Shoddy construction, midprocess design changes and mismanagement have claimed another major nuclear energy project in the United States.
Earlier this month the U.S. Department of Energy (DOE) terminated construction of a facility in South Carolina designed to transform 34 metric tons of surplus military plutonium, enough for about 17,000 nuclear weapons, into fuel for nuclear power plants. DOE says the project is unnecessary and too expensive, while supporters say it is needed to keep a federal promise to move the plutonium cache out of state and to preserve 1,800 jobs at the site.
The Aiken, S.C., project began in 2007 and was at least US $2.6 billion over its $4.9 billion estimated cost and still years from completion. The cost escalations and delays were akin to those afflicting the pair of Westinghouse AP1000 nuclear reactors under construction in nearby Vogtle, Ga., and another pair killed last year at South Carolina's VC Summer plant.
Mismanagement is only half the story, however, according to Edwin Lyman, a physicist and nuclear expert at the Union of Concerned Scientists in Washington. Lyman says the plant was also plagued by safety, technology, and regulatory challenges specific to handling plutonium. Trace amounts of plutonium cause lethal cancers and its 24,110-year half-life means small releases could render lands uninhabitable for generations making it an attractive material for would-be makers of “dirty” bombs.
The Aiken project was conceived to take plutonium stockpiled close by at the U.S. Department of Energy’s Savannah River Site and blend it with uranium to produce mixed-oxide fuel. Such MOX fuel is used by several dozen nuclear power plants, primarily in Europe. The MOX plant was largely a carbon copy of a 22-year old MOX plant in France. As a result MOX Services, the joint venture building it for DOE, expected to have it operating in 2016, reasonably snappy for a major nuclear project.
However, MOX Services’ two parent firms are not doing well. Chicago Bridge & Iron is the contractor that bungled the AP1000 projects (and was recently taken over by McDermott International). Paris-based Orano, which runs France’s MOX plant, is part of the former nuclear giant Areva whose troubled reactor projects contributed to its break-up by the French government in 2017.
Problems emerged early at the Aiken site. In January 2008, for example, a section of rebar shattered when hammered by a MOX site worker. An investigation revealed that the rebar was construction-grade rebar instead of the high-grade steel specified by the project’s license from the U.S. Nuclear Regulatory Commission (NRC). According to federal prosecutors 142 tons were built into the plant [PDF], necessitating additional reinforcement of concrete structures that were supposed to withstand aircraft strikes and other assaults.
Quality assurance problems continued thereafter, according to DOE. In 2016 its auditors estimated that one quarter of the partially completed plant’s pipes, wires, and ducts had been reinstalled. The need for further rework contribute to diametrically contrasting assessments of the project’s status; in 2016 MOX Services pegged it at 70 percent complete, whereas DOE judged it to be 72 percent incomplete.
Lyman says design changes after construction began compounded the management issues. The design evolved because NRC and DOE standards differed from the 1990s French standards under which Melox was built. Transposing the design thus required more than converting from metric to imperial (which industrial experience shows to be a non-negligible challenge). Critical safety and security issues had to be reevaluated.
Technology also contributed to design shifts. Whereas Melox uses relatively pure plutonium, some of DOE’s plutonium contained contaminants that were unwelcome in commercial reactors. Much of Savannah River’s plutonium came from nuclear weapons cores or “pits” and was alloyed with gallium. And some had accumulated the plutonium breakdown product americium.
Chemical separations can remove these impurities, but not all were ready for industrial use. “The chemistry might have been available but it still required substantial chemical engineering. That greatly complicated the plant design,” says Lyman.
Efforts to kill the Aiken MOX plant began under the Obama Administration in 2013 but were blocked until now by South Carolina’s Congressional delegation and by a court challenge filed by the state. And it’s not over. DOE’s cancellation of the plant this month came one day after the lifting of a Federal court injunction, but the lawsuit is still pending. And one week after the DOE termination, GOP senator Lyndsey Graham and other South Carolina politicians were at the White House pleading their case with President Donald Trump.
President Trump may have actually helped seal the project’s fate, according to Lyman. Trump wants to ramp up nuclear weapons production and Lyman says the U.S. defense establishment sees repurposing the Aiken site as a quick way to jump-start large-scale production.
“That’s their No. 1 option for rebuilding pit manufacturing capability,” says Lyman. “When the Pentagon decides it wants that facility, it changes the game.”
Repurposing the incomplete MOX plant could, however, be more fraught than they anticipate. Lyman points out that MOX Services did not systematically track and manage rework before 2014, so “the full extent of the problems may never be known.” It would also be darkly ironic, since the project was funded out of the DOE’s nonproliferation account.
Lyman is backing a more peaceful use of the Aiken site: training nuclear security personnel. This, he says, would take advantage of the site’s Category 1 internal and external security specifications.
Meanwhile, new trouble is brewing as DOE implements an alternate plan for the aging and impure plutonium at Savannah River. DOE says it has begun to mix the plutonium with unspecified materials that confound its use in bombs, and it is sealing this blend in canisters for shipment to a high-level waste repository.
As long as the plutonium leaves South Carolina, DOE will have met its obligation to the state. But the agency’s “dilute and dispose” approach has already ignited opposition in New Mexico, which hosts the DOE Waste Isolation Pilot Plant slated to receive the plutonium. Officials and activists there say the added plutonium may exceed the amount of high-level waste that New Mexico has agreed to accept.