Small size, big problems: NuScale’s troublesome small modular nuclear reactor plan

  • Two energy experts discuss the design risks and excessive costs of the NuScale small modular nuclear reactor.
  • NuScale project distracts from the need to push clean energy sources.

Despite its small size, NuScale has outsize cost and safety problems.

NuScale is one of several companies making long-shot attempts to commercialize what are known as small modular nuclear reactors, or SMRs. Its 77-megawatt project is the furthest along in the Nuclear Regulatory Commission, or NRC, licensing approval process, but in the earliest stages, with a long way to go. But the NRC has identified serious safety concerns, and cost estimates have ballooned in recent years. 

EWG has long warned about the folly of investing in nuclear power, including SMRs that are unlikely ever to get off the ground.

And in a new analysis commissioned by EWG, two nuclear experts with decades of experience note significant NuScale cost and safety drawbacks that have been raised by NRC staff.

 The experts recently analyzed the November 15, 2022, pre-application readiness assessment report the NRC issued to NuScale, which details many concerns about the project’s safety. The two authors are Arjun Makhijani, Ph.D., president of the Institute for Energy and Environmental Research, which advocates for a safer environment, and M.V. Ramana, Ph.D., a professor at the School of Public Policy and Global Affairs, University of British Columbia. 

Their findings further strengthen the case against more funding for NuScale – yet another nuclear boondoggle that will fleece American taxpayers.

The primary issues they identified were escalation costs and design issues, for which the company has not properly addressed the safety issues involved. These include:

Costs. The projected construction costs of the first proposed NuScale project have grown from $5.3 billion, as estimated in November 2021, to $9.3 billion, in January 2023.

Risks. The NRC and its Advisory Committee on Reactor Safeguards identified several safety risks in the design for the reactor, in particular with the steam generator.

Energy companies, states and the government should stop throwing good money after bad, wasting it on lofty “all of the above” nuclear plans that will never come to fruition. 

Instead they should focus on promoting workable, clean power solutions that already exist, like wind, solar and distributed generation, and associated technologies. Taxpayer dollars should be spent only on technologies that fight the climate crisis and do not have a history of persistent, inevitable ratepayer and taxpayer bailouts. Nuclear power and carbon capture and sequestration both fail that test.

The nuclear money pit

The nuclear industry survives in part thanks to assertions of clean, cheap power, which have never materialized, and an oversize influence in Congress and state legislatures.

Earlier projects saw billions of dollars of construction-related canceled plants and enormous cost overruns that were dumped on ratepayers and taxpayers. Then a series of bailouts followed to keep uneconomic plants online.

Huge amounts of funding have been provided to nuclear companies and other organizations to bring new nuclear reactor designs, including SMRs, to market. This funding is unlikely to lead to any significant progress reducing carbon emissions or mitigating climate change.

Experts: NuScale’s costs soaring 

NuScale’s first SMR plant is intended for the Utah Associated Municipal Power Systems, or UAMPS. The goal is to provide power to electric utilities in Utah and surrounding states. The target date is 2029, though nuclear plants have typically been plagued by significant delays. Its estimated cost is over $9 billion for just six small reactors that would, in total, be less than half the size of the standard large nuclear unit. 

That estimate has increased by $4 billion in less than two years.

But the government keeps throwing taxpayer dollars at NuScale, promising $1.4 billion to the UAMPS project on top of the $400 million it has already squandered. 

Other than these expected costs spiraling out of control, Makhijani and Ramana in their analysis find that even though NuScale keeps changing design specifications for its unit, NuScale’s safety analyses have not evaluated the impact of these design changes.

Experts: Changes in design present dangerous power projections 

NuScale has increased by 50 percent the power output of its yet-to-be-built SMR reactor design. This means there will be more heat, pressure and radioactivity, which will further stress critical components of the reactor. These factors increase the risk of a catastrophic breakdown and radiation leak.

Unlike any nuclear power plant that’s already online, NuScale would house the reactor core – the nuclear fuel – and steam generator in the same vessel. This would be a departure from the traditional design, in which the steam generator is separated from the fuel, outside the reactor vessel but inside the secondary containment.

The helical design of the steam generator has also never been used in any other commercial nuclear power plant, which makes it hard to evaluate how it would behave in the long run.

Experts: Risky reactor design

The NRC has preliminarily approved NuScale’s design, despite serious questions about the steam generator. And NuScale still hasn’t produced the necessary analysis of all the accidents that could occur. 

As Makhijani and Ramana write: 

[T]the NRC staff stated that further analysis or testing results to ‘demonstrate the design and performance of the steam generators’ could be included as part of the application for the license to construct and operate the reactor, even though ‘[s]ome uncertainty will remain until a NuScale Power Module is built and operated.’ 

A major accident is a little late to determine whether the reactor and its steam generator will operate safely.

Steam generators are subject to severe heat and vibrations, as Makhijani and Ramana note. Replacing them in a standard reactor is already extremely difficult and expensive. A failed steam generator in the NuScale reactor vessel design would be much more complicated to replace.

The authors state: “It is entirely possible that, if the steam generator fails, the reactor might have to be shut down permanently, the equivalent of having to junk a car because it is too costly and difficult to replace a failed transmission.”

Experts: NRC ignored risk guidance  

The Advisory Committee on Reactor Safeguards, or ACRS, warned in a letter to NRC the “design and performance of the [NuScale] steam generators have not yet been sufficiently validated.”

The 1954 Atomic Energy Act requires ACRS to review and report to the NRC commissioners and staff about safety studies and reactor facility license and license renewable applications, among other issues. 

The ACRS noted that NuScale’s plan “introduces different failure modes.”

Vesna Dimitrijevic, Ph.D., who is an expert in probabilistic risk assessment and a member of the ACRS, dissented from the decision to certify the reactor before steam-generator-related issues were settled. She writes that “the steam generator integrity is too significant of a safety issue to not have received finality in the NuScale design certification.”

NRC staff ignored Dimitrijevic’s warning. 

Experts: A flawed energy plan

Makhijani and Ramana conclude that the NuScale project, referred to as VOYGR, has too many problems and that there is insufficient information to justify NuScale’s safety claims.

“[T]he 77-MW VOYGR . . . has not received standard design approval, much less full Commission certification. On the contrary, it has received a letter from the NRC staff with 99 ‘significant’ observations and six major challenges,” they write.

Further, they warn: 

These problems need real-world analysis, design, and most important, real-world testing to be resolved. Premature wear of the steam generators and their potential failure were not analyzed properly and insufficiently tested even for the (previous) 50 MW design. The hurdles are even higher with the 77-MW version.

The NuScale project is a trainwreck waiting to happen. 

It would be irresponsible for the NRC to proceed at this juncture with any further approval. The question for NRC is whether the agency wants to keep the financially unviable, unsafe nuclear industry alive or focus on public safety and legitimate options for fighting the climate crisis.  

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