The Nuclear Regulatory Commission last week approved the final safety evaluation report for NuScale Power’s small modular reactor (SMR) design, which proponents hope will revive the nation’s nuclear power industry. Others are skeptical that this latest promise of a nuclear “renaissance” will come to pass given cheap natural gas and declining renewable and storage costs.

The commission greenlit the SMR design on Friday after completing its Phase 6 review of NuScale’s design certification application (DCA), making the Portland, Ore.-based company the first and only SMR manufacturer to successfully complete a DCA review.

“This is a significant milestone not only for NuScale, but also for the entire U.S. nuclear sector and the other advanced nuclear technologies that will follow,” company CEO John Hopkins said in a press release.

Two of the biggest threats to nuclear plants are the loss of water to keep their fuel from overheating and loss of power needed to operate pumps, valves and monitoring equipment.

NuScale’s pressurized light water reactor simplifies or eliminates systems used in earlier-generation plants and employs passive safety features that the company says will ensure the plant can shut down safely.

The passive design was instrumental in the approval process. “The NRC concludes the design’s passive feature will ensure the nuclear power plant would shut down safely and remain safe under emergency conditions, if necessary,” the commission said.

NuScale’s SMR, called the NuScale Power Module, encompasses the reactor, steam generators and pressurizer, and the use of natural circulation eliminates the need for large primary piping and reactor coolant pumps, according to a company spokesperson. Each module has a generating capacity of 60 MW, and the design is scalable, allowing for combinations of up to 12 modules for a total of 720 MW.

By comparison, the smallest nuclear reactor in the U.S. is New York’s R.E. Ginna Nuclear Power Plant, which has one reactor with a capacity of 582 MW. Arizona’s Palo Verde nuclear power plant, the largest in the U.S. with three reactors, has a total capacity of 3,937 MW.

High construction costs and three reactor accidents still scar the industry: Three Mile Island’s partial meltdown in March 1979; the April 1986 accident at Chernobyl; and the 2011 accident at the Fukushima Daiichi plant, in which three nuclear cores largely melted after the plant was swamped by a 45-foot tsunami that disabled the power supply and cooling.

NuScale says its plant can safely shut down and cool itself indefinitely without pumps, AC or DC power, or additional water.

As in traditional reactors, control rods are inserted to stop the fission reaction. But NuScale says its design allows the decay heat removal system and the steam generators to reduce the core thermal power to about 1.1 MWt (megawatt thermal) in one day. (The heat from 3 MWt is enough to generate 1 MW of electricity.)

After three days, core thermal power drops to about 0.8 MWt and reactor pool water begins to boil. For the next 30 days, the water level decreases as core thermal power falls to 0.4 MWt. After 30 days, the reactor pool is emptied, but the reactor remains cool indefinitely by transferring heat to the surrounding air via natural convection.

The company said it is actively engaged with its manufacturing partners to ensure its SMR is ready for delivery to its first client in 2027. It says it has signed agreements with entities in the U.S., Canada, Romania, the Czech Republic and Jordan.

In addition, a 12-module, 720-MW NuScale plant is planned by the public power consortium Utah Associated Municipal Power Systems (UAMPS). The first module is expected to be operational by mid-2029, with the remaining 11 modules to come online for full plant operation by 2030, a company spokesperson told RTO Insider.

To date, NuScale has invested close to $1 billion in the technology development and licensing, which includes more than $300 million in cost-shared funding from the U.S. Department of Energy. NuScale’s majority investor is Fluor, a global engineering, procurement and construction corporation.

Marc Nichol, senior director of new reactors at the Nuclear Energy Institute, said SMRs could aid in bringing the U.S. closer to meeting its clean energy target and making electricity more accessible. “This milestone demonstrates the nuclear industry can meet the demands for reliable, safe and affordable carbon-free energy here in the U.S.,” he said. Adding that clean energy is in demand globally, Nichol said there is a growing interest in SMR technology in Canada, Europe and the Middle East.

Neither NEI nor NuScale directly answered questions about the economic viability of SMRs and how they will compare to renewables and natural gas generation.

A paper published in February in the journal Renewable and Sustainable Energy Reviews found that a manufacturer would need to sell four 180-MW SMRs at $1.5 billion each to recover the cost of a $1 billion factory. It cited a base construction cost of $3,465.72/kW for the 12-module NuScale SMR.

NuScale announced in 2018 that it had reduced the cost of a 12-module plant to $4,200/kWh. The company has set a goal of a $65/MWh levelized cost of electricity.

Lazard’s latest levelized cost of energy puts onshore wind at $28 to $54/MWh, utility scale solar at $32 to $42/MWh, gas combined cycle plants at $44 to $68/MWh and conventional nuclear at $118 to $192/MWh.

‘Big Grain of Salt’

Critics of nuclear power have expressed wariness over NRC’s announcement last December that it is considering shrinking the emergency planning and evacuation zones around the smaller, new reactors from the current 10-mile radius.

“When you’re talking about a reactor that’s never been built or operated, you have to take with a big grain of salt the claims that it’s actually safer or more secure,” Edwin Lyman at Union of Concerned Scientists told NPR.

Lyman said weaker reactor containment shells and off-site operators at certain facilities are on the industry’s wish list. UCS believes companies should follow current construct rules, even when building smaller reactors. “You have to work out the kinks of these new plants,” he told NPR. “And then over time, you might be able to adjust your requirements accordingly. But you don’t do that at the get-go.”

DOE’s National Nuclear Security Administration mirrored a few of Lyman’s concerns in comments sent to NRC, saying the current rules provide “the last layer of a defense-in-depth for low-probability, high-consequence accidents.”

A spokesperson for the commission declined to comment on the safety worries. “The NRC ensures nuclear power plants (and other civilian uses of radioactive material) are safe; questions about the relative benefits of reactors designs are best directed to the Department of Energy’s Office of Nuclear Energy, or to the Nuclear Energy Institute.” Neither responded to RTO Insider’s questions.

Expansion Troubles

Nuclear supporters hope SMRs are the good news the beleaguered industry needs.

As recently as 2010, nuclear proponents talked excitedly of a “renaissance” in the U.S. NRC, which hadn’t issued a construction permit for a nuclear reactor since 1978, streamlined its licensing process and hired hundreds of additional staff to process applications for 30 new generators received after 2007. Some environmentalists had begun to talk about nuclear power as part of the solution to climate change.

By the end of 2010, however, most of the applicants were having second thoughts because of falling natural gas prices, reduced demand projections as a result of the Great Recession and Congress’ rejection of legislation to impose costs on carbon emissions.

While about a fifth of domestic electricity is produced by nuclear power, according to the Energy Information Administration, experts predict a decline in usage in the next few years. Just last week, Exelon announced it would shut down its Byron and Dresden nuclear plants in November 2021 if it fails to win subsidies. (See related story, Exelon to Close Ill. Nukes as Gov. Touts Clean Energy Plan.)

Not helping the industry are failed projects, delays and costly overruns common within new reactor construction.

Georgia Power’s plans to expand Plant Vogtle ran into soaring construction costs, as had been warned by the project’s critics.

Vogtle’s AP1000 design also incorporates passive safety features not present at the Fukushima plants or the current U.S. fleet of reactors. A July 2011 Near-Term Task Force report on insights from the Fukushima accident said the AP1000’s passive designs should keep the reactor core and spent-fuel pools from overheating for 72 hours without power or operator action.

Vogtle, currently the only commercial nuclear power plant expansion underway in the U.S., is billions of dollars over budget. The two reactors under construction were slated to begin commercial output in the spring of 2016 and 2017, but state officials said it is “highly unlikely” the reactors will be online soon.

A Georgia Power spokesperson said in June the company hopes to bring Vogtle Unit 3 online in November 2021 and Unit 4 in November 2022.

The Vogtle project lined up billions of dollars in federal loan guarantees and hundreds of millions of dollars in federal tax credits under both the Obama and Trump administrations.

In neighboring South Carolina, the V.C. Summer expansion by state-owned Santee Cooper experienced years of overruns and delays before the $9 billion project was canceled in July 2017 — dubbed by The Post and Courier as “one of the greatest business failures in state history.”