Completion of the mixed-oxide fuel facility at Savannah River Site, one of the federal government’s biggest projects, is stuck between the recommendations of competing experts.
Construction has cost more than $5 billion, and about one-third remains to be built. Completion is estimated to take an additional $3 billion and last until 2022.
Once the facility is operating, the MOX program will require billions more and stretch at least a decade as it converts 34 metric tons of weapons-grade plutonium into reactor fuel that can be sold to power companies. The plan comes from a 2000 agreement with Russia in which each country promised to burn up an equal amount of bomb-making ingredients as a way to lessen the possibility of nuclear war.
The expense and time investment has grown so large that the Obama administration decided to halt the MOX program before it begins, instead favoring a process it calls “dilute and dispose.”
“Unlike the MOX approach, the Dilute and Dispose approach offers opportunities for introduction of efficiencies which could reduce life-cycle duration and cost, many of which could be implemented after the program is underway,” stated a 2015 Energy Department report.
This alternate approach reduces nuclear materials’ concentration and stores it forever a half-mile underground in a New Mexico salt dome called the Waste Isolation Pilot Plant.
Besides the issue of whether Russia will go along with the change – and President Vladimir Putin says it won’t – is a brewing debate among experts on which option is the best.
The Energy Department hired some consultants, Aerospace Corp., and drew on its in-house Red Team to criticize MOX and support the New Mexico plan. Meanwhile, the MOX Services Board of Governors, which oversees the consortium building the MOX facility, hired its own consultants, High Bridge Associates.
“If you can convince me there’s a cheaper way to do this that meets our international commitment and overcomes the regulatory and statutory hurdles, I’m all ears,” U.S. Sen. Lindsey Graham, a MOX supporter, told one Energy Department witness during a Senate hearing. “But don’t give me an ill-conceived plan no one has thought through that doesn’t have a snowball’s chance in hell of working.”
One of the most contentious issues is called criticality. It has to do with whether storing the canisters holding the diluted material will eventually reach a critical mass needed to start a chain reaction, essentially becoming a bomb or at least generating enough energy that radioactive material gets disbursed into the atmosphere.
The reason the New Mexico site was considered in the first place is twofold. First, residents there support it as a jobs creator. Second, the mass of salt 2,000 feet thick tends to move slowly over long periods in such a way that it’s said to “heal” small cracks that develop, maintaining a seal around any canisters ultimately crushed by the collapse of the dome ceiling.
However, High Bridge warns that the crushed containers will cause leaks that can result in criticality.
“The extremely high pressures created as the salt cavern closes in on the storage drums will force the plutonium closer together, creating the geometry of crushed storage drums which facilitates a critical chain reaction,” the MOX builders’ experts wrote in a recent report.
The government’s goal is a solution for the next 10,000 years.
High Bridge concluded the only way to avoid criticality is to spread out the drums more in the New Mexico site, adding to the time and expense of the dilute-and-dispose method.
The Energy Department’s Red Team, based at Oak Ridge National Laboratory, wrote that “contrary to conclusions in the High Bridge report, risks associated with the Dilute and Dispose option are far lower than the MOX approach, since both the technology and the disposition process associated with Dilute and Dispose are far simpler.”