Energy makes the modern world go round, but the availability or sustainability of, say, fossil fuels — has placed a limit on societal progress. Until now.
Researchers interested in nuclear power's capacity to help transition the world's energy supply toward carbon neutrality suggested extracting uranium from a source other than raw ore, opting instead to use a new hydrogel capable of effectively "straining" uranium from seawater, according to a recent study published in the journal Nature Sustainability.
This could offer a near-limitless supply of fuel for nuclear power.
New peptide hydrogel material extracts fuel for nuclear power
Nuclear power generation is due to become more reliable in the public eye in the coming decades, but as of writing the primary source of uranium is terrestrial ore — which scientists estimate contains 7.6 million tons of the element. The ore also has limits, since it can only energize the nuclear power industry for a limited number of years, notwithstanding the growing rates of consumption. Worse still, the distribution of terrestrial uranium globally is not equal, with eight countries in possession of the largest uranium reserves, accounting for 80% of worldwide resources of the element.
However, scientists estimate the ocean contains 1,000 times more uranium than land — and could serve as a gigantic alternative resource so long as ongoing technological developments enable the procurement of uranium at competitive costs, according to the study. Crucially, more than 75% of the world's countries involve more ocean than land, which means access to the resource via seawater is far more evenly distributed than land containing the ore.
However, the development of uranium extraction technology has serious challenges ahead, because of the very low concentration and presence of several other metal ions, and the aggregation of microorganisms. But a bifunctional polymeric peptide hydrogel showed strong selectivity for and affinity to uranium in seawater — in addition to a substantial resistance to biofouling.
"Detailed characterizations reveal that the amino acid in this peptide material serves as the binding ligand, and uranyl is exclusively bound to the oxygen atoms," inhibiting the growth of roughly 99% of marine microorganisms, read the recent study. This could deliver an extraction capacity of 7.12 mg/g — and, most critically, the peptide material is reusable, which makes it sustainable. The results of this study might open a new door for the design of low-cost, sustainable materials capable of providing viable nuclear fuel.
Nuclear power gaining credibility as a sustainable resource
This comes on the heels of another breakthrough in 2018, when researchers designed a yarn capable of extracting natural trace amounts of uranium in seawater. The proof-of-concept accumulated a sufficient quantity of the element to procure five grams of yellowcake — which is a powdered form of uranium concentrate that can fuel nuclear power generation.
"This is a significant milestone," said Gary Gill of the Pacific Northwest National Laboratory (PNNL), in a Science Alert report. "It indicates that this approach can eventually provide commercially attractive nuclear fuel derived from the oceans — the largest source of uranium on Earth."
Notable scientists are warming to the idea of classifying nuclear power as a sustainable energy resource, to help fill the power gap expected as fossil fuel takes an increasingly marginal role in the coming decades. Experts in the European Union finished a draft declaring nuclear power a green investment — capably matching the prerequisites to qualify as a sustainable energy source. With technology capable of extracting uranium from the oceans of the world, it could take a leading role in carbon-neutral alternatives.