MOX Fuel Fabrication: A Path Forward for Nuclear Energy in the United States?

Recently, the House Appropriations Committee approved a $30.4 billion FY2014 Energy and Water Appropriations bill, including a $320 million provision for construction of the Mixed Oxide (MOX) Fuel Fabrication Facility at the Savannah River Site near Aiken, South Carolina. This sum is approximately $115 million below the facility’s FY2013 budget and reflects increasing congressional pressure to improve project management and trim costs on a project whose total construction budget has risen from $4.9 billion to $7.7 billion.

At the same time, the Obama administration has indicated a desire to draw back funding for the plant as an element of overall administration budget reductions, preferring instead to explore alternatives to MOX fuel fabrication. As it stands, the MOX Fuel Fabrication Facility faces an uncertain future; on the one hand, there is increasing resistance from the administration to complete the project, while on the other hand, there has been increasing congressional support for project completion although such support has been accompanied by severe budget cuts.

For its part, the MOX Fuel Fabrication Facility is the result of the 2000 Plutonium Management and Disposition Agreement (PMDA), which entered into force in July 2011. Under the agreement, both the United States and Russia agreed to dispose of at least 68 metric tons of surplus weapons-grade plutonium in an effort to permanently reduce the threat posed by excess fissile material. Enough plutonium for approximately 17,000 nuclear weapons will be eliminated and converted to fuel for use in commercial nuclear power reactors under this arrangement.

The MOX Fuel Fabrication Facility at the Savannah River Site will play a key role in carrying out this process. Yet despite the potential non-proliferation benefits, a number of questions still exist regarding cost effectiveness, waste management, and the safety and security of MOX fuel that require a closer look from the policy community as it decides the future of MOX fuel fabrication in the United States.

Q1: What is MOX fuel?

A1: MOX fuel uses both plutonium and uranium oxide as its fissionable elements. At the MOX Fuel Fabrication Facility, mixed oxide fuel powder will be manufactured using five percent plutonium-239 and 95 percent uranium-238. Essentially, MOX fuel uses fissionable plutonium in place of the 3 to 5 percent of fissionable uranium-235 that is normally combined with uranium-238 to form uranium oxide fuel.

At the facility, the powder will subsequently be milled to ensure a uniform composition, shaped into small pellets, and baked at high temperatures. Finished pellets will be placed into fuel rods that are then bundled into groups of 264 to form an entire fuel assembly, which can then be loaded into a commercial reactor. Once the fuel is irradiated in a reactor, it will no longer be suitable for use in nuclear weapons, thus fulfilling the United States’ international non-proliferation obligations as defined in the PMDA.

Q2: What are the potential benefits and challenges related to MOX fuel fabrication?

A2: Cost, safety, and the storage of irradiated fuel are the major challenges facing MOX technology as an alternative to uranium oxide fuel. In a 2002 Department of Energy report to Congress, MOX fuel fabrication was cited as the preferred option for disposing of excess weapons-grade plutonium when compared with lower cost alternatives, such as long-term storage, immobilization, or use of the plutonium in advanced-type reactors, due to the approach’s consistency with U.S. non-proliferation and security objectives. Not only is the MOX-based approach consistent with the United States’ disposition obligations under the PMDA (which requires the conversion of plutonium in to an unusable form), but it also enjoys the most support from Russia and the greater global community. Accordingly, it provides the greatest guarantee that Russia will remain committed to a parallel disposition program for its share of excess plutonium. Thus, despite the high cost, policymakers must weigh the potential gains in nonproliferation that a MOX-based approach provides.

Much of the controversy surrounding the MOX facility centers on the total project cost forecast of $7.7 billion and the relatively high cost of MOX fuel fabrication as compared with low-enriched uranium (LEU) fuel fabrication. According to a 2009 MIT report on the economics of nuclear fuel cycles, current comparisons of the cost of MOX and uranium oxide fuel cycles are based on the assumption that fuel from both cycle types will be sent to geologic repositories once spent. However, the study noted that it is also possible to extract transuranics from spent light-water reactor fuel for use in fast reactors. If it is cheaper to extract transuranics from spent MOX fuel than from uranium oxide fuel, the report concluded, then the relative cost of MOX fuel may be less than what has traditionally been calculated.

Currently, the Tennessee Valley Authority is considering the use of MOX fuel in its nuclear power reactors and according to its 2012 Draft Surplus Plutonium Disposition Supplemental Environmental Impact Statement, “expects that MOX fuel could help fulfill [its] mission, as a safe and cost-effective fuel to generate electricity.” The international market for MOX fuel—which includes France, Germany, Belgium, Switzerland, and Japan—also provides some evidence for its economic viability as compared with uranium oxide fuel.

The safety of MOX fuel should also play a major role in policy discussions on its future use in U.S. nuclear power reactors. Support for MOX fuel has diminished since the discovery of plutonium in soil samples after the 2011 disaster at the Fukushima Daiichi power plant, where reactor No. 3 used MOX fuel. On the other hand, proponents of MOX fuel have argued that, even when reactors are loaded with traditional uranium oxide fuel, plutonium is produced and fissioned as a natural byproduct of uranium fission. The resulting mix of material at the reactor’s core effectively becomes a lower-plutonium form of MOX fuel.

Finally, the question of the storage of spent MOX fuel poses a major challenge to its use in U.S. commercial nuclear reactors. With regard to interim storage, the Nuclear Regulatory Commission “expects no significant difference in the way used MOX fuel and used uranium fuel is stored.” On the question of long-term waste disposal, however, the viability of MOX fuel greatly depends on the licensing of a high-level waste storage facility, especially due to the uncertainty that currently surrounds the Yucca Mountain project’s continuation.

Q3: What is the future of MOX fuel fabrication abroad and in the United States?

A3: Although 31 light water reactors worldwide currently use MOX fuel, future international demand for MOX fuel is uncertain. Since the Fukushima meltdown, Japan, who was previously one of the biggest supporters of MOX fuel, has expressed hesitancy over the future use of nuclear energy overall. Indeed, the effects of the 2011 disaster have been far reaching—shortly after the event, Britain’s Nuclear Decommissioning Authority announced the closure of the Sellafield MOX Plant, citing the lack of orders for MOX fuel. In the United States, similar concerns over the safety, storage, and cost-effectiveness of MOX fuel will remain key components of policy conversations on its future use in commercial nuclear reactors. Accordingly, it may be necessary to conduct further inquiry into the costs and benefits of MOX fuel with the understanding that any approach to the disposal of surplus plutonium will likely have significant cost, safety, security, and nonproliferation implications.

Michael Wallace is director of the Nuclear Energy Program at the Center for Strategic and International Studies (CSIS) in Washington, D.C. Alayna Rodriguez is a research intern with the Nuclear Energy Program at CSIS

Critical Questions is produced by the Center for Strategic and International Studies (CSIS), a private, tax-exempt institution focusing on international public policy issues. Its research is nonpartisan and nonproprietary. CSIS does not take specific policy positions. Accordingly, all views, positions, and conclusions expressed in this publication should be understood to be solely those of the author(s).

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