state can produce plutonium, which it might use as fuel in certain types of nuclear reactors and also as fissile material in nuclear weapons. Obtaining fissile material is widely regarded as the most difficult task in building nuclear weapons. (For an illustration of the nuclear fuel cycle, see Appendix A .) These proliferation concerns have generated increased congressional interest in laws governing bilateral nuclear cooperation agreements. Recent congressional debates over 123 agreements with India, Russia, the United Arab Emirates (UAE), South Korea, and Vietnam highlighted concerns about the need to balance nonproliferation, commercial, and strategic goals. Additional agreements are expected to come before Congress for consideration in the next few years. Sixteen countries are planning to build their first nuclear power plants by 2030, according to the World Nuclear Association. IAEA estimates that world nuclear power generation by 2030 will grow 46%-142% from 2012, led by the Far East and Eastern Europe (along with possible reductions in Western Europe). Concerns about the safety of nuclear power and its economic competitiveness are the major near-term inhibitors of nuclear growth, according to IAEA. But the agency predicted, "In the longer run, the underlying fundamentals of population growth and demand for electricity in the developing world, as well as climate change concerns, security of energy supply and price volatility for other fuels, continue to point to nuclear generating capacity playing an important role in the energy mix." World nuclear power generation has dropped since 2006, particularly after Japan's reactors shut down following the 2011 Fukushima disaster. Nuclear power critics contend that construction delays, cost overruns, and competition from renewable energy will strongly inhibit the future of nuclear power. They point out that three countries—China, India, and Russia—account for two-thirds of the reactors currently under construction worldwide. In the countries considering their first nuclear reactors, such projects are at various stages of planning (see Appendix B ). Ten countries that are currently building or formally planning reactor projects—Bangladesh, Belarus, Egypt, Indonesia, Jordan, Kazakhstan, Poland, Turkey, the UAE, and Vietnam—have never operated nuclear power plants. According to the Organization for Economic Cooperation and Development (OECD), 36 countries that have never had nuclear power are "actively preparing" or have "expressed interest in starting a nuclear power programme." OECD categorizes the potential nuclear newcomer countries by the size of their economies and their electrical grid capacity, because those factors "may provide a rough indication of which countries may be the strongest candidates to proceed with nuclear development" (see Table 1 ). Only Canada, China, France, Japan, Russia, South Korea, and the United States export nuclear reactors. India is reportedly attempting to join this group. Some emerging nuclear power states have concluded agreements with non-U.S. reactor suppliers. For example, Vietnam has such contracts with Russia and Japan, Turkey has an agreement with Russia, and the UAE has signed a reactor contract with South Korea. The United States has nuclear cooperation agreements with 25 countries, the IAEA, and Euratom (see Appendix C ). State Department officials have said that approximately 17 nuclear cooperation agreements will be negotiated, renegotiated, or extended in the next three years. Currently, the United States is negotiating a 123 agreement with Jordan, although those negotiations have been suspended. The most recent 123 agreement—with Vietnam—entered into force on October 3, 2014. The preamble of the agreement includes a political commitment that says Vietnam intends to rely on international markets for its nuclear fuel supply, rather than acquiring sensitive nuclear technologies. At the same time, the United States pledges to support international markets to ensure a reliable nuclear fuel supply for Vietnam. Article 6 of the agreement specifically prohibits Vietnam from enriching or reprocessing U.S.-obligated nuclear materials—for instance, materials that are transferred from the United States—without specific future U.S. consent. The United States has concluded Memoranda of Understanding (MoU) regarding potential nuclear cooperation with Bahrain, Jordan, Mongolia, and Saudi Arabia. However, a state's conclusion of such an MoU is neither necessary nor sufficient for a country to conclude a 123 agreement. Only a limited number of countries conduct commercial enrichment and reprocessing of fissile materials and can supply this technology. At the present time, supplier states are not planning any transfers of enrichment or reprocessing technology. As is discussed below, the Nuclear Suppliers Group recently added criteria to its guidelines for the supply of fuel cycle technologies. Commercial reprocessing is now being done in France, the United Kingdom, Russia, Japan, and India. China has a pilot reprocessing plant and plans to open a larger facility around 2017, possibly followed by a full-scale commercial plant to be built by the French firm Areva by 2025. South Korea is pursuing a research and development program on pyroprocessing. Some countries with few natural energy resources, such as Japan, argue that they want to reprocess their spent fuel to reduce dependence on foreign energy sources. Reprocessing proponents in those countries prefer a closed fuel cycle, in which spent nuclear fuel from reactors is used to make fuel for other reactors; opponents raise questions about weapons proliferation risks and high economic costs. Commercial enrichment is currently being done in the United States, Russia, France, Japan, China, and countries in the Urenco consortium (the United Kingdom, Netherlands, Germany). The Eurodif consortium's enrichment plant is on French soil, and France does not share the enrichment technology with co-owners Belgium, Italy, Spain, and Iran. Argentina is in the process of re-commissioning its gaseous diffusion enrichment plant at Pilcanyeu to provide fuel for one of its nuclear power reactors. Brazil has been gradually expanding a small enrichment facility for its nuclear power reactors. Only Russia and the United States, as well as the European multinational consortia Urenco and Eurodif, supply enriched uranium for commercial purposes to other countries. The only currently operating U.S. enrichment plant, which started up in 2010, is the Urenco USA facility in New Mexico. Some reports argue that, for the foreseeable future, current commercial enrichment capacity will be able to provide for global nuclear fuel needs and, therefore, building new enrichment plants on purely commercial grounds may not be justified. According to the World Nuclear Association, world enrichment capacity is likely to continue substantially exceeding world nuclear fuel requirements at least through 2020. Most states depend on foreign enrichment services for their nuclear fuel, and current enrichment providers have been expanding their capacity in anticipation of an expanded market in the future. In addition, Russian and U.S. stockpiles of high-enriched uranium (HEU) from dismantled nuclear weapons are being down-blended for use as low-enriched uranium (LEU) fuel, further adding to market supply. However, an increase in nuclear power plants in countries without enrichment capabilities may increase interest in domestic enrichment in new states. There has been a renewed interest in multinational fuel cycle services as a way to provide fuel supply assurances. Urenco and Eurodif have provided commercial enrichment services for over three decades. The International Uranium Enrichment Centre in Angarsk, Russia, began operations in 2007. It is a commercial uranium enrichment consortium that does not share sensitive enrichment technology, but does share profits. Participants include Russia, Kazakhstan, Ukraine, and Armenia.