Technology to recover uranium from seawater may act as a potential backstop on the production cost of uranium in a growing international nuclear industry. Convincing proof of the existence of an effective expected upper limit on the resource price would have a strong effect on decisions relating to deployment of uranium resource consuming reactor technologies. This evaluation proceeds from a review of backstop technologies to detailed analyses of the production cost of uranium extraction via an amidoxime braid adsorbent system developed by the Japan Atomic Energy Agency (JAEA). An independent cost assessment of the braid adsorbent system is developed to reflect a project implemented in the United States. The cost assessment is evaluated as a life cycle discounted cash flow model to account for the time value of money and time-dependent performance parameters. In addition, the cost assessment includes uncertainty propagation to provide a probabilistic range of uranium production costs for the braid adsorbent system. Results reveal that uncertainty in adsorbent performance (specifically, adsorption capacity, kg U/tonne adsorbent) is the dominant contributor to overall uncertainty in uranium production costs. Further sensitivity analyses reveal adsorbent capacity, degradation and production costs as key system cost drivers. Optimization of adsorbent performance via alternate production or elution pathways provides an opportunity to significantly reduce uranium production costs. Finally, quantification of uncertainty in production costs is a primary policy objective of the analysis. Continuing investment in this technology as a viable backstop requires the ability to assess cost and benefits while incorporating risk. / text