NuScale: Improved Nuclear Energy

Is nuclear energy the unsung hero of the alternative energy movement? Modern research and engineering is demonstrating that carbon-free nuclear reactors can be made safer, smaller, and more available. These new reactors, like the Small Modular Reactor (SMR) technology being developed at Corvallis’ own NuScale Power, are poised to further revolutionize energy production as well as other fields like water desalination and hydrogen fuel production.

Defining Next-Generation Nuclear
NuScale’s co-founder and Chief Technology Officer (CTO) is Dr. Jose Reyes, an emeritus professor at OSU’s School of Nuclear Engineering and Radiation Health Physics. The Advocate spoke to Dr. Reyes in order to understand how NuScale is different than traditional nuclear energy, and why their technology is about more than just power generation.

NuScale grew out of a Department of Energy research project started in 2000, seeking innovative designs for small, multi-purpose reactors. OSU’s School of Nuclear Engineering participated in this project. After its conclusion, the participants filed patents on their designs and research, laying the foundation for what would become NuScale Power. 

NuScale’s SMR design is considered to be on the leading edge of a new generation of nuclear technology. They utilize passive safety systems designed to prevent human error, and possess self-contained cooling systems requiring minimal water as just one way to minimize the impact on local environments. Their small size also means they can be assembled remotely and shipped to serve individual businesses and communities. Dr. Reyes’ desire to widen the scope of nuclear energy is becoming common among a new generation of scientists who believe nuclear power can help address global issues like reducing atmospheric carbon or desalinating drinking water.

What is an SMR?
A Small Modular Reactor (SMR) is precisely what is says: small and modular.

Older-generation reactor facilities, with their giant concrete-reinforced towers, can reach hundreds of feet high and occupy hundreds of square miles. According to NuScale’s plans, their reactor module, containing the core and its cooling system, will be only 76 ft. tall. NuScale’s plans for their pilot facility in Idaho will use only 34 acres of land, with the reactors aligned horizontally and partially underground to further reduce the facility’s footprint. It will still require a certified facility in which to operate, but the vastly decreased size will reduce multi-billion dollar construction costs and the amount of land needed for modern facilities.

Modular means that these reactors can work in series. According to the database of the International Atomic Energy Agency, the global organization which monitors and regulates nuclear activity, most operating nuclear power plants run anywhere between one to six reactors inside, and generate between 500 and 1500 MWe (megawatts electric, how we measure electricity output from a power plant). One NuScale module generates only 60MWe, but the reactors are designed to work individually or as an array. The pilot facility in Idaho will include an array of 12 reactors, totaling about 720MWe, a fairly average output for a nuclear power plant. This ability to scale the power output from nuclear reactors to match local needs and limitations has already drawn utilities across the world to NuScale’s model.  

Addressing basic safety
Skepticism of nuclear power as a reliable, renewable source of energy is often rooted in safety and containment issues for both humans and the general environment — and for good reason. Mismanagement and ignorance have caused historical disasters like in Chernobyl, Ukraine and more recently in Fukushima, Japan. According to both Dr. Reyes and NuScale, safety has been a watchword of theirs since the beginning.

Part of what is revolutionary about NuScale’s reactor is its ability to shut down and cool itself without any additional human or mechanical systems, using no external power or water. The improper operation or malfunctioning of external safety systems was a factor in previous nuclear accidents like Three Mile Island. Traditional-style reactors, like Westinghouse Nuclear’s AP1000 system, use externally-powered safety systems that must be attached to the pressure vessel; the container that holds the nuclear fuel. These pressure vessels are built to withstand extreme pressures and temperatures, and adding something as seemingly benign as a cooling system pipe can create structural weaknesses. The NuScale reactor module houses both the pressure vessel and cooling systems, surrounded by a vacuum chamber which acts as another heat sink for the core. This reduces operator error and removes the need for external safety systems.

It is important to note that the word safety, in regards to nuclear energy, is a relative term. There is no such thing as a completely safe nuclear reactor, as the process of nuclear fission is an inherently chaotic one. In a 2013 study, nonprofit advocacy group the Union for Concerned Scientists (UCS) stated they believe the addition of  an active cooling system would make the NuScale SMR more robustly safe, given the addition would offer more options in the instance of an event beyond what was anticipated in the current design. UCS maintains that the vessel design could be modified to still accommodate the addition of a cooling pipe. 

UCS often criticizes nuclear power industry practices and regulatory standards. They argue that even as SMRs are inherently less likely to suffer internal safety compromising events, the benefit may be outweighed at multi module sites. For example, in the instance of three SMRs doing the work of one larger reactor, the probability of a “beyond design” external event effecting one of the three reactors would be increased,  

They further argue that such external events present a higher probability that multiple reactors at a site would be effected, than would an internal event, and these sorts of events spread responding personnel more thinly.

It is worthwhile noting that the IAEA’s database indicates many nuclear power plants currently operate multiple reactors. The Bruce Generating Station in Ontario, Canada has eight. 

Environmental concerns
Long-term environmental health and safety are part of NuScale’s plan as well. Older reactors pump in large amounts of water for cooling, increasing costs and physical size. NuScale’s “natural circulation” cooling system uses a minimal amount of water, which is cycled through the reactor by the natural expansion and compression of water and steam, as opposed to requiring external pumps and power. In case of an emergency, the reactor will not require any additional water to shut down. 

Smaller reactors also require less fuel and less storage space. 

“A NuScale SMR power plant would require less than one percent of the land that renewables such as biomass, wind, solar and hydro power need for the same amount of generation,” said Dr. Reyes.

Dr. Reyes noted that only one acre of their land would be used to store their spent fuel, a much smaller ratio than older plants. There are real and ongoing concerns with the storage of spent nuclear fuel, as it remains highly radioactive and therefore costly to transport and store safely. The federal government designated Yucca Mountain in Nevada to be the long-term storage site for radioactive material like nuclear fuels. But Yucca Mt. sits just over 100 miles from Las Vegas, home to most of Nevada’s population. Political pressure and numerous lawsuits over the last few decades have questioned the choice of site, and the rigor of the process determining its safety for long-term storage. It was supposed to begin accepting fuel in 1998, but the ongoing challenges to the location and changing federal priorities have brought the process to a standstill.

UCS objects to the perpetual on-site storage of spent fuel and pushes the federal government to secure a more viable long-term storage site, but have also endorsed the use of the dry-cask storage method that NuScale plans to use, at least for interim storage. 

In addition to improving storage solutions, Dr. Reyes and NuScale also promote the practice of reprocessing spent fuel. According to NuScale, spent fuel is 96% reusable, and reprocessing can reduce storage needed for it by 75% and the toxicity of the fuel by as much as 90%. This is not insignificant, as nuclear facilities produce a small fraction of the physical waste compared to carbon-heavy ones.

Dr. Reyes noted that the U.S. does not reprocess much fuel, even though the technique was developed here. This is concerning, given some waste can remain toxic for hundreds of millions of years. 

When asked why other nuclear states like England, France, and Japan use this process, Dr. Reyes’ answer was simple: economics. Uranium is currently cheap, and as long as it remains cheap, expensive reprocessing isn’t good business. 

Still, economics remain a real concern for NuScale who, despite their rising star, are competing in a demanding global industry. A 2011 study by the Energy Information Administration estimated the cost of various methods of producing electricity. Carbon-sequestered coal (“clean coal”) plants cost ~$4,600/kW, and nuclear power plants cost ~$4,700/kW. Recent testing of NuScale’s SMR showed it would cost ~$4,200/kW. The cost difference is not dramatic, but it is competitive. 

To note, the savings from switching to zero-carbon electricity goes beyond financial concerns, especially in light of recent UN studies on the impact of human-generated climate change caused primarily by the burning of carbon-based fuel.

Widening the scope of
nuclear energy

One goal that Dr. Reyes communicated clearly was to broaden the applications of nuclear energy. He wants to change the perception that nuclear energy is only used for power production. An experience working for the IAEA opened his eyes to the fact that “their issues were not only about power, but infrastructure, capital, even water.” 

Some countries could not meet the massive construction costs of typical nuclear power plants. Among those who could afford it, their electrical grid could not handle all the power from a standard-sized facility. Dr. Reyes realized lower-output, scalable reactors could cut upfront costs and allow countries without highly developed electrical grids to invest.

These next generation reactors have the potential to make a difference in the environment as well, according to Dr. Reyes. He said that a single NuScale reactor could provide up to 60 million gallons of clean water per day. Desalination is a power-intensive process, usually run on carbon fuels, and switching to a carbon-free method reduces the environmental footprint of important human services like clean water. Dr. Reyes said a full array of 12 reactors could provide enough water for the city of Cape Town, South Africa. He also mentioned their utility in generating hydrogen for fuel-cell cars. Really, he says, “anywhere we can start removing carbon emissions.”  

What’s Next?
While there are many companies across the world designing SMRs, NuScale’s is the first SMR design to pass the first phase of the Nuclear Regulatory Commission’s licensing process – a major hurdle. Their Idaho pilot plant will serve the Utah Associated Municipal Power Systems (UAMPS), and is planned to be finished by 2026. UAMPS is only one of a group of over two dozen utilities that meet regularly with NuScale. Dr. Reyes said NuScale’s quick progress through the rigorous federal licensing process has drawn wide interest, but it helps that a utility like UAMPS was willing to take the first step.

“[Some] don’t necessarily want to be first, but they certainly want to be second or third,” said Dr. Reyes with a laugh.

NuScale’s progress has made waves outside the U.S. as well. Dr. Reyes said they currently have executives flying all over the world gauging interest and building relationships, specifically mentioning there is a lot of interest from the United Kingdom. 

Like many large, heavily-regulated businesses, the nuclear industry isn’t likely to change overnight. But people with new ideas like Dr. Reyes, instead of getting the industry to catch up, are moving ahead and setting the stage for the next generation of carbon-free energy technology.

By Ian MacRonald