On the 26th April 1986, engineers at the Chernobyl nuclear power plant in Ukraine were performing checks at low power to test a new emergency cooling system. Previously in order to get coolant into the reactor for emergency shutdown in the event of local power failure, four diesel generators would be required to produce the power for the pump. These however took approximately one minute to reach full speed, and this was deemed unacceptably long. Instead a system was designed using the momentum of the winding down turbines to produce enough power for the coolant pump while the generators started.
The test began at about 1 am, and the main turbine was wound down. What the engineers did not realise, however, was that as the flow rate of water through the turbines decreased, more steam bubbles appeared, reducing the ability of the coolant to absorb neutrons. This led to a massive power spike and sudden overheating. Panicking now, someone pressed the manual override button, which began to lower the control rods into the reactor. The rods took about twenty seconds to descend, which was about ten seconds too long.
It is estimated that reactor output jumped to ten times the normal level and a vast explosion was triggered, blowing off the 2000 ton upper plate, sending a plume of highly radioactive particles into the sky and creating the worst nuclear disaster in human history .
The WHO at the time estimated that the blast caused less than 50 direct deaths. About 600,000 people were deemed to have been seriously exposed to radiation, of whom it was estimated that 4,000 would die of cancer over the course of their lives as a result of the explosion at Chernobyl. The figures are horrific. However, to put them in perspective, based on UN estimates from 2001-2004, during this period one person would die of starvation every second. That’s nearly 4,000 an hour .
Worryingly, with an urgent need for carbon emissions to be cut and a sustainable and cost-effective source of energy desperately needing to be found, Chernobyl is still cited as a reason not to invest in nuclear power. It is true that Chernobyl is not the only accident that has occurred at nuclear power plants: accidents at Three Mile Island in the US and Windscale in the UK both caused small releases of radioactive material, but no deaths resulted. As one commenter pointed out, TMI was the worst nuclear disaster in US history; and yet it led to no injury or death and almost no environmental damage. That was 30 years ago .
There are some good reasons why nuclear power is such an emotive issue. Perhaps most crucially, it is unclear just what should be done with the waste from reactors, some of which will be radioactive for 100,000 years. Currently, some waste is being stored and some reprocessed. The majority of what can’t be reprocessed will be buried when underground storage comes online, probably this year, but plans are being mooted for putting it at the bottom of the ocean or shooting it into outer space. Clearly none of these options are ideal .
Another major problem with nuclear power is its cost. These projects are hugely expensive and take a very long time to bring online, so investors need to be pretty certain that there will be demand for their power in twenty years’ time or so when the plant comes online. The reason projects take so long is partly due to Chernobyl: safety standards took a leap after the disaster, and planning restrictions came down heavily, which is no bad thing. However, if governments want investors to spend on nuclear power, they have to offer some sort of guarantee for the future, at least in the West. In emerging markets such as China and India, demand is so great that there is little for investors to worry about. Unfortunately, the West is where anti-nuclear sentiment is strongest .
This sentiment is misplaced. The rapid and careless expansion of nuclear power leading to the Chernobyl disaster was clearly irresponsible, but now that safety standards have been hiked, nuclear power is incredibly safe. Chernobyl was horrific enough for that to be more or less certain. The International Atomic Energy Agency (IAEA) has a system of rigorous safety standards that are applied worldwide, wisely using a system of peer review – if your neighbour’s reactor is likely to blow up then it is you who should be worried. Belarus found this out to its cost after Chernobyl .
New nuclear plants are designed such that an accident that could damage the reactor’s core would be expected to occur once every 10 million years. Furthermore, should such damage occur, it is nearly impossible that any radiation would escape. In stark contrast to Chernobyl’s reliance on manual operation, new reactors are designed so that they do not even have to rely on computers or mechanical systems, let alone people. Emergency coolant is provided using gravity should something go wrong. And the cores (at least in the US) are designed to be able to withstand a direct hit from a jetliner .
Even assuming that nuclear power plants are safe however, is that enough for us to welcome their construction? I for one would not be particularly impressed if one turned up in my back garden. But the benefits of nuclear power are huge. They produce (including mining and shipping of uranium as well as plant construction and operation) roughly equivalent carbon emissions to wind or solar power. One power plant can supply 1.5 million homes; and is not reliant on weather. This is in contrast to wind farms; one of the larger turbines can supply about 1,000 homes. To equal the output of a nuclear power plant therefore you would need 1,500 wind turbines, and they would need to be placed somewhere that has plenty of wind. With demand for clean energy rocketing this is simply not practical .
Furthermore it is possible to limit the number of people affected by the building of nuclear power. Most of the proposed new plants in the UK are simply extensions of old ones. A plan to offer tax incentives for people to accept new plants is being proposed. And a nuclear power plant is no worse an eyesore than a coal, gas or oil fired power station.
This does not, admittedly, solve the problem of nuclear waste. Waste is building up at an alarming rate, and cannot be buried forever. Shooting it into outer space seems rather irresponsible. But researchers worldwide are working on a solution. It is already possible to reprocess a large amount of the waste, and the remaining ‘high level waste’ that must be buried for thousands of years is a relatively small proportion of the total waste. A typical power plant produces about 30 tonnes of high level waste per year. Contrast this to an equivalent coal-fired power station, which produces 300,000 tonnes of ash per year, which is blasted into the atmosphere rather than safely contained. Furthermore, with so much research into it, a better solution than burying it all is likely to emerge fairly soon; and the more people accept nuclear power as the best option, the more likely this is to occur .
Nuclear power does not hold all the answers. Clearly diversity is the key to dealing with the world’s renewable energy requirements. But nuclear is remarkably clean, safe and powerful. Fusion is likely to make it even more effective in a few years’ time. It is unfortunate that a single disaster, Chernobyl, is what sticks in people’s minds when they think of nuclear power, and when they come up in arms against it. If we are serious about cutting carbon emissions, nuclear power is our only serious option. Now is the time to invest.
 IAEA Website; “What’s the situation at Chernobyl?”; http://www.iaea.org/blog/Infolog/?page_id=25
 United Nations Information Service; “Independent Expert On Effects Of Structural Adjustment, Special Rapporteur On Right To Food Present Reports: Commission Continues General Debate On Economic, Social And Cultural Rights”; United Nations, March 29, 2004
 Guardian UK; “How safe are the new nuclear reactors?”; http://www.guardian.co.uk/environment/2010/jun/21/how-safe-new-nuclear-reactors
 Guardian UK; “How nuclear power works”; http://www.guardian.co.uk/science/2008/apr/30/particlephysics.energy1
 McDonald, A.; “A look at nuclear power generation around the world and its future prospects”; IAEA Bulletin 49.2, March 2008
 IAEA; “How safe is nuclear energy?”; http://www.iaea.org/blog/Infolog/?page_id=23
 British Energy; “Heysham 1”; http://www.british-energy.co.uk/pagetemplate.php?pid=92
 American Wind Energy Association; “Wind Energy Basics”; http://www.awea.org/faq/wwt_basics.html
 IAEA; “Managing Radioactive Waste”; http://www.iaea.org/Publications/Factsheets/English/manradwa.html