Researchers have developed a technology which uses adsorbent polymer fibers woven into fabric and assembled in the form of long braids to extract Uranium from seawater. The conceptual design involves deployment of these braids in an in ocean environment through moorings distributed over a regular grid. The adsorbed uranium is extracted from the fibers by fractional elution with hydrochloric acid upon recovery of the moorings from the submerged farm. The undersea farm design resembles a kelp forest. There is evidence that dense kelp forests offer resistance to coastal currents.  There is concern that commercial scale deployment of braided-mooring-farm would cover a large area ( ≈ 680 km<sup>2</sup>) and has the potential to modify large scale ocean currents and circulation patterns and impact water quality. A preliminary modeling based assessment was conducted using a kelp-type structure module incorporated within a finite volume coastal ocean model. The classic momentum sink approach was used to modify the momentum terms within the computational scheme to simulate the form drag effect resulting from a farm of passive uranium extraction devices on the flow field. The module was first quantitatively validated against laboratory flume experiments for both velocity and turbulence profiles. The model was then tested against qualitative information and available data from kelp forests off San Diego, CA. Model results suggest that the reduction in ambient currents could range from 4% to 10% using adsorbent farm dimensions and mooring densities previously described in the literature and with typical drag coefficients. Modeling based tests in Salish Sea region of the Pacific Northwest showed minimal impact on estuarine exchange flow and conventional water quality parameters such as salinity and dissolved oxygen from changes in circulation and transport.

Impacts of seawater uranium extraction on oceanic circulation and transport

249th National Meeting (2015)

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