1 - Uranium Chemistry in the Environment
Bret Kugelmass: How did you get into the nuclear space?
Andrew Sowder: Andrew Sowder studied physics, specifically optics, at the University of Rochester. After graduation, Sowder went to North Carolina State University for a fellowship in nuclear engineering and then went to Clemson to major in environmental health physics, completing his PhD on uranium chemistry in the environment. Sowder completed some post-doctoral research focused on cleanup of the nuclear weapons complex at the Savannah River Site. Most of the uranium Sowder looked at was a co-contaminant with other heavy metals that were discharged in the riparian wetlands environment using the contemporary practices of the day. The team looked at how metals went up the food chain and nickel turned out to be the bigger hazard. Uranium liked to form very strong associations with the soil and organics in the soil, so it was tightly bound in the sediments. Nickel tended to be more mobile and available to travel up the food chain. The biggest problem from uranium was radon, which is part of the decay chain. Radon is a noble gas that can be transported and inhaled into lungs, where it decays into things that stick to the lung tissue which causes the most damage. Uranium tends to be more of a chemical toxin than a radio toxin, acting more like a heavy metal. Popular media tends to confuse the idea of the presence of radioactivity with an unbounded risk.
2 - Domestic and International Nuclear Outreach
Bret Kugelmass: How did you transition into the State Department as a foreign affairs officer?
Andrew Sowder: The American Association for the Advancement of Science administers science policy technology fellowships. This fellowship brings scientists and engineers into the policy environment in D.C. to provide technical inputs. Andrew Sowder’s fellowship was at the Environmental Protection Agency (EPA) in the Office of Radiation and Indoor Air, which was working on an outreach project with the Navajo nation dealing with abandoned uranium mines and contaminated well water. There was real potential for exposures in this community because people had incorporated mine tailings and uranium ore into the concrete in walls and structures. Sowder brought radon detection equipment and other instruments to the community and completed testing. Andrew Sowder was hired into the State Department to complete oversight of U.S. assistance to the Chernobyl shelter program. Unit 4 was the reactor involved in the Chernobyl accident; one or two of the other units continued to operate after the accident, as they were unharmed during the explosion and Ukraine needed reliable electricity during the winter. At least one of the reactors also had to stay operational to provide heat to the nuclear site; a coal plant was later sponsored by the U.S. to be built on-site to provide district heating. Chernobyl. U.S. led in raising funding for Ukraine to manage the reactor issues and other funds were raised for management of spent fuel. Sowder transitioned to the Electric Power Research Institute (EPRI) as his family started growing and they moved to Charlotte, NC.
3 - Nuclear Fuel Cycle
Bret Kugelmass: What were some of the initial things you worked on while at the Electric Power Research Institute (EPRI)?
Andrew Sowder: Andrew Sowder has been tied to the nuclear fuel cycle at EPRI, but came in working on a program for Yucca Mountain. EPRI was the only other program, besides the U.S. Department of Energy (DOE), that was developing and conducting assessments on total system performance of the repository. EPRI’s U.S. members were paying into the nuclear waste fund and had an interest in the repository. There is no such thing as a perfect site; the goal should be to have an adequately safe site that meets the regulations and protects the public. EPRI exited from Yucca Mountain a year before the termination of the project, but they did review a history of where they ended up with regulations and recommendations for future evaluation of repositories. Both the Environmental Protection Agency (EPA) and the Nuclear Regulatory Commission (NRC) rolled out new rules, regulations, and standards for repositories and had jurisdiction. EPRI can weigh in with technical insights without advocating for a position. There are different repository approaches around the world, including levels of compliance for storage. The term “accident tolerant fuels” came out of post-Fukushima events and the desire was to have a nuclear fuel that could delay or prevent another core meltdown like happened at Fukushima. Development of these fuels were already in place, but were focused on robustness instead of coping time for operators. The biggest drawback to zirconium cladding is the higher temperatures in the presence of oxygen and water, which creates runaway oxidation reactions that lead to further generation of heat. During a shutdown in a standard, traditional reactor, the heat must be removed because it keeps building and something will fail. The general concept is to improve the cladding with a coating or substituting it with a different material that doesn’t have the same drawbacks as zirconium.
4 - Advanced Materials in Nuclear Fuels
Bret Kugelmass: What other materials don’t oxidize with higher temperatures like zirconium does?
Andrew Sowder: There is no such thing as a meltproof or accident proof fuel in a light water reactor system, because at a certain temperature, all materials will fail if heat is not removed. The original reactor fuels in the U.S. were stainless, but they imposed a penalty because they absorbed neutrons. Another equivalent that was proposed was an Iron Chrome Aluminum (FeCrAl) alloy that was an analog to the stainless steels of the past. The more advanced approaches move away from metallics and towards things known to withstand high temperatures, such as silicon carbide. Like zirconium, they don’t absorb many neutrons, but it is brittle and is more difficult to work with. If more coping time can be demonstrated, then the plant may be less reliant on a certain safety system and typically, lowering the classification of systems is less expensive to maintain. Eliminating or reducing the dependency on certain systems comes with savings. Even though fuel is a relatively small fraction of the cost of a nuclear plant, it is still important and there is a focus on longer cycle lengths and more performance because it contributes to the economic performance.
5 - Benefits of Advanced Nuclear Concepts
Bret Kugelmass: Tell me about some of your work in understanding and communicating the issues around advanced reactors.
Andrew Sowder: There are a number of developers and entrepreneurs trying to develop the next big concept in nuclear. The value and benefit of nuclear is that it is unique in what it provides in one package: scalable, dispatchable, energy dense, and the focus on limiting emissions of greenhouse gases and other environmental factors. Should storage come into fruition at a sufficient scale, renewable can start filling those same niches. If carbon capture sequestration gets developed to a point at which it is economic at scale, then natural gas can perform in that niche. While the current nuclear fleet is operating safely, new nuclear designs offer the promise of simplification, greater margins, reduced emergency planning requirements, and reduced staffing costs. With lower pressures come lower pressures come thinner wall components and maybe lower costs. Most advanced concepts operate at a substantially higher temperature, which brings a higher efficiency electricity generation. This heat can also be used to produce chemicals and hydrogen. The Electric Power Research Institute (EPRI) receives many requests from the developer community for help understanding what customers want. Developers must consider what the market will be like in five or ten years and what the customers will want. The customer is the owner/operator, not just utilities. Some of the greatest gains in new markets will not be solely for electricity.
6 - Nuclear Heat Production
Bret Kugelmass: Are your economics three times better in nuclear heat production?
Andrew Sowder: There is a benefit of not converting from one form of energy to another and maybe having to convert back again. Electricity is very transportable and can be accessed where it is needed once it is on the grid. What you gain in efficiency in heat production, you lose in flexibility. There have been proposals of energy parks, where a reactor is sited and industrial development is encouraged around it. The Electric Power Research Institute (EPRI) and the Idaho National Lab (INL) are looking into hybrid energy systems. EPRI has a model called Regen which models what expansion of which generation assets or mixes are needed to meet certain criteria. If the plants costs less to build and operate, it encourages the model to say nuclear has a promising future. Favorable policy related to carbon constraint or cost also drove nuclear builds according to the model. Another factor in the success of nuclear was revenue. If the nuclear owner/operate received extra revenue, the level of revenue had the greatest impact on the model. EPRI is looking into the real value of a nuclear plant and other technologies. Understanding what value different assets bring and what you lose when you remove them from the system is on the cutting edge of where people are today in understanding how markets are priced.
7 - Measuring Value of a Power Plant
Bret Kugelmass: What are all the characteristics of value of a power plant?
Andrew Sowder: Some markets may receive some values that others may not. Because the electricity grid was built using coal and other plants that had big spinning turbines and generators, there ended up being a lot of inertia on a system and frequency regulations. Wind can produce something that is a synthetic version of that and introducing storage helps as well. Black start capability is in conversation for advanced reactors. When the grid becomes unstable, nuclear plants currently need to shut down. There are applications for nuclear where it doesn’t need to be connected to a grid in a microgrid operation. During the 2014 polar vortex, the U.S. had a curtailment or loss of natural gas supplies to electric power production because home heating is given preference, creating a reduction in gas pressure. There were also coal piles that froze in the South. Having a plant that doesn’t need fuel brought to it and could ride out the storm has strategic value. There is a big opportunity in the U.S. and the world where there is an interest in bringing old concepts back to light. Depending on what you believe to be problems and challenges of the future, whether it be climate change, energy supply, resource limitations, or others, there is a need or value to having an option like nuclear that could step in and be deployed if needed. The real benefit value of nuclear and continuing to invest in nuclear energy is that it provides you with a valuable option for the future that is available if you need it. In the financial market, options have real tangible value and options should be kept on the table.