Posts Tagged ‘[lang_en]Nuclear Power[/lang_en][lang_fr]Nucleaire[/lang_fr]’

Nuclear power and radiation exposure: should you worry?

Sunday, April 25th, 2010

Mention nuclear power to someone, and, of course, the subject of radiation exposure comes up. Radiation is a subject that, rightly or wrongly, strikes fear into a lot of hearts. But why?

Koeberg Nuclear Power Station
Image by Mark H via Flickr

Some people believe that there is no level of exposure which is safe, and that any radiation of any kind must be avoided. Some believe that nuclear power stations emit radiation, much as coal-fired stations emit smoke. Political parties like Europe Ecologie even claim, in their manifesto, that we should abandon nuclear power in France because of the radiation it puts out. These views are very widely held, but is there any truth in them?

I don’t think so. I think that radiation exposure can be perfectly safe providing the level is low enough, because zero exposure is simply not possible. You and I are exposed to several sources of background radiation on a constant basis, and I feel just fine, thank you very much! Let me tell you about some of these sources.

One source is my own body. No, I don’t glow in the dark, but like all people, my body emits a low level of background radiation. Potassium and carbon isotopes present in the body contribute about one tenth of the total radiation we receive.

Radiation also reaches us from outer space, and it comes up from the ground. It varies from place to place, but there’s nowhere on earth that you can avoid it. Medical procedures, such as x-rays and scans, also contribute to our exposure.

What if we stay indoors, and never go to the doctor? Alas, that might not help. Many things found indoors emit low levels of radiation. Granite, which we might use for our kitchen workspace, is one example. Natural gas, which we use to heat our homes and cook our food, is another. Radon, a naturally occurring radioactive gas, can build up in confined spaces such as homes. Radon accounts for fully half of the exposure we get. So staying indoors might well increase your exposure!

Many buildings, such as Grand Central Station in New York, have higher than average background radiation levels, because of the materials they were constructed with. The radiation emitted by Grand Central Station exceeds the levels allowed for a nuclear power plant. Think about that next time you’re waiting for a train!

Taking the plane may not be much better. Airline pilots and frequent flyers can receive twice as much radiation as those of us who stay on the ground, because the thinner air at high altitude provides less protection against radiation from space.

What about nuclear power stations, how much radiation do we get from them? Not much. About 0.014%. That means that, of your daily dose of radiation, nuclear power accounts for 12 seconds worth. Nuclear power plants may actually reduce your radiation exposure, because the fossil fuels they displace emit more radiation than they do!

Of course, too much radiation is dangerous. Radiation can and has killed people. But it’s the dose that makes the poison. You can enjoy a beer or a glass of wine from time to time without long-term effects, but drink a bottle of whisky a day and you can expect your liver to pack up. You can smoke the occasional cigar with no worries, but smoke 40 cigarettes a day and don’t be surprised if you end up with lung cancer. So many of the things that we encounter or enjoy in everyday life are toxic in large quantities, yet we don’t notice any adverse effects if we keep our exposure low.

So, you and I are surrounded by radiation, wherever we are and whatever we do. It’s not because we have nuclear power stations, either, the dose they give us is nothing to worry about. Is there any form of radiation that does cause me concern? Well, yes, there is. I try to avoid getting sunburn.

Copenhagen – now what?

Sunday, January 10th, 2010

The Copenhagen meeting finished some time ago now, and didn’t succeed in delivering anything useful. I’ve resisted the temptation to write about it earlier, rather I wanted to see what others said first, before making up my own mind about it. There’s been an awful lot of analysis published in the blogosphere since the meeting ended, I’m sure I’ve not encountered every view, but here are my own conclusions.

One thing is obvious, we did not get the fair, ambitious, and legally binding document we were all hoping for. Not even close. All we got was the ‘Copenhagen accord’, a piece of paper with no legal weight written by a few of the participants. That accord has no numbers in it that we can use to actually set policies. It does not state when emissions should peak, what reduction in emissions is required, in what timescale, or anything like that. There is no way to turn it into a plan of action, to decide how to tackle climate change based on what it says. It is worthless in itself, and is quite possibly worse than having no agreement at all.

By stepping outside the UN framework to produce that accord, those few countries that created it have seriously weakened the UNFCC process.
President Obama announced the accord to the press before most of the national representatives had even seen it, which shows a distinct lack of respect for protocol. How can the UNFCC be taken seriously now that a handful of leaders have ignored it and made up their own agreement?

On the other hand, it is not at all clear that anything else was on the table. I have not seen anything mentioned anywhere that the formal process of the UNFCC had created a document that was ready to be signed at the end of the meeting. If you know otherwise, please let me know via the comments. And, worthless as it is in practise, it is nonetheless significant that America and China have both signed even so weak a document as they did.

In the aftermath, the inevitable finger-pointing has taken place, with most people blaming someone half the world away for the failure. It’s difficult for an observer like myself to know what really happened, who is at fault, and why the process broke down. There was clearly a lot of good intention from many places, I doubt so many world leaders have ever been assembled in one place before. They wouldn’t all go there to look bad, I’m sure many of them wanted to come away with something real. Many countries went to Copenhagen having made pledges which, while inadequate, were much stronger than anything they have comitted to in the past. So what happened?

President Obama was clearly a key player, and he went there empty-handed. He didn’t offer anything new, much to the disappointment of many. The offer of ‘mobilising a fund of $100 billion annually for mitigation’ by 2020 is not worth much. Americans spend that much each year on bottled water, so it’s not exactly digging deep into their pockets. Besides, the International Energy Agency estimates that, for each year we delay action, the cost of tackling climate change will increase by $500 billion. So having $100 billion per year by 2020 really isn’t impressive.

It seems likely that, had America made a bigger comittment to cutting its own emissions, the conference could have gained a lot of momentum. With one of the highest levels of emissions per person in the entire world, America, like many western countires, has a clear debt to pay for the wealth it has accumulated. People were looking to President Obama to take the leading role he claimed he would when he was sworn into office. He failed to do that. To be fair, when you see the political pressure and tactics wielded by the fossil-fuel industries in America, it’s hardly surprising that President Obama couldn’t offer more. He simply doesn’t have that much power.

George Monbiot of the Guardian points out that Obama demanded concessions, despite offered nothing in return. On the other hand, Mark Lynas blames China for systematically blocking all attempts to name concrete targets. In Mark’s own words:

it was China’s representative who insisted that industrialised country targets, previously agreed as an 80% cut by 2050, be taken out of the deal. “Why can’t we even mention our own targets?” demanded a furious Angela Merkel. Australia’s prime minister, Kevin Rudd, was annoyed enough to bang his microphone. Brazil’s representative too pointed out the illogicality of China’s position. Why should rich countries not announce even this unilateral cut? The Chinese delegate said no, and I watched, aghast, as Merkel threw up her hands in despair and conceded the point. Now we know why – because China bet, correctly, that Obama would get the blame for the Copenhagen accord’s lack of ambition.

China, backed at times by India, then proceeded to take out all the numbers that mattered. A 2020 peaking year in global emissions, essential to restrain temperatures to 2C, was removed and replaced by woolly language suggesting that emissions should peak “as soon as possible”. The long-term target, of global 50% cuts by 2050, was also excised. No one else, perhaps with the exceptions of India and Saudi Arabia, wanted this to happen. I am certain that had the Chinese not been in the room, we would have left Copenhagen with a deal that had environmentalists popping champagne corks popping in every corner of the world.

You can read more on Mark’s views of Copenhagen at the New York Times dotEarth blog, it’s worth reading.

I think that both George and Mark make good arguments, as do many other writers, but I have to say I give a lot of weight to Mark’s analysis. Mark was in the room for the negotiations, he saw it all first-hand. I’ve read Mark’s book, Six Degrees, and was impressed at how well he took such a large body of research and summarised it in terms we can all understand. He’s also one of the few environmentalists who has come to understand the importance of nuclear power in addressing climate change. That’s why I trust him as an observer and a critical thinker, and take his opinion seriously.

So, given that the UN framework didn’t yield a result, and that those who wanted to do something were prevented from doing so by those that don’t, what does that mean for the future? Here, the blogosphere seems to be more in agreement, people-power still matters, and there are a lot of people who aren’t giving up.

People from all walks of life have been calling for action on climate change. George Monbiot, in that same article above, is quite blunt about blaming people for complacency.

For the past few years good, liberal, compassionate people – the kind who read the Guardian – have shaken their heads and tutted and wondered why someone doesn’t do something. Yet the number taking action has been pathetic.

I guess he’s right. I know I came late to the party, and wish I had acted sooner.

At the other end of the scale, a group of international investors managing $13 trillion in assets also called for strong action (full report (PDF)). You can bet that they wouldn’t be asking for strong legislation to attack global warming unless they thought that it was needed for the global economy to survive.

Young people are getting in on the act too. Take a look at the video below, produced by the Australian Youth Climate Coalition. Their message to world leaders is load and clear:

Those of you who say it can’t be done should get out of the way of people already doing it. Our future will not be written for us, but by us. You’re not done yet. And neither are we.

It’s great to know so many people from such different levels of society want action, but it won’t be enough to simply tell governments to act. It’s important that people both understand what is needed and agree on how to act, so a clear, unified, and sensible message is sent to political leaders. One of the biggest problems here is that a lot of people think that renewable energy sources can solve our energy needs, and many environmental groups remain opposed to nuclear power.

Advocates of ‘renewable energy’ regularly fail to consider the cost or effort required to satisfy demand. Replacing conventional electricity production with renewable sources is simply not sensible when you look at the amount of raw material (e.g. concrete and steel) that is needed, or at the amount of land that would be needed for the installation. Never mind the fact that solar or wind power are useless in a cold spell of weather like we are having at the moment, so we would still need something reliable to provide power when we need it most. See David Mackay‘s free ebook, Sustainable Energy without the Hot Air, for some clear discussion about the theoretical limits of renewable energy and decide for yourself if you think it’s really a viable option.

I’ve written before about green-groups misguided opposition to nuclear power. Few of them seem to understand the realities of modern nuclear power, which is cheaper, cleaner, safer, and more reliable than it was during the cold-war days of the nuclear arms race. By perpetuating this myth, they are supporting the fossil-fuel industry. How? as Steve Kirsch said recently:

If you want to get emissions reductions, you must make the alternatives for base-load electric power generation cheaper than coal. It’s that simple. If you don’t do that, you lose.

Needless to say, weather-dependant renewable energy cannot provide that base-load, and the only real competition to fossil-fuel is nuclear power. If I were a fossil-fuel CEO, I would certainly want to spread fear of nuclear power, and would happily let the green-groups do my dirty work for me!

If you want a good idea of what it takes to replace fossil-fuel with either renewable or nuclear power, take a look at They consider the practicalities of cost and build-rate for a range of options, and conclude that anything other than massive deployment of nuclear power simply won’t cut emissions in time.

Until green-groups embrace the need for nuclear power instead of renewable energy, we are not sending a coherent or useful message to world leaders, one that they can use to enact legislation that will genuinely cut emissions. Secretary of Energy Stephen Chu surely understands this, so President Obama must know it too. Small wonder that he couldn’t offer much at Copenhagen when the environmental movement don’t want the changes that will work, and the coal and oil industries are spending a fortune to mislead and misinform the American public.

That’s not to say that this problem is specific to America, it’s a drama that is repeated the world over. The sooner we realise that, the sooner we can start making the changes that matter. Maybe then we can persuade others to do the same too.

How many Physicists does it take to change a light bulb?

Sunday, November 15th, 2009

David MacKay is a professor of natural philosophy at Cambridge University. At the beginning of October he started work for the Department of Energy and Climate Change (DECC) in the UK. He is now their Chief Scientific Advisor, and if you ask me he is clearly the right man for the job.

He’s written a book, Sustainable Energy – without the hot air, which you can download for free from the web (in several formats). Unlike many scientists, he’s an excellent communicator, able to put things in terms that are easy to understand with just a bare minimum of maths. As the book title suggests, he explains a lot about the realities of sustainable energy, in plain english, and with numbers to put it all into context and to set the scale of things.

For example, he converts everything to kilowatt-hours, the amount of energy used by leaving a 1 kW heater on for one hour. By converting everything to the same units, he makes it easier to compare things directly, like the energy you use by driving your car, flying off on holiday, or heating your bath. The kilowatt-hour is also the unit you are charged for on your electricity bill, so it’s something we can all relate to.

He doesn’t have a personal agenda to promote, either. Or rather, he does, but his agenda is to ensure that people can make informed decisions on their own, based on the facts. As he says:

I don’t want to feed you my own conclusions. Convictions are stronger if they are self-generated, rather than taught. Understanding is a creative process. When you’ve read this book I hope you’ll have reinforced the confidence that you can figure anything out.


This book is emphatically intended to be about facts, not ethics. I want the facts to be clear, so that people can have a meaningful debate about ethical decisions.

As a scientist, he obviously accepts the concensus view that we need to stop using fossil fuels, and fast. He points out that nine-tenths of the electrical power in Britain comes from fossil fuels, so replacing it means increasing the amount of every other form of energy by a factor of 10, or some equivalent mix.

The British are famous for opposing change. Brits are opposed to having windmills, wave-machines, or nuclear power stations anywhere near them, protest groups will spring up like daisies anywhere you propose to put them. There are currently about 2400 wind turbines in Britain; if we were to attempt to power Britain from wind alone, we would need 600,000 of them. That’s 6 wind turbines per square mile (2.5 per square kilometer). Next time someone tells you that Britain could be powered by wind alone, ask them where they’re going to put all those turbines!

Steel, concrete, and land-use by wind, solar thermal, and nuclear power, from

Steel, concrete, and land-use by wind, solar thermal, and nuclear power, from

Nor is it easy to construct that many wind turbines. They take a lot of steel and concrete to build, and a lot of cable to connect them to the electrical grid. Barry Brook has an excellent article about the cost and effort of building such infrastructure (I’ve borrowed one of his charts, on the right).

Barry is not the only one speaking out, the Institute of Mechanical Engineers have recently criticised the UK government for setting climate-targets without providing the support needed to make them happen. They say there’s no way to build that much new infrastructure without a significant change of strategy.

I’m sure they’re right, but I’m not convinced by some of their proposals for solving the problem, which include carbon capture and storage (as yet unproven) and building ‘artificial trees’ (also unproven technology). I guess engineers would naturally choose an engineering solution! However, they also propose giving much more authority to the DECC, where David MacKay has just started work, and that sounds like a great idea to me.

David has a real knack for putting all these facts and figures into easily understandable forms. But rather than me telling you about him, why not take a look at the video and see for yourself. It’s only six minutes long. (Thanks to Charles Barton of The Nuclear Green Revolution, which is where I found it!)

If you like the video, why not read David’s book, or maybe start with his own 10-page synopsis of it if you’re pressed for time. You’ll get a clear, no-nonsense analysis of what it means to power Britain with sustainable energy, with no politics attached. Though his analysis is specific to the UK, many of the lessons apply elsewhere, of course.

I find it very encouraging that the UK government has decided to listen to David. I hope more people do too, he’s someone we can all understand.

Nuclear Power, Yes Please!

Tuesday, August 18th, 2009

Nuclear Power, Yes PleaseNuclear power has a bad reputation, and many environmental organisations are so strongly opposed to it that they resort to rather extreme measures. For example, Greenpeace consider any use of nuclear power to be an affront to the victims of Hiroshima and Nagasaki, which seems a bit of a stretch.

Even the World Wildlife Fund is blatantly fabricating numbers to make nuclear power look bad. You can see that in their ‘G8 Climate Scorecards‘, where they state that they use numbers from fossil-fuels to replace numbers from nuclear power in calculating a nations’ emissions. The WWF scorecards rank France third, for example, despite the fact that it has far lower emissions than England or Germany, which they rank as better! If a company were to use similar methods on their annual reports, we would call it fraud, and expect someone to go to jail.

Six Degrees, Our Future on a Hotter PlanetTo be fair, not all environmentalists are against nuclear power. Mark Lynas, author of ‘Six Degrees, Our Future on a Hotter Planet‘, has declared his support for it. He says the environmental stance is based on myth and dogma, not facts.

So why is it that some environmental organisations are willing to go to such extreme measures and risk tarnishing their reputations to criticise nuclear power? The main reason, of course, is fear, but fear of what? Radiation, perhaps?

Nuclear power can, in principle, lead to radiation exposures in a variety of ways:

  • nuclear accidents, meltdowns, failures of safety systems, leaks large or small
  • long-lived radioactive waste that will be here until well after the human race has gassed itself to extinction with fossil fuels
  • proliferation of weapons of mass destruction, using radioactive materials produced by nuclear reactors
  • terrorists, either attacking a nuclear power plant or stealing radioactive material to make bombs

That list can be summed up in two groups: harm caused by the reactor or associated machinery (provoked or accidental), or harm caused by the waste produced during normal operation of the facility.

So what if it were possible to build a reactor that could not malfunction in a harmful manner? That would solve one problem. What if that reactor produced only short-lived nuclear waste which was easy to manage and not useful for making bombs? That would solve the other problem. Surely that would make nuclear power more attractive to everyone?

As it happens, you can produce nuclear power safely, with minimal and manageable waste. Oh and it’s not difficult either, it’s been done already, about 30 years ago. It’s called an ‘Integral Fast Reactor‘ (IFR), and there’s a very good summary of it by Barry Brook in ‘Brave New Power for the World‘, or an easy Q&A summary by George Stanford at The National Center for Public Policy Research.

Prescription For The PlanetIFRs are specifically designed to address those two major problems, safety and waste. They also happen to be extremely efficient, cost-effective, and easy to construct. If they’re so good, you might wonder why the world hasn’t heard much about them? The project to develop the Integral Fast Reactor was shut down by the Clinton administration in 1994, and since Bill Clinton’s energy secretary at the time was a former lobbyist for the fossil-fuel industries, that more than likely has something to do with it. In Tom Blees’ book, ‘Prescription For The Planet‘, there’s an account of the history and operation of IFRs. The Department of Energy actually issued a directive that the technology was not to be publicised, which you might interpret as the need to keep it a secret. Odd, then, that the chief engineer for the project, Leonard Koch, was awarded an international prize by Vladimir Putin for the work he had done. No state secrets there!

Back to those two big questions, first, why do I say that IFRs are safe? Their safety does not come from redundant backup safety systems, highly trained operators, or anything like that. Their safety comes from the laws of physics. We use the laws of physics every day in all sort of mundane safety systems. The fuse in your television, the emergency-release valve on your pressure cooker, and even the thermostat on your central heating system, these are all things that guarantee your safety by using the laws of physics to stop bad things happening in your home.

IFRs have their own built-in thermostat in the fuel itself. As the reactor heats up, the fuel expands in the heat, which in turn causes the nuclear reaction to slow down. The reactor cannot overheat, so it cannot possibly meltdown. In addition, the reactor core is cooled by a liquid metal (sodium), which does not actually need to be pumped in order to cool the core. Turn off the cooling pumps, the liquid sodium will still circulate by convection, and the core will still be kept under control.

This is not theoretical, these tests have actually been done with a real nuclear reactor running at full power. Cooling systems were turned off, the normal safety systems were disabled, and the reactor was left to itself. It shut itself down safely with no human intervention, in as little as 5 minutes. Sorry to disappoint the Star Trek fans out there, there will be no warp-core breaches in an IFR!

Incidentally, those tests were performed just three weeks before the Chernobyl disaster happened. Chernobyl had none of these inherent safety features. Condemning IFRs because of Chernobyl would be like condemning air-travel because of the Hindenburg.

On to the second question, what about the waste from IFRs? Long-lived nuclear waste is produced by reactors that do not burn their fuel efficiently, they only extract a tiny fraction of the energy from it, about 1% or less. IFRs, on the other hand, burn their fuel almost entirely, so that they actually consume the material that other reactors would produce as waste. In fact, you can power an IFR with waste from other types of reactor, burning it completely, and thereby solve the problem of what to do with all the waste we already have! It’s like the difference between a garden fire that smoulders gently and releases a lot of toxic smoke, compared to an incinerator that burns the same stuff to ash in a far cleaner manner.

The waste that does come out of an IFR is radioactive for far less time than the waste that comes out of other types of reactor, precisely because the fuel is burnt so efficiently. Instead of remaining radioactive for tens of thousands of years, the waste from an IFR is radioactive for only about 300-500 years. That’s about one tenth of the age of the pyramid at Giza, so building something to contain it while it decays should be easy enough. The plastic we throw away will take longer to decay than that. IFRs also produce much less waste than other reactor types, so there’s less volume to handle.

What about the bomb-question, can IFRs be used to make weapons-grade plutonium? In principle, yes, since they do produce plutonium inside the core (and then burn it), there is plutonium to be had. In practise, it is far harder to process the fuel from an IFR to extract weapons-grade plutonium than it is to obtain such plutonium by any other means. For more information, see this Q&A by Steve Kirsch (search for “non-proliferation efforts”). Meanwhile, ask yourself this: which government are you trying to prevent from getting their hands on the plutonium?

There are many countries that already have nuclear power. Many of these have signed a non-proliferation treaty, and allow international oversight to verify that they are in compliance. If they were to convert their installations to IFRs, compliance would be easier to verify, and they could even consume the stockpiles of plutonium that they have amassed by using it as fuel in those same IFRs. This ‘nuclear club’ also happens to account for 80% of the worlds emissions of greenhouse gasses, so even if you restricted IFR technology to them alone, you would be able to make the world a safer and more habitable place, on several fronts.

Of the countries that don’t have nuclear power, many want it. The big question is, do they want it for weapons, or for electricity? Not telling them how to build nuclear power stations isn’t going to make them go away. Do we really think nations that want nuclear power for themselves will not get it sooner or later? Maybe it’s better to help them towards proliferation-resistant nuclear power instead of just leaving them to their own devices? Politically, as well as technically, IFRs can be a tool for reducing proliferation.

That leaves terrorism as a consideration. Stealing fuel from an IFR would be extremely difficult, because while it is in the core it is lethally radioactive. The reactor itself can be protected by several layers of containment vessels and concrete bunkers, over-topped with earth if you like, so it would be impervious to a missile attack (or an aircraft crashing into it, for example). Frankly, there are easier targets, and terrorists have shown that they are imaginative enough to find them.

So, at the end of the day, I’m puzzled as to why many environmental groups are ignoring the facts and taking such an anti-nuclear position. IFRs emit no greenhouse gasses. They provide constant power, not relying on variable sources like wind, waves, or sunshine. They can be made cheaply, because they can replace coal-fired power stations in-situ, using the existing generators and distribution infrastructure. They can eliminate our stockpiles of nuclear waste, and solve the nuclear-waste problem. They are inherently safe. And they can power the world for millennia.

So why aren’t we building them?