In defence of nuclear power

Schematic of a Boiling Water Reactor
A Boiling Water Reactor. Image from Wikipedia.

When I was ten I remember being given some sort of exercise at school that required me to draw my answer. I drew a nuclear reactor. I drew it in some detail, including fuel rods and control rods and cooling system. This wasn’t actually unusual for me; I frequently drew machinery of many kinds, huge cogs and mechanisms and bizarre perpetual motion machines. Imagine my astonishment when the first thing my teacher said on seeing my drawing was “So you’re in favour of nuclear power then?”

I was astounded. It hadn’t occurred to me that anyone could be against nuclear power. It was a machine! It was THE ultimate machine! How could anyone not love it?

Twenty two years later I am still in favour of nuclear power, although this time for much more considered reasons.

Perception of danger

Nuclear power is much safer than you might think. Think of the safety of nuclear power as something like an aircraft. Cars have frequent accidents, killing quite a lot, injuring more often. Aircraft few accidents, but when they go wrong, they really go wrong and generally kill everyone on board. A car accident might make the local news if there’s something odd about it. An aircraft accident will probably make the international news. Despite the differing attention given between these two, road accidents kill and maim many more people than air accidents do. The safety record of electricity generation is much the same. Fossil fuelled power stations might have accidents, but generally they are of little consequence. Even so, fossil fuel waste causes a lot of damage to the surrounding area and people living nearby. Nuclear power stations have very few accidents, but when they do, they have really serious ones.

People imagine an accident in a nuclear reactor as something like a bomb. Say “nuclear accident” and they see mushroom clouds and flattened cities but it isn’t like that. A nuclear bomb makes use of a runaway chain reaction which requires the uranium to be dense enough and large enough to reach “critical mass.” Nuclear reactors have their fuel split up into smaller parts encased in fuel rods which are held too far apart for a nuclear explosion to occur. What can actually happen is a meltdown, where the fuel rods melt, run together into a pool at the bottom of the reactor, then burn down through the floor and leak radiation. This can happen when the fuel is not kept cool enough. In most reactor designs there are three levels of containment around the core, and molten fuel will be contained by a very thick concrete basin under the reactor and prevented from leaking.

Apart from meltdown, a reactor that uses water as coolant can also produce hydrogen when things go wrong, and evaporating coolant can cause a build up of pressure inside the reactor. If the coolant stops circulating, the heat of the reactor can crack the water into hydrogen and oxygen and fill the containment up with this explosive mixture. In old (or Russian) reactors it could explode inside the containment and break it open. In more recent designs, the hydrogen is vented from the core before it can explode and expose the fuel to the outside world. The vented gasses are themselves radioactive, but usually not very much and not for very long since the radioactive particles have a half-life measured in minutes. (That is, they break down very quickly.) A big flaw with old reactor designs such as those at Fukushima and all Russian reactors is that the coolant will stop circulating if the pumps lose power. Modern reactors are designed in such a way that if the power stops, the coolant will keep circulating through convection.

In summary, modern nuclear reactors are much safer than those from the 1970s. They have multiple level of containment to catch molten fuel. Coolant can keep circulating even without power. High pressure and explosive gasses are removed from the core before they can explode and destroy it. Instead of setting a reaction going and then restraining it, modern designs require human intervention to keep them going. If the people aren’t there, the reactor shuts down. The rules on dealing with accidents are incredibly strict, almost paranoid. Finally, there are many more advanced designs of reactor to choose from than just pressurised water reactors or boiling water reactors. Pebble Bed Reactors, in particular, are designed so that they produce less power as the temperature rises, and so are self-limiting and cannot overheat.

Dealing with waste

Radiation Warning SymbolI will admit, dealing with nuclear waste is a problem. I would like to make some points about this. First of all, fossil fuels also produce waste. That waste in the form of ash, CO2, sulfur dioxide, nitrous oxide and other gasses has traditionally been pumped into the atmosphere where it causes acid rain, smog and climate change. Pollution from fossil fuels affects the workers at the power station and the residents in towns nearby. Recent attempts to scrub pollutants out of smoke before releasing it have reduced this a little, but not enough. Carbon capture will improve things but is very difficult and hugely expensive. Secondly, fly ash from coal is actually radioactive! Not just radioactive, but during day-to-day operation a coal power station releases 100 times more radiation than a nuclear power station producing the same amount of electricity. People living near coal-fired power stations actually have more radioactivity in their bodies than people living near nuclear power stations.

Nuclear waste is usually buried deep underground. It will remain dangerous for millions of years. I think though, that I would much rather have waste that can be buried than pump smoke and ash into the atmosphere and destroy the planet.

We could actually produce far less nuclear waste than we do at the moment. Used nuclear fuel can be re-processed, and can be re-used to fuel Breeder Reactors. These reactors produce more fuel as they use traditional fuel and so they produce a lot more energy from the same fuel, and the waste is more effectively used up. They can also run on thorium, which is more readily available than uranium. Unfortunately Breeder Reactors are generally not used because they create plutonium and governments are terrified that it would be used to create nuclear weapons.

Thank you for reading this far. In my next post I will explain why I believe that nuclear power is neccessary and why renewable sources are not adequate. Please also note that I am not a nuclear physicist, I am a computer scientist that happens to be fascinated by nuclear power. If I am wrong and you can provide evidence, feel free to say so in the comments.

More information

Author: Latentexistence

The world is broken and I can't fix it because I am broken. I can, however, rant about it all and this is where I do that when I can get my thoughts together. Most of the time you'll find my words on Twitter rather than here though. I sometimes write for Where's The Benefit too.

5 thoughts on “In defence of nuclear power”

  1. a good post mate. The waste is the problem, but then it is for many industries. I think we do need to look at renewables, nopt as in to use whats there but to research and try to find more effeciant generators as well as cutting down on our own wast fullness when it comes to power.

  2. This is very long, but well worth a read…

    http://www.withouthotair.com/Contents.html

    …it’s neither pro- nor anti- renewables, or climate change. It’s just putting the numbers there clearly for everyone to see.

    The way most politicians and policy makers talk, you’d think they were blissfully unaware of these numbers. In fact, if you read this book, you’ll be so well informed that you will find the crap talked by most politicians to be quite scary.

    Having worked out the numbers, the book does show some possible future scenarios with and without nuclear power. It’s got to be said, _none_ of the possible scenarios is particularly appealing!

    Cheers,
    David.

    P.S. seems we can all play at planning the UK’s energy future…
    http://2050-calculator-tool.decc.gov.uk/
    from
    http://withouthotair.blogspot.com/2011/03/version-2-of-2050-calculator.html

    1. I had a go on the calculators, the for the normal people (link on withoutair page) rather than the more complex looking one government aimed one (2050-calculator).
      The CO2 emissions target is actually very hard to achieve!! They don’t give you much information about the environmental impact of any of the types of energy production. And interestingly the more cars using electrical power doesn’t seem to make much changes to the amount of electricity needed, it’s all a bit surreal really but a good bit of fun to eat away your time!!!

  3. I have come to believe, in the past few years, that nuclear power is the “least worst” form of power generation until we can have true “green” energy (and not green as in “glowing green from all the radioactivity”… sorry, obviously watched too many dodgy sci-fi parodies).

    Anyway, I’m all for increasing the UK nuclear power output for the short-to-medium term, in the long term I’d like to see investment in renewable sources.

    I agree that the waste is a big issue, but like you say there are issues with fossil fuels too. I think nuclear waste is probably better than increasing the level of pollution, especially given that I think climate change is a real issue and needs to be addressed ASAP.

  4. I’m not overkeen on the whole idea of nuclear power… I think mostly I don’t like the idea of producing anything that toxic, which when it goes wrong can cause so many problems for such a large number of people. Perhaps newer nuclear technologies are improving but I don’t know.
    The difference importantly with cars accidents killing more people, which I’m sure you are correct about, is that when it happens it will only effects a very small number of people in a single incident, the fact that the number of times it happens is a side issue. The problem with nuclear accidents as seen by the Russian disaster from 25 years ago is the sheer number of people effected by a single occurance, and I’m also concerned by the fact that 25 years on they are still clearing up toxic waste from that disaster/plant.

    You may also be correct in saying that on a day to day basis it is safer and gives off less radioactive material than fossil fuel burning plants, however there is only limited supplies of fossil fuels and people realistically should be looking for alternatives. The current choices seem simply inadequate!
    I found an article in a newpaper’s magazine talking about the environmental impact of our ‘green wind farms’ which require each turbine to have some massive magnet (very technical terms used by me obviously!!) made in China or something which are generating some massive pool of toxic poison outside the factories. Which is obviously no better.
    Biofuel has the obvious drawback of the vast amount of land required for planting which obviously prevents food being grown there instead.
    I don’t know that much about energy produced by solar or water types. Maybe they have similar drawbacks too.

    I supposed it’s about considering all things in relation to each other and assessing which is the least worst. But then also considering what will happen if the whole lot goes wrong. A production system that is 100% safe and efficient and environmentally friendly when working is a big problem if when it goes wrong cause 1 million people to die or become chronically sick (obviously not real statistics and not relating to any particular technology, I simply sought to make a point). There may be some more suitable source of energy waiting to be discovered or utilized!

Comments are closed.