Here’s a new word for you: phytonugget. It’s a tiny bit of gold, the dimensions of which are roughly half the thickness of a human hair. It doesn’t sound particularly interesting until you hear that it grows on trees. Not all trees, mind. Only trees that are sitting above a deposit of gold ore. Trees mine their soil for water and nutrients; the gold comes up with the good stuff and gets deposited in the tree’s leaves.
Earth science engineers in Kensington, Australia made the discovery. So no more expensive mining and prospecting: you can now do an X-ray analysis of a few twigs and leaves to work out where the gold is buried.
If only we could do the same with lithium. One of the few upsides of Chinese involvement in the next generation of nuclear reactors to be built in the UK is that we may not face the woes now troubling the US.
The US Government Accountability Office (GAO) has issued a warning that an imminent shortage of lithium for its 65 pressurised water reactors “places their ability to continue to provide electricity at some risk”. Every year, the US gets through about 300kg of the isotope known as lithium-7, an essential ingredient to prevent corrosion of water pipes in reactors. Because lithium-7 is a byproduct of processes to produce nuclear warheads, and the US is letting its stockpiles shrink, the US no longer manufactures any. That leaves China and Russia as the only suppliers.
Given the links to weapons programmes, the amounts available in these two countries are a closely guarded secret. With China embarking on a vast nuclear construction programme, the US is facing the possibility that there won’t be enough lithium-7 to go round. The GAO recommended that the US think about restarting domestic production of lithium and look into the possibility of reducing its reactors’ reliance on the element. Both options will take years and the US may not have that long.
There is precedent for this type of problem. When the US department of homeland security started to build a stockpile of bomb detectors for use at airports, it quickly used up reserves of the helium-3 isotope that the detectors needed. Helium-3 is another byproduct of warhead production and the US had stopped making any in 1988.
The biggest losers were the scientists who use the isotope to perform research at below -272° Celsius – helium-3 being the only way to get temperatures so low. And with their stores depleted, many researchers had no choice but to abandon their experiments.
It’s not clear which department is going to be blamed for the impending shortage of the gas that gives our party balloons a lift, though. Supplies of the lighter-than-air isotope helium-4 are falling rapidly. The US supplies 80 per cent of world demand but is trying to get rid of its reserves by 2015 and so it sells helium at an artificially low price.
That means helium consumers such as hospitals – it is used to cool the magnets in MRI machines – and party suppliers are buoyant for now. But once the helium is all gone we’ll have to pull it from the air. That will be so expensive we’ll be filling party balloons at £100 a pop; there will be no squeaky-voiced shenanigans at that price.
We desperately need to find more natural deposits of helium. It does occur, like gold ore, in underground rocks but locating it has proved even harder than finding extractable gold ore. If you spot any trees floating slightly above ground level, let the GAO know.