Posted on behalf of Nicola Jones
The world has only a limited supply of helium, and only a tiny fraction of that is the useful isotope helium-3. This fact has become a major concern in recent years for scientists who increasingly need the gas for cryogenics, medical imaging and more . In 2009, when the White House He-3 Interagency Policy Committee was established to study the problem, things looked dire. “We knew we’d be completely out of gas by this year,” says Julie Bentz, who works for the President’s office and sits on the committee. But, she told the American Association for the Advancement of Science today, they have managed to avert the crisis — for now. “We have pushed out the time of ‘no more helium’ by 6 years,” she says.
Helium-3 is the light, stable cousin of the more common Helium-4 (the gas used to fill party balloons). Most of the Earth’s supply is found underground, and is mined along with natural gas and oil, primarily in Texas. Helium-3 is also formed by the decay of tritium, which was manufactured in the United States as part of their now-much-reduced nuclear weapons programme, and for some nuclear reactors. But helium-3 was largely seen as a “waste product”, says Bentz, making US government officials happy to sell their stockpile at cost to anyone who wanted it.
The number of people who want it has been growing fast — largely thanks to its use in detectors that check for nuclear material at border crossings. After the September 11 terrorist attacks of 2001, US demand started to rise quickly, from less than 10,000 litres to nearly 60,000 litres in 2009. The gas is also used for low-temperature physics — liquid helium with a dash of helium-3 is perfect for getting down below 1 degree Kelvin — and to image lungs using helium-diffusion MRI. Demand drove prices from hundreds of dollars per litre to a peak of $5000 per litre on the black market.
In 2008, says Bentz, the US government put the brakes on the stockpile sales, and their committee was formed a year later to sort out the problem. Their first step was to put a lid on what gets allocated, and to whom. “We went to the folks who said they needed 100,000 litres and said, ‘no, really…’,” says Bentz. “When we asked: ‘no kidding, what do you need?’ demand dropped by orders of magnitude.” They also commissioned a team of scientists to work out how to get helium-3 out of a particularly recalcitrant batch of tritium left-over from warhead manufacture. That is now being implemented, and will lead to a one-time, 10,000 litre bump in supplies next year, says Bentz. The committee is hoping to secure deals with nations that have heavy water nuclear reactors to see if they can get further supplies of helium-3 from them in future.
Meanwhile the inter-agency group is encouraging people to switch to alternatives. For nuclear-material detections, some companies have developed boron-trifluoride or boron-lined alternative systems that are just as good, says Joe Glaser of the National Nuclear Security Administration. New supplies of the gas have effectively stopped going to the border patrol gates — they are using their own stockpiles until switching to boron-based systems, which will likely start to happen in the coming months. “Boron companies are very happy,” says Glaser.
Scientists who need the gas for their research now have to all go through a central online clearing house, established in late 2010, to plead their case. The major US grant-giving agencies, including the national science foundation and the national institutes of health, have agreed not to give grants to scientists who haven’t pre-secured their helium-3, says Bentz. Previously, some scientists found themselves with grants to do research but unable to get supplies to do it, she says. “That was the real heart-break.”
Bentz says the helium-3 ‘rescue’ has been a real success thanks to many government agencies working together on the problem — even if spurred by an unfortunate crisis. “It was a bad way to do good inter-agency co-operation,” agrees Glaser. The committee estimates the US can count on an ongoing supply of more than 25,000 litres per year in future, and think a price of about $1500 per litre would both be fair and help to drive innovation on alternatives.