IT SEEMS obvious: if you’re planning a new generation of nuclear power stations, you should invest in the most advanced and efficient designs available. Yet that’s not what seems to be happening in the US.
The first new nuclear power plants on American soil for 30 years could soon be under construction. President Barack Obama has promised tens of billions of dollars in loan guarantees for reactor builders, of which $8.3 billion was last month committed to back the construction of two Westinghouse AP1000 light water reactors.
These reactors differ only slightly from plants built by the US in the 1970s, yet they have problems of their own, notably questions about whether they can withstand severe hurricanes and earthquakes. The UK is looking to similar light water reactors for its own nuclear expansion.
Meanwhile, other countries are exploring newer technologies. France, Russia, China and Japan are backing Generation IV reactors (see table), which are more efficient and in some respects safer. Further into the future, advanced fission-fusion hybrid reactors may hold promise (see “The third nuclear option”).
China has already begun site preparations for a Generation IV reactor called the HTR-PM, a gas-cooled “pebble bed” reactor powered by fuel in the form of spheres rather than rods. Due for completion as early as 2013, it will run far hotter than existing reactors, and produce roughly 30 per cent more electricity from a given amount of fuel.
The higher temperature means that waste heat from the HTR-PM can be used to split water molecules to generate hydrogen for use as a clean fuel for vehicles. The design is also inherently less likely than light water reactors to suffer meltdown following a runaway reaction, as its fuel becomes less reactive if heated beyond normal operating temperatures.
For the US, perhaps one of the biggest advantages of some Generation IV designs would be that they produce less waste. Generation IV “fast reactor” technology – which is named for the high-energy or “fast” neutrons that drive the nuclear reaction – can burn spent fuel from conventional light water reactors. The US is stopping work on the Yucca mountain project – its only potential repository for spent fuel.
Despite these potential advantages, sections of the Obama administration appear to be at odds with each other over the desirability of Generation IV reactors. A letter written in December by US energy secretary Steven Chu, and seen by the trade publication Energy Daily, reveals that the White House sought to ban the Department of Energy from doing research on fast reactors.
This stems from concerns over weapons proliferation. To burn spent fuel in fast reactors, it has to be reprocessed to extract plutonium, which can also be used in weapons.
Nevertheless, Chu’s letter expressed “deep concerns” about the potential ban, noting that other countries are racing ahead. “If the United States does not have a broad fast reactor research program,” he wrote, “we will have no opportunity to influence design of these foreign reactors from a vital national security perspective such as proliferation resistance.”
The White House has since changed tack, and is including a modest $10 million for fast reactor research in the 2011 budget.