Catawba Nuclear Station MOX Fuel Project

Catawba Nuclear Station MOX Fuel Project

Fig. 1: Catawba Nuclear Station (Source: Wikimedia Commons))

After the Cold War, the U.S. Department of Energy (USDOE) initiated a project in collaboration with Duke Engineering and Services, Cogema, and Stone & Webster to facilitate the disposition of excess weapons-grade plutonium through mixed-oxide (MOX) fuel fabrication and reactor irradiation services. One facility where this disposition strategy started was the Catawba Nuclear Station, situated near Rock Hill, South Carolina (see Fig 1). The plant is overseen by Duke Power for its power generation across both North and South Carolina. [1]

Catawba Unit Specifications

Catawba Unit 1 initially achieved criticality in 1985. Catawba Unit 2 followed suit in 1986. [2] Both reactors are classified as Westinghouse pressurized-water reactors. Unit 1 produces 1165 MWe of net electrical output and Unit 2 produces 1145 MWe of net electrical output. [2] The core configuration of the reactors consist of 193 fuel assemblies and utilizes a 17 x 17 design. [1]

Fabrication Process

The United States signed an agreement with Russia in 2000 for each country to dispose of 34 metric tons of excess weapons-grade plutonium. [3] The USDOE planned to combine the surplus plutonium with uranium to create MOX fuel to be used by commercial nuclear reactors. In addition to powering other nuclear plants, the creation of MOX fuel served two other uses. First, the plutonium in the fuel would be destroyed by fission in the reactors themselves. Second, isotopes of plutonium that would not be useful in weaponry would be created. [4] On a more technical level, the fabrication of weapons-grade plutonium MOX fuel assembly employs the use of advanced micronized master blend (A-MIMAS) processes. The result of this process is ceramic PuO₂ and UO₂ fuel pellets containing 2 to 5 wt % fissile plutonium, which is consistent with the MIMAS process utilized for reactor-grade MOX fuel fabrication. [1]

Conclusion

The Catawba Nuclear Station MOX Fuel Project presented a significant step towards the disposition of excess weapons-grade plutonium. The meticulous design considerations and fabrication processes allowed for the project to aim to ensure compatibility and reach optimal performance with the Catawba reactor core.

© Kyle Kang. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.

References

[1] R. J. Ellis, "System Definition Document: Reactor Data Necessary for Modeling Plutonium Disposition in Catawba Nuclear Station Units 1 and 2," Oak Ridge National Laboratory, ORNL/TM-1999/255, September 2000.

[2] "Annual Radiological Environmental Operating Report - 2022," Duke Energy, April 2023.

[3] "Mixed Oxide Fuel," U.S. Nuclear Regulatory Commission, April 2017.

[4] M. Holt and M. B. D. Nikitin, "Mixed-Oxide Fuel Fabrication Plant and Plutonium Disposition: Management and Policy Issues," Congressional Research Service, R43125, December 2017.