Nuclear power: the future of green energy?
BY Tom Hodgen
Electricity is a huge part of most of our day-to-day lives. Without it we would not have lights, telephones, TV, internet, computers (Facebook!), mobile phones, and the list goes on. But where does it all come from? Burning fossil fuels generates around three quarters of the electricity in the UK, while only 20% comes from nuclear generators and around 4% from renewable sources. All this coal and natural gas being burned releases carbon dioxide (CO2) into the atmosphere: electricity generation is the single largest source of CO2 emissions worldwide. Given CO2’s huge environmental impact, and the fact that we will run out of coal, oil and gas at some point, what are our options?
The first is to use less energy. This is the most environmentally friendly choice, and something that we should all strive to do, but it is not realistic on a large scale. Most people, me included, are simply not willing to give up their computers and mobile phones. Of course there are steps we can all take, such as installing energy-saving light bulbs or switching lights off when we are not using them: all of which have the happy side effect of reducing our bills! These small reductions, while still a great step, pale into insignificance when compared to the massive increases in demand expected from China and India over the next few decades.
Another option is to generate more electricity from renewable sources. Wind, solar and hydroelectric power have the advantage of not needing any fuel to be bought to power them, in addition to emitting no CO2 once they are built. However, renewable sources do have their own drawbacks. The most obvious being that solar panels do not produce electricity at night (and less when it is cloudy), and wind turbines do not produce electricity when the wind is not blowing. This means that solar and wind need to be supplemented by a baseload of constant power, so that hospitals do not lose power at night and your freezer does not defrost unexpectedly! This means that renewable sources can only supply a total of around 35% of our power requirements, with the rest coming from more reliable sources.
So where do we get the rest of our electricity from? Here is where the much-maligned nuclear power comes in. Put simply, it is the only energy source capable of generating reliable power without destroying the environment at the same time. Nuclear power plants fundamentally work in the same way as those powered by fossil fuels: they use heat to boil water, and then use that steam to drive turbine generators. The main difference lies in the way that heat is generated; while thermal power stations simply burn fuel, nuclear stations rely on a special property of uranium. Around 0.7% of naturally occurring uranium is made up of uranium-235, with the remainder being composed of uranium-238. The different numbers refer to distinct isotopes of uranium: isotopes are variants of an element with different amounts of neutrons in the nucleus. Basically, isotopes have the same chemical properties, but different nuclear properties: the main one being radioactivity. Uranium-235 is fissile, which means it will spontaneously split into two smaller atoms, releasing two or three neutrons, and a lot of thermal energy. These neutrons will cause other U-235 atoms to fission, releasing even more neutrons and heat. So if enough uranium-235 is brought close together, it will set off a chain reaction, releasing huge amounts of radiation and heat, which can then be used to produce electricity. Control rods, made of a material that absorbs neutrons, can be inserted into the nuclear reactor to control the rate of the reaction.
Obviously nuclear power does not come without its own set of disadvantages: it produces waste that has to be stored underground for millennia, it can be used to disguise the production of nuclear weapons, and accidents can be catastrophic when they happen. The waste issue has no easy solution, but if the alternative is coal smoke, ash (which is actually more radioactive than nuclear waste!), acid rain, and smog, I personally would take small amounts of easily controllable radioactive waste every time. Banning ‘breeder’ reactors, which are required to manufacture nuclear weapons, can solve the issue of nuclear proliferation. The issue of safety is largely overblown; even Fukushima, a plant from the 70s that was hit by an earthquake and tsunami of twice the magnitude it was designed for, has not caused any deaths. When compared to the estimated 500,000 people who die every year as a result of coal generation in China alone, nuclear is very safe, causing fewer deaths per unit of energy generated than even solar and wind energy.
Of course even uranium is a finite resource, so what happens when it runs out? What is the power source of the future? What if there was a power source that was clean, proliferation resistant and safe, and did not produce waste that needed to be stored for thousands of years? Well, actually, there is! Its been known about for decades, and a test power station was even built in the 1950s: it is called the Molten Salt Reactor. Powered by thorium instead of uranium, these reactors could be the future of power generation. As they are not pressurised, they are not at risk of the kind of explosions that caused Chernobyl and Fukushima. Furthermore, they produce much more power and much less waste, and the waste that they do produce is only radioactive for a matter of decades, instead of tens of thousands of years. Worldwide thorium supplies would provide enough energy to last until at least the year 3000, giving us plenty of time to come up with another source. So why are we not already building them? Because of thorium’s other advantage: it cannot be used to produce nuclear weapons. During the Cold War uranium and thorium technologies were proposed as potential energy sources. The American government decided to fund the one that could help them make more nuclear weapons.
A power source as abundant and easy to harness as thorium could literally change the world. All kinds of energy-hungry processes suddenly become viable: for example, the production of carbon-neutral ammonia feedstock for fertilisers or dedicated power stations desalinating sea water and pumping it inland to irrigate drought-prone countries. If everyone in the world had ample food, water and energy would there be anything left to fight wars over? We could also produce enough power to replace all cars with electric equivalents, and create a new carbon-neutral fuel, for aeroplanes and other transport that cannot run on batteries, by removing atmospheric carbon dioxide: processes that would mitigate the effects of global warming. Thorium reactors can even be used to process existing nuclear material; in other words, we could burn nuclear warheads and nuclear waste for power.
However, there are significant barriers to overcome before thorium becomes a viable power source. Because it has not been used in the development of weapons for decades (unlike uranium), the process of extracting and purifying it into fuel is still prohibitively expensive, and the technology is still unproven on a commercial scale. The existing nuclear industry has huge amounts of money sunk into current uranium technologies and is unlikely to fund its own competition. A large-scale publically funded research programme is the only way thorium will see the light of day. Investment in infrastructure is one of the best ways for a country to work its way out of a recession, therefore creating jobs and feeding money into the economy from the bottom up. Russia, India and China all seem to have realised this and are funding research into thorium power, and hopefully the UK will follow suit.
For a 5 minute video on thorium power, visit thoriumremix.com.