Written by Craig Stover, Senior Program Manager - Advanced Nuclear Technology
EPRI’s supplemental projects are research, development, and demonstration projects that are offered outside of our annual research portfolio.
Supplemental research projects allow ANT participants and non-members alike to fund research that meets specific interests and needs. These projects typically evolve from past and ongoing research activities in the Advanced Nuclear Technology program, and research results are then incorporated back into the program.
Supplemental research can be conducted in response to emerging issues that warrant quick investigation and research, issues applicable to technologies or equipment used by a subset of participants, or issues that require plant-specific application of new technologies.
The Advanced Nuclear Technology program has recently been working on multiple supplemental projects to facilitate the fabrication, deployment, and commercialization of advanced reactors (ARs), including non-light water moderated reactors, small modular reactors (SMRs), and microreactors.
Research and Development to Support Deployment of Advanced Nuclear Energy Systems
Advanced nuclear energy systems based on ARs bring new sets of technology-related questions. Investigating and evaluating these questions can be resource-intensive.
Our supplemental projects provide time- and cost-saving assessments, analysis, guidance, qualifications, and demonstrations addressing various aspects related to advanced reactors, including:
Advanced Manufacturing
AR designs are expected to benefit from lower construction costs by making use of modular construction and advanced manufacturing techniques, such as powder metallurgy-hot isostatic pressing (PM-HIP) to facilitate large component fabrication, electron beam welding (EBW) to reduce weld times and materials needs, and diode laser cladding (DLC) to increase pressure vessel cladding efficiency. EPRI is currently developing and demonstrating advanced manufacturing techniques in the construction of a ⅔ scale NuScale Power Module™, with our latest results available in 3002023900.
Deployment of Heavy Section Electron Beam Welding (EBW) Technologies
Advanced manufacturing and fabrication technologies will likely be necessary to reduce overall construction and assembly costs for ARs, especially SMRs. EBW has the potential to significantly decrease weld times, costs, and materials needs, but it has seen limited use to-date in the fabrication of heavy (thick) sections such as reactor pressure vessels (RPVs).
A number of hurdles must be overcome for EBW to realize its full potential. Based on stakeholder feedback, we launched this supplemental project to address the barriers currently prohibiting EBW from being openly deployed across the industry, including:
Elimination of preheat for welding RPV steels
The project is capturing welding data to provide the technical basis for whether welding preheat is necessary in EB vacuum environments with RPV steels.
Elimination of the keyhole at the termination of the circumferential weld
The project is demonstrating slope welding methods (at low and high voltages) to potentially eliminate the termination keyhole.
Availability of repair methods for EB welds
The project will release a report on various repair methods for EB welds if a flaw is encountered.
Availability of nondestructive evaluation methods for EB welds
The project will provide summary descriptions of nondestructive evaluation (NDE) methods for EB welds and defects, including data on critical flaw sizes.
Availability of proven surface preparation methods
The project will compile guidance on the use of demagnetization, surface preparation, and cleaning methods for performing EB welds.
The results of our EBW project will allow vessel manufacturers and developers, EBW equipment manufacturers, and large component fabricators to readily apply EBW methods and technologies, significantly reducing overall welding assembly time and costs.
More information about the Heavy Section EBW Deployment supplemental project is available in 3002027860. We also encourage readers to view our latest progress using EBW in the fabrication of a ⅔ scale NuScale Power Module™ in 3002023900.
Advanced Reactor Materials Initiative
ARs will require new materials that can withstand more challenging operating environments. EPRI is spearheading research to develop and characterize new and existing materials to meet the needs of ARs. For an overview of AR material needs, consult the Advanced Reactor Materials Development Roadmap (3002023876).
The research needed to address the challenges of capturing and understanding material behavior in time-dependent temperature ranges and under irradiation and various coolant environments can be too resource intensive for any one organization to address. Coordination, prioritization, and cooperation is required to accelerate the deployment of existing material options and the qualification of improved materials to increase design options.
EPRI is launching the Advanced Reactor Materials Initiative (ARMI), a multi-year global collaborative project focused on developing and deploying new and existing materials to support the licensing and long-term operation of advanced non-light water reactors (ARs).
ARMI directly addresses several critical focus areas associated with de-risking the use of materials in advanced reactors:
- Extend operating envelope (temperature and lifetime) for materials already qualified
- Develop required data to add new materials to codes & standards (ASME, RCC-M, etc.)
- Generate, compile, and curate environmental data (irradiation, corrosion, etc.) to support reactor design, licensing, reduce project risk and long-term operation.
- Develop accelerated qualification approaches and technical basis to de-risk reactor licensing and support timely deployment of AR designs.
- Conduct manufacturing and fabrication demonstrations for an available supply chain
Risk and Safety Methods and Tools Considerations
Many AR technologies are designed with inherent or improved safety features. For example, passive cooling can prevent damage to the core even if a reactor suffers a loss of coolant or power. Risk analysis, particularly probabilistic risk assessment, is a vital element in the development, licensing, and deployment of the next generation of nuclear power plants. Advanced reactors (ARs), however, will operate differently than the existing light water reactors for which risk methods and tools have been developed and successfully implemented. For example, many of the emerging AR designs will depend on advanced nuclear fuels and passive safety systems. Such differences present opportunities to apply risk analysis in a new and optimized way.
In addition, different reactor designs, materials, sensors, and digital technologies are allowing for more efficient risk-informed inspections that reduce operating costs.
The operating environments, coolants, and fuel forms of ARs can include higher temperatures, pressures, corrosion, and radiation compared to conventional reactors. These new technologies may require new safety guidelines to be drafted and implemented before they can be licensed and deployed.
EPRI is contributing to developing risk and safety considerations for ARs. We outline the tools available to help technology developers create a robust safety case in 3002015752. EPRI has reviewed current risk analysis methods and tools to assess their readiness to support AR designs, and a listing of higher-priority topics for short-term research is included in 3002026495. A new supplemental targeting risk and safety methods and tools is under development to develop the priority methodologies and guidance needed for advanced reactors.
EPRI’s Supplemental Projects Support the Deployment of Advanced Nuclear Technologies
We encourage all current and prospective owner-operators of nuclear plants to become EPRI members. This grants you access to our annual research portfolio. However there are instances where pooling of funds for tailored collaboration to address specific technical needs via supplemental projects is the best approach.
In addition to consulting our research, members may find even greater benefit by getting in contact with EPRI for coordinated solutions and strategies for specific projects. You can get in touch with us at ant@epri.com.