What makes smaller nuclear power systems so exciting?
Let me start by dispelling the notion that I think smaller, modular, manufactured nuclear power systems – often called SMRs or micro reactors – are the be all and end all solution to anything, including climate change or energy security.
Though not THE solution, they have the potential to be a crucial, uniquely capable part of a fully-integrated, 0% emission climate-solving grid.
The best of the breed build on lessons from aircraft manufacturing, submarine construction, electric vehicles, wind & solar and even computers. They are leavened with six decades worth of experience in building, operating and maintaining extra large nuclear systems. They address some of the public relations challenges that have plagued very large reactors.
Some of the system designers are paying close attention to the social science lessons and teachings of groups like “The Good Energy Collective” and designing their systems with customer needs and wants in mind. They often state that they are planning to build reactors that people want to buy. Many of the people or communities interested in buying those reactors are planning to live, work, and play right next to the power system. (Regarding the “play” part of that statement – at least one of the proposals I’ve seen includes directing the waste heat from the power system to a community swimming pool.)
Economy of series production & operation
As former submarine engineer officer who also had the rare opportunity to plan and budget for fleet level nuclear power training, maintenance and construction programs, I have a personal understanding of how economies of series production and standardization work to help keep costs under control and schedules predictable.
It is enlightening to see how much costs fall when you can train a group of operators in a common speciality and send them out to several dozen plants that have identical equipment, spare parts lockers and layouts. It’s also easy to see how maintenance procedures can be written once and used by all and how alterations can be planned, reviewed and implemented. These are just a few of the examples I can list. Rules protecting confidential information prevent me from sharing quantified details. Space prevents me from listing other examples.
It shouldn’t surprise anyone who has made anything that people learn to do things with experience or that doing the same thing repeatedly produces better results the more often the task is done. Those learning curve-related improvements don’t require mass production of thousands or millions of units, they start improving cost and performance with the second unit.
Widely cited literature from thought leaders like Clay Christensen (Innovators Dilemma and other works) show that there is a relation between costs and doubling of cumulative unit production.
The modern renewable industry – wind and solar energy collection systems – demonstrate the utility of replication. Starting from the high cost systems of the early 2000s, the industry took advantage of tax credit and mandates originally designed to help them build markets and achieve scale economies. Their impressive cost reduction performance is more attributable to the economy of learning by doing than it is to technological innovations and new inventions.
Aside: Some of the techniques used for the dramatic cost improvements in wind and especially solar power systems are not actions that we will to use to drive down nuclear costs. The sector has an admirable tradition of paying living wages to people who eagerly accept the responsibilities that come with high quality work and a strong safety culture. It also does not concentrate its manufacturing in countries with lower standards. End Aside.
Of course, cost and schedule improvements that result from experience can be lost, team relationships can be broken and skills can atrophy with a lack of practice. Smaller nuclear power systems will not be immune to these advantages and vulnerabilities. But unlike far larger plants that might be able to serve five, ten, or even fifteen years worth of electricity demand growth with a single unit, smaller systems will need numerous units to be steadily brought into service.
Smaller nuclear systems do not replace extra large power plants
Some challenge the idea that we should add small reactors to our product catalog. They believe that we know how to build large reactors, we have proven that we can operate them with incredible safety records and each one can make a big difference in both energy supply security and CO2 emissions. They claim that smaller reactors make the tasks more difficult and that many of the smaller reactors still need many years of operating experience to catch up with larger units.
SMRs and micro reactors are not intended as replacement products for situations when customers want large or very large power units. They are an addition to the options list for those who want or need their power in smaller quantities or who want to learn how to build and operate nuclear plants in a more gradual fashion.
Some object to those of us who characterize modern nuclear power systems as “advanced” because they claim we have done them all before. While it is true that world nuclear energy history includes projects that envisioned or actually used many of the potential combinations of fuel form, coolant, fuel enrichments, and secondary power systems, it isn’t true that they explored all available technological advances. Today’s designs benefit from innovations and developments that were not available back when some of the original research and testing was done.
The fact that there was a thriving market for electric cars that took off in the 1890s, even before the Model T years, does not make the Tesla any less advanced of a vehicle.
Aside: There are numerous smaller and micro reactors that are already in operation today. Two most recently completed examples are Russia’s Akademil Lomonosov and China’s HTR-PM. But the hundreds of reactors that have propelled naval vessels in a half dozen or more countries for decades also demonstrate many of the principles that make commercial SMR worthy of excitement. Indian PHWRs also have many of the characteristics of modern SMRs, including power rating. End Aside.
Note: The Wright Brothers and Henry Ford built internal combustion engines 120 or more years ago. That does not negate the statements by current automobile manufacturers that their power plants are advanced or modern. Modern electric vehicles may be descended from earlier products built on roughly the same combination of features, but they are still marvels of advanced technology.
Security, Insurance and Non-Proliferation
Some claim that rules aimed at ensuring security and preventing the proliferation of nuclear weapons will make smaller systems unaffordable. They overlook the efforts that are going into the system designs to make security easier to implement, the ways that safeguards are being designed into the systems and the fact that some of the rules are being changed because responsible leaders have recognized that they do not actually improve safety or security. Some of them were implemented with the express purpose of slowing nuclear energy development. The immediacy of climate change is stimulating efforts to identify and alter requirements that serve primarily to undermine nuclear economics.
There are even some who cling to the shibboleth claiming that nuclear energy is somehow subsidized because it has a specially designed group insurance program under the 1957 Price Anderson Act (as amended over the years.) While there are changes needed in that Act, it has never been a subsidy for nuclear energy. The truth is that insuring nuclear power plants has never cost taxpayers a dime in paid damages and the insurers that specialize in providing the required commercial insurance have been hugely profitable by collecting premiums and rarely, if ever, paying a claim.
When opponents point to the long-term costs of the accident at Fukushima Dai-ichi as a reason to believe that nuclear plants are under insured, they have some basis in fact. But most of the nuclear-related cleanup costs associated with that accident have been self imposed by the Japanese national, prefecture and local governments. They set radiation exposure standards that were much more stringent than already conservative international standards. Simply using international standards for radiation doses would have greatly reduced evacuation and relocation costs. Basing those actions on a more complete understanding of radiation and its risks would have virtually eliminated costs of actions taken outside of the plant fences.
Rebuilding an area decimated by an earthquake and tsunami isn’t cheap, but it shouldn’t be attributed to events at an industrial facility that did not harm its neighbors.
Are SMRs a good investment?
The answer is, it depends. As with every industry that is experiencing a new generation of technological innovation, some entrepreneurial teams are progressing well, successfully pitching their vision to investors, building their teams, executing against their milestones, learning from set-backs, adjusting to regulatory and market conditions and keeping their eye on the ball. And others not so much.
At Nucleation Capital, the partner team has a combined total of several decades spent investigating and observing the growing potential for advanced nuclear power production. We know that nuclear energy is clean enough to run inside sealed submarines full of people and safe enough for caring parents to not worry when their children work in close proximity to an operating nuclear power plant. We also know that commercial nuclear plants have amassed an admirable safety and reliability record.
That gives us tremendous hope and confidence that great teams will emerge that can learn from our historical performance, from the navy and otherwise, and that new designs will emerge that competitively meet the challenge to deliver clean energy reliably and cost-effectively with newer implementations of amazing carbon-free technology. But we also recognize that not every design will work as hoped or be well-suited to the market demand that exists. Not every team will have what it takes to be successful in a complex market.
Furthermore, we understand the concerns that many people have about the unknowns regarding new designs and the risks of deploying many more small reactors in an widening array of applications. Just as with the deployment of electric vehicles which cannot succeed on the basis of a car design alone but must be matched with a robust national grid of charging stations, this next generation of nuclear ventures will need to solve for an array of related challenges, including nuclear fuel production, long-term waste handling and storage, spent fuel transportation and reprocessing, among other things.
Fortunately, there are quite a lot of groups and entities that are eager to work on these issues, so that new nuclear systems can help us address climate change, provide humanity with reliable power in a climate-stressed world and also succeed in winning public support. There are valid concerns and there are good ways to address them. We also believe that we will have more success overcoming these concerns if coalitions of people across all spectrums participate in helping to solve them collaboratively.
We are very pleased to be in a position to talk with founders, get briefed on detailed, often non-public information and discuss with them their development goals and challenges, as well as their experiences dealing with a range of potential funders, regulators, suppliers, strategic partners and potential customers.
Of course, we cannot be specific about those interactions, but we can express how confident and energized they make us feel for this next generation of reactor developers to broaden the zero-carbon toolset to help reverse the trend of ever increasing CO2 emissions. In the foreseeable future, those new designs will likely contribute to the gargantuan task of reducing the existing emitted inventory of over a trillion tons of greenhouse gases already afflicting our climate, by working in combination with a range of carbon capture and removal technologies.
Our investments do not give us a “conflict of interest.” Rather, we believe they give us a broadening window into the future of decarbonization. We will continue to work with the ventures in our portfolio to help them navigate in the ever-shifting policy, regulatory and investment environments. We will keep our eye on the progress towards commercialization goals and continue to drill down into technological and competitive progress being made, so we can better determine our future investment activity.
We are not policy makers nor government officials. We have “skin in the game.” We will be participating to the extent of working to make sure that the developing advanced nuclear energy industry focuses on meeting customer needs and wants and ensuring that there are cost-effective methods for delivering these over the longer term.
We are also enthused by the opportunity to expand the world of “clean energy” and “climate tech” investing to include nuclear energy. We know that a large portion of the clean, near zero-emission energy produced in the world today comes from long ago investments in nuclear power plants that have been operating reliably for decades. While some look at the hiatus in new builds and believe it indicates that nuclear power is on its way out, we look at the same hiatus as the impetus to improve upon and achieve major strides towards perfecting this extraordinary but still overlooked technology. We will be working our hardest to make sure that we and our investors are able to participate in the growth and success of those ventures which best meet the climate challenge with the right set of products and services.
I find the prospects for nigh-complete decarbonization of built up areas to be a very interesting prospect of SMRs. The Xe-100, with its 400 yard accident planning boundary, is suitable for placement in e.g. commercial zones in cities. This would allow its waste heat to be used for space heat. 120 MW of waste heat is the equivalent of 7.78 tons of methane per hour. That’s about 4095 therms/hr, 98000 therms/day. That’s enough to heat something like 30-35000 homes in January here at 45° N.
Another possibility is the freeing of larger island grids from the tyranny of petroleum. Hawaii is a case in point. Oahu’s grid is far too small to handle a GW-scale power plant, but a number of NuScales or Xe-100s would do the job and probably cheaper than oil. The reduced cost might make it economic to run HVDC cables to less-populated islands, decarbonizing them too.
I did some work at a hydro plant years ago that was located 40 miles from a Metropolitan area. The hydro plant sometimes had to operate at times not necessarily for power, but to minimize voltage drop across the 40 miles of line.
Is there the possibility that SMRs could be plopped at a substation and eliminate the expensive building of additional transmission lines? It could keep the voltage to the proper level and provide power. Could SMRs give rise to additional municipalities generating their own power and reducing the rates of the taxpayers they serve?
Could these be nearly totally remote controlled with minimal security and operating staffs? Would local emergency plans be greatly simplified? Too many requirements may force an ever increasing size to pay for the requirements.
I learned a new word with this one, “shibboleth.” Thanks for the piece.
The biggest advantage of SMR is that they can be mass produced and deployed far out to sea for the production of methanol and other synthetic hydrocarbon fuels. Such fuels could be distributed by tankers (nuclear or methanol fueled) to any coastal location in the world.
Methanol is an excellent replacement for natural gas in natural gas power plants and only requires relatively cheap modifications to such facilities. Reformed methanol fuel cell power plants could also be used as peak load power facilities.
So the existing US natural gas electric power infrastructure could be easily and cheaply modified to use methanol produced at sea from remotely sited floating nuclear reactors.
Carbon neutral methanol from nuclear energy can also be easily converted into dimethyl ether (a diesel fuel substitute) gasoline and even jet fuel– all carbon neutral. And, of course, methanol can be used as an automobile fuel itself in internal combustion engines and in hybrid fuel cell engines.
Replacing fossil fuels for electricity and transportation with synthetic fuels produced at sea would require the mass production of tens of thousands of small remotely deployed nuclear reactors and probably the eventual extraction of uranium from seawater.
But NuScale of Oreogon is already working with a Canadian company, Prodigy Clean Energy, to develop and deploy floating nuclear energy barges.
Russia, of course, is already deploying small floating reactors. And Europe and China both plan to deploy floating nuclear reactors.
“…the eventual extraction of uranium from seawater.”
This seems to be another meme concept for several reasons. Nobody seems to mention the obvious challenges of biofouling of the sorbents – everything quickly crusts in the ocean – hulls are often painted with sacrificial copper. Additionally, to add perspective regarding relative concentrations of solutes, the EPA allows 30 ppb Uranium in drinking water, and some wells in rocky places exceed 900 ppb.* The cutoff for negligible blood lead in children is 500 ppb**, and we wouldn’t consider mining them. Ocean uranium extraction isn’t fake science, but it is ‘bad science’. The wonderful people at ORNL, JAEA, etc., have investigated many other things that are “possible” but wholly impractical – It’s not their fault. Humanity has never run out of any mineral by exploiting it until exhaustion. Whenever reserves of whatever start to dwindle, price increases and exploration and mining lower grade ores becomes incentivized – naturally, we would exploit crustal deposits of 100 ppm U before floating Rhode Island sized mats of polyethylene fiber. We already have massive gyres of plastic in the ocean clogging the guts of every sea creature. To me, stating that the ocean has 4.5E9 tons of uranium dissolved in it garners a big, “so what?” The uranium there is the very definition of a vanishing trace.
* https://portal.ct.gov/-/media/Departments-and-Agencies/DPH/dph/environmental_health/private_wells/2018-Downloads/050818-uranium_in_well_water_September_2016.pdf
** https://www.cdc.gov/nceh/lead/advisory/acclpp/actions-blls.htm
50ppb on the blood lead, forgot 1dL is 100ml. Still an order of magnitude greater than the 3ppb of U in seawater.
I’m also dubious of uranium from sea water extraction. There’s an abundant resource on land.
I often think of the fact that there’s an area in the US where the natural gas supply used to contain He in concentrations up to 30%.
Considering fact that He is an alpha particle that picked up a couple electrons. That implies there’s likely to be deposits of alpha-emitters below those helium-laced pockets of gas.
Yes, you are right there. The crustal concentration of uranium is 1.8 ppm, implying about 40e12 tonnes U. If current global consumption remains around 40,000 tonnes per year (it is more like 60 kt/a), that ultimate resource would last a billion years. If used fuel were being recycled into fast reactors, that would be 200 billion years. However even that is considered to be a finite resource, so does not qualify as “sustainable” in the current EU taxonomy for carbon tax credits. Let’s hope the EU changes the criterion soon.
That’s more sustainable than the Sun, which will be a white dwarf within 10 billion years.
Only 10 billion? Surely you have more enduring faith in He fusion than that!
https://astronomy.com/magazine/ask-astro/2020/09/what-will-happen-to-the-planets-when-the-sun-becomes-a-red-giant
My reading on the subject indicates that the red giant phase of G-class stars lasts only a few hundred million years due to the prodigious output of such stars, so 10 billion years from now the Sun will be about 80% planetary nebula and 20% helium-rich white dwarf.
I used to be skeptical of seawater uranium too, but biofouling isn’t a valid reason… the polymers are quite abiotic and economical schemes require short extraction cycles anyway.
Main reason why I changed my mind was advances in materials (and secondarily simpler cheaper geometry such as anchored braids).
Here is some recent research which is encouraging:
https://pubs.rsc.org/en/content/articlelanding/2020/ta/d0ta07180c
That said, in situ leach has also made terrestrial mining a lot lower impact.
Biofouling isn’t valid? Sure PE is abiotic, we use it for everything from water pipes to food containers, but that doesn’t make it any less of a substrate for biofilms, and simply stating it ‘won’t be a problem’ is not a valid counter argument. People often have trouble visualizing scales involving simultaneously huge and vanishingly small quantities taken together… Any civilization that is harvesting uranium from the ocean is taking its last gasps.
As a geophysicist, I worked to guide uranium explorers to prospective areas. (And yes, there’s plenty it.) Colleagues monitor the rehabilitation after mining, which is particularly demanding because all of the uranium daughters are left behind in spoil made pervious by the processing until weathering seals it again. Above ground mining can be inspected for any mess, whereas in situ mining is underground and any damage is hidden. (Even then, insignificant compared to damage by underground carbon dioxide sequestration schemes!) Although thousands of times more dilute than ore, uranium can be extracted from seawater by itself, leaving the radioactive daughters dispersed harmlessly in the wider ocean – by Nature herself.
Technology and material science is always advancing, what might be impractical and too expensive today probably won’t be in a few decades. Not that we’d need the uranium from seawater on that timescale anyway.
It’s not just slow spectrum reactors that are rapidly being developed, there are a number of fast spectrum designs in the works. Some of them waste burners.
It’s easy to see a system developing – including SMRs – where slow spectrum solid fueled reactors provide the fuel in the form of spent fuel for fast spectrum molten salt reactors. Which in turn can breed as much fissiles as needed to power slow spectrum reactors. Even depleted uranium becomes a fuel source at the fast spectrum and there are vast stockpiles of that.
When nuclear power becomes the main economic and technological driver on Earth – which will have to happen if we want to survive – we’ll stop asking “what can we do?” in regards to nuclear power and fuel cycles and be faced with a pretty nice alternative.
‘What can’t we do?”.
‘Indian PHWRs also have many of the characteristics of modern SMRs, including power rating’
The 700MW power output of the latest Indian IPHWR is identical to the that of the Candu 6E. Given the events surrounding Canada’s anti nuclear Harper government giveaway of its $23B investment in AECL in 2011, it’s likely the Indians have access to the Candu’s blueprints.
The comment quoted below is from a poet on works
of art. If you believe that works of engineering, well done,
have something in common with works of art, then what
he says is relevant.
From Writer’s Almanac, 8 Oct 2021:
https://www.garrisonkeillor.com/radio/twa-the-writers-almanac-for-october-8-2021/
He said, “I think survival is at stake for all of us all the time. … Every poem, every work of art, everything that is well done, well made, well said, generously given, adds to our chances of survival.”
The quoted poet is Philip Booth, whose birthday is today (08 Oct 2021).
The Writer’s Almanac says more about his life and works.
I got here after accidentally coming across your post “Was Arnie Gundersen a Licensed Reactor Operator and Senior VP Nuclear Licensee?” and once here, read this piece, which I found interesting, but have no comments on it specifically.
Your post on Gunderson is timely for me. I have been making small edits to the Wikipedia article on the accident at Three Mile Island. (https://en.wikipedia.org/wiki/Three_Mile_Island_accident). Some of Gunderson’s claims are included on the page. I’ve already added well-sourced information that refutes one of his claims. I’m not a highly experienced Wikipedia editor so I am moving slowly and carefully to provide objective information. I would like to further refute his claims and credibility. The information in your post helps.
My professional background before retiring was in nuclear power—first in the nuclear navy as a nuclear mechanic, then in commercial nuclear power as a non-licensed operator, reactor operator, and, after leaving the Operations Department, senior reactor operator licensed instructor. After retiring, I worked periodically as a contracted operations instructor until December 2017.
The reactor engineers I work with occasionally joke about Arnie Gundersen… He is alarmist disinformation incarnate.
Gunderson’s Wikipedia page, second sentence, used to say, “His curriculum vitae[3] shows Gundersen is a licensed Critical Facility Reactor Operator from 1971-1972.[4]”
It now says, “Gunderson was a licensed reactor operator from 1971-1972 on Rensselaer Polytechnic Institute’s zero-power open-pool university research reactor at the Reactor Critical Facility in Schenectady, New York,[3] where he was a nuclear engineering graduate student.[4][5]” https://en.wikipedia.org/wiki/Arnold_Gundersen
I’ve been having fun learning how to better edit Wikipedia pages and correctly cite sources. I deleted the poorly structured references in that sentence and replaced them with improved version and added a reference on the reactor, with a quote “The Rensselaer Polytechnic Institute (RPI) Reactor Critical Facility (RCF) has provided hands-on education and training for RPI and other student for almost a quarter of a century. The RCF was built in the 1950s by the American Locomotive Company (ALCO) as a critical facility in which to carry out experiements in support of the Army Package power(sic) Reactor (APPR) program. A number of APPRs were built and operated. In the middle 1960s, ALCO went out of business and provided the facility to RPI. Since that time, RPI has operated the RCF primarily in a teaching mode in the nuclear engineering department, although limited amounts of reactor research, activation analysis, and reactivity assays have been carried out as well.”
Mike – Your decision to become a skilled and well-informed Wikipedia editor should pay dividends. Thank you for your efforts. I hope you continue to enjoy the power it brings to your voice.
Hi Mike, and welcome to Atomic Insights! At the very top of the page, in fine white print on a blue background, you will find an obscure little tab labeled “Archives”.
If you are of the Dungeons and Dragons bent, click on “Archives” and enter “Three Mile Island” in its search bar.
Rod has several articles of interest, albeit one of the more interesting was written by guest author Mike Derivan, who “was the shift supervisor at the Davis Besse Nuclear Power Plant (DBNPP) on September 24, 1977 when it experienced an event that started out almost exactly like the event at Three Mile Island on March 28, 1979.”
There were a lot of lessons to be learned there. Some of them eventually were.
https://atomicinsights.com/tmi-operators-took-actions-trained-take/?highlight=three%20mile%20island
Thanks, Ed
I’m familiar with the name Mike Derivan, just wouldn’t have been able to say in what connection. I’m also familiar with the 1977 DB event though not to the level that I’m seeing already in some of what you referred me to.
In one (or more) of my EOP classes that dealt with small break LOCA, I discussed the PORV sticking open at other B&W facilities. I had actually found documentation that it had happened at ANO, too. I don’t remember when and, not working out there anymore, wouldn’t be able to find it.
Interestingly, as I went to the link you provided, I also had the Rogavin report up on another screen where it is talking about the training of the operators and the procedures not addressing a pressurizer steam space leak.
Again, thanks
At the time of the Fukushima accident I remember Gundersen making claims that 1 million lives would be lost as a result of the radioactive material released there. So I did a quick online search and it brought me right back to this site which often happens in regards to nuclear power. Rod Adams is one of the best resources online for nuclear power and has been for years.
https://atomicinsights.com/arnie-gundersen-caught-on-video-lying-about-risk-of-radiation-released-during-fukushima-event/
There is also the “work” of Helen Caldicott and her making similar claims as Gundersen about the Chernobyl accident. She also claimed that almost 1 million people died as a result of radiation released there. George Monbiot, the British environmental journalist got into a running battle with Caldicott and he demonstrated how her claims often contradicted her own books.
It was Caldicott who was claiming North America would become uninhabitable if the SNF stocks at Fukushima caught fire and she was planning to move to South America. A study done by Lawrence Livermore found that in the worst case scenario of a SNF fire at Fukushima the immediate area would have to be evacuated and sites as far south as Tokyo people would have to remain indoors until cleanup was done.
The more people out there debunking nuclear power alarmism the better off we all are.
I’ve been following the science of climate change for 40 years, everything that was predicted way back then and worse has come to pass. What is being predicted now is even starker, the viability of essential ecosystems is rapidly disappearing. Whether it’s coral reef systems or oceanic kelp forests.
On land we have a transition to conditions that become increasingly hostile, this year’s record North American heat dome could become a frequent occurrence. Here in British Columbia hundreds of people died from the heat and an estimated 1 billion marine organisms died on our coast. Then the massive wildfires take off in the hot dry conditions.
This is no longer a discussion on the ideal methods of generating energy to power our lives and societies. And even if it was, with its energy density, safety and available fuel, nuclear power would top the list.
Do SMRs have a place in this long overdue transition to a real sustainable energy model, of course they do. So do all nuclear reactor designs that offer an alternative to a means of providing energy that we’ve known with a high degree of certainty have externalized costs that will soon be incalculable. That applies to coal, oil and natural gas.
That will never be the case with nuclear power where advances in design and understanding the best operating procedures and use of the production – not just electricity but process heat and many valuable isotopic byproducts – means the sector become progressive more competitive and beneficial.
It’s a pretty clear choice, the possibility of a bright future through nuclear power in combination with all other low carbon alternatives.
Or following a energy model path that is already catastrophic with a growing magnitude with each decade.
I didn’t serve in the Navy, but my American Grandfather was on an Assault Transport in the Pacific in WW II and I have deep respect for members of this service and their courage. The Navy has a principle in times of emergency, “all hands on deck” We are now in an all hands emergency and it is nuclear power technology largely developed and introduced by the US Navy that will save us.
Just my opinion….
Regarding Rod Adams’ question about what I find most exciting about
SMRs: to me, it is their factory-based construction and decommissioning,
which strongly suggests a revival of closed fuel cycles and nuclear recycling.
With those changes, a drastic reduction in need for uranium mining, enrichment,
and long-lived nuclear waste storage will likely follow. And whether the path to
those benefits is through thermal reactors or fast, I think the main objectives to be reached despite obstacles will be verifiable safety and understanding by a well-informed
public and government.
SMRs for the most designs is a financial model more than anything else. Take Rolls Royce SMR, it is a three loop 400MWe ~1300MWth plant design similar in size to an AP600. Westinghouse developed the AP1000 from the AP600 because they didn’t see how they could make the AP600 cost competitive on price per MWh. The same issue exists with most water moderated SMRs simply due to the very strong economies of scale.
The financial model of smaller plants may be attractive in de-regulated markets where the cost of capital for large nuclear builds largely drives the cost of the plant. The UK government even produced a graph illustrating the cost of the EPR at Hinckley if it borrowed the money at government interest rates if 2% where it fell from £90/MW with the current financial model to £45/MW.
For HTGR plants, the economics are slightly different and due to weaker economies of scale sauce that the learning curve from building multiple plants can be more important than most reductions due to increasing size.
Essentially the success or otherwise of SMRs is completely dependent on the technology and financing model of the market they are selling into. State backed financing will always lead to large plants being cheaper for PWRs, conversely where the cost of capital is high the switch to smaller plants can be cheaper due entirely to bringing the financing cost down. If a different technology is picked then the optimum size clearly changes