Renewable energy has a role in reducing carbon emissions, but the greenest solution may yet be nuclear, writes Peter Jones
Nuclear energy, received Scottish wisdom as purveyed by First Minister Alex Salmond tells us, is unsafe, unreliable, and yesterday’s technology. But what if nuclear reactors were designed that could not melt down, produced little waste, or even consumed existing waste as fuel? If they were economic, might they not become a highly desirable technology of the future?
This isn’t a fantasy. And a race is developing to make it a reality. The genesis of a joint UK-French bid to get into it was made last week when Prime Minister David Cameron and President Nicholas Sarkozy signed an accord to get new nuclear power stations built in the UK.
The prospect of much safer and cleaner nuclear generation which can supersede existing technology is why many governments, despite the dreadful accident at Fukushima and the public hostility to nuclear power created by it, are willing to bet a lot of taxpayers’ money on nuclear power.
There are several different approaches which are exciting attention in different parts of the world. On some calculations (which, admittedly, we heard in the 1960s at the start of the nuclear age) the electricity such new technology reactors produce could be extremely cheap, cheaper indeed than renewable energy.
But first, the Scottish Government looks to be in a minority in believing that nuclear energy is finished. Yes, Germany, after Fukushima, decided that it would wind down its nuclear industry. But 18 other countries, from Turkey to Thailand, are planning to start up.
Around the world, there are just over 440 nuclear electricity-generating plants. Another 62 are under construction, and a further 158 are planned (ie, projected to be working by 2020). China, as you might expect, is one of the biggest atomic investors. It has 13 reactors, a further 27 under construction, and 50 more are planned. Just this month, America’s Nuclear Regulatory Commission approved construction of two new reactors in the state of Georgia, and consent for four more will be sought later this year.
Most, if not all, of these will be existing technology reactors which, we are told, are dirty and dangerous. Odd, therefore, that they are going to be built. And even odder when you consider that those reactors nearing completion – in Finland and France – are over-budget and late.
Perhaps some of these new reactors are going to take advantage of a prospective new type of fuel. A Canadian company has been working on coating uranium pellets with an oxide made from beryllium, a non-reactive metal. One of uranium’s disadvantages is that it is a very poor heat conductor, so you have to achieve very high temperatures in the reactor core to get enough heat to the coolant which is then used to generate steam.
But beryllium is an excellent conductor. That means you can operate a reactor at much lower temperatures but achieve the same heat output from the coolant. It doesn’t completely solve the problem of potential meltdown, but it makes it a lot less likely.
It also doesn’t solve the waste problem. But there are reactor designs, classified as fourth-generation, which may well deal with the waste issue. One, which has convinced Bill Gates that it is worth spending some of his billions on, is called the travelling wave reactor. It is so called, because the reaction starts at the core and then gradually moves outwards to the edge.
In theory, once switched on, it could run for decades without the need to pull out fuel rods. And the fuel can be depleted uranium, currently a waste by-product of enrichment processes that create conventional nuclear fuel. In effect the reactor makes its own fuel and then consumes it, leaving relatively little waste.
Lots of engineers see plenty of problems. None has been built, but a private company is busy developing one, backed, somewhat unusually, entirely by private money. And the Chinese are extremely interested.
Also exciting interest is the idea of using thorium as a fuel. It was thought about in the 1950s, but uranium was favoured because early reactors produced material for atomic weapons. Thorium is about three times more abundant than uranium, and, while radioactive, is not fissile. To make thorium usable as a nuclear fuel, you have to add a neutron to each thorium atom, converting it into a fissile form of uranium. One rather intriguing way of doing this is to put it into a reactor and fire neutrons at it. A reaction then takes place, producing heat for electricity generation. But if you turn off the particle beam, the reaction slows and stops.
Had the Fukushima reactor been a thorium one of this type, the main problem – loss of power which caused the coolant to stop circulation – would have shut the reactor down, and no meltdown could have occurred. India is doing a lot of research on such reactors.
Finally, GE Hitachi have a design of reactor called Prism. It works in much the same way as a conventional uranium-based reactor but, rather excitingly, can use uranium and plutonium waste as its fuel. It’s a development of a reactor which has been operating in the US for about 30 years, and the UK government has recently become very interested.
That’s because the UK has about 100 tonnes of plutonium and 35,000 tonnes of depleted uranium which nobody knows what to do with. So there are thoughts that a couple of these Prism reactors could be built at Sellafield and use these stockpiles as fuels.
This has also got some environmentalists, such as George Monbiot, very excited. Although the Prism reactor does produce waste material, it stops being radioactive after a few hundred years. And when it uses and destroys current waste which stays highly radioactive for thousands of years, that is quite a big environmental gain.
Sure, lots of work will have to be done and lots of money spent before any of these ideas become commercially viable. But if they do, they may bring the biggest environmental gain of all – electricity and heat being produced with relatively little in the way of carbon emissions.
And while I don’t doubt that wind, wave, and tidal power have an important role in achieving that goal over the next half century, it is also possible that fourth generation nuclear power is the long-term answer.