Now that the climate change bill has cleared its first hurdle in the Commons, it seems likely the government will have to reduce carbon emissions by at least 60 per cent by 2050. But while you might think this strengthens the case for a new generation of nuclear power stations, they will not necessarily be required. There is nothing in the bill to stop the government discharging its obligation by buying carbon credits from other countries, while not lessening emissions one jot.
Even if this loophole is closed, some people argue that massive investment in alternative energy technologies, particularly carbon capture and storage (CCS), can bring about the reductions instead. CCS, in which carbon dioxide is removed—or "scrubbed"—from power station emissions before it reaches the atmosphere, and is then stored underground, looks increasingly like a technology whose time has come. Veteran climate scientist Wally Broecker of Columbia University has been promoting the carbon scrubber developed by his engineer colleague Klaus Lackner, while the former British chief scientific adviser David King is also a fan of CCS. (As is Nicholas Stern—see our interview in this issue.)
But King thinks the nuclear option will be needed too, especially if (as he hopes) the emissions target becomes even more stringent. At the Hay festival, discussing his new book The Hot Topic, written with Gabrielle Walker, he pointed out that the waste disposal problem should not be seen as a crucial objection. He argued that a new, more efficient generation of reactors would add perhaps just 10 per cent or so to the waste that already sits awaiting disposal at Sellafield from the nuclear programme of the past few decades.
Why is this stuff still there? Experts largely agree on how to dispose of it—encase it in borosilicate glass (the Pyrex sort), package it in metal canisters, and sink them into tunnels deep underground. But no one has been able to decide where to put these tunnels.
A white paper published in June proposes that local authorities should bid to host the burial sites—not as bizarre an idea as it sounds, given the jobs and infrastructure that a nuclear waste repository will create. It's already clear that there will be takers. And even opponents of nuclear power must agree that waste is safer in an underground repository than sitting in a hangar in Cumbria.
What the Americans do (not much)
In America they do things differently. For a long time, the plan has been to dispose of high-level nuclear waste in a repository in the semi-arid wilderness of southern Nevada, at a site called Yucca Mountain. This location was selected in 1987, but has been mired in controversy ever since. The US Environmental Protection Agency stipulates that environmental release of very long-lived radioactive elements in high-level waste should be prevented for 1m years—an absurd timescale.
Now two of the geologists involved in the Yucca Mountain project since the beginning have decided it's time to break the deadlock. In the journal Science they argue in favour of starting a pilot project at the site, which would be monitored for decades before taking any decision on a large-scale repository. At present, the waste is stored at 72 reactor sites all over the country, many near to urban centres, rivers and lakes. It could just stay there—but is that a better plan, or just the absence of one? The problem with nuclear waste is that, however much we don't want it, we've already got it.
Physicists to make particle soup
At the Large Hadron Collider (LHC) in Cern, near Geneva, things aren't so much hotting up as cooling down. Before the first particle beams start circulating in the new supercollider in late June, the tubes that will hold them must be chilled to within about 2 degrees of absolute zero. It's a slow process: each of the collider's eight sectors, housed in a circular tunnel 27km long, has been cooling one at a time since late last year. The collisions between accelerated particles, which will mimic the first instants of the big bang, won't happen until a few months after start-up.
The talk so far has focused on finding the Higgs boson, the particle that gives other particles their mass. But the LHC has an array of other projects. It hopes to create a particle soup called the quark-gluon plasma, a phenomenally dense mixture of those two classes of fundamental particles before they condensed into the protons and neutrons of atomic nuclei. That all happened a few millionths of a second into the big bang.
Another experiment aims to discover where all the antimatter went—why, within just a second after the big bang, an initially equal mixture of matter and antimatter had become so lop-sided. The answer seems likely to lie in the behaviour of so-called "beauty quarks," one of the six quark variants or "flavours." And there are hopes to glimpse several of the exotic items that rank among physicists' boldest hypotheses: specks of the dark matter believed to bind galaxies; extra dimensions beyond space and time.
The flaky idea persists that the LHC will produce mini-black holes or so-called "strangelets," which will then destroy the world. But will its advocates be more disappointed than relieved when these fail to materialise?
