by Steve Levenstein
Japanese researchers are considering the possibility of constructing giant undersea sponge farms to collect uranium suspended in seawater. If enough farms are built, every nuclear plant in Japan could soon be running exclusively on ocean-sourced fuel.
The stakes are huge and so are the numbers: Japanese nuclear reactors process 8,000 tons of radioactive uranium each year. That may sound like a lot but approximately 4.5 billion tons of uranium are suspended in the world's oceans. The concentration is very low - just 3.3 parts per billion - but the proposed sponge farms are designed to selectively adsorb these low-level concentrations.
The sponges are made from irradiated polyethylene fabric developed by Dr. Masao Tanada of the Japan Atomic Energy Agency. Explains Dr. Tanada, "At the moment, Japan has to rely on imports of uranium from Canada and Australia, but this technology could be commercially deployed in as little as five years." He is suggesting a pilot project that would see the first sponge farm, covering an area of 400 square miles, absorb enough uranium to meet a sixth of Japan's annual uranium requirements.
With current land-based sources of uranium expected to be mined out in just 100 years, time is of the essence in finding a workable alternative. The obvious choice is to exploit oceanic uranium which is approximately 1,000 times more plentiful than all the known un-mined uranium on land - and the clock is ticking on efforts to "mine" it. "Other countries are conducting similar research but none are as advanced as we are," stresses Dr. Tanada. With $720 trillion worth of uranium "just floating around", Japan's lead could prove to be a very lucrative one.