Nuclear power: Safe, clean and efficient

Andrew Kenny sees nuclear power as the solution to South Africa’s growing need for electricity.

Summary - Nuclear power is the safest, cleanest source of electricity in existence. Most leading democracies rely on it for a large proportion of their electricity, and it has a far better safety record than any other energy source. The worst nuclear power station accident in the western world, at Three Mile Island in the USA in 1979, killed no one. Chernobyl, the single fatal nuclear accident, was caused primarily by a reactor design that would not have been allowed in the West. The only environmental concern is radiation – but about 87 per cent of the radiation we get comes from nature (the sun, rocks, soil and water); about 12 per cent is medical. Less than 0,1 per cent comes from the nuclear industry. Every energy source creates long-lasting waste. Solar power units use lead batteries to store electricity, but lead is a deadly toxin that causes brain damage in children. This is not an argument against solar power – we are perfectly capable of handling lead safely. The same is true of nuclear waste: it is easy to store safely so that it presents no danger either now or in the future. If we want to avoid greenhouse gas emissions, nuclear power is the best energy technology. Furthermore, independent studies by reputable organisations such as the US National Cancer Institute have found no increase in cancer in people living near, or working in, nuclear power plants. The connection between nuclear power stations and nuclear weapons is extremely slight. Natural uranium contains only 0,7 per cent uranium 235. To create a bomb, this must be enriched to 90 per cent. The uranium used at Koeberg, by contrast, is enriched only to 3,5 per cent. Enrichment is difficult, expensive and conspicuous. Nuclear weapons have never been made from nuclear power plant waste. Nuclear power is also economical. Wind and solar power, while good for small-scale applications, are hopelessly unreliable and expensive for the bulk electricity demands of an industrial economy. The cost of wind electricity is more than double that of nuclear, gas or coal, and on a windless day one still needs an alternative power source. Solar power is even more expensive. The two biggest problems with nuclear power are public perceptions and high capital costs, both of which can be blamed largely on existing reactor designs. Now South Africa is designing a better nuclear power station – the pebble bed modular reactor (PBMR). The PBMR is small, simple, cheap and inherently safe. Neither uncontrolled fission reaction, which caused the Chernobyl accident, nor damage to the fuel from over-heating, which happened at Three Mile Island, is possible with a PBMR. And because the uranium fuel comes in small pellets that are encased in graphite balls or ‘pebbles’ which provide extremely durable containment, the waste is even easier to store than Koeberg’s. The PBMR has been reviewed favourably by experts at MIT. We need new power stations. Our gas fields are too small, and wind and solar power are impractical. Coal, which now supplies 92 per cent of our power, will continue to dominate, but it must be augmented by cleaner nuclear power. Countries around the world need more generating capacity and are showing increasing interest in South Africa’s PBMRs. None of the 27 nuclear power plants currently being built in Asia, Europe and South America are as economic or as safe as the PBMR. The PBMR offers a potentially huge export market for South Africa.

Nuclear power is the safest and cleanest large-scale source of electricity we know, and in many countries, the most economical. The use of nuclear power as a source of electricity began fifty years ago. It now provides 17 per cent of the world’s electricity. Most of the world’s leading democracies, such as Sweden, France, Japan, Canada, Germany and the USA, rely on nuclear power for a large share of their electricity. The huge advantages of nuclear power come not from man but from nature. Nuclear energy is so concentrated that it can easily be controlled and causes minimum disruption to the environment.

The safety record of nuclear power is far, far better than that of any energy source. The worst ever nuclear power station accident in the western world was at Three Mile Island in the USA in 1979. It killed nobody, injured nobody and had no ill health effects afterwards. More people can be killed in one weekend in South Africa by paraffin stoves than have been killed in the whole Western world in the entire history of nuclear power. The Paul Scherrer Institute, looking at the full energy cycle, including mining, fuel preparation, operation, decommissioning and waste disposal, counted the number of accidents in energy that killed five people or more between 1969 and 1996. The result is shown in Graph One. (LPG: liquid petroleum gas)

The single fatal nuclear accident was Chernobyl, caused primarily by a crazy reactor design that would not be allowed in the West. Since 1996 there have been no such accidents in nuclear but many in other energy sources, including the natural gas accident in China last December that killed 233 people.

The only environmental concern about nuclear power is radiation. But radiation is part of nature. From the beginning of life on Earth billions of years ago, all living things have been bathed in radiation thousands of times greater than you would get from a local nuclear power station. A Rem (Roentgen Equivalent Man) is a measure of both radiation dose and its danger to man. A milliRem (mRem) is a thousandth of a Rem. No harm to human beings has ever occurred at a radiation dose of below 10 000 mRem a year (imagine this equivalent to the height of Table Mountain). Natural background radiation gives you about 250 mRem a year (an eight-storey block of flats). A nuclear power station close by will give you less than 0,25 mRem a year (a matchbox). A coal station gives you more radiation than a nuclear one but it is still utterly insignificant.

About 87 per cent of the radiation we get comes from nature (from the sun, rocks, soil and water, from the food we eat and from our own tissues). About 12 per cent is medical (X-rays, radiation diagnosis and radiotherapy). Much less than 0,1 per cent comes from the nuclear industry. Radiation is very easy to measure, so you cannot have large radiation releases without somebody noticing them.

Every source of energy for generating electricity gives rise to long-lasting waste. Solar power units, for example, have a lead battery to store electricity when the sun is not shining. Lead is a deadly toxin that remains dangerous for billions of years, indeed forever, and causes foetal damage and permanent brain damage in children. Is this a serious argument against solar power? Of course not. Mankind is perfectly capable of handling lead safely. But still less is the question of nuclear waste a serious argument against nuclear power. Nuclear waste is solid, stable and tiny in size. It is very easy to store safely so that in presents no danger to man or the environment, now and in the future. The same cannot be said for coal waste, which contains not only gaseous pollutants but also heavy metal toxins that last forever, such as mercury, arsenic and cadmium; toxins that are simply scattered into the environment.

If you want to avoid greenhouse gas emissions, nuclear power is the best energy technology. Nuclear power releases no greenhouse gases in operation and over the full energy cycle, including construction, fuel preparation, operation and decommissioning. Nuclear power releases among the lowest, if not the lowest, quantity of greenhouse gases per kilowatt-hour (kWh) of any energy source.

Massive studies by reputable, independent institutions such as the US National Cancer Institute and the UK Office of Population Censuses and Surveys have found no increase in cancer in populations living near nuclear installations or in nuclear workers. (Indeed the cancer rate in nuclear workers is usually lower than in the population at large.)

The connection between nuclear weapons and nuclear power stations is slight, almost as slight as the connection between the lead in batteries and bullets. An atomic bomb requires either 90 per cent Uranium-235 or Plutonium-239. Since natural uranium contains only 0,7 per cent U-235, you have to enrich it, which is difficult, expensive and conspicuous. Koeberg only has enrichment to 3,5 per cent, which is why it is impossible for it to explode like a bomb. The apartheid government enriched uranium to over 90 per cent and made several atomic bombs at Valindaba near Pretoria. To say that Koeberg was a front for the bomb programme is rather like saying a nunnery is a front for a brothel: the two activities are so different it would have fooled no one.

The plutonium in Koeberg’s waste is next to useless for weapons, and none have ever been made from such reactors. Now that apartheid has gone and we have joined the nuclear Non-Proliferation Treaty, nuclear power without nuclear weapons fits in perfectly with our new democracy, as it does in Sweden, Finland and Japan.

Nuclear power is economical. Even in Britain, which has it own gas and whose nuclear power programme has been poorly managed, the Royal Academy of Engineers estimates the cost of electricity in pence/kWh as follows. Coal: 2,5; gas: 2,2; nuclear: 2,3; wind without stand-by generation: 3,7; wind with stand-by generation: 5,4. In Japan nuclear is the cheapest source of electricity. In the USA the production costs of nuclear are lower than coal, oil and gas. Finland, needing another power station, decided last year on nuclear because it was the cheapest.

Renewable energy, such as wind and solar, is good for small scale applications (such as I saw last month on a farm in the remote Northern Cape). For bulk electricity, which South Africa requires for its industrial economy, renewable energy is hopelessly unreliable and expensive. The fuel is free but it is very dilute and intermittent. The sun does not shine at night and the wind often does not blow when you need it. If you want reliable electricity you have to install alternative power of the same capacity every time you erect a wind turbine. No bulk electricity from renewable energy is economically possible without huge operating subsidies. The costs of wind electricity around the world average over 6 Euro/kWh, more than double the operating costs of nuclear, gas or coal. Solar is even more expensive.

To generate the same amount of electricity as Koeberg Nuclear Power Station, you would need over five thousand wind turbines, each about 90 metres high (the height of the Statue of Liberty). The electricity would be at least twice as expensive as Koeberg’s and on a still day you would not get one watt. In Europe, wind turbines are furiously resented by local residents, who consider them an environmental blight. They cause property values to fall. Last year, readers of Country Life magazine voted wind farms the worst eyesores in Britain.

The two big problems with nuclear power are public perceptions and high capital costs. To a large extent both can be blamed on the designs of existing reactors, light water reactors (LWRs), which are essentially over-sized nuclear submarine propulsion units. LWRs, such as Koeberg’s, are complicated and take a long time to build and commission. Their safety record is excellent but it comes at the cost of expensive active safety mechanisms. It has been clear to engineers that there are better designs for power stations and it was only a matter of time before some country seized the opportunity to develop one. Now one is doing just that. It is South Africa.

South Africa is developing the Pebble Bed Modular Reactor (PBMR), based on a proven German reactor, the AVR, which ran flawlessly for 21 years. Unfortunately, the Germans then built a much bigger and more complicated nuclear reactor known as THTR, which negated all of the advantages of the AVR and ran into political problems in 1989 when it was shut down. South Africa is not going to make this mistake and is going to exploit all the benefits of the original reactor.

The fundamental design philosophy of the PBMR is inherent safety. It is impossible for any safety system to fail because there are no safety systems. The control rods and absorber spheres can shut down the reactor quickly but safety does not depend on them. Safety in built into the design. No matter what human error or equipment failure, you cannot have an accident that endangers the public.

There are two types of nuclear power accident. The first is uncontrolled fission reaction. This is what happened at Chernobyl. The other is damage to the fuel from over-heating. This happened at Three Mile Island. Neither is possible when using the PBMR. Good physics ensures that the fission reactions are always under control at all power levels. Because of the PBMR’s small size and low power density, heat always escapes rapidly enough to ensure that the fuel never reaches temperatures high enough to damage it, even under the worst possible accident.

The PBMR is small, simple and cheap. It uses helium as a coolant and carbon (graphite) as a moderator. (The moderator slows neutrons down, making them more likely to cause fission.) The uranium fuel comes in small pellets about 0,5 millimetres in diameter, which are enclosed in multiple strong barriers. The pellets are embedded in graphite balls or “pebbles”, each about 60 mm in diameter. The reactor heats helium, which then drives a turbo-generator. It has high efficiency.

Waste fuel never leaves the unit until its life is complete. The waste is even easier to store than Koeberg’s because each pebble provides extremely durable containment for the uranium.

The PBMR has passed commercial assessments and has been reviewed favourably by distinguished foreign experts such as the Massachusetts Institute of Technology (MIT) in the USA.

South Africa needs new power stations. There are only two indigenous options: coal and nuclear. Our local gas fields are too tiny. Wind and solar power are much too costly and erratic. Coal now supplies 92 per cent of our electricity and, despite siting and environmental problems, will continue to dominate, but it must be augmented by cleaner, more flexible nuclear power. The PBMR, if all goes well, should be able to start delivering bulk electricity after 2010.

This will come from grouping the PBMRs into modules of eight (which is why it is called “modular”). In its National Integrated Resources Plan, the National Electricity Regulator estimates that the first PBMRs would deliver electricity at 27 cents/kWh compared with 22 cents/kWh for new coal stations. But the costs for subsequent PBMRs would drop to 19 cents/kWh, the cheapest option for the future.

Around the world, countries need more generating capacity, and more and more eyes are turning towards the little reactor in South Africa. Right now, 27 new nuclear power plants are being built in Asia, Europe and South America. None is as economic as the PBMR. None is as efficient. None is as safe and simple. The PBMR offers a huge export market for South Africa, and a chance to establish a niche industry to boost our economy, increase employment and establish the high value manufacturing that we have been seeking for decades.

The author has supplied additional material of a technical nature which is available to readers on request: