Researchers racing to usher in a new nuclear renaissance are exploring all of the ways to make the process as sustainable as possible.
A recent study by researchers at Ritsumeikan University in Japan shows that the key may already exist in the sustainability movement: reduce, reuse, and recycle. However, this time instead of plastics, the three R’s are applied to nuclear energy.
The study, published in the August 2022 volume of the Journal of Cleaner Production, focused on key factors, central to the process of creating nuclear energy. They aimed to assess the environmental impact of nuclear energy, because while nuclear reactors don’t produce greenhouse gas emissions, the energy to mine uranium does, and there is still a lot to learn about the total resources used during the process of nuclear generation.
The research is happening at a pivotal moment for the industry as across the country and around the globe governments are spending millions (and in some cases billions) of dollars to restart an industry that has mostly been dormant for decades.
For instance, President Biden recently backed mini nuclear power plant efforts in Colorado could generate electricity around the planet and in space.
These efforts could help the U.S. meet integral climate action goals. And the urgency of the situation is clear: earlier this month the Biden administration awarded $61 million to 40 universities, reflecting the emerging need to better understand and facilitate nuclear energy.
Nuclear engineers at Colorado School of Mines and the University of Colorado working at federal facilities say they are racing to perfect small-scale nuclear power plants as quickly as possible, according to the Denver Post.
Why? “We need all of our low-carbon energy technologies as soon as we can get them. Every day we wait is putting off the solution,” Jeff King, director of CSM’s Nuclear Science and Engineering Center and member of Colorado’s Radiation Advisory Committee told the Denver Post. “We have to get nuclear in the mix. Or else, we have to accept the consequences of uncontrolled climate change.”
The race for nuclear extends past the west. The trade association for U.S. nuclear plant operators says it hopes to nearly double its output over the next three decades, according to ABC news. This massive expansion comes as demand for alternative energy swells across the globe, and renewable energy sources like wind and solar can’t keep up despite the increasing availability.
And because wind and solar are not meeting the demand for clean energy, this could mean that the U.S. may not meet its ambitious plan to have a net-zero carbon economy by 2050, according to the New York Times. Moreover, with Russia’s invasion of Ukraine, questions about the national security implications of oil and gas have reemerged, putting nuclear back on the table in many parts of the world.
Understanding the role of resource mining in nuclear power
Generally, to understand how energy sources affect the environment, researchers conduct a life cycle assessment (LCA). Hence, a lot of studies on the impacts of electricity generated via nuclear power have assessed both cumulative energy consumption, as well as greenhouse gas emissions. However, as reported by a news release in EurekAlert! siloing research on these two factors might lead to a narrow assessment of environmental impact and sustainability.
Thus, the researchers set out to look at going nuclear from a higher vantage point. Their findings indicate that the resource use of nuclear power generation significantly decreases when the spent fuel, fuel already used to generate power, is reprocessed. This fuel takes years to properly cool and decrease its radioactivity. When fuel is reprocessed in this way, the process is known as a “closed cycle.” When the fuel is only used once, this is known as a “once-through” or “open cycle.”
“We found that a closed cycle that reprocesses uranium fuel uses 26% lower resources than an open cycle that does not reuse its by-products,” Professor Eiji Yamasue told EurekAlert! in discussing the impact of fuel cycles.
The traditional model for the nuclear lifecycle is the linear once-through system. Uranium is mined, milled (a process where it is crushed and chemically separated), converted into gas, enriched, and fabricated into fuel to be generated into electricity. The materials are used once and then buried.
However, according to Nuclear Engineering International, “An increasing number of reactors now require decommissioning. The question that arises is how to decommission a nuclear facility in a manner that is consistent with circular economy principles.”
In a circular economy, products are made to last longer and are used in a continuous cycle rather than in a linear fashion. In the case of nuclear energy, the three R’s apply to resource reduction, fuel reuse, and recycling.
Looking at resource reduction, the team analyzed specific ways the nuclear process can be more sustainable by measuring the total resource material (TMR) coefficient. In examining factors such as ore grade, nuclear reactor types, and mining methods, the team found that the grade of uranium ore had a huge impact on the TMR coefficient, meaning that TMR varied significantly with different mining methods.
Uranium is mined using three methods: open-pit mining, underground mining, and in situ leaching, where the uranium is leached directly from the ore, the natural rock or sediment containing the mineral. In the study, in situ leaching had the lowest TMR. However, the mining method had a more significant impact on resource utilization as compared to its impact on greenhouse gas emissions.
Interestingly enough, the researchers also found that 1) the natural resource use of nuclear power generation was similar to that of renewable energies and significantly lower than that of thermal power generation; 2) global warming potential and the total material resource use of nuclear power generation showed very different trends; 3) along with lower greenhouse gas emissions, nuclear power generation also used fewer natural resources, making it an environmentally favorable source of power generation.
Associate Professor Shoki Kosai, the corresponding author of the study has hopes for the economic and policy impact of the team’s work. “Maintaining a circular economy, even for resource use, is important,” Dr. Kosai told EurekAlert!, “Our findings can assist policymakers in formulating long-term energy policies which consider electricity and power generation using nuclear power.”
As countries restart nuclear energy programs for zero-emission energy, circularity needs to be the focus. Is the future nuclear? The cycle may be pointing to yes.