In the effort to achieve carbon neutrality, nuclear power has become increasingly popular as an alternative source of low-carbon electricity and heat. Even without much widespread improvement or innovation in commercial nuclear technologies in the past 70+ years since its initial deployment, it has still played a considerable role in the alternative energy space. Indeed, it currently makes up more than 50% of the world’s non-carbon causing energy.

Arguably, the decarbonization effort today is going to require a broad, integrated approach, taking advantage of all possible low and no carbon technologies. See our last article on the current general outlook for advanced nuclear in the energy transition.

Jesse Jenkins, an energy systems engineer and professor at Princeton University, in response to a disagreement between Senator Bernie Sanders (against nuclear energy’s implementation in the energy transition) and Senator Cory Booker (pro increasing funding for nuclear’s role in the former), stated that there is a “predominance of evidence” to suggest that the most cost-effective way to decarbonization does, in fact, include nuclear.

Leading climate scientists also wrote openly to the COP and IPCC prior to the COP26 to inform them that global targets simply will not be met without the utilization of advanced nuclear technology. It must be noted that those analyses opposing nuclear power’s importance in the energy transition have been using data from only existing nuclear plants and have not taken into account the incredibly fast evolution of advanced nuclear technology in the past decade and its stage in the commercialization process. In an analysis of why nuclear was “side-lined” at the COP26, it was noted that there is a general public opposition or unfavorable view of nuclear power. This “nuclear fear” is discussed in the previous Darcy article on the current outlook of nuclear’s role in the energy transition and is mentioned in our previous forum.

But what does the “need case” for investing in and deploying new nuclear technology look like? Ultimately, nuclear should only be considered if it is indeed essential in supporting alternative renewables in energy transition initiatives; this case should be strengthened by:

• economic and market context
• consumer cost
• the extended energy landscape of other commercial renewables
• health and safety
• long term implications
• regulation optimization
• timeline

Third Way, a D.C. based public policy think tank, recently released an analysis for 2021, including a statistically derived map of the global market for Advanced Nuclear Technology. Their analysis was based on a few general factors. Not only is electricity demand rapidly growing with no reduction in the foreseeable future, advanced nuclear is also in a key development zone to meet that new demand. In fact, they claim that the global market for nuclear power could triple by 2050. This analysis and interactive map project take into account research not only by Third Way, but also by other research organizations, international programs actively developing, demonstrating, deploying, and commercializing advanced reactors, new energy initiatives/policies, and new funding in this area.

The result of this and other recent analyses conclude that nuclear readiness is hard to ignore as a tool to meet the projected electricity demand, alongside other renewables, by 2050. In addition, the findings indicate clear market opportunities for advanced nuclear globally, given continued development and process/regulation optimization, considering the nature of new commercial technologies.

There are a few main concerns and goals in this space that need to be addressed by all new technologies, if the need case for nuclear is to be successfully made:

• Safety and security—not only of nuclear sites, but also of materials. (e.g. eliminating proliferation concerns, eliminating nuclear disaster concerns, and managing politically responsible fuel procurement, given the predominance of mines in Russia, and current political climate.)
• Economics and timeline of new advanced reactors and sites. This includes a necessary overhaul of the current regulatory system with respect to new technologies, as well as optimization of production and fuel handling costs, etc.
• Impacts on local environments.
• Reliability and efficiency of nuclear.
• Reactor footprint and necessary site size/radius of “emergency planning zones.”
• Job opportunities.
• Nuclear’s role as a part of a mixed energy system dominated by renewables.

So, the market outlook is good (according to most) for advanced nuclear. Let’s dig deeper. How do these advanced technologies really differ from the nuclear we are familiar with? And who are the major players?

In recent Darcy coverage on the current nuclear outlook, we hosted a forum discussing nuclear technology, outlined the broad status of advanced nuclear tech in an article, and identified a few key new reactor technologies and some of the major players in each space. The associated framework can be found here.

In this framework, some common technologies in small modular reactor design, fusion, and other are outlined, but in this article, we’re going to delve a bit deeper and discuss the technologies, separate from size, and how they respond to the above-mentioned “need case” as well as the main concerns and goals with implementation of advanced nuclear technology in general.

please note: any cost predictions listed are estimated on the high end from online research and general predictions per technology type. Each individual nuclear innovator is working on cost reduction through various methods and technologies, so these sample predictions are listed only as a springboard off which discussion with innovators can begin.

SMALL MODULAR REACTORS (SMRs)

Since many of the technologies that will be discussed below are, in fact, also being designed as SMRs, it is important to mention some of their features separately. SMRs can be either thermal or fast, with varying coolant and moderator choices. The main advantages of small reactor technologies is their small footprint, modular design, and low sample cost predictions. SMRs are designated as having an output capacity of less than 300MW, meaning they would be ideal for use in district heating applications, but, due to their modular design, they can be essentially “stacked” to produce larger scale power down the line.

A sub-group of these are known as Micro-reactors. Micro reactors have an output of 2-50MW and are being developed using a number of advanced technologies.

• Benefits: SMRs (in general) feature some major safety benefits, with most new designs boasting passive safety features and modern fuel handling approaches. They also offer a lower cost, versatility and flexibility in design and scale, and, of course, industry decarbonization. These, due to their size, can be deployed in remote, energy poor areas.
• Challenges: Unfortunately, due to the low energy output, many larger utilities can’t afford enough SMRs to meet demand. Previous nuclear technologies have all argued the economics of scale when designing reactors, and in the case of SMRs, this might be less that for larger designs (think of all the large scale projects abandoned prior to implementation). In considering SMR implementation, the market outlook and timeline for scaled implementation need to be considered hand in hand. Nuclear alone might not be the answer to meet the full demand of utilities, but how can it help?
• Status: One of the most attractive features of SMR technology is their production status. There are several already in production worldwide, and many more in development and working through the licensing process. In our next article, we will be diving deeper into "next steps" for investors, utilities, and policy makers and relating new technologies and their associated innovators to their timeline of commercialization.

SUPERCRITICAL WATER-COOLED REACTORS (SCWRs)

SCWRs can be either thermal or fast reactors with supercritical water utilized as a coolant. Water is generally also used as the moderator. These reactors range from 300MW to 1,700MW output capacity. Most of the commercial nuclear reactor technologies that we are familiar with (Generation I, II, III) are water-cooled reactors. This new advanced SCWR technology takes into account the concerns derived from earlier technology and has attempted to address them with new innovations.

Cost of these reactors can be gauged by specific example in submarine utilization. A SWCR for this purpose costs about $2.71 billion (US) dollars in capital with approximately $50 billion in annual operating cost.

• Benefits: The new advancements in SCWRs have increased the efficiency of the technology, improved waste management processes, and are able to lean on over 70 years of light-water reactor research and implementation.
• Challenges: These reactors hold similar disadvantages to their predecessors. Additionally, high temperatures and pressures cause them to be appreciably more expensive.
• Status: SCWRs are currently in active development globally.

MOLTEN SALT REACTORS (MSRs)

This class of reactor has been under development for several decades but is only now coming to the commercial playing field. Their capacity varies: they have an output of less than 300MW for SMRs but can range up to 600MW. They utilize molten fluoride salt typically as their coolant source with varying moderator technologies.

An MSR with around 600MW of output capacity would cost approximately US $50 per MW-hr, and less than US$1 billion altogether.

• Benefits: There are many safety benefits with new MSR technology; in fact, most new technologies under development offer passive safety features and avoid proliferation concerns. This could be one of the reasons that there are such a large number of new innovators active in this space as opposed to other reactor technologies. This technology also boasts lower cost, improved waste management, and increased efficiency to traditional reactors.
• Challenges: In traditional MSRs, there are dangers that have to be considered involving the separation of fuel and coolant. If the fuel and coolant mixes due to corrosion by the salt, it becomes incredibly dangerous to operators.
• Status: MSRs have decades worth of development under their belt but are just now coming to the point of piloting and deployment.

HIGH TEMPERATURE GAS REACTORS (HTGRs)

A very common technology for SMR reactors, HTGRs are thermal reactors that utilize helium gas (generally) as a coolant with graphite moderators. Since current HTGRs are typically designed as SMRs, their output capacity is capped at around 300MW. The cost for these reactors includes around a $4 billion US dollar investment with approximately $76 million each year for operation, maintenance, and fuel. This technology is highly established, with many years of deployment and advancement. These technologies utilize a Brayton or Rankine cycle that is direct or indirect and coated particle fuel. Beyond this, there are prismatic (block) reactors, that utilize fuel in graphite blocks, and pebble bed reactors that use fuel in small sized spheres.

• Benefits: HTGRs, like many advanced reactor technologies, offer improved safety benefits and lower proliferation risk. In addition, HTGRs reduce accident potential with their incredibly high heat tolerance. This allows them to be deployed even in remote locations.
• Challenges: Due to their level of technological maturity, there are not many specialized challenges that this technology faces compared to other advanced reactors.
• Status: Of advanced reactor technologies, HTGRs are some of the most developed. In fact, they have been operated as prototypes for over 50 years. The most advancement in this reactor design is being made in China, where at least one plant is currently active in producing power for a research university, with many more in progress.

GAS-COOLED FAST REACTORS (GFRs)

GFRs are high-temperature, helium cooled fast spectrum reactors that implement a closed fuel cycle. The coolant used, as mentioned, is generally helium, and no moderator is used. These reactors range in output capacity from 0.5MW to 2400MWth thermal power capacity and cost around the US $3500-$4000 range per KW (for a ~500MW module). GFRs utilize similar fuel recycling processes to Sodium Cooled fast reactors and the same reactor technology as HTGRs (but with a difference in neutron spectrum—thermal versus fast), so it takes advantage of the feasibility and developed technology of HTGRs and boasts innovation in core design, fuel utilization and management, and safety approach.

• Benefits: GFRs feature advanced safety benefits, competitive cost, improved waste management processes (long term sustainability of uranium resources and waste minimization through fuel multiple reprocessing and fission of actinides), low proliferation risk, versatility/flexibility, high thermal efficiency and heat production (beneficial for hydrogen production), and modularity.
• Challenges: Helium is typically chosen as coolant, but it unfortunately is incapable of, in the case of an accident, absorbing as much heat as other coolants. In terms of manufacturing, the hot gases in the system make it difficult to develop and procure materials that can hold up, on the long term, to the heat.
• Status: The first demonstrated GFR is currently in licensing and planning for launch in 2025.

SODIUM-COOLED FAST REACTORS (SFRs)

SFRs are among the most mature advanced reactor technologies in the status quo. These utilize fast reactor technology and liquid sodium as the primary coolant, along with a liquid metal as a secondary coolant. One of the greatest benefits of this technology is its ability to operate under near-atmospheric pressure conditions and, due to the heat-transfer properties of liquid sodium, would allow for passive cooling via natural circulation. The majority of SFR designs utilize a closed fuel cycle: this allows plutonium and uranium to be reused from spent fuel. These designs achieve a high burnup of actinides in spent fuel, which greatly reduces long term reactivity of waste produced.

• Benefits: SFRs have highly competitive safety benefits, increased efficiency, low risk of proliferation, improved waste management and fuel use processes, ad modular design ability.
• Challenges: Highly reactive sodium, when used as a coolant, reacts violently with both air and water. The management of this adds both cost and complexity to SFR systems and introduces safety concerns. In fact, the most shutdowns of SFRs built to date have been caused by fires resulting from sodium leaks. This also causing logistical difficulties in design, fabrication, and management.
• Status: There are multiple SFRs currently in operation globally, with development of new reactors still actively taking place.

LEAD-COOLED FAST REACTORS (LFRs)

LFRs are fast reactors that utilize a closed fuel cycle, using lead-bismuth eutectic (LBE) alloy or molten lead as the primary reactor coolant. This allows not only for low pressure operation, but also passive cooling in case of an accident. It also has the property of high retention rate of fission products, allowing it to prevent release of radionuclides into the atmosphere in case of accident. Additionally, molten lead/LBE are relatively inert, unlike sodium, so this has both logistical, economic, and safety advantages. LFRs are also capable of burning actinides.

• Benefits: Lead cooled fast reactors offer fast reactor benefits, improved safety features, lower cost than traditional reactor designs, modular design, versatility/flexibility, improved waste management processes, factory manufacturing, and low proliferation risk.
• Challenges: Molten lead can be highly corrosive to structural steel at high temperatures. Lead is additionally an opaque substance, preventing visibility and causing challenges to monitoring the core. It is additionally is incredibly dense and very heavy, causing structural concerns. Lead also has a very high melting point, requiring innovation in retaining the lead in liquid state for circulation in lower-temperature situations.
• Status: Russia is currently in the lead for development of LFRs, and many other countries are also actively developing this technology.

FUSION REACTORS

The ever elusive and ever promised future commercial fusion reactors, as opposed to functioning via fission of heavy nuclei, would fuse light atomic nuclei. These light nuclei would, generally, be isotopes of hydrogen, heated to millions of degrees to form a plasma held together by various means, in the hopes of creating “ignition” or a “burning plasma,” where the fusion energy produced would keep the plasma needed for the reaction heated. Research and development in fusion efforts has received significant funding in cycles throughout the last decades as promises have been made for its timeline of realization, most often resulting in no positive outcome. We are in a new fusion craze, with over US $20 billion in global cooperative funding being put into an International Thermonuclear Experimental Reactor (ITER) in France, as well as much funding for R&D within individual companies that promise remarkably fast timelines to commercialization.

Fusion reactor coolants could be water and/or helium with water utilized as a moderator. Since these designs are all still very early stage, the output capacity can be gauged by the ITER theoretical project, which plans on producing an output of 500MW. Cost of these reactors, based on ITER, would range somewhere between US$22-65 billion dollars.

• Benefits: Fusion reactors have long been idealized as potential safe, efficient energy producers. They would offer waste management benefits, low proliferation risk, and could, theoretically, create unlimited carbon free energy with no radioactive waste production.
• Challenges: Due to the extreme conditions necessary for a self sustaining plasma state required for fusion reactions (that produce more energy than they take), ideal fusion has not yet been achieved in a lab or pilot project. There are also concerns given the investment and interest history of fusion technologies. Is this new fusion craze going to leave us disappointed like the last ones?
• Stage: The type of fusion reaction necessary for self sustaining and energy efficient success has not yet been achieved in the laboratory. However, there is a large amount of investment and momentum in the space.

NEXT STEPS

Beyond the basic features of each advanced reactor type, there are many strides being made by individual developers to strengthen the need case of nuclear as well as their projects' economics and market potential. Since improved safety features are the main public view hurdle to overcome, every new technology has invested a lot of time and energy into this goal. Additionally, companies are building their need case with actions like adding energy storage, lobbying for new energy policies, and working with regulatory agencies to simplify and streamline the regulatory and licensing process. It is argued that by 2034, many natural gas plants will be close to retiring. Advanced nuclear provides an alternative energy option that not only provides a similar baseload and load-following, responsive set of characteristics to fossil fleets, but also, with advancements in the technology, has much lower operating costs after initial investment. As commercialization of nuclear begins over the next decade, it will have a major impact on the economics of grid resources. But what is the ultimate potential, really, for advanced nuclear's market penetration? And how do we navigate this process?

In the next article in Darcy's series of nuclear coverage, we will be discussing "next steps" for utilities, investors, and policy makers in their approach to diving into the advanced nuclear market, outlining some key takeaways of nuclear's need case and market cost/demand growth predictions, and highlighting technologies and their associated innovators by their commercialization timeline.

Do you plan on expanding into the nuclear space? What are your biggest concerns and what kind of coverage would you like Darcy to provide in the upcoming months? Comment below and let us know!

References:

• https://www.rff.org/publications/explainers/advanced-nuclear-reactors-101/
• https://arpa-e.energy.gov/sites/default/files/20200714LCMEITNER%20REPORT-FINAL.13.20.pdf
• https://www.everycrsreport.com/files/20190418R4570686fb03d4ca6ab0e3f37bb71cfe23f44274a0ce84.pdf
• https://www.gen-4.org/
• https://www.thirdway.org/memo/2021-update-map-of-the-global-market-for-advanced-nuclear
• https://www.nirab.org.uk/cdn/uploads/attachments/advanced-nuclear-technologies-engagement-report.pdf
• https://energypost.eu/why-was-nuclear-side-lined-at-cop26/
• https://energypolicy.columbia.edu/sites/default/files/A%20Comparison%20of%20Nuclear%20Technologies%20033017.pdf
• https://www-pub.iaea.org/MTCD/Publications/PDF/PUB1944_web.pdf