Designing heat exchangers for safer, smarter nuclear power

Can you share a bit about your journey into heat exchanger design and what led you to specialize in this field?

“My degree is in chemical engineering, which I completed in 2018. I initially worked in lab roles, and ended up battery materials, which was an exciting but volatile field. At one point, the department I was in shut down, and I found myself looking for new opportunities. That’s when I was introduced to a role in graphite heat exchanger design. It wasn’t something I had considered before, but I found the complexity and precision of the work fascinating. The transition to Rolls-Royce SMR came naturally as I wanted to work on a larger scale with nuclear applications, which offered a new layer of challenges and learning opportunities.”

What does your day-to-day work as a Heat Exchanger Design Engineer involve?

“Currently, I work in the nuclear sector, specifically designing components for a new type of nuclear power plant—small modular reactors (SMRs). The aim is to create a modularised, scalable system that can all be slotted together – a bit like IKEA furniture. This is meant to simplify construction and enable faster build times while maintaining stringent safety and efficiency standards.”

“My day-to-day involves a significant amount of documentation due to the highly regulated nature of nuclear engineering. Each major design decision requires a robust technical report to ensure it complies with safety protocols and accounts for downstream impacts on the plant’s operation and construction. Much of this means collaborating across different teams within the business.”

“From a technical perspective, my focus revolves around optimising heat exchangers. This includes critical tasks such as material selection, sizing to fit modular constraints, and ensuring compliance with the unique specifications of SMRs. The modular design presents a distinct challenge compared to traditional plants, where space and dimensions are less restricted.”

How do you balance efficiency, safety, and regulatory requirements in the design process?

“In nuclear engineering, safety always comes first. There’s no room for compromise in that regard. If something can’t be done safely, it doesn’t get done at all. Efficiency is something we work towards within those constraints—optimizing materials, layouts, and thermal performance to get the best results possible.”

“The regulatory landscape is another significant factor, as nuclear energy is one of the most highly scrutinized industries in the world. Every step of our process needs to be validated through rigorous testing and analysis. That can make innovation slower than in other fields, but it ensures that the end product is as reliable and safe as possible.”

What are some key considerations when designing heat exchangers for SMRs compared to traditional large reactors?

“The biggest difference is the need for modularization. SMRs are designed to be assembled in a factory and transported to the site, rather than being built from scratch at the location. This requires a level of standardization that traditional nuclear plants don’t always have. That affects everything from the physical size of the heat exchangers to the way they interact with other components.”

“We also have to consider supply chain factors—since we are aiming for mass production, we need materials and components that can be sourced consistently and cost-effectively. Another factor is scalability. SMRs are designed to be deployed in various locations, including regions that might not have extensive nuclear infrastructure, so we have to make sure our designs will meet regulatory and safety requirements wherever our plants are built.”

What types of heat exchangers do you primarily work with, and why are they suited for nuclear applications?

“In the nuclear industry, we typically use traditional designs like shell-and-tube heat exchangers because they are well-understood and proven to be reliable. While there is always interest in developing new heat exchanger technologies, nuclear is a very conservative industry.”

“Introducing a completely new type of heat exchanger would require a lot of work from us to prove that designs are safe and gain regulatory approval, which can take years. Instead, we focus on optimizing existing designs—improving materials, efficiency, and manufacturability. Our priority is reliability and safety, so we stick with technologies that have a long history of successful operation in nuclear plants.”

How do you select materials for heat exchangers in a nuclear environment?

“Material selection is guided by several criteria, primarily durability, temperature resistance, and corrosion resistance. The materials must withstand the demanding environments within a nuclear plant, including prolonged exposure to high temperatures, weak radiation, and potential corrosive agents.”

“In nuclear engineering, safety
always comes first. There’s no
room for compromise in that
regard. If something can’t be
done safely, it doesn’t get done
at all.”

“For instance, one of the critical goals is to avoid the generation of corrosion products that could circulate within the reactor coolant system, leading to radiation concerns and safety hazards. Moreover, materials must exhibit mechanical stability over time and maintain performance across the anticipated lifespan of the reactor.”

“Collaborating with material scientists and leveraging advancements in metallurgy is integral to refining this selection process, ensuring that components meet both safety and operational requirements.”

What are some of the emerging trends in heat exchanger design that you see sticking around in the coming years?

“Automation is becoming increasingly important. Many aspects of heat exchanger design and manufacturing rely on highly specialized engineers and craftspeople, which poses a challenge if those experts become unavailable. Automating certain processes can improve efficiency and consistency.”

“Collaborating with material
scientists and leveraging
advancements in metallurgy
is integral to ensuring that
components meet both safety
and operational requirements.”

“Additionally, there’s a growing demand for advanced materials as new reactor technologies, such as molten salt and fusion reactors, push temperature limits far beyond what traditional materials can handle. Fusion reactors, for example, operate at temperatures of about 50 million degrees Celsius, which presents an entirely new set of engineering challenges. Finding materials that can withstand those conditions will be a major focus in the coming years.”

“Last, but not least, modularity, which is critical to SMRs, is influencing component designs across the sector. Engineers are developing scalable, flexible solutions that meet the demands of smaller, decentralised power plants. These trends suggest a broader shift toward innovation focusing on efficiency, sustainability, and accessibility.”

Final thoughts

Katrina Bradley’s insights highlight the meticulous engineering that underpins nuclear advancements like small modular reactors. Her expertise in designing heat exchangers ensures that components align with the ambitious goals of safety, efficiency, and modular accessibility within the nuclear industry. With emerging trends such as increased efficiency and sustainability, professionals like Katrina play a vital role in shaping the energy solutions of the future.