Reinventing nuclear power with a digital backbone

Relying on one integrated environment

As a developer of advanced nuclear reactors and fuel technology, X-energy must effectively manage the complexity of multidisciplinary system design while navigating strict requirements that support the safe and reliable operation of their technology.

To succeed, the company required tools that could connect design, analysis and verification in one integrated environment, so they chose Siemens’ integrated digital tools to design efficient, reliable and intrinsically safe nuclear technologies. This included Teamcenter® software, NX™ software and Simcenter™ STAR-CCM+™ software, all part of the Siemens Xcelerator business platform of software, hardware and services.

Providing the backbone

Using Teamcenter provides the backbone for managing configuration datasets, computer-aided design (CAD) models, analysis data, system models and requirements. Using NX supports detailed CAD modeling while leveraging Simcenter STAR-CCM+ enables advanced multiphysics simulation for reactor performance, thermal hydraulics and fuel movement within the pebble bed core.

“The single biggest improvement has been the ability to manage CAD data and construct a clear bill-of-materials of our plant design,” says Jacob Schwab, manager of mechanical engineering at X-energy.

TRISO-X fuel pebble

Achieving high-fidelity CFD simulation

X-energy uses Simcenter STAR-CCM+ as their primary computational fluid dynamics (CFD) software to capture the detailed thermal-hydraulic behavior of plant components. Although some tools are suited to modeling system-level behavior, using Simcenter STAR-CCM+ enabled them to resolve the details of component geometry, identifying potential failure points and helping to ensure safe, reliable operations.

A unique strength of Simcenter STAR-CCM+ that became apparent was its discrete element method (DEM) capabilities. As one of the very few Gen IV nuclear reactor designs with a continuously fed pebblebed core, X-energy required precise modeling of fuel movement.

DEM provides exactly the level of fidelity needed to simulate the flow and interaction of thousands of fuel spheres within the reactor core.

The capabilities of CFD simulation have advanced rapidly, allowing X-energy to model reactor behavior today in ways that were not possible a decade ago. With Simcenter STAR-CCM+, they gained two key benefits: safety analysis, simulating critical thermal-hydraulic scenarios to anticipate risks, demonstrate safety margins and reduce the likelihood and consequence of adverse events; and design optimization, predicting system performance and fine-tuning designs to maximize reactor efficiency and improve outputs such as steam and electricity.

Achieving model-based systems engineering

Until recently, X-energy managed designs with paper documentation. Working with Applied CAx, a Siemens platinum expert software partner, they created a roadmap to transition into model-based systems engineering (MBSE). Applied CAx helped configure Teamcenter for scalability, supported developer needs and guided integration of new tools into their systems lifecycle management framework.

Going forward, requirements management, design configuration and simulation results will be fully integrated, providing end-to-end traceability. This improves confidence, speeds iteration and simplifies communication across teams.

Xe-100, X-energy’s small modular reactor.

Simulation-driven safety

X-energy uses digital verification and validation to ensure designs meet their intended safety requirements. By managing configuration data and linking it with verification and validation information through Teamcenter and MBSE tools, engineers can maintain a clear, organized digital thread. This integration allows the team to confidently demonstrate to regulators that the reactor design satisfies all safety criteria.

“Teamcenter is best-in-class for product lifecycle management and scales as we grow,” says Aaron Wertz, who is the director of emerging technologies at X-energy.

A critical component of this process is NX, which supports detailed CAD modeling. While highly detailed models are ideal for capturing design intent, they are not always optimal for rapid analysis. By simplifying models for simulation while maintaining proper configuration control, the team can iterate quickly, test various scenarios and make sure that analysis reflects the actual design accurately.

Together, this combination of model-based systems engineering, digital configuration management and simulation tools enables faster, more reliable design iterations and a stronger, evidence-based safety case. It is a critical part of ensuring that complex nuclear systems are both efficient and safe.

Furthermore, because Simcenter STAR-CCM+ was developed in an NQA-1 compliant program – a quality assurance system that adheres to the American Society of Mechanical Engineers (ASME) NQA-1 standard – it provides a strong foundation for safety-related analyses, reducing the need for costly commercial-grade qualification. “Having Simcenter STAR-CCM+ already developed under NQA-1 compliance puts us in a strong position for safety-related analysis,” says Wian van der Merwe, who is manager of mechanical engineering at X-energy.

Connecting design, simulation and operations

X-energy uses NX and Teamcenter to support its integrated product lifecycle management (PLM). These tools have been part of their workflow since the company’s early days, and they continue to leverage Teamcenter because it can scale with their growth. As they push toward production, integrating their toolset in the Teamcenter framework enables consistent configuration control and smooth management of complex design data.

For model-based systems engineering, X-energy adopted System Modeling Workbench for Teamcenter to connect requirements, design, simulation, testing and operations in a unified digital thread. Similarly, they continue to leverage Simcenter STAR-CCM+ to perform detailed analysis and verification.

Together, these tools allow X-energy to fully integrate their engineering workflow, manage configuration and verification data efficiently and maintain a controlled, traceable digital thread from initial requirements to operational deployment. This integration is central to ensuring both efficiency and safety in the design of advanced nuclear systems.

Preparing for scale

Today, X-energy has over 11 gigawatts (GW) of committed projects, and an order book of 144 Xe-100 small modular nuclear reactors (SMRs) from major companies such as Dow, Amazon and Centrica. As the company works to deploy at this scale, efficiency and alignment will be critical to successful commercialization. With the help of Siemens’ digital engineering solutions, X-energy is better able to manage complexity in design, provide safety and achieve this scale with confidence and precision.