ANS weighs in on NNSA’s Pu disposition plan

February 1, 2021, 12:00PMRadwaste Solutions

The American Nuclear Society is urging the National Nuclear Security Administration to rethink its “dilute-and-dispose” plan for managing surplus weapons-grade plutonium. In comments submitted to the NNSA, ANS notes that a better solution for the agency’s inventory of surplus plutonium is to convert it to nuclear fuel for advanced reactors, as was originally intended.

The comments are in response to a December 16 Federal Register notice by the NNSA that it intends to prepare an environmental impact statement on the scope of its Surplus Plutonium Disposition Program. According to the notice, the NNSA intends to dispose of the entire 34 metric tons of surplus plutonium using its dilute-and-dispose approach, whereby the material will be downblended and shipped as transuranic waste to the Department of Energy’s Waste Isolation Pilot Plant (WIPP) in New Mexico.

Under the Plutonium Management and Disposition Agreement, signed by the United States and Russia in 2000, the 34 tons of plutonium was to be converted to mixed-oxide nuclear fuel using the MOX Fuel Fabrication Facility at the Savannah River Site, in South Carolina. However, the Obama administration, citing rising costs, halted construction on the facility in 2016, and the project was eventually canceled in 2019.

Recommendations: In a January 29 letter to the NNSA, ANS president Mary Lou Dunzik-Gougar and executive director/chief executive officer Craig Piercy note that using the surplus plutonium as advanced reactor fuel has several notable advantages over dilute-and-dispose. Those advantages, the letter states, are summarized as follows:

  • Use as reactor fuel would produce a valuable and useful product—clean energy—from the material that was produced at great expense to the American people. In contrast, dilute and dispose produces no useful product.
  • The surplus plutonium could be an attractive source of fuel for advanced reactors, particularly those with a fast neutron spectrum. Advanced reactors offer many potential advantages as a clean, safe, and reliable energy source, and there is considerable public and private investment in bringing designs into operation. The surplus weapons plutonium could be a reliable initial fuel supply for some designs.
  • Dilute and dispose does not destroy any plutonium and does not degrade the material isotopically. From a nonproliferation perspective, it would be preferable to use the material as reactor fuel, thereby destroying some plutonium and transmuting much of the remainder so that it would not be attractive for use in nuclear weapons.
  • Use of dilute and dispose for all of the surplus plutonium would have significant adverse impacts on WIPP, the country’s only geological disposal facility for transuranic waste. The NNSA environmental impact statement should address all WIPP impacts, including the country’s much-reduced transuranic waste disposal capacity that would result from a decision to implement dilute-and-dispose at WIPP.

Dunzik-Gougar and Piercy also note that Russia did not recognize the dilute-and-dispose approach in its agreement with the United States and that it would be prudent for the NNSA to provide a plutonium disposition alternative that is more acceptable to Russia than disposal.

The advantages of using surplus military plutonium as nuclear reactor fuel are discussed in more detail in ANS Position Statement #47, Disposition of Surplus Weapons Plutonium.

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