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A number of questions swirl around the governor’s plan to put a small modular nuclear reactor in Southwest Virginia to generate carbon-free energy, and many of them center around concerns about the waste it would produce.
Unfortunately, with construction of the first SMR as much as a decade away and only one design approved by the Nuclear Regulatory Commission, there are many questions yet to be answered.
About nuclear waste
By the numbers:
92 – Number of nuclear power plants in the U.S.
75 – Number of sites where nuclear waste is stored in U.S.
2,000 – Metric tons of used nuclear fuel rods produced in the U.S. each year
86,000 – Metric tons of spent nuclear fuel stored in U.S.
3,124 – Metric tons of used nuclear fuel stored in Virginia
Sources: U.S. Government Accountability Office; U.S. Department of Energy
Although there have been a few studies attempting answers on SMR waste, they appear to be contradictory. For example, a study published in May by Stanford University and the University of British Columbia states that despite their smaller size, SMRs would actually produce more radioactive waste than conventional nuclear power plants.
Yet, according to an analysis of the waste that would be produced by three SMR designs released in November by Argonne National Laboratory, SMRs do not produce more waste. “All told, when it comes to nuclear waste, SMRs are roughly comparable with conventional pressurized water reactors, with potential benefits and weaknesses depending on which aspects you are trying to design for. Overall, there appear to be no additional major challenges to the management of SMR nuclear wastes compared to the commercial-scale large LWR (light-water reactor) wastes,” said Take Kyum Kim, senior nuclear engineer for the U.S. Department of Energy’s Argonne National Laboratory.
Scott Burnell, public affairs officer for the NRC, said the agency is aware that several reports have been done on waste from SMRs.
“Some of those reports did not seek NRC input, nor our review of their conclusions,” Burnell wrote in answer to questions from Cardinal News. “It’s important to note that until companies formally apply for design approval and licensing of advanced reactor facilities, there’s a great deal of uncertainty in what sort of volumes or material (and the corresponding disposal requirements) will come from a given technology. Applications for advanced reactor technologies will have to provide sufficient evidence to demonstrate these facilities will meet the relevant requirements for public health and safety. There are diverse views on this topic and we welcome additional studies and analysis as we learn more about spent fuel and waste in advanced reactors.”
He added that the NRC will continue to work with stakeholders to understand these issues and protect the public and the environment.
The NuScale SMR design – the only design approved by the NRC – would be a light-water reactor like the traditional, larger nuclear reactors operating in this country for decades. So, more is known about the waste, which would have much in common with what comes from conventional reactors, according to Burnell.
Much less is known about how to deal with spent fuel from SMR designs cooled by something other than water, Burnell said.
Nuclear waste from traditional reactors
Here’s what we know about the waste from today’s large reactors, how it’s handled and where it ends up.
When you’re talking about waste from nuclear reactors, you’re primarily talking about spent fuel. Each year, about 2,000 metric tons of used nuclear fuel rods are produced by the 92 nuclear power plants in the U.S.
As a result, there are about 86,000 metric tons of spent nuclear fuel from commercial reactors stored at 75 U.S. sites, according to a U.S. Government Accountability Office (GAO) report published in September 2021.
Still, the Nuclear Energy Institute (NEI) says the total amount of nuclear waste produced in the U.S. over 60 years doesn’t take up a lot of space.
If stacked end to end, it would “fill one football field, 10 yards deep,” the NEI states on its website.
Nuclear experts agree that the best solution for the waste is to bury it, which is called deep geological disposal. The NRC describes a geological depository as using a mixture of natural and engineered barriers like tunnels to isolate the waste from the surrounding environment.
Since 1987, the plan has been to store all this country’s nuclear waste at one site, Yucca Mountain in the desert in Nevada. But that plan has been mired in politics for decades and in 2010, the U.S. Department of Energy announced it would withdraw its application for a license to store nuclear waste there. But the Nevada site remains designated as the nation’s nuclear repository by law.
Since the federal government currently has no site for disposal, it has paid reactor owners about $9 billion for storage, the GAO says on its website.
Virginia’s nuclear waste
In Virginia, there were 3,124 metric tons of used nuclear fuel in storage at plant sites, according to an October 2020 report by the U.S. Department of Energy. The report is based on numbers from Dec. 31, 2019, and are the latest figures available, according to the NRC.
Dominion operates four reactors at two nuclear power plants in the commonwealth, North Anna in Louisa County, and Surry in Surry County, and each stores 1,562 metric tons of spent fuel.
Spent nuclear fuel is mostly uranium and is considered dangerous, high-level radioactive waste. The NRC has regulatory authority over the storage and disposal of all commercial nuclear waste in the U.S.
Radioactive waste naturally decays over time. But the time range for decay ranges from a few hours to hundreds of thousands of years, according to the U.S. Environmental Protection Agency.
Low-level radioactive waste includes contaminated protective clothing, tools, filters and rags from nuclear power plant maintenance and operations, plus some medical facility wastes and a few other items.
According to the NRC, low-level waste is normally stored at a plant site until it decays and can be disposed of like regular trash, or shipped to a low-level waste disposal site.
Currently, there are four existing low-level waste disposal facilities in the U.S. that accept several types of low-level waste, and they are in Barnwell, South Carolina; Richland, Washington; Clive, Utah; and near Andrews, Texas.
Virginia’s spent nuclear fuel storage
In Virginia, each reactor at the North Anna and Surry nuclear power plants holds 157 fuel assemblies and each assembly is made up of more than 200 fuel rods that each hold around 350 uranium dioxide fuel pellets about the size of an adult finger, according to Scott A. Miller, manager of communications and media relations for Dominion Energy Nuclear. That’s 10.99 million fuel pellets in each reactor.
The life of a fuel assembly for commercial reactors is about 4.5 years. Every 18 months, about a third of the fuel reaches the end of its useful life and is removed from the core and entered into the long-term used fuel storage process, Miller said.
“That means that every 4.5 years, all the fuel assemblies in the reactor will have been replaced,” Miller wrote in an email to Cardinal News.
Initially, all used fuel assemblies are placed in the station’s spent fuel pool, which is a steel- and concrete-reinforced structure filled with water to a depth of 40 feet. The water serves to shield the radiation and cool the rods. The ongoing circulation of water in the pool prevents the buildup of “decay heat” from the radioactive material in the used fuel, Burnell said. The assemblies remain there for about five years until they cool enough to move to dry storage.