In Defence of Nuclear
Lance Kennedy (November 1, 2018)
New Zealand has a nuclear free policy. In relation to weapons, I totally agree with that. A nuclear bomb is an obscene and horrible device and the sooner the world can see its way to eliminating all of them, the better. But what of nuclear energy? Should that share the same horror? Lots of people think it does, but why?
There is a principle in psychology that helps to explain what has happened. If a lie, or a misleading statement is repeated often enough, most people will come to believe it, even in the absence of credible evidence. Not skeptics, of course, who are too rational to fall into that trap? But that very human quirk was used to great effect by Donald Trump during his presidential campaign. By referring constantly to “crooked Hillary “, he had a large number of the more gullible voters convinced she was seriously corrupt, even though there was no credible evidence. It may have won him the election.
The same thing happened to the image of nuclear energy (and genetic modification). In this case, the slanderers were politically motivated “environmental” organisations like Greenpeace. By repeating over and over again that nuclear energy was too risky to use, they persuaded many people to accept that it was a horrendously dangerous technology, even in the absence of strong evidence. I have a confession. As a callow and foolish youth, I joined Greenpeace. This lasted two years, thereby proving I am a slow learner. The killer was their own newsletter. As a science geek, I had real problems. As I read their newsletter, I could not help saying, over and over: “That is not right.” “That is not right.” “That is so not right!”
On nuclear power, with this misleading influence, I went along with their silly view point. But even a slow learner like me can have an epiphany. It came with an article I uncovered on nuclear power, published by the British Royal Society. The BRS is an organisation I respect, and I was interested to see that their view of nuclear power was guardedly approving. Guardedly - because no scientist seems to be able to draw a conclusion without being very cautious. They did not portray nuclear power as being dangerous. Maybe we should take a look at the evidence that exists, and properly evaluate the risk.
Risk
When evaluating risk, the first thing that must be realised is that risk is not an absolute. It is a meaningless idea except relative to something else. A few years ago, a car being driven at speed in Auckland left the road, flew through the air, through the side of a house, and killed a small boy asleep in his bed. Does this mean your own bed is a risky place to be? Well, no. The risk is very low. It is just that absolutely everything in life must be considered to be risky. But the term risk becomes meaningful only when compared to something else. Nuclear energy does indeed carry a risk. But is it bad?
So to evaluate how risky nuclear energy might be, we need to compare it to something. What? Obviously, the best comparison will be to other methods of generating energy, meaning electricity. Fortunately, experts have done the work for me, and I need merely quote their findings. They make their comparisons on the basis of the number of human fatalities per unit electricity generated. I must apologise for the fact that these findings are not hard numbers, such as an experimental physicist would generate. They are estimates based on what data exists, and on the basis of various calculations. But if you allow for a reasonable error factor the overall numbers are valid. You can find such estimates on many different web sites. This one comes from www.nextbigfuture.com/2008/03/deaths-per-twh-for-all-energy-sources.html I have chosen it over a number of similar sites because it is simple.
There are eight generation methods listed, all global major systems. The number given below is deaths per terawatt hour of electricity generated.
Surprised? Clearly, of all the major methods of generating electricity, nuclear power is the least risky, and by a very wide margin! Burning coal is the worst, because it creates enormous air pollution, which exacerbates respiratory illness. It has been suggested that more than 3 million people every year who die of respiratory problems have their deaths accelerated by the pollution coming from coal burning power plants. Burning biomass and oil are similar.
Hydroelectricity is a killer. In 1975, in the Chinese province of Banqiao, a dam burst, instantly killing about 80,000 people, and another 80,000 later by epidemics and famine, while 11 million were made homeless. About ten other dams have burst in other parts of the world, killing many. Right now, the giant Kariba dam in Zimbabwe is looking very, very dangerous.
Gas pipelines leak, catch fire, and explode. Wind towers cause builders and maintainers to fall and die. Rooftop solar cells lead to people installing them having ladder accidents and dying. Yet, very few people have died as the result of nuclear power plant accidents. As the table above shows, in relation to electricity generated, nuclear power is the safest of all the major electricity generating methods. The journal “Chemical and Engineering News” goes further, claiming that nuclear power in fact has saved nearly two million lives so far, by preventing more coal burning power plants being built. http://cen.acs.org/articles/91/web/2013/04/Nuclear-Power-Prevents-Deaths-Causes.html
So perhaps the real problem with nuclear power is its effect on natural environments?
Environmental Impact
We all have an interest in preserving the natural world, and even, perhaps, making it better. But nuclear power has been seen as a risk to this. Is it? That is unlikely. Nuclear power produces less pollution than almost any other system, and especially is great for reducing greenhouse gas emissions. Do nuclear power plant accidents do great harm to the environment?
The worst nuclear power plant accident in history happened on April 26, 1986 in Chernobyl, then part of the Soviet Union. Radioactive material was scattered far and wide, causing alarm all around the world. People died from thyroid cancer and from radiation poisoning. Surely this incident caused massive environmental harm!
The authorities at the time set aside an exclusion zone of about 30 kilometres around the accident site, to prevent people living in a contaminated area, or even spending too much time there, and becoming harmed by radiation. Thirty years have passed. What is the zone like today?
National Geographic have made several documentaries on the final result.
Their investigations, and the work of several natural scientists, reveal that there has been a population explosion of wildlife. In the exclusion zone there are now red deer, roe deer, boar, moose, wild horse, bison, brown bear, lynx, wolves, two species of hare, beaver, otter, badger, martins, mink, polecat, hawks, eagles, owls, storms and swans, plus more. Most investigators believe the wildlife is healthy and unaffected by radiation.
There is no doubt that the radiation released during the nuclear accident was very harmful. But thirty years appears to have removed that harm. The small amount of radiation that remains is far less harmful than the presence of humans, and without that ultimate predator, the wilderness has thrived. The Chernobyl exclusion zone is now one of the most important wildlife refuges in Europe.
This leaves us with a question. Radiation is definitely a hazard. Radioactive isotopes exposed to humans and animals can kill, cause cancers or mutations, and shorten lives. Why is it that nuclear power plants cause very few deaths, and the radiation around Chernobyl has not managed to inhibit the health and vitality of so many animals?
Exposure to Radiation
In science, it is vitally important to quantify issues in order to have the confidence to make predictions. In dealing with the effects of radiation, we must first put numbers to the amount of radiation that might potentially do harm. How do we do this?
There are many ways to measure radiation, but this topic is about exposure. The best modern unit used to quantify such exposure is the sievert. One sievert is defined as one joule of radiation energy per kilogram of body mass. Or, to put it more visually, if less accurately, one sievert is what you experience if the equivalent of three million average nuclear particles strike your body. So what does one sievert of radiation do to you? Answer, it increases your lifetime risk of cancer death by 5%. Since the average lifetime risk of death by cancer is 38%, exposing yourself to one sievert of radiation will increase your risk of such death to 40%. Astronauts on the International Space Station are exposed to about two sieverts per year. NASA must have some interesting employment contract documents!
More radiation increases harm, and less radiation reduces the amount of damage. Exposure to ten sieverts will certainly kill you from radiation poisoning, within a month. But if you reduce the amount, then the harm is less. For lower levels of radiation exposure, we normally talk of millisieverts, where one millisievert is one thousandth of a sievert, or the equivalent of being struck by 3,000 nuclear particles. When such a particle strikes, the harm it does depends on where it strikes. Most such particles are harmless, since they hit water, fat, or protein molecules. It is only the rare case when a DNA molecule is damaged that genuine harm, like mutation or cancer, or cell death results.
There is another complication. Time. The human body has a wonderful ability, known as healing. This applies even to DNA molecules. If radiation damages DNA, and the body is given enough time, it heals. So to determine if radiation will cause real harm, we not only have to decide how much exposure occurs, but also over what period of time, to see if healing is able to repair the damage. This means there are two kinds of exposure, which we can call acute, happening in a short period, or chronic, occurring over a longer period, such as a year. The amount of radiation required to cause harm depends on time. How much radiation is needed to cause real harm?
For acute harm, we turn to the results of the research on Hiroshima victims. The Hiroshima survivors have been the subjects of a study that lasted a full human lifetime. Many died of cancers induced by radiation. But the researchers could find no increase in cancer rate, compared to the rest of Japan, for those who received 100 millisieverts or less. Perhaps there is a threshold for acute radiation harm, of about 100 millisieverts?
For chronic harm, we turn to the town of Ramsar in Iran. The people there are exposed to a natural source of radiation (radon and radium) from geothermal waters, which they bathe in regularly. Hot stuff! Natural radiation is no different to radiation from nuclear power, and the Ramsar inhabitants are exposed to radio isotopes which spit out the same nuclear particles as radio isotopes from nuclear power. Exposure varies, but is frequently 250 millisieverts or more per person per year. Researchers have found a surprising result in Ramsar. The local residents on average appear to be unharmed by the radiation, but show signs of adaptation, being more resistant to such harms as radiation induced mutation. Tough dudes! Does this mean that 250 millisieverts per year is tolerable?
My conclusion from all this is that if people or animals are exposed to radiation levels that deliver an acute dose less than 100 millisieverts, or a chronic dose over one year of less than 250 millisieverts, they are unlikely to suffer harm.
The global average exposure for radiation is just over 3 millisieverts per year (about 10,000 nuclear particles striking your body each year), and this is clearly harmless. But natural background radiation varies dramatically, and it is just as clear that the human body can tolerate much higher doses without harm. How does this relate to nuclear power plant accidents?
Nuclear Accidents
The worst thing to happen in a nuclear power plant is reactor melt down. This has happened three times. At Three Mile Island in the USA, at Chernobyl, and at Fukushima in Japan. How much harm did these accidents cause?
As the previous discussion shows, it all depends on how much radiation exposure occurred. At Three Mile Island most of the radiation was successfully contained and no one was exposed to high levels. No harm to people. We do not blame the advent of Trump on Three Mile Island. The end result of this accident was a fatality rate of zero. Despite a small release of radioactive gas, no statistically significant increase in local cancer rates was recorded. The main effect of this accident was political, with anti-nuclear organisations pushing hard for restrictions on nuclear power.
At Fukushima, the results were much more tragic, though not because of radiation. No one died from radiation exposure, and it is likely that few if any will suffer cancers, though it is still too early to say. There were heroic workers who entered the plant in order to shut it down, and experienced higher radiation. I take my hat off to them for their gallantry, and hope they never have to suffer for it. But radiation levels outside the plant, even just a few hundred meters away, were lower than the thresholds already mentioned. Experts in radiation effects advised the Japanese government not to take drastic action, since risks were low. However, for political reasons, government and bureaucrats decided to order an immediate evacuation of every person anywhere nearby.
Nuclear power plant Dukovany, Czech Republic. Photo taken by Petr Adamek in October 2005
300,000 people were forced to leave, with urgency. This included the frail elderly, people in critical care, and premature babies. An estimated 1600 people died as a result of the stress of the evacuation, making Fukushima the worst nuclear power accident of all. Yet not a single person died as a result of the nuclear accident. There were just victims of government and bureaucratic stupidity. The moral of this story is to listen to the scientific experts, and not to the dictates of short term political expediency.
Chernobyl remains the only nuclear power plant accident to actually kill people. So how many died? In fact, the number of deaths was 49. http://en.m.wikipedia.org/wiki/Deaths_due_to_the_Chernobyl_disaster
These deaths were from radiation poisoning, a helicopter crash, and from thyroid cancer. Of course, myriad claims exist for much greater numbers. At the time, thirty years ago, various scientific groups tried to calculate a prediction for number of cancers, and especially leukemia. The results suggested that anything from 4,000 and up would be the result. It would appear that they were all wrong. Even the low estimate of 4,000 would be an increase of 3% over the leukemia rate before the accident. It did not happen. Today, the local medical authorities admit they have not seen any statistically significant increase in any cancers with the exception of thyroid cancer.
Thyroid cancer is a special case. It is very localised and easily treated. It is the result of an isotope of iodine (iodine 131) that is radioactive. Iodine is concentrated in the thyroid gland, meaning that the isotope causes local cancer of that gland. After the accident, radioactive iodine was scattered over a large area. Cows eating grass consumed it, and the isotope then concentrated in the milk. When the milk was unwisely given to children, it caused the thyroid cancers. A total of 6,000 people developed it. Happily, only 16 died. These 16 were part of the total of 49. Apart from industrial accidents, which can happen anywhere, 49 is the total of all deaths from nuclear power. But I do insist on a few weasel words. I am not counting radiation harm from two Soviet nuclear submarine accidents, or nuclear weapon events, or medical radiation accidents, which are separate issues, not related to standard nuclear power. So why are there so few deaths?
Estimates of exposure suggest that those within the Chernobyl 30 kilometer exclusion zone soon after the accident were exposed to between 3 and 180 millisieverts. The higher doses were mostly due to radioactive iodine as mentioned above. Doses lower than 100 millisieverts were unlikely to cause harm. Whenever radiation becomes a factor in the news, there is alarmism. My suggestion to the more rational among us is to quantify the radiation. Put numbers on it. If it is less than the probably safe thresholds, then there is no need for panic. Compared to power plant accidents like the dam burst at Banqiao, nuclear power plant accidents have caused very little loss of life. Perhaps it is nuclear waste which is the real problem?
Nuclear Waste
Out of the eight different types of power plant I mentioned earlier, take a guess at which kind generates the most radioactive waste. Did you pick nuclear? Wrong!
In fact, surprisingly, it is coal. If you compare a coal burning power plant to a nuclear power plant of the same generating capacity, the coal plant will produce 100 times as much radioactive waste. These radio isotopes are found in the smoke going up the chimney, and in the coal ash left behind.
https://www.scientificamerican.com/article/coal-ash-is-more-radioactive-than-nuclear-waste/
Does this matter? No. Not at all. Coal smoke and ash is quite toxic just from a chemical viewpoint, but the addition of those radio isotopes does not increase the hazard. Why not? Because the radiation given off is well below the necessary thresholds.
The problem with waste from nuclear power plants is not the amount, but the concentration. If that waste was as well dispersed as the radio isotopes from burning coal, there would be no problem. At 100 times lower levels, the harm thresholds would never be reached. But it is not dispersed. The most concentrated nuclear waste is called high level (HLW). Most radio isotopes in nuclear waste take this form, and my comments are addressed to this concentrated form.
The best thing about this waste is that there is not much of it. Compared to the waste from coal power, the amount is miniscule, only roughly 10,000 tonnes per year globally, from over 400 power stations. With a very high density, this means low volume, making it easy to store, since it occupies relatively little space. It would be possible to place all the high level nuclear waste ever produced, and stored in dry casks, in a small town land fill, and have ample space left over.
The current approach is to take spent nuclear fuel, and store it in water filled pools for at least ten years. During this time, it ceases to give off heat, and becomes far less radioactive. It is then stored in dry casks, giant barrels made of stainless steel and encased in cement. These are so safe that you could spend a lot of time hugging them and not get exposed to hazardous radiation. (Tree huggers, eat your heart out.) Most of the high level nuclear waste ever generated is still in such storage. Not a problem since radioactive decay makes it less hazardous as time passes. In fact, over 40 years, it becomes 1,000 times less radioactive.
So why is nuclear waste so hazardous? Answer, it is not. When stored securely, and treated responsibly, it causes no harm whatever. A big complaint about nuclear waste is that most of it is not in any permanent repository. But while this seems desirable, there is no urgent need. After all, the temporary storage in secure warehouses keeps it safe, and no one is harmed. The longer this goes on, the lower the level of radioactivity.
How long does it need to be stored? This depends on your desired end point. If you want something totally non-radioactive, it will take hundreds of thousands of years. But the origin of nuclear fuel, and hence nuclear waste, was substantially radioactive in its original ore. If you want to store high level waste until it is about as radioactive as the original ore, it will take 1,000 to 10,000 years. Safe, long term repositories are under development, and in use in several countries. In the meantime, the waste not so stored is still fine, and getting less radioactive every decade. Current waste handling systems are incredibly safe.
So should nuclear power be more widely generated? My personal view is that we should not permit superstition and misleading political ideas to direct our decisions. Deciding to build nuclear power plants is something that should be based on the empirical, objective, and credible data. We need to look at advantages and disadvantages, and make an intelligent and balanced decision.
Pros and Cons
Advantages of nuclear power include:
- It does not generate greenhouse gases - major environmental benefit.
- Fuel supply is long term. If we include fuels under development, like thorium, there is enough to provide humanity with abundant energy for thousands of years.
- Electricity generation is steady and reliable. There is nothing intermittent such as we see with solar and wind power. Power-without-hiccups. No need to spend money on energy storage.
- The day to day operating costs are low. Fuel is used in such small amounts that it is exceedingly cheap.
- High energy density. A plant that covers a tiny area can generate many megawatts of electricity.
- It is safe, relative to any other generating method.
- There are serious future prospects. New compact systems under development would permit unlimited energy in places such as other planets (Mars, here we come), and to replace dirty fuel such as in commercial shipping.
On the other hand, it has its disadvantages.
- By far the biggest problem is political. So much false and misleading information has been promulgated by those with little regard for truth that the general population will oppose anything nuclear.
- Capital cost. This is the biggest practical problem, exacerbated by the politics. With all the legal requirements, it simply costs a very large sum of money to build a nuclear plant. Capital costs are by far the biggest costs involved in nuclear power.
- Decommissioning cost. At the end of its life, a nuclear power plant must by law be fully decommissioned. This is about 10% of the cost of original construction.
- Nuclear waste. Again, more a political problem than a real one, but great care, and a lot of money goes into handling high level waste.
- Nuclear accidents. Once more, it is mainly a matter of perception since nuclear accidents kill fewer people than hydroelectric power accidents, for example.
- Security. Evil, like rust, never sleeps. Nuclear fuels will always tempt those who are out to harm society, and money must be spent to maintain high levels of security.
The overall cost of nuclear power, per kilowatt hour generated, is traditionally similar to its competitors. It is now more expensive than solar power, but that comparison is reversed if the solar power has to be stored for night time use. Solar and wind power technologies are improving, but so is nuclear. There are some very interesting new approaches coming.
It looks very like the future of nuclear power lies with small modular reactors, and there are several concepts under development. My favourite is the travelling wave reactor.
https://en.m.wikipedia.org/wiki/Travelling_wave_reactor
This system has the great advantage of being able to use different fuels, such as depleted uranium (the USA has about 700,000 tonnes in storage. Wouldn't they just love to be able to sell that stuff !), or even thorium, which is incredibly abundant. If all the bugs can be ironed out, there is fuel enough for millennia. The system is very efficient, burning enough fuel to reduce the nuclear waste by 80%. It is a non-pressurised method, meaning no risk of steam explosions. Safe, compact, cheap and available by 2022 according to the researchers.
What does this mean for New Zealand? Possibly not much. But the country has a real need for a major source of electricity close to Auckland, especially with electric vehicles looking like taking over. Perhaps we should forget that silly nuclear free policy and take another look, especially with the new nuclear technologies. However the decision is made, let's not be swayed by fallacies and misdirection. Let's look at the data.