Transforming Nuclear Waste into an Energy Resource
What if there were a solution to one of the most significant obstacles hindering the expansion of nuclear energy—the disposal of high-level nuclear waste (HLW)? Dauren Sarsenbayev, a third-year doctoral student at MIT’s Department of Nuclear Science and Engineering, is tackling this pressing issue through innovative research.
Addressing High-Level Nuclear Waste with Innovative Thinking
Sarsenbayev focuses on a key challenge associated with HLW: the decay heat released by radioactive waste. His approach aims to extract this heat from spent fuel, serving two critical purposes simultaneously: maximizing energy output from a carbon-free source and minimizing the challenges associated with storage and handling of HLW. “The value of carbon-free energy continues to rise each year, and we want to extract as much of it as possible,” Sarsenbayev explains, emphasizing the importance of efficiency in energy production.
Reframing the Narrative Surrounding Nuclear Waste
Despite advancements in the safe management and disposal of HLW, exploring creative solutions remains essential for fostering public acceptance of nuclear energy. “We’re reframing the problem of nuclear waste, transforming it from a liability to an energy source,” he says. This shift in perspective is crucial, particularly in dispelling public fears and misconceptions about nuclear power.
A Personal Connection to Nuclear Energy
Sarsenbayev’s journey into the realm of nuclear energy isn’t just academic; it stems from a deeply personal background. Growing up in Almaty, Kazakhstan, he was acutely aware of the lasting scars left by Soviet-era nuclear testing. As the world’s largest producer of uranium, Kazakhstan carries a complicated legacy regarding nuclear issues, a reality that’s hard to escape.
Alongside this backdrop, Sarsenbayev witnessed the severe air pollution in Almaty every winter due to the burning of fossil fuels. This stark contrast motivated him to contribute to the decarbonization of energy sources. Pursuing undergraduate studies in environmental engineering at Kazakh-German University, he quickly realized that every energy source, including renewable options, comes with its inherent challenges. Ultimately, he gravitated toward nuclear energy as it offers reliable, low-carbon power. “I was exposed to air pollution from childhood; the horizon would be just black. The biggest incentive for me with nuclear power was that, as long as we did it properly, people could breathe cleaner air,” he reflects.
Understanding Radionuclide Transport
A fundamental aspect of safely managing nuclear resources is studying the long-term behavior of radionuclides in geological repositories. Sarsenbayev discovered his interest in nuclear waste management during an internship at Lawrence Berkeley National Laboratory, where he focused on modeling the transport of radionuclides from a nuclear waste repository’s barrier system to surrounding rock. He was fascinated by the ability to predict future interactions, viewing it as foreseeing challenges that future generations would face.
The timing of this internship proved fortuitous, as he collaborated with Haruko Murakami Wainwright, who had recently joined MIT NSE. With the aspiration to further his studies in nuclear waste management, Sarsenbayev followed Wainwright to MIT, where he honed his skills in modeling radionuclide transport. His work has led to significant publications that improve models depicting the interactions between engineered barriers and their surrounding environments.
Excelling in Computational Geochemistry
At MIT, he has made noteworthy contributions while working under prominent experts in computational geochemistry. His modeling predictions have shown promising alignment with experimental results from Mont Terri research site in Switzerland, renowned for its studies on cement-clay interactions. “I was fortunate to work with Dr. Carl Steefel and Professor Christophe Tournassat, leading experts in this field,” he recounts, reflecting on the collaborative nature of his studies.
However, creating accurate simulations is no small feat. These reactive transport models, which simulate fluid flow, chemical reactions, and the transport of substances through subsurface materials, demand extensive computational power, often taking days to weeks. To mitigate this, Sarsenbayev is developing AI-based “surrogate models” to enhance efficiency. By training on simulated data, these models can approximate physical systems, delivering quicker predictions with less computational intensity.
Exploring Geothermal Energy from Nuclear Waste
Sarsenbayev’s doctoral research focuses on evaluating the potential of using spent nuclear fuel as a geothermal energy source. “Geothermal heat primarily arises from the natural decay of radioisotopes in Earth’s crust, so using decay heat from spent fuel is conceptually similar,” he explains. The energy generated from a single canister of nuclear waste could equal that of a substantial area of solar panels.
The process involves a binary cycle system, where heat is extracted indirectly. As the canister warms a closed water loop, the heat is transferred to a secondary fluid that efficiently powers a turbine. Sarsenbayev’s innovative work in modeling such a geothermal system powered by HLW has yielded promising results, currently at the proof-of-concept stage.
Balancing Science and Artistry
Despite the demanding nature of his work, Sarsenbayev pursues his passion for reflective poetry in both Kazakh and Russian and enjoys astrophotography. He finds joy in capturing the beauty of celestial bodies, often venturing out to the canyons near Almaty during family visits. His love for his native land shines through as he describes, “Almaty means ‘the place where apples originated.’ This part of Central Asia is very beautiful; although we have environmental pollution, this is a place with a rich history.”
Sarsenbayev is committed to communicating the inherent link between art and science to future generations. He believes that “you have to be technically rigorous and get the modeling right, but you also have to understand and convey the broader picture of why you’re doing the work.” This perspective underscores the significant impact of his research, aiming to alleviate nuclear energy’s bottleneck by ensuring effective disposal of radioactive waste while generating carbon-free power.