I think in your link "economical extraction" means "economical extraction at current or similar prices". At suitably high prices, even extraction from seawater becomes reasonable (google gave me http://www.technologyreview.com/news/514751/novel-material-s... with an estimate of $1e3–2e3/kg). I assume this would have a limited effect on electricity prices because uranium prices are probably a minor component of nuclear power costs.