Nuclear Fuel Materials
Oak Ridge National Labs
1 - Nuclear Material Science
Bret Kugelmass: How did you get interested in the nuclear space?
Kurt Terrani: Kurt Terrani completed his undergraduate degree in materials science at Arizona State University. His interest in large systems drew him to the materials side of nuclear energy, inspired by his childhood dream of being a nuclear physicist. The nuclear industry can do a better job in outreach and education, but recently the Department of Energy Office of Nuclear Energy has started some significant activities in this area. Terrani went to UC-Berkeley for grad school where he worked with Don Olander, a member of the National Academy and the author of “The Fundamental Aspects of Nuclear Fuel Elements”. Olander analyzed and extracted basic, fundamental, transient elements out of big bodies of data for this book. Terrani enjoys making things and doing experimental work, but also the back-of-the-envelope modeling to predict experiment results. If one material is 3D printed and another material is inserted into it, a hybrid material is created after subjection to thermal mechanical treatment. The material goes up in temperature and back down, which creates stress in the material. This stress can be predicted with simple equations as well as finite element analysis.
2 - Path to Oak Ridge National Lab
Bret Kugelmass: What’s the value of doing rough order of magnitude calculations to think of things from a systems perspective?
Kurt Terrani: Looking at things from a systems perspective is a more holistic and complete perspective. People should not be divided between computational and experimental specialties; everyone should have those tools in their toolkit which will provide a more complete understanding of what is going on. Kurt Terrani joined Oak Ridge National Lab in 2010 straight out of his PhD program. He applied for neutron scattering time in 2009 while at Berkeley and was one of the first users of Spallation Neutron Source (SNS). This was one of the first beam lines that backscattering spectrometer came online. One of his advisors recommended that Terrani put his name in the hat at Oak Ridge, which he did, but Terrani didn’t think he would even consider a position. Terrani looked around at the capabilities and materials during a two-day interview and realized that Oak Ridge is the place to be for certain types of research and development.
3 - Transformational Challenge Reactor
Bret Kugelmass: What are some big things happening at Oak Ridge?
Kurt Terrani: One of the big projects currently going on at Oak Ridge National Lab is the Transformational Challenge Reactor (TCR). The vision is not to pick a reactor technology, but instead to find a new way to design, develop, deploy, and license nuclear energy systems. The technology used in the nuclear industry worldwide is late 1940’s and 50’s technology that is efficient, but uses less than a dozen materials across all the nuclear energy systems. These materials are pre-1970’s materials that mostly existed before the dawn of the nuclear era. Licensing and qualifying is being done now as it has always been done, but it’s getting more expensive. Material science has come a long way and, with phenomenal computational tools, materials can be designed for a specific function since there is a profound understanding of radiation effects in materials and incredible characterization capabilities. TCR combines massive computational power, advanced manufacturing, and advanced material science to do things differently. Advanced manufacturing can fundamentally disrupt the way things are designed and there is freedom from constraints such as geometry. When additive manufacturing is used in advanced monitoring, things like acoustic or infrared signals can be continuously monitored as it is built, providing a massive data set. This in-situ data is combined with ex-situ data in a supercomputer to find links between signatures during advanced manufacturing and final performance of conformance to a certain set of criteria.
4 - Material and Manufacturing Qualification Process
Bret Kugelmass: Has economic analysis been done on the cost drivers for nuclear components?
Kurt Terrani: Most of the money in large, gigawatt nuclear plants is in the construction of concrete and steel. Small modular reactors (SMR’s) and microreactors are much more manageable. However, the interesting, ambitious designs are limited by previously qualified components and types of manufacturing that produce their product economically since they already exist. Kurt Terrani’s passion and focus is, after 50 or 60 years, having a dozen materials available people to realistically consider in their designs and different avenues to realize the construction of their reactor systems. The Transformational Challenge Reactor (TCR) at Oak Ridge National Lab (ORNL) is a blueprint and another tool in the toolbox for realizing advanced systems in ways that were not previously possible. Post-Fukushima, ORNL went in search of advanced cladding materials to replace zirconium, since zirconium generates heat and hydrogen during accidents. The team picked out an alloy and spent a few years proving it out before it was deployed in a commercial nuclear power plant, GE’s Hatch 1 in Georgia. The goal of TCR is to advance manufacture a nuclear core and make it go critical and generate heat. The way the new blueprint will be adopted is by educating colleagues in industry, especially the regulator. Doing a complete demonstration that complies to requirements using existing rules and providing additional data showing how computational approaches were used in combination with advanced manufacturing to certify that things will function will get the conversation started to design manufacturing qualification license.
5 - Design and Demonstration of New Nuclear
Bret Kugelmass: What comes first: taking an advanced manufacturing reactor critical or proving to the regulatory body that it is safe?
Kurt Terrani: That National Labs need to be pushing the boundaries. There are multiple pathways, including Department of Energy (DOE) rules and Nuclear Regulatory Commission (NRC) rules. The DOE regulatory space has a lot of computational tools available. Design and safety analysis is completed and presented to a safety analysis board who completes a review and makes a recommendation on moving forward or not. The NRC rules have flexible rules for research reactors. Labs ultimately rely on calculations and assumptions on the source term and bounding scenarios to show that the risk is minimal. Oak Ridge National Labs (ORNL) has nuclear facilities that new companies, startups, or existing companies don’t have, such as hot cells and demonstration pools that are there to be used. With his materials education and focus, Kurt Terrani advocates that that materials are key to performance. It is a problem that no more than a dozen materials are used in existing nuclear systems. His passion is understanding how to push materials to extreme levels of radiation damage and chemical evolution under extreme gradients.