Uranium from sea water?

There was a news item in TOI dated 22 Feb. 2017 on “Harnessing N-Power from Oceans”.  Presence of naturally occurring radioactive materials like uranium and thorium in water, soil and rocks is known. However, the concentration of these materials in very low, in parts per million (ppm) or parts per billion (ppb). Recovering the elements at such low levels from such complex matrices is very difficult and not cost effective. Japanese and Indian researchers have done good amount of work in the extraction of uranium from sea water.

Uranium concentration in sea water is about 3 ppm (3 milligram of uranium in one cubic meter of sea water). If one multiplies this by the total volume of sea water, there will be billions of tons of uranium potentially available. As per Japanese study, the cost of uranium may work out to be over 300 USD per kg! May be, it can be the last desperate resort for producing uranium for power generation.

Do we have to resort this when other better options are available? Thorium is more abundant on the surface of the earth (ex. Monazite minerals on sea beaches). The thorium can be effectively utilised for power generation. India is one of the countries which extensively studied thorium fuel cycle for producing U-233 which is fissile material and can be used in nuclear reactors for producing power. Countries should focus on this instead of recovering uranium from sea water on commercial scale, at unimaginable cost.

Then there is unlimited fusion energy which can be harnessed. It is also satisfying to see the solar power being harnessed world-wide for producing electricity.