Review of cost estimates for uranium recovery from seawater

• Adsorption capacity was the largest driver of cost.
• A higher capacity did not necessarily mean a lower cost.
• Many substrates were employed: polyethylene was the most widely and recently used.
• Passive mooring systems were more economical than pumping seawater systems.

The 4.5 billion tonnes of uranium in seawater is sufficient to power the world's reactor fleet for 13,000 years. For decades, the transformative potential of this enormous resource has prompted interest in technologies for recovering uranium from seawater. Since the 1960s, though, cost analyses of such technologies have failed to convincingly demonstrate a cost-competitive alternative to conventional uranium recovery from terrestrial mining. Hence, uranium from seawater has come to be considered as a backstopping technology that has the potential to establish a price ceiling for the uranium resource. Such an upper bound is valuable because it removes uncertainty surrounding uranium prices when developing and deploying nuclear power systems. This paper reviews cost estimates as the technology has evolved over the past five decades. During this time, systems that actively moved seawater gave way to those where the adsorbent sits passively in seawater. The adsorbent material changed from hydrous titanium oxide to the higher-capacity amidoxime ligand. Early efforts used amidoxime grafted onto an acrylic substrate, which was later replaced by polyethylene because of its increased durability and lower cost. The review shows that capacity, in grams of U per kilogram of adsorbent, is a strong driver of cost along with reusability of the adsorbent. The most recent estimates reviewed are seen to place the U production cost at $400–$1000/kg of U, several times higher than the 2014 spot market price, which has remained near or below $100/kg of U.