The use of reference designs in the U.S. has a good history in the form of the experience of the U.S. Railroad Administration during World War I.  To reason by analogy, nuclear reactors boil water to make steam to turn that energy into useful power.

Is there a case to be made to borrow the idea of reference designs from steam locomotives to apply it to the next generation of advanced nuclear reactors? This article explores this question.

In the second decade of the 20th century, just over 100 years ago, steam locomotives, which do somewhat the same thing as nuclear reactors, which is to boil water to make steam to produce useful work, were in need of a making a major leap in terms of designs that would deliver more power more efficiently and which could be manufactured quickly and  in large numbers.

The International GEN IV forum has been working on reference designs for advanced reactors since 2002. Two decades later, there is an opportunity to extend the idea of reference designs to incorporate a role for agencies and organizations that are involved with safety regulation, testing of prototypes, validation of the ability to manufacture components to build the designs, and to apply nuclear quality assurance standards to these designs and their components.

If there were detailed reference designs for advanced reactors, and the standards developed around them were integrated into the development process, could it boost confidence by potential customers and investors that the developers had a sound basis for their efforts?

If the global response to climate change, and the need for decarbonization of major industrial and transportation sectors that will use electricity, is to build hundreds of large and small nuclear reactors, they can’t be “stick built” one-a-time like the U.S. did in the 1960s and 70s.

Reference designs could be instrumental in standardizing component manufacturing which in turn could facilitate factory-based manufacturing of SMRs and large long lead time components / systems for larger reactors.

A key concept for this proposal is a systems perspective that runs from the proof of concept prototype to the specifications and quality assurance requirements for the supply chain to installation and operation.

Speeding Up Time to Market for Advanced Reactors
Using Reference Designs

The current state of play for development of the next generation of micro, mini, small, and full size nuclear reactors is that there are several dozen active developers (both LWR and fast spectrum), and other types of designs in the U.S. and Canada. Some analysts have referred to the startup landscape as a “cottage industry,” but there is nothing small about the thinking of talented engineers looking to deploy the next big thing in nuclear power.

While some of these developers may seek market share in the U.S., many are looking at export markets for customers and nations that cannot afford a large LWR type reactors in the power range of 1000MWe or more.

All of these developers will need to build and test prototypes of their reactors to prove to potential customers that the designs work, that they are safe and can be licensed by the regulatory agency having jurisdiction,  and that the designs can be built on time, within budget, and can be operated with known costs.

Every one of these designs is unique and therefore requires a built from scratch in a soup-to-nuts effort to determine if they will work, are they safe, and can they be built and operated by a commercial utility. If the design work used a detailed reference design as the kickoff point, a lot of the complexity might be removed from the process of getting a product to market in less than a decade.

Framework of Advanced Nuclear Reactors. Image: Third Way

This is the premise and the goals of the GEN IV program, but it so far its effort hasn’t been linked as closely as some would like to the standards development process or supply chain feasibility for components based on these standards.

The problem for these developers is that while there are detailed reference designs for them to rely on, some of the relevant R&D work that might be helpful was done at least 50 years ago.  A case in point is the work on molten salt reactors that took place at Oak Ridge National Laboratory in the 1950s.

If there were detailed reference designs, and the standards developed around them were integrated into the development process, then they might be able to boost confidence by potential customers and investors that the developers had a sound basis for their efforts.

Work by the international GEN IV program, discussed below, would be an important input to the U.S. effort to bring reference designs down to the working level and to link them to performance and risk based standards for nuclear reactors.

Currently, the knowledge engineering to understand what will work, and what won’t, for various types of designs is being developed from scratch. At least three types of designs seem to be at the head of the packs

1. High temperature gas cooled (HTGR) often using TRISO fuel,
2. Various kinds of molten salt reactors, both with the fuel dissolved in the salt and as separate elements in the core, and
3. Sodium cooled reactors based on the concepts developed for the Integral Fast Reactor.

Other more exotic designs from the GEN IV reference design concepts include lead/bismuth, and, beyond that, several nations have development work underway for unique fast spectrum designs. GEN IV remains the most mature effort to date to develop reference designs.

Moving Designs from Hype to Prototype

The challenge  is that the information needed to speed up time to market by shortening the duration of the design effort remains a key issue.

Next in line is the challenge of how to get the design from a being a paper reactor to building and testing a prototype with an eye on the eventual safety reviews by regulatory agencies and licensing for construction.

At the present time many of these designs may not be ready for commercial revenue service, in some cases, until the mid-2030s, or later. What can be done to shorten the development time frame?

Are These Ideas Feasible and Would They be Worth the Effort?

The ideas that follow are necessarily presented at a conceptual level. Of course, there are many reasons why these ideas could work, but also here are many institutional, commercial, and legislative/regulatory barriers might make such an effort more trouble than it is worth.

These ideas are presented with the intention of stimulating a dialog among key stakeholder groups to see if any of parts of this proposal are feasible, and if so, how it be implemented, in whole or part, to speed up time to market for advanced nuclear reactor designs.

A Role for the ANS Standards Program

The American Nuclear Society (ANS) has an ongoing standards development program with a long and successful track record of publishing nuclear safety and design standards in the U.S.

The question is could the ANS standards program be used as a fulcrum for leveraging its standards work to extend to development of reference designs for various types of advanced nuclear reactor? Obviously, ANS would need to collaborate with other key organization to carry out such an endeavor. Here are some ideas about how that collaboration could work.

A role for ANS Standards could be to convene working groups composed of relevant organizations to develop and document reference designs for these reactor types to help speed up the overall development timeline of these types of advanced reactors.

The designs could be made available in a knowledge engineering database that would also accumulated test data from work on prototypes which would be used to refine the reference designs.

As some of the testing of new advanced designs may take place at national labs, some of this information would automatically be in the public domain as it would have been paid for by the government. There would need to be careful to protect propriety information until such time as it was covered by patents and could be licensed if desired by the owners of the intellectual property.

The reason for this aside is that it may be that some developers of advanced nuclear reactor designs have it in mind to cash out by licensing their work to organizations that have the organizational horsepower, and investor confidence, to actually build them. 

Advantages of Reference Designs

As we know from the work of the GEN IV international forum, having a body of technology-based standards for each of the reactor types with regard to their unique characteristics is helpful. A force multiplier would be to address these conceptual efforts from the perspective of the technology neutral standards that ANS has published.

It would not only simplify the design effort for each developer, but also give the U.S. Nuclear Regulatory Commission (NRC)  a framework to assess the safety of each design type. The agency has been authorized by Congress to work on this issue since 2018. Over the years, the U.S. Nuclear Regulatory Commission (NRC) has identified specific policy issues associated with licensing advanced, non-light-water (non-LWR) and LWR reactor designs. Readers are advised that reviewing this library of policy papers an daunting undertaking.

A Proposal for Roles and Responsibilities for Collaboration

No single organization can make the journey alone to develop a series of reference designs. Nuclear reactors are just too complex for complete technical mastery to live in one place. The organizations that would need to be involved in the standards process are;

• U.S. Nuclear Regulatory Commission (regulation)
• INL Nuclear Reactor Innovation Centers (testing)
• American Society of Mechanical Engineers (quality standards for components)
• United States Nuclear Industry Council – (supply chain fabrication)
• U.S. Department of Energy (funding and program management)

The ANS Standards program, as a neutral scientific and technical organization, is in a unique position to facilitate the development of reference designs through the standards development process because of its long experience in convening industry subject matter experts to come together to write performance and risk-based standards for the industry.

The role of the Nuclear Regulatory Commission would be to provide requirements on the types and level of detail of the data in the reference designs that it would need to conduct a safety design review and licensing of a new advanced reactor for each of the three types.

The role of the Nuclear Reactor Innovation Center (NRIC) would be to develop methods of test to confirm design details, e.g., performance, materials, pressures, radiological protection, etc.

The role of the American Society of Mechanical Engineers would be to adapt its nuclear quality standards for the evolving technical performance characteristics of advanced reactors.

The role of the United States Nuclear Council  (USNC) would be to provide not only the one-off components for prototype systems for testing, but also to assess how manufacturing of key components could scale to support factor construction of reference designs as adapted by each nuclear reactor vendor.

The role of the Department of Energy would be to provide funding and program management to pull the pieces together.  This would lift the administrative burden from ANS and the other collaborating organizations so that they could conduct their work. 

If successful, the potential outcome is that the publication of reference designs for the three reactor types noted here, could reduce the development time scale for bringing these designs to market and to deploy them to address decarbonization objectives.

The ideas here aren’t unique for use just in the U.S. In fact, if successful in the U.S., the concept of linking performance and risk based standards to the conceptual reference designs developed by the GEN IV could be extended to international collaboration. Such an effort might break down regulatory barriers in export markets potentially speeding up the entry of advanced designs to them as a result. While GEN IV is indeed an international effort, the role of collaboration among key stakeholders at the national level looks like a useful next step.

History of the Impacts of  Reference Designs in the U.S. – Railroads

To reason by analogy, nuclear reactors boil water to make steam to turn that energy into useful power.

In the second decade of the 20th century, just over 100 years ago, steam locomotives, which do the same thing, were in need of a making a major leap in terms of designs that would deliver more power more efficiently and which could be manufactured in large numbers.

The United States Railroad Administration (USRA) was the name of the nationalized railroad system of the United States between 1917, and 1920. It was possibly the largest American experiment with nationalization, and was undertaken against a background of wartime emergency for World War I.

A later effort by the U.S. Government to deal with problem railroads took place during the 1970’s. The Department of Transportation created what became the Consolidated Rail Corporation to deal with several bankrupt railroads. It also consolidated designs for locomotives as well as freight and passenger rolling stock

Note: The government was not interested in permanent ownership of operating commercial railroads. In 1987 Conrail was returned to the private sector in what was then the largest initial public offering in U.S. history, raising $1.9 billion. Norfolk Southern Corporation (NS) and CSX Corporation (CSX) agreed to acquire Conrail through a joint stock purchase.

While the proposed ideas in this article do not include nationalization of the development of an advanced reactor fleet, the experience of the USRA is useful because it illustrates that good standards and reference designs, when developed in tandem, can have long lasting positive effects on adoption of improved technologies by an inherently conservative industry.

In 1918 Railroads Weren’t Getting the Job Done

The problem in 1918 was that U.S. railroads were unable to mobilize their equipment, locomotives and rolling stock, and rail lines, to support the vast logistical demands of the war effort. The locomotives in service at the turn of the century were under powered for the train loads that the war time effort demanded of them. Rail cars were unable to carry the larger volumes of cargo that needed to get materials and equipment to U.S. ports to support troops in Europe.

The USRA standard locomotives and railroad cars were designed by the United States Railroad Administration, the nationalized rail system of the United States during World War I. A total of 1,856 steam locomotives and over 100,000 railroad cars were built to these designs during the USRA’s relatively short three-year tenure.

The locomotive designs,, in particular were the nearest thing the American railroads and locomotive builders ever got to standard locomotive types. After the USRA was dissolved in 1920 many of the designs were duplicated in significant numbers with 3,251 engines of various designs being constructed overall. A total of 97 railroads used USRA or USRA-derived locomotives. U.S. railroads continued to adapt USRA designs for new steam locomotives until 1953 more than 45 years after the concepts came off the drawing  boards.

Here are two examples . . . A total of  625 of the USRA Light Mikado type were constructed, making it the most populous USRA type.

The USRA 2-8-2 in revenue service on the Nickel Plate Road RR

A total of 106 of the USRA articulated 2-8-8-2 locomotives were constructed primarily to haul long trains of coal hoppers to steel mills and power plants.

The Norfolk and Western Railway, in particular, continued building this type after the USRA period, developing and modernizing it over time. The railroad’s class Y6B was the last conventional freight-hauling steam locomotive built in the United States. Video – Norfolk& Western Articulated Locomotives

History of Reference Designs for Nuclear Reactors – GEN IV

Generation IV Systems – For more than a decade, GIF has led international collaborative efforts to develop reference designs for the next generation nuclear energy systems that can help meet the world’s future energy needs.

Generation IV designs will use fuel more efficiently, reduce waste production, be economically competitive, and meet stringent standards of safety and proliferation resistance. These designs are the kinds of products that could be adapted to this proposal.

With these goals in mind, some 100 experts evaluated 130 reactor concepts before GIF selected six reactor technologies for further research and development. These include the:  Gas-cooled Fast Reactor (GFR), Lead-cooled Fast Reactor (LFR), Molten Salt Reactor (MSR), Supercritical Water-cooled Reactor (SCWR), Sodium-cooled Fast Reactor (SFR) and Very High Temperature Reactor (VHTR).

Generation IV Goals – Eight technology goals have been defined for Generation  IV systems in four broad areas: sustainability, economics, safety and reliability, and proliferation resistance and physical protection.

These ambitious goals are shared by a large number of countries as they aim at responding to the economic, environmental and social requirements of the 21st century. They establish a framework and identify concrete targets for focusing GIF R&D efforts.

A Technology Roadmap for Generation IV Nuclear Energy Systems – The technology roadmap defines and plans the necessary research and development (R&D) to support the next generation of innovative nuclear energy systems known as Generation IV.

The six systems feature increased safety, improved economics for electricity production and new products such as hydrogen for transportation applications, reduced nuclear wastes for disposal, and increased proliferation resistance.

As part of the GIF Strategic Planning activity launched in 2012, the Technology Roadmap was updated.  The updated Roadmap takes into account plans to accelerate the development of some technologies by deploying prototypes or demonstrators within the next decade.

GEN IV Economic Modeling – G4ECONS – The Economic Modelling Working Group has upgraded the nuclear-economic model, G4ECONS and issued version 3 in 2018. This Excel-based model conforms to the assumptions and algorithms described in the Cost Estimating Guidelines for Generation IV Nuclear Energy Systems and calculates two key figures of merit, namely, the levelized unit electricity cost (LUEC) and total capital investment cost (TCIC).

The model is generic in the sense that it can accept as input the types of projected performance and cost data that are expected to become available from Generation IV concept development teams and that it can model both open and closed fuel cycles.  The model is suitable for international use as it does not include country-specific taxation and other economic parameters.

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