Opinion Since the Fukushima meltdown - as a result of which, not a single person is set to be measurably harmed by radiation - we know that nuclear power is safe. New discoveries by US scientists have now shown it's sustainable as well.

That's because US government scientists have just announced research in which they've massively increased the efficiency of techniques for extracting uranium from the ocean - and that means that supplies of uranium are secure for the future even if the entire human race moves to fission power for all its energy needs.

"We have shown that our adsorbents can extract five to seven times more uranium at uptake rates seven times faster than the world's best adsorbents," says Chris Janke of the US Oak Ridge National Laboratory, one of America's top nuke labs.

At the moment people don't use nuclear power much (the UK's small and aged nuclear fleet can barely generate four times as much power as its wind farms, showing just how little energy we're talking about here: under 2 per cent of our national energy needs are derived from nuclear right now). As a result there's no scarcity of uranium, and indeed nobody has bothered exploring for more of it for decades.

But one day people really will have to stop using fossil fuel for nearly everything - either to prevent a global warming apocalypse, or (perhaps more realistically) because supplies will eventually run out. There's no chance of renewables generating the sort of energy the future human race will require to live above the poverty line, so something else will be required.

Anti-nuclear people have always argued that the something had better not be nuclear because more nuclear powerplants equals more weapons-grade material (not by any means necessarily true, though it seemed as though it might be the case back in the early days of nuclear technology). And even if you think nuclear bombs are OK, the fearmongers have always added that there just isn't enough uranium about to keep the lights on for long.

That may very well be correct, provided all the uranium must be dug out of the ground and run through a powerplant just once before being classified as waste and dumped. But in fact almost all of the spent fuel can be recycled and used again (nobody bothers much right now, as new uranium is cheaper - and in the States recycling the waste has actually been banned at the behest of the anti-nuclear tendency).

And best of all, there's an awful lot more uranium in the sea than there is in the ground. But until now, the costs of getting it out have been so steep as to make it unfeasible even given nuclear-power economics. (Normally, fuel price isn't a big deal for nuclear power as it is a tiny proportion of the cost of having a station - so double-price uranium only sends up the cost of the electricity by a few per cent at most. But seawater uranium to date has cost many times double.)

But now Janke and his colleagues at Oak Ridge and the Pacific Northwest federal atom labs have massively increased the efficiency of seawater extraction.

"Our HiCap adsorbents are made by subjecting high-surface area polyethylene fibers to ionizing radiation, then reacting these pre-irradiated fibers with chemical compounds that have a high affinity for selected metals," says Janke. The allied US government experts behind the tech presented details at a major boffinry conference in Philadelphia yesterday.

Nobody's saying that the new HiCap tech can compete with ordinary mining on cost yet - but that's almost irrelevant. What HiCap offers is, first, assurances to nuclear powerplant operators that they will still be able to obtain uranium for the foreseeable future with no more than a massive price increase - say no worse than three or four times over - no matter whether landbased reserves play out or become oversubscribed. That means their plants' total operating costs won't climb by any more than a marginal amount. Thus, a major source of risk for investors is removed.

Secondly, the prospect of being able to extract billions of tons of uranium from the sea means that humanity has access to enough fuel to meet all its energy needs - all of them, not just present day electricity demand but also the other 90 per cent currently supplied in thermal form - for thousands of years.

One US government statement issued this week says that oceanic uranium could last 6,500 years: but a more conservative estimate assuming use of recycling (as offered by Professor J C Mackay of Cambridge) is say three millennia with all humans using as much energy as a present-day European does. So we've gone with that for our headline.

There's more from the US government labs here and here. ®