Boston Atomics' Substack

As explored in depth by Stephen Ezell at ITIF, China is surpassing the U.S. and Europe in nuclear technology, and in order to compete, we may need a “whole of government” approach. To reestablish advanced reactor leadership, we need a long-term strategic vision that accounts for the specific challenges and opportunities of advanced reactors. Further, we need to lay the groundwork to create an entirely new industry, with new supply chains, business models, and technology, not just develop one-of-a-kind projects. What follows is inspired by the history of advanced reactor development and our own efforts to develop novel nuclear power technology.

Advanced reactor history: still on the way to 2nd-of-a-kind

Metal cooled reactor history

The first “usable” electricity from nuclear power was from a liquid metal cooled reactor, the Experimental Breeder Reactor I. Liquid metal reactors have used mercury, sodium, sodium-potassium eutectics, lead, or lead-bismuth eutectics to cool the core instead of water.

While these concepts showed promise, they have yet to scale. The closest it came to serial use was in the Alfa-class submarines in the Soviet Union, but they faced several challenges. The coolant was a lead-bismuth eutectic, and the reactor design was technically compelling with higher operating temperatures making it more efficient and giving it a higher power density. However, the reactors were very difficult to maintain. Out of seven built, four had major issues, and the remaining units were all eventually decommissioned (if sinking to the ocean floor counts as decommissioning…).

Outside of these submarines, liquid metal reactors have mostly been one-of-a-kind projects. The U.S. built ~6 liquid metal reactors, none of which were commercial successes. France has a long term (multi-decade) reactor development program that stared with Rapsodie in the 1960s, then built Phenix, and finally Superphenix in the 1980s. France had intended to continue with another one-of-a-kind project, ASTRID, but this project was unfortunately cancelled in 2019. Russia has been working on the BN series reactors which have evolved from 5 to 800 MWe over 5 reactors and 50 years. The goal is that the BN-1200 will enter into “serial production” after demonstration in the mid-2030s.

The point here is that to develop an advanced reactor into a product ready for “serial production”, it took Russia 5 demonstration reactors over 70 years.

Gas cooled reactor history

Gas reactors were similarly explored in the early days of the industry. There have been reactors cooled with air, CO2, helium, and nitrogen. Several countries, including the United Kingdom, China, France, Germany, and the U.S., explored gas reactors through various research programs.

The first gas-cooled reactors in the UK, France, and the U.S. were simply air-cooled graphite piles. Examples include GLEEP (UK), G-1 (France), and CP-2 and X-10 (US). These later evolved into fully fledge reactor programs, but similar to the liquid metal reactor history, each reactor was a one-of-a-kind project. Even reactors carrying the same title, such as the AGRs were vastly different in internal architecture and engineering.

Other advanced reactors, like molten salt reactors, have not had the attention and deployment of gas and metal cooled reactors. The Molten Salt Reactor Experiment in Oak Ridge operated for 13,000 hours or less than two complete years. No scaled-up versions followed, although Oak Ridge did estimate the next demonstration reactor required for molten salt reactor development would have cost $2.5B in 2024 dollars.

We made these timeline charts to show just how much the industry was building and testing, and despite all of these efforts, light water reactors were still the only commercial success. If we want an advanced reactor industry, we need a similar level of building and testing.

Focus for the long-term

Success requires a long-term focus. Engineering is challenging, and the long-term view sharpens focus on solving the problems of today without diversion. In advanced reactor programs, apparent shortcuts can distract engineering teams when they are facing challenges. For example, the Next Generation Nuclear Plant program (NGNP) shifted internal focus to study printed circuit heat exchangers (PCHE) when facing the challenges of manufacturing large helical coil steam generators (HCSG). PCHEs have many attractive attributes, but there is no ASME code approved pathway to using them in nuclear reactors today. One could argue that the NGNP team should have focused on developing HCSG manufacturing capability which have better positioned the industry today as X-Energy is planning to use an HCSG.

The global reactor development experience shows us that going from concept to commercial takes at least 20 years with several prototype reactors along the way. Even still, after decades, these programs often shift focus to a new design or get cancelled. We are convinced that a focused, well-funded, multi-decade (less depending on funding) effort will be required to break this pattern and create an advanced reactor industry. This is what Idaho National Lab was built for!

Creating an industry, not a prototype

Creating an industry is much more than designing a reactor. We need new manufacturing capability, new fuel fabrication lines, novel regulatory approaches, new business models, suppliers for components, parts, services and more. The good news is that there are many startups in this space, and their collective capital and drive is larger than any one company’s drive could be. Third Way’s Advanced Nuclear Map shows 130 projects worldwide, and the slide below from the NRC shows over 30 in the U.S.

When focused on MIGHTR, we made the calculated decision that the outsized number of HTGRs among advanced reactor developers would be to our benefit – helping to seed the development of all parts of the necessary industry. We intentionally carved the <30 MWt range out of our original MIGHTR patent because we knew it would be useful if someone else was developing similar technology. For example, we faced several technical challenges, where we would have benefited from someone’s success:

• Helical coil steam generator manufacturing

• Printed circuit heat exchanger ASME code case development

• Helium circulator development

• Vessels, seals, and large-scale helium containment

• Auxiliary tooling and robotics

The technology and regulatory success from ongoing HTGR projects will benefit the whole industry, and it could be a major turning point for HTGRs in the U.S.. Success for the larger players is likely to help the early-stage companies as well.

How the advanced reactor industry can move faster

There are several forces already accelerating the creation of an industry:

• The highest level of public support for nuclear in decades is creating new policy opportunities and easing siting concerns.

• The Advance Act may create more industry and regulatory willingness to innovate in a way that accelerates deployment.

• Risk informed licensing, either through the Licensing Modernization Project (Reg Guide 1.233) or 10 CFR Part 53, may create the environment for innovative safety cases or regulatory approaches, which may simplify licensing, development, and construction.

However, the advanced reactor community can likely move faster than it is, so it is useful to identify some of the forces that slow its development:

• Total cost to design and engineer a novel power plant system is in the billions of dollars. Look forward to a future post on this topic.

• Complex system integration creates project management challenges. These aren’t specific to nuclear. The extensive supply chain for the Boeing 787 was notorious for causing delays. SpaceX has had great success with vertical integration. Westinghouse’s tried to resolve some construction cost overruns at Vogtle and Summer through an acquisition of CB&I Stone & Webster. Just look at how extensive the TerraPower list of suppliers is.

• Aversion to regulatory risk and licensing uncertainty. Design engineers see rejection as too high a cost to pay late in a project, so they design-in conservatism that sometimes is unnecessary. This can materialize in several ways: refusal to adopt a new code or method or assuming an LWR safety system is necessary for an advanced reactor, when in both cases the NRC has shown themselves to be innovative and flexible. However, there may be other cases where the extra conservativism was necessary to deal with licensing uncertainty that stemmed from early design uncertainty. This licensing uncertainty does not necessarily come from the NRC. It also come from the inherent complexity in the design process internal to the reactor design organization.

On the integration, Kairos Power is vertically integrating to resolve this challenge, but others in the space are relying on a host of suppliers, so management will be key to their success. There is a lot of room for software development of configuration management tools to integrate suppliers.

On the regulatory risk, the nuclear community has an interesting culture of innovation. There are many advanced reactor startups bringing new ideas into the industry. However, their willingness to use different tools, license new materials, license new manufacturing methods, or present new safety cases to the regulator has been limited. In many of these areas, there is a huge reward for successfully delivering something novel, but also a huge risk of wasted time and money if you fail to deliver. Firms likely need to shield engineers and managers from the risks or reward them explicitly for the wins to encourage a new culture of innovation.

How to do tech selection

Selecting which projects to fund that maximize the industry’s success is a critical piece of the puzzle. The capital for developing advanced reactors should concentrate around the best advanced reactor projects which means we need methods for assessing the “best projects”. These selections should happen based on TRL, cost to deploy today, team capacity/credibility, market potential and other benefits.

Market potential can be assessed by considering the realistic market this technology could serve in the next 20+ years. This comes from identifying what markets could need nuclear power on that timescale. Process heat is a good example here.

In our view, technology readiness should be evaluated based on both past and present developments. While recent advancements might accelerate the maturation process, it is unlikely that any breakthrough in energy will enable the development and deployment of full nuclear technology, such as ARs or SMRs, at more than twice the historical rate. Considering that Water-Cooled Reactors took 40 years to mature in construction and operation, we estimate a timeframe of at least 20 years to achieve technological maturity and near-full economic potential from scratch. Technologies further along the development path may require less time, but this needs to be carefully judged for technology selection.

Estimating the cost of deployment today is complex. Detailed cost and timeline projections are not feasible until a design is fixed and detailed. However, high-order cost modeling techniques, based on footprints, building volumes, and main components, can provide preliminary estimates. It is crucial to remember that a cost estimate can only be as accurate as the design it is based on. Designs with attractive cost estimates but low TRL and early-stage plant designs are likely to be misleading. To mitigate this, we proposed a “develop by embodiment” strategy, as published in ANS, which significantly reduces the risk of unexpected design growth and cost overruns from the early days until the design is complete.

Because early cost estimates often underestimate final costs, the industry should explore low(er) cost pathways to increase the accuracy of these modeling efforts. One option is increased non-nuclear system demonstrations to prove manufacturability, constructability, and operability. This can be coupled with an independent design review on licensability. Together, this could get a reasonable look at the comparable costs between different technologies without requiring expensive FOAK nuclear projects.

Concluding remarks

Advanced reactors will face many of the same issues that light water reactors do, and there is a lot of knowledge and experience to share between the communities. There are a few key elements we observe in other countries with healthy advanced reactor programs:

• A thriving light water reactor industry

  • Russia has 20 VVERs under construction globally

  • China has 17 total HPR1000s and CAP1000 under construction

• Long term funding continuity over decades.

• Technical focus on bringing a single reactor type to completion before pivoting.

Paired with wise technology selection, we believe there is a path to a thriving advanced nuclear industry.

Boston Atomics is a nuclear R&D firm. As experienced advanced reactor designers, we offer insights in system integration, techno-economic analysis, and technology barriers and opportunities for advanced reactors. Our vision is to foster a policy, regulatory, and technical environment that enables advanced reactors to scale and thrive.

We work with our partners to develop cost-reducing technology for new nuclear and provide consulting services to the broader energy industry. In early reactor conceptualization, single technical disciplines often dominate the design philosophy at the cost of other disciplines. This makes realizing performance improvements challenging because changes that improve one dimension often hinder others.

At Boston Atomics, we employ a multi-disciplinary approach, allowing us to more readily identify innovations with realizable benefits. This holistic perspective enables us to see the broader picture of the advanced reactor landscape. Through this blog, we aim to explore and discuss the necessary technological and regulatory developments that will propel the advanced reactor community forward. Our goal is to contribute to the field's evolution from isolated, one-of-a-kind projects to a robust, scalable industry.

Design for constructability

Through reconciling disparate fields: civil and nuclear engineering, we invented a novel reactor concept called MIGHTR. MIGHTR introduces a unique approach to exploiting modular construction techniques for nuclear systems.

It was born from the idea that constructability needs an equal place among other objectives in early reactor conceptualization. Advanced reactors (ARs) and small modular reactors (SMRs), because of their lost economy of scale, need paradigm shifting innovation – ideas that shift the cost curve, not just optimize down the curve.

The MIGHTR concept integrates the largest components of High Temperature Gas Reactors (HTGRs) and rotates them from a vertical orientation to a horizontal one. Under a subcontract through MIT, we embarked on a DOE funded 3 year, $4.9M effort to evaluate the safety systems, main components, core physics, and thermal fluids of our new architecture, which included collaborators from University of Michigan, Argonne National Lab, MPR, and SGH. We continue to incubate MIGHTR in collaboration with universities and national labs, and our website has links to all the publications describing our progress.

Our work developing MIGHTR demonstrates why we believe in designing-for-constructability from the beginning. Civil structures dictate the pace and cost of nuclear construction, so design for constructability is a winning approach, but it typically enters the design process too late, after much of the design architecture is fixed. By this time, you are working down the value engineering curve, not shifting it to unlock real cost reductions.

At the height of nuclear construction in the U.S., United Engineers and Constructors published a report on nuclear plant construction costs, and they stated:

The most significant factor dictating construction sequence is gravity. By investigating elimination of the vertical component in plant arrangement, it is possible to substantially change the sequence of erection. The reduction of the vertical component has a further advantageous effect in that it reduces lifting requirements, vertical access for crafts, and related safety and indirect cost considerations.

The potential of our approach is uncertain, but as part of the ARC-20 project we estimated the cost savings to be on the order of 30%.

What is clear, however, is that we are going to hear extensively about the need for value engineering and constructability for ARs and SMRs. That work will be critical, and how well each reactor architecture and firm can value engineer their way down the cost curve will determine their success.

Why an HTGR?

HTGRs are a great complement to water cooled reactors (WCR), because of their relative technology maturity, global development effort, and market opportunity in industrial process heat.

The global HTGR coalition

HTGRs, like many advanced reactors, have many attractive features: passive safety systems, high temperature output and thermal efficiency, reduced emergency evacuation zones, and others. Relative to WCRs, however, they are technologically immature and with nascent supply chains and regulatory readiness. According to the IAEA, today’s global WCR supply chain services >400 reactors, and WCRs are 94% of reactors in construction. Therefore, when selecting an advanced reactor to develop, we wanted to choose one with global development inertia.

The last three decades have seen significant investment in HTGR technology:

• The experimental HTR-10 in China (design in 1992, construction in 1995, operation started in 2003)

• The commercial demonstration HTR-PM in China (design in 2001, construction in 2012, operation started in 2023)

• The Next Generation Nuclear Plant (NGNP) R&D program in the U.S. made progress in regulatory readiness and fuel development.

• The GEMINI Initiative and NC2I in Europe focuses on design, fuel supply chain, regulatory readiness, and customer demand.

• Commercial ventures: X-Energy, Ultra Safe Nuclear Corp, Radiant Nuclear, and others

• UK advanced modular reactor program

• The advanced reactor program in France supporting Jimmy

• The pebble bed modular reactor program in South Africa

The broad coalition of HTGR development meant that the supply chain, regulation, and technology readiness were outsized relative to other advanced reactor technology, and the odds of commercial success were substantially higher. Further, all the recent deployments of HTGRs have taken place in China, making it in the strategic national interest to develop this capability in the U.S.

In the same vein, we knew that the operational performance of advanced reactors has historically been worse than the water-cooled fleet. Therefore, we wanted to select a coolant with substantial operating history. Water-cooled reactors dominate the global operating experience with 90% of the commercial reactor-years, but gas-cooled reactors have more than 9X the experience that metal-cooled reactors do.

Process heat - valuable market opportunity

In the effort to decarbonize our economy, industrial process heat is an enormous challenge and therefore an opportunity. In a report on Low Carbon Heat Solutions, the Columbia Center on Global Energy Policy found that nuclear could offer the lowest cost source of zero-emission heat for certain temperature ranges. Nuclear power produces heat that is converted to electricity at ~33% efficiency, so if nuclear plants sold heat directly, it would reduce the cost per unit of energy by 1/3. This gives nuclear a strong economic advantage over electrified heat from renewable sources.

Historically, HTGRs have had the highest reactor outlet temperatures which will give them the most flexibility to meet the various demand cases. The HTTR in Japan is famous for a jaw-dropping 950°C core outlet temperature. In the ranges achievable for nuclear, there is almost 2X the demand for heat greater than 250°C than below which opens a much larger market size for high temperature reactors. The combination of the expected growing demand for zero-carbon high temperature heat and intrinsic cost advantage made a compelling case for HTGRs.

Winding down MIGHTR activities…for now

From the beginning we said that we needed at least $1B in design and engineering before starting construction. Here is a screenshot from our first pitch deck in 2022. This was certainly sub-optimal from a fundraising perspective, but we wanted to partner with folks who had a realistic picture of what was required to deploy an advanced reactor.

In 2023, we did more in-depth planning, and we saw this was a lower bound. We are working on a future post that discusses the cost of designing multi-disciplinary machines, but in short, the NuScale plant and the AP1000 were both ~$1.5B design efforts, and they were incremental steps in pressurized water reactors. Advanced reactors are much more nascent, and lack active supply chains, and therefore we believe have higher development costs in today’s world.

Finally, the MIGHTR cost advantage was over other HTGRs, not LWRs. It is unclear if MIGHTR is cost-competitive with LWRs, or if any advanced reactor can be. There is a world where advanced reactors are equal or lower cost than LWRs, but it probably isn’t here yet, and until it is, we think capital should consolidate around deploying LWRs and developing the best advanced reactor concepts. In a future post will discuss what needs to be true for advanced reactors to provide cheap, abundant power, and how to select the projects that are most likely affordably deploy advanced nuclear energy. Regarding MIGHTR, what we can say now is that we don’t expect to demonstrate any fueled version before the late 2030s.

Let’s work together

We transitioned Boston Atomics from a reactor development company to a nuclear R&D and consulting practice, with specialties in systems integration and techno-economic assessment for nuclear systems. In that vein, we have already partnered with national labs, universities, governments, reactor developers, and utilities. Reach out if you are interested.

In parallel, we are planning follow-up posts on topics like:

• The cost to design complex machines

• Kickstarting an advanced reactor industry

• What’s needed for advanced reactors to be cost-competitive

• The MIGHTR project

If you are in the advanced reactor ecosystem and have a topic that you have been itching to write about, please reach out: info@bostonatomics.com.