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Honey, I Shrunk the Nuclear Reactor!

image credit: ID 89436090 © Vaclav Volrab |

I immediately apologize for that lame title, but I wanted to take a moment to talk about the ability that the R&D into increasingly smaller nuclear reactors might have in the future of a decarbonized energy mix. 

The U.S. Department of Energy has been touting their efforts into Advanced Small Modular Reactors (SMRs) as a key part of the future of clean and affordable energy. 

NuScale Reactor Building

According to DOE:

Advanced SMRs offer many advantages, such as relatively small size, reduced capital investment, ability to be sited in locations not possible for larger nuclear plants, and provisions for incremental power additions. SMRs also offer distinct safeguards, security and nonproliferation advantages.

The Department has long recognized the transformational value that advanced SMRs can provide to the Nation’s economic, energy security, and environmental outlook. Accordingly, the Department has provided substantial support to the development of light water-cooled SMRs, which are under licensing review by the Nuclear Regulatory Commission (NRC) and will likely be deployed in the next 10-15 years. The Department is also interested in the development of SMRs that use non-traditional coolants such as liquid metals, salts, and helium because of the safety, operational, and economic benefits they offer.

What's excited me about these SMRs is that the economics can flip around and make nuclear more accessible and reasonable as a solution. The battle that's been going on over Vogtle, the only nuclear construction project in the United States that's been inundated with delays and a ballooning budget, have demonstrated that the prospect of building new nuclear plants at current sizes seems farfetched. While the economics of keeping existing nuclear going can compete with and often beat building new renewable energy, without the ability to build new nuclear there's an inherent (and declining) ceiling on how much nuclear can contribute to the future decarbonized grid. BUT, these SMRs offer the ability to overcome those economics, while presenting increased safety (since they are smaller and don't need as extensive protections as their larger cousins) and might help overcome a lot of the knee jerk reaction people have to nuclear.

While these SMRs have been discussed for a while now, what prompted me to post this topic was a new effort I recently came across: "Nuke on a truck." The idea is similar-- dropping down the size of nuclear plants in great steps, to the point they could fit on the bed of a truck and function as a nuclear battery. Some choice quotes from this article include:

Picture this: a remote Army base in frigid Alaska, some 150 miles from the Arctic Circle.

Taking risk is necessary for growth. This series profiles the region's entrepreneurs, policymakers, scientists and others who have embraced challenges and incorporated new ideas – sometimes the kind that seem a little crazy – into their plans. 

“Most of the year there’s no sunshine,” said Yasir Arafat (his real name), Westinghouse’s technical lead for eVinci. “Wind turbines would ice up. The only thing that works there is diesel.”

The diesel must be replenished every six months. The fuel trips command resources and have national security implications.

The eVinci idea would function like a nuclear battery. “Once it’s plugged in, it will work for 10 years straight,” Mr. Arafat said.


Microreactors will have to prove that they are not just a scaled down version of a large nuclear reactor — either in design or in deployment.

To think up the eVinci model, Westinghouse drew inspiration from nuclear reactors that power space ships, as those are “probably the only nuclear reactor concept that run autonomously, without any operators,” Mr. Arafat said.

The concept also requires more advanced materials to withstand temperatures up to 600 degrees Celsius, nearly twice the heat inside an AP1000 reactor vessel.

The cost and timetable would have to be selling points for microreactors.

Commercial operations of these units wouldn't begin until 2024, but again the idea that nuclear reactors-- if done correctly-- could fit into a DER type model and be located close to where they're needed, while providing the baseload generation needed to pair with renewables until storage technology can fill in those gaps, greatly excites me. 


What do you think?


Bob Meinetz's picture
Bob Meinetz on Jan 5, 2019 5:32 am GMT

Matt, as I recounted in an earlier post I had the opportunity to participate in NuScale's first "NGO Day" in October, and came away thoroughly convinced SMRs are the future of electricity.

While in Corvallis I spoke with NuScale co-founder Jose Reyes, Ph.D.,  a congenial and enthusiastic physicist who warns guests "If I talk too fast, let me know," before launching into a detailed explanation of NuScale's approach.

Its advantages are those you list - affordable, safe, dispatchable energy for remote locations (or anywhere, really). Though prices have yet to be determined, an estimate is $700 million / 60MW module, including the facility where they would be housed. I asked Reyes about the popular notion Gen 4 reactors won't be available for 15 years, too late to meet our needs for global warming. He smiled.

"That's why we've been working on NRMs [NuScale Reactor Modules] since 2003 - we're putting on the finishing touches. Don't forget, pressurized-water reactors have been around for a long time. The physics are well-established."

I don't believe NuScale emphasizes enough the specific advantages of those physics: NRMs have an operating temperature of 450ºF, too hot to bake cookies, but hot enough to boil water. Their operating pressure is 1750 psi, 20% lower than existing PWRs. So by past standards, NRMs are generating electricity at a slow boil, with passive cooling (no pumps) and passive safety.

More importantly:

"...while providing the baseload generation needed to pair with renewables until storage technology can fill in those gaps..."

If NRMs function as predicted, they would make the land use, expense, and fossil fuel backup of renewables unjustifiable - with or without storage. For utility-scale wind and solar advocates that's a tough pill to swallow, but it's the truth. 


Maury Markowitz's picture
Maury Markowitz on Jan 7, 2019 6:31 pm GMT

an estimate is $700 million / 60MW module

Are you sure about that number? That is at least double what it would have to be to be competitive outside of niche markets.

Bob Meinetz's picture
Bob Meinetz on Jan 11, 2019 7:14 pm GMT

Maury, either the rep I was talking to wasn't familiar with pricing or I misunderstood.

On their website they say a net-684MW plant (assuming #12 60MW modules) would cost "about $3 billion," or $250 million / module.

More information here.

Joe Deely's picture
Joe Deely on Jan 4, 2019 8:24 pm GMT


I share most of your enthusiasm.  In particular, I like the small and modular configuration of these reactors. A 200-600MW project is much more feasible in US vs the latest 1-2GW nuclear projects.

The biggest hurdle remaining is actually seeing these plants break into the market.  Hopefully, we will see the first of these reactors go live in Utah/Idaho around 2026.

If that project comes in on-time and at a reasonable cost, I could see a bunch more of these projects planned soon after.  We might even see 20-50 GW of this technology go live by 2035.

This would certainly help with replacing some of the current nuclear generation that will retire by then. 

In the meantime, solar,wind and storage along with some help from NG will retire most of the remaining(240GW) coal plants in the US.  The current 1,750 MMT of CO2 from electric power generation will be below 1,000 MMT by 2030 - with most of these emissions coming from from NG. If these modular reactors really do hit their stride by 2035 then they can help to replace that NG.

I have no problem whatsoever seeing these modular nuclear plants eventually take market share from solar and wind. The more low carbon sources the merrier.


John Benson's picture
John Benson on Jan 8, 2019 9:33 pm GMT

Matt, excellent post. Thanks for this information.

I saw the article linked below just before the first of the year, and put in my queue to investigate further. In my post on the viability of current design nuclear reactors ("Nukes" in October), I made a conscious decision to only look at reactor designs that were at least being built, which led me to the conclusion that none of these were viable. After I saw your post, I set aside a few hours this morning to look at NuScale’s design and progress. The design is sound and tremendously simpler than any existing design. Also the manufacturing and logistics should be much easier. I will continue to dig into this and probably post a paper in February. I still believe that solar, wind and other renewables will take the lion’s share of business in the next few decades, but as I said in Nukes, “… other areas with less land for renewables, fewer cloudless days for solar and less wind might well need nuclear power to achieve cost-effective decarbonization.”




Matt Chester's picture
Matt Chester on Jan 9, 2019 11:01 am GMT

I agree with the sentiment that nuclear is a part of the solution that can and should be working in tandem with renewables. Particularly, if SMRs become viable they can and should readily replace coal and gas as the baseload complement to widespread renewable generation to aid in their inherent intermittency (along with storage solutions, as well)

Charles Botsford, PE's picture
Charles Botsford, PE on Jan 8, 2019 11:30 pm GMT

Hi Matt,

Good post for discussion. I remain an SMR skeptic. To me it's all about economics, which must take into account market competition, and market obstacles. To me, the SMR cost trajectory doesn't look good. Let's say in the DOE time frame of "10-15 years", the capital and installation costs, and the O&M costs stay the same as today. No one really knows today's costs because SMRs aren't in wide deployment--just a few worldwide. 10-15 years is forever for today's power market.  In 10-15 years, renewables costs, which are already low, are projected to decline rapidly. Sure, renewables don't have a reputation for dispatchability, but with the Hywind offshore farm (Scotland) demonstrating 63% capacity factor last year, that's better than many existing coal and gas plants. I also don't like the inverted economics of SMRs. How does the cost of siting, permitting, and constructing twenty 50MW SMRs beat one Vogtle? Can you imagine the NIMBY problem of 20 SMRs? I can see the case for one or two SMRs in remote locations. However, one or two SMRs does not justify a complete and robust supply chain. I'd have to see some hard numbers to be pursuaded the economics of SMRs work.

Michael Keller's picture
Michael Keller on Jan 9, 2019 5:54 am GMT


Would have to agree with Charles. Hard to see how the economics work, particularly when the competition is natural gas.

The idea of smaller is better stands in stark contrast  with classic economies-of-scale where bigger, better, more efficient is how you beat your competitors. That is exactly what occurs with both gas turbines and renewable energy.

Also, the lower pressure of the NUSCALE plant means it is a lot less efficient than the large nuclear units (~28% versus ~34%) That means more nuclear fuel is required per megawatt hour of electrical production. Ditto for nuclear waste.

Following the cost trajectory pattern of building bigger gas turbine power plants, I’d predict the NUSCALE production costs will be about 10% higher than the larger  conventional nuclear plant. This is for a 12-pack SMR. More than twice the production cost of using a natural gas combined-cycle unit.

Unclear why a utility would build a SMR unless the  taxpayer heavily subsidizes the effort. That is exactly the NUSCALE business model. While that may be fine for NUSCALE and Idaho, I do not the value for the rest of the country.


Matt Chester's picture
Matt Chester on Jan 9, 2019 11:03 am GMT

To play devil's advocate-- SMRs might not get heavy taxpayer subsidies, but the economics could maybe be tilted with a carbon tax that's hefty enough to make the zero-emissions generation of nuclear more competitive with gas?

Michael Keller's picture
Michael Keller on Jan 9, 2019 4:57 pm GMT

You are assuming carbon is a major problem. That remains to be seen.

in any case, why should the consumer and taxpayer pay more of their hard earned money just to subsidize products that are grossly non competitive? The actual benefits are non-existent (indeed they are negative) to those alive today. Why not just deploy more cost effective technologies that have minimal environmental impacts? 

Matt Chester's picture
Matt Chester on Jan 10, 2019 2:16 am GMT

I definitely assume carbon is a major problem, as does a near consensus of the scientific community.

Combine that with the idea that I'm 100% also concerned with benefits to those who are not yet alive today, with passing off a functioning and healthy environment to the future generations, not just the immediate economic impacts to those alive today (not even mentioning how the long-term economic benefits to those today dictate addressing the carbon problem), and it seems like we're coming from a completely different perspective on these issues. 

Michael Keller's picture
Michael Keller on Jan 10, 2019 5:51 pm GMT

So your fine with massive increases in the price of energy for an issue that is essentially a religious dogma?

The climate is too complex to ascertain the impacts of CO2 on the distant climate. Fact. 

Paving the country with wind turbines and solar panels is massively destructive to the environment.

Building massively expensive nuclear plants is massively damaging to the pockets of consumers.

The point is, a middle-of-the-road approach is best for all, with a market (vice government) based approach providing a solution that produces a reasonably clean environment and reasonably priced energy. Technology advancements will be The catalyst, not subsidies for the non- competitive.


Bob Meinetz's picture
Bob Meinetz on Jan 11, 2019 7:32 pm GMT

Michael, the cost of nuclear fuel is insignificant, as is the amount of nuclear waste, compared to other methods of dispatchable generation (cost of fuel at a coal plant is 87% of total marginal costs per MWh; at a nuke plant it's 14%).

There are lots of benefits to SMR plants vs. natural gas. Gas requires a pipeline; an SMR plant requires one delivery every eighteen months. Otherwise it is 100% self-sufficient.

Oh, and NuScale plants generate no carbon emissions, no matter where you are in the country. Folks in the U.S. Southeast, where 13,000 premature deaths are attributable to emissions from coal plants each year, might pay a little more to have clean air to breathe.

Michael Keller's picture
Michael Keller on Jan 12, 2019 10:42 pm GMT


We import most of the uranium used in our commercial nuclear plants. Not exactly energy independence.

We are completely self sufficent using natural gas.

Emissions from natural gas plants are insignificant.

In my view, simply not worth paying the SMR's nearly 3 times the cost of using natural gas, particularly when considering the minisculle benefits of "zero" carbon.

Bob Meinetz's picture
Bob Meinetz on Jan 13, 2019 1:39 am GMT


Even if Trump starting levying import tariffs on uranium from both Canada and Australia and the U.S. had to go it alone on domestic uranium, we'd have enough for 23 years. But in that case we'd almost certainly begin recycling spent fuel, only 5% of the U-235 in which has been used. Recycling would make enough fuel available to power the U.S. for thousands of years after natural gas reserves have been depleted.

In 2017, CO2-equivalent emissions from natural gas burned at U.S. electricity plants was 1,207 million metric tons -- 3.3% of total global carbon emissions, including electricity, home heating, fire pits, cars. cruise ships, freighters, trucks, trains, buses, industry, aviation, everything. So no, emissions from U.S. natural gas plants are not "insignificant."

Not sure what it means, but how do you figure "paying the SMR's" is "nearly 3 times the cost of using natural gas"?

Charles Botsford, PE's picture
Charles Botsford, PE on Jan 10, 2019 10:43 pm GMT

Hi Matt,

To me, it's all about economics. A while back I posted an article on EnergyCentral, "Nuclear Power: Can Carbon Credits Save the Industry?". I agree with you that the zero carbon value of nuclear power should be compensated. However, even then the economics, when you take all value/obligation chains into account, don't turn the picture around.

In the mean time, renewables, especially wind, keep plodding along--zero carbon, ever improving economics, ever improving capacity factors, ever improving value to the grid. Onshore wind runs into NIMBY now and then, but has competitive economics even without the PTC. Interestingly, the Audubon policy gives wind a thumbs up. Offshore wind economics aren't as good currently, but the capacity factors and grid value are impressive. If you're a a utility, you have to pick where to invest. EIA predicts wind will comprise 46% of new US electric capacity additions in 2019. 

Bob Meinetz's picture
Bob Meinetz on Jan 13, 2019 2:03 am GMT


Since 2011 renewable energy has received 27 times as much cash in federal financial incentives as nuclear, so I'm not sure how you can conclude renewables are more economical - even with construction costs included.

Considering marginal operating costs alone nuclear is the clear winner, costing 23% less than renewables plus the natural gas needed to accommodate their variability.

As you can see from the chart, nuclear's costs of operation are significantly higher, mostly due to security requirements. But cheap fuel more than makes up for the dependency of "free" renewables on natural gas.

Michael Keller's picture
Michael Keller on Jan 15, 2019 4:20 am GMT

Cost for the infrastructure to recycle spent fuel will be enormus -the abandoned + 7 $ nillion MOX facility in South Carolina provides an inkling of the cost.

 CO2 from natural and man made sources in the US are more like billions of tons. Natural gas power plant emissions are insignificant.

You cannot ignore the debt re-payment and return on investment associated with the operation of nuclear plants. That is why the machines are not cost effective,

The cost of energy from a NUSCALE plant will be about 3 times that from a combined-cycle natural gas power plant. 

Bob Meinetz's picture
Bob Meinetz on Jan 16, 2019 4:07 am GMT

"CO2 from natural and man made sources in the US are more like billions of tons. Natural gas power plant emissions are insignificant."

CO2 from natural sources, i.e., the animals, plants, etc. are part of the holocene carbon cycle in which humans evolved. Fossil fuel emissions, some 37 billion tons every year, are made up of ancient carbon which has been sequestered for tens of millions of years.

By polluting our atmosphere with this ancient carbon we're gradually returning our climate to a time when average temperatures were 18+ªF hotter than they are now - to the time of the dinosaurs. If we continue business-as-usual, we can count on one out of every four species alive today going extinct in the next century (plants and animals around today weren't built that way).

The combustion of natural gas in the U.S. alone makes up 3.3% of the fossil fuel carbon emissions worldwide, and it's very signficant.

"The cost of energy from a NUSCALE plant will be about 3 times that from a combined-cycle natural gas power plant."

Because you're unable to provide any source for this statement, I'm left to conclude it's a fabrication.

Michael Keller's picture
Michael Keller on Jan 17, 2019 3:30 am GMT

It calculated using a financial Pro Forma model with the build cost ($/KW) 10% higher than a conventional nuclear plant with the NUSCALE efficiency of 28%.

The model pegs combined cycle plants at about $55/mW-h, conventional nuclear at plus  $120/mW-h, NUSCALE at well over $140/mWh.

I am getting really weary of nuclear proponents ignoring economic reality in defense of obsolete technologies that cannot compete.

By the way, what are your sources? Propaganda from the nuclear industry or actual financial calculation.

Michael Keller's picture
Michael Keller on Jan 17, 2019 3:36 am GMT

3% is not significant by most measurement standards.

CO2 levels have been much, much higher in the ancient past than they are now. There is simply no reason to panic over levels we see today and absolutely no reason to bankrupt the country over CO2 emissions. That also applies to the renewable energy folks.

Michael Keller's picture
Michael Keller on Jan 11, 2019 1:50 am GMT

One of the downsides of wind is lack of reliability and a habit of showing up when not needed. Both drive up power costs because reliable resources are pushed off-line and that drives up their production costs. Ultimately the power users cost of energy must go up.

Higher wind capacities occur because the machines are getting stupefyingly large. That chews up vast amounts of land because of the exclusion area needed to protect houses and people from rotors and ice flying off the machines. 

Wind turbines are a blight on the natural landscape because of their size. The disruption of the environment is not helpful to wildlife. We are talking tens of thousands of acres versus conventional power plants occupying a minor fraction of that amount.

To be blunt, renewable energy is an insult to nature. All of this for inconsequential impacts on CO2 emissions, but I guess the elite can feel good about themselves as long as they do not see the blight created by gargantuan renewable energy operations.

John Benson's picture
John Benson on Jan 11, 2019 2:54 am GMT

When I start a paper I rip through it pretty quickly. I’m about 90% done with this one. I’m considering posting it in about a week rather than in February.

As a teaser, NuScale has:

Passed the first phase of their Nuclear Regulatory Commission (NRC) design review

Has a signed memorandum of understanding from the DOE, Utah Associated Municipal Power Systems (UAMPS) and Idaho National Lab's Battelle Energy Alliance (BEA) for the first cluster of these reactors.

Also, go through the link below and click on: “Economic viability of light water small modular nuclear reactors: General methodology and vendor data”. This paper has a good economic analysis of NuScale’s design, and so far it looks good.

Matt Chester's picture
Matt Chester on Jan 11, 2019 6:20 pm GMT

Looking forward to your post on the topic, John!

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