Radiation
Radiation is ubiquitous. We are all constantly exposed to varying levels of ionizing radiation. It comes from natural radon gas (from decaying natural uranium in the ground), cosmic radiation (from the interaction between photons & alpha particles from outer space and the Earth’s atmosphere) and even the food & drink (bananas, brazil nuts, red meat, carrots and some bottled spring water). For cosmic radiation, exposure increases with altitude. So that air crews are officially designated as ‘radiation workers.’ Every transatlantic flight will on average expose each passenger to a radiation dose equivalent to 5 chest X-Rays. Other significant sources of radiation exposure include medical radiation (from X-Rays, CT scans and nuclear imaging). Even some building materials used in the UK give off radiation.
Furthermore, radiation is complicated and often – for the general public – counterintuitive. For example, the isotope ‘Iodine 131’, which accounted for approximately 45% of the radioactivity dispersed by the accident at Chernobyl, can cause cancer of the thyroid. Yet that thyroid cancer can easily be avoided by taking Potassium Iodide tablets, just like you would pop a couple of paracetamols. That’s because of the way the chemistry inside the thyroid gland works. Unfortunately, the Soviet authorities were obsessed with secrecy. So they did not distribute the tablets. Nor did they warn the local people of the risk. Consequently, thyroid cancer cases rose uncontrollably, primarily in children who drank cow’s milk contaminated by fallout from the stricken reactor. These medical cases are presented by anti-nuclear campaigners as evidence of the dangers of radiation, when in fact they are evidence of the dangers of a paranoid dictatorship. However, cancer of the thyroid is easily treated. Counter-intuitively it is often treated with … Iodine 131(!) which kills any remaining cancer cells. Iodine 131 – whilst highly radioactive – has a half-life of only 8 days, which means for instance that a piece of cheese that was radioactive after exposure to Iodine 131 will not be radioactive and (mould aside) would be completely edible – without harm – only 3 months later.
Radiation though can best be described as energy on the move (https://www.abebooks.co.uk/Radiation-Reason-Impact-Science-Culture-Fear/22511507048/bd). Radiation arising from radioactivity is the result of changes in the structure of the atomic nucleus. There are several different types of radioactivity: alpha and beta particles, gamma waves and neutron particles; corresponding respectively to streams of helium ions, electrons, electromagnetic radiation (similar to X-rays) and uncharged particles.
Gamma radiation forms part of the electromagnetic wave spectrum which covers the range long wave radio waves to very shortwave X-rays and gamma waves. The visible spectrum forms a very narrow band as part of this with moderate energy levels. The shorter the wave length the more energy contained in a quantum of energy (photon) and hence potentially the more damage resulting from exposure. The spectrum can be roughly divided into two parts separated by about 10 electron volts (eV). Radiation with energies greater than 10eV is called ionising radiation, that below non-ionising. Ionising radiation has the ability to ionise molecules and break them apart and is the region of the spectrum which contains radioactivity – ie at the more energetic end of UV light. Non-ionising radiation, eg from overhead power lines or mobile phones, can only cause damage by heating and if heating is not experienced this type of radiation is safe.
The key question is how much ionising radiation can the human body tolerate before damage occurs? Initially, in the 1940s and 1950s, the working hypothesis was that radiation might cause damage at all doses, ie a linear no threshold model (LNT) was used in discussions of effects of radiation. However, as knowledge about radiation damage to biological tissues has increased, it is now increasingly accepted that there is a threshold below which no radiation damage to biological tissue occurs. The basis of this statement has come from extensive studies carried out since 1950 on the following groups of people who have been exposed to radiation:
a) Survivors of the bombing of Hiroshima and Nagasaki;
b) Effects of radiation following the Chernobyl accident;
c) Incidence of lung cancer and its correlation to the levels of radioactivity in the area people live in;
d) The health records of people who have worked with radiation for several decades, including medical radiologists;
e) People who worked with luminous paint in the decades up to 1950; and
f) People who have radiation in the course of medical diagnostic imaging, or in radiotherapy treatment.
Some of these examples will be considered in more detail below.
In order to assess the effect of radiation, not only does the amount a body received need to be measured but also a factor allowing for the sensitivity of the region of the body has to be determined. Another factor is the ability of the radiation to penetrate into the internal tissues. Gamma radiation is the most penetrating with beta-radiation less penetrating. The least penetrating radiation is alpha, the radiation from which does not penetrate the unbroken skin and can be stopped by paper. However, if alpha particles do enter the body, through a cut, injection or inhaled into the lungs they are very damaging to tissue, as they are relatively large ionised particles.
The unit used to measure the dose of radiation received by a body is the sievert. The definition of a sievert takes into account not only the amount of radiation received per gram of tissue but also the effect of the type of radiation on the tissue. X-rays, gamma rays and beta rays have a weighting factor of 1 and alpha-particles 20.
The average dose rate of radiation experienced by the UK population is 2.7 milli-sieverts (mSv) per year. Approximately 50% of this is due to radon and gamma radiation emitted by natural radioactive sources contained in water, soil and rock. Cosmic radiation accounts for 12% of background radiation and medical treatments 15%. In contrast, the radioactivity received from occupation (ie workers in the nuclear industry and from fallout) is trivial amounting to 0.5% of the total average dose. Public Health England (PHE) stated in 2011 that a person was subjected to 0.08mSv radiation during a transatlantic flight whereas a nuclear power station worker received 0.18 mSv/ year. Thus, passengers flying from London to New York will receive more radiation after 2-3 trips than staff working in nuclear stations receive in a year.
Survivors of Hiroshima and Nagasaki
At the time of the bombing the population of the cities was 429,000. It has been estimated that in the explosion, the fire and early effects of radiation more than 103,000 died. Since 1950 the effects of radiation on the survivors have been extensively studied.
An important question is how many inhabitants of these Japanese cities in 1945 succumbed to radiation-induced cancer in the period 1950-2000? The overall conclusion is that the chance of surviving to 1950 and then dying from cancer (not caused by radiation) between 1950 and 2000 was 7.9%. In comparison, the chance of surviving and then dying of radiation-induced cancer during this period was only 0.4%.
Hiroshima by Rap Dela Rea.
Most importantly, for our understanding of the effects of low to medium levels of radiation on cancers, it was found that doses of radiation below 100 milli-sieverts did not increase the number of cases of leukaemia significantly. Survivors who received doses of radiation above 200 milli-sieverts, sadly did have an increased chance of developing leukaemia. The control group in this study was a group of 25,580 people who lived in Japan outside the bombed cities and had received no significant radiation.
What were the health consequences of Chernobyl
The 1986 Chernobyl accident is the only commercial reactor accident to have killed anyone.
This is not to belittle the significance of the accident but to put it in the context of the thousands of deaths caused by accidents in the fossil fuel industries over the past 50 years.
Two people died immediately in the accident from the explosion and a third from a heart attack. 237 first-responders were hospitalised and 134 of them were diagnosed with acute radiation syndrome. Five firefighters died the first night and an additional 23 died within a month from acute radiation syndrome. By 2004 an additional 19 people in the group exposed to the highest levels of radiation had died, possibly as a result of their exposure to radioactivity after Chernobyl. Thus, as a result of the accident at Chernobyl, a total of 28 people died from acute radiation effects, one from a heart attack and 19 from uncertain causes.
Many studies have been carried out on the long-term health consequences on the people exposed to radiation from the Chernobyl accident. Because there was so little public health information available for the exposed population before 1986 it is difficult to make accurate assessments. The International Atomic Energy Agency (IAEA) established a Chernobyl Forum in 2003 to study the environmental and health consequences of the accident. The most definitive report on the accident was published in 2006. The Chernobyl Forum included experts from the IAEA, WHO and United Nations Scientific Committee on Atomic Effects of Radiation (UNSCEAR) as well as representatives from Belarus, Ukraine and the Russian Federation. A full report was published by the Chernobyl Forum in 2006 which predicted that eventually 4,000 people may die from cancer relating to the Chernobyl accident.
Chernobyl, Kiev Oblast by Viktor Hesse
Two other reports, one from Greenpeace claiming that there were up to 200,000 deaths from Chernobyl by 2004, and the second by TORCH, commissioned by the Greens/European Free Alliance Party in Europe, estimate that 30,000 to 60,000 cancer deaths will result from Chernobyl. Clearly there is a large disagreement between the official scientific report and the ones commissioned by environmentalists – so who is right?
One way to estimate the likely cancer deaths from Chernobyl is to compare the radiation levels different groups of people experienced with natural levels of radiation experienced in the region and then compare the cancer levels for each background radiation group with the estimates for The Chernobyl Forum and the environmental groups. This is similar to the analyses carried out on the effect of radiation on cancer levels following Hiroshima and Nagasaki.
There were four groups of people who were exposed to significant doses of radiation from Chernobyl.
a) 240,000 people involved in the clean-up operation (the liquidators). The average level of radiation for this group was 100mSv.
b) A group of 116,000 people evacuated in 1986 from the highly contaminated 30 km exclusion zone. This group had an average dose of 33mSv.
c) A group of 220,000 evacuated from a larger area during 1986-2005 with a cumulative dose of over 50mSv over those years.
d) 5 million people living in the larger zone that received fall-out from the accident and received doses of 10-20mSv during 1986-2005.
Doses for anyone else in Europe were negligibly small. In contrast, the TORCH report does not accept that doses for the rest of Europe were negligible and so have included estimates for the effects of radiation on all the contaminated areas in Europe. All reports, however, stress that there will be considerable uncertainty in the figures quoted.
To help set the scene, the annual background radiation varies in different parts of the world.
In the UK it is 2.7 mSv. Thus over 20 years on average UK citizens receive a cumulative dose of 54 mSv. Most of this comes from radon, a gas emitted by mineral sources such as water, soil and rock. Radon emission is higher in parts of Devon and Cornwall than in the rest of the UK. There is no evidence to suggest that lung cancer is significantly higher in these counties than the rest of the UK. (Lung cancer is the relevant cancer as radon, an alpha emitter (half-life (t1/2) = 3.8 days), is inhaled into the lung.)
The background dose of radiation in Kiev is just under 1 mSv a year or a cumulative dose of 20 mSv over 20 years. Other important figures are that a single dose of 5,500 mSv results in 50% mortality and that cancer risks are detectable above 100 mSv, but radiation doses below 100 mSv are essentially risk free. It would thus appear that only the 240,000 members of group (a) the Liquidators (the group of people sent in immediately after the accident to start clearing up the damage), may have some increased risk of developing cancer as a result of exposure to radiation following Chernobyl. Based on the number of deaths following Hiroshima and Nagasaki an extra cancer risk per 1000 following exposure to radiation has been calculated at 0.9-1.3 %. The International Commission for Radiological Protection calculate the chance of cancer related death as 5% per man-sievert (collective dose in a group of people over a period of time). The exposure of the population to radiation following Chernobyl has been estimated as 150,000 man-sieverts. Thus, based on a 5% chance of cancer related deaths, this would suggest a figure of 7,500 cancer related deaths. However, if the low doses are excluded, which would be the correct adjustment based on current data, then a cancer related death of about 4,000 additional deaths above the expected number if Chernobyl had not happened would be expected.
We have gone into some detail on cancer related deaths from Chernobyl to try and give a feel for the approximate nature of the numbers and also to make the point that all the evidence so far is that the numbers of deaths suggested by the environmental groups are on the high side. A more detailed account of the effects of radiation on the population of Hiroshima, Nagasaki and Chernobyl, quoting sources, can be in Chapter 6 of this book.
There is one important exception to the above statement. Iodine-131 was released as a result of the Chernobyl accident. This readily enters the food chain via milk produced by cows eating iodine-131 contaminated grass and hence accumulates in the thyroid gland of children. Between 1986 and 2002 4,837 children and adolescents in the neighbouring countries to Chernobyl were diagnosed with thyroid cancer. This is about ten times the incident rate expected if Chernobyl had not occurred. This is particularly disgraceful as, if the Russian/Ukrainian authorities had acted quickly to give potassium iodide to the children in the affected area for several weeks this would have diluted the radioactive iodine and greatly reduced the chances of developing thyroid cancer. Only a few weeks are necessary as the t1/2 (half-life) of iodine is eight days. In the event, most of the sufferers have received therapy successfully but there have been 15 deaths up to 2002 (IAEA (2006) Chernobyl’s Legacy).
A final comment on the after effects of Chernobyl. In spite of the relatively high levels of contamination in the town of Pripyat adjacent to the Chernobyl reactor, a visit in September 2012 found that the environmental impact was minimal. In fact, the overall conclusion was that the environment can survive radioactivity much more easily than it can survive human habitation.
Studies over the years have shown that biological cells have sophisticated mechanisms to repair cells and damage to DNA caused by low doses of radiation (up to 100 mSv). Thus, a safety level of 100 mSv per month for chronic doses of radiation is recommended. There is now good evidence that biological tissue, including human tissue, is able to withstand low levels of radiation.
Comparative safety
A comparison of deaths per Terawatt/hr for various sources of energy shows that nuclear power compares very well with wind and solar as one of the least dangerous ways to produce energy. The following values, for low carbon energy sources, are reported as deaths per terawatt-hour.
This conclusion is supported by two other studies: one by The Paul Scherrer Institute and the other by the EU project called ExternE. In both studies, Nuclear had fewer deaths per GWy (Giga Watt year) than wind. Both energy sources had death rates of below 0.2 per GWy which is considerably better than biomass at about 1.5 deaths per GWy. Another study quotes figures (per thousand Terawatt hour) as 1,400; 440; 150 and 90 for hydro: roof top solar: wind and nuclear respectively.
Waste disposal
One aspect of nuclear power which follows from it being a very concentrated energy source is that the volume of waste is very small and can be up to a million times smaller than the volume of waste generated by an equivalent fossil-fuel power station.
The average UK person consumes about 16kg of fossil fuel per day which generates 11 tons/year of CO2 (30kg/day) – the same weight as 53 pints of milk. In contrast, the same amount of energy is provided only 2 grams of uranium and the resulting waste weighs 0.25 gram. In other words, the waste from the UK’s 10 nuclear reactors is equivalent to 840 ml per person per year (the volume of a bottle of wine). Of this 760 ml is low level waste, intermediate waste is 60 ml and high-level waste (ie with long half-lives) occupies only 25ml. These figures put the problem of dealing with high level waste into perspective. The problem of storing relatively small amounts of high-level waste for 1000s of years is technically achievable.
It has been calculated that at 25ml per year, the high-level nuclear waste component of nuclear waste for 60 million people during their life time, would occupy the same volume as 35 Olympic swimming pools. If this waste were buried in a layer one meter deep it would occupy one-tenth of a square kilometre.
It is important to stress that there is no immediately pressing problem regarding the storage of nuclear waste.
Currently, waste is managed at nuclear power stations by storage in cooling tanks for a few years to allow much of the heat and radiation to decay. The next step is to move the waste to dry storage in casks either on site or in regulated storage sites. It is widely agreed by industry experts, by the Nuclear Regulatory Authorities, by scientists and The US National Academy of Sciences that this is a safe way to store nuclear waste and can be carried out for the next century if needed.
An important question is whether to recycle or simply permanently store the waste in dry casks underground. France, England and Japan have all shown that it is both economical and safe to recycle ‘waste’ from nuclear power stations.
More generally, radioactive materials are currently managed and have been managed since the early 1940s, with one of the four following strategies: 1, reprocess and reuse; 2, concentrate and contain; 3, dilute and disperse; and 4, delay and decay. Spent fuel elements and their support cladding from reactors are the most radioactive types of waste. Disposal is handled with strategies 4, 1 and 2 in succession.
Waste converted into weapons
Concern is sometimes expressed that if terrorists or rogue states could get hold of nuclear waste they could use this to manufacture weapons. This concern is extremely unlikely for the following reasons.
Firstly, nuclear waste is well protected not only by secure locations but also by the fact it is radioactive. This makes it extremely difficult to steal.
Secondly, and most importantly, the concentration of uranium and/or plutonium isotopes in waste from nuclear power stations which are suitable for nuclear weapons is extremely low. No-one now uses plutonium formed as a waste product from civil nuclear power stations to make nuclear weapons. Thus, the concentration of uranium-235 in nuclear waste is about 1% whereas the concentration of uranium-235 required to make a nuclear weapon is 80%. In contrast, the main aim of early nuclear power reactors, developed during the cold war period, was to run them so as to maximise plutonium-239 production. Relatively little electricity was generated as this was a secondary consideration. Commercial nuclear reactors today aim to run for several years to maximise electricity production from each batch of fuel. The outcome is that nuclear waste from commercial nuclear reactors, even if stolen by terrorists, would be most unsuitable as a source of weapon grade plutonium.
This is because in a nuclear power station plutonium-239 is generated early in the fuel-processing cycle. As the fuel cycle continues an increasing proportion of plutonium-239 is converted into plutonium-240, which is not suitable for making nuclear weapons. Thus, in a fuel cycle lasting 2-3 years the concentration of plutonium-239 in the nuclear waste is too low to act as a source of weapon grade plutonium.
The reasons for this confident statement need some description of atomic structure and nuclear physics which are set out elsewhere on this site. More detailed descriptions can be found here.
Unfortunately, the perception in the general public is coloured by the experiences of the early nuclear power reactors whose main function was the development of weapon grade plutonium-239 rather than domestic electricity.
Thirdly, an additional safeguard is that when nuclear power was first developed as a useful source of electricity production, the international community established the International Atomic Energy Agency (IAEA) as an independent arm of the United Nations. This had the mandate of inspecting nuclear power programmes around the world and making sure the civil nuclear power programme was not being used to make fuel for nuclear weapons as a side aim.
The IAEA has been very effective. Its inspectors have the power to make intrusive inspections, to leave cameras in place to monitor the workings of civil nuclear power stations, to place seals on containers so that they cannot be secretly opened and to interview scientists to check that no secret manufacture of weapon grade fuel is occurring.
It is very hard to keep nuclear secrets in today’s world. When Iran enriched uranium the world found out. When North Korea made a deal to shut down its plutonium production but kept running a secret uranium enrichment programme, the world found out.
The point is that if rogue states try to subvert their civil nuclear programmes to generate weapon grade fuel the world finds out. There may be a problem persuading rogue states not to pursue nuclear arms production but this is not altered by whether or not the rest of the world is developing civil nuclear programmes. Incidentally, both Israel and N Korea have nuclear weapons but neither country has civil nuclear power.
Nuclear power station accidents
More details on the following three accidents can be obtained from Chapter 10 of this book and this book.
Three Mile Island (TMI)
28 March 1979
This was a pressurised water reactor (PWR). At 4.00am TMI-2 was being monitored during normal operations when a pump in the secondary cooling system failed causing the system to start shutting down. If operators had not reacted to the warning lights and sirens, the system would have continued to shut down.
However, due to confusion (partly due to poor design) a series of operator errors were made that led to partial core melt down. In particular, the operators turned off the emergency cooling water as they thought there was a danger of flooding. In fact, as a valve had stuck open, contaminated water was being vented into the primary containment building. It was only when relief staff arrived at 6.00 am that the valve was turned off and the cooling water was turned back on. The situation was brought under control by the end of the day.
However, on the morning of March 30th 13M curies of noble gasses (mostly isotopes of xenon and traces of Iodine-131 (17 curies) were released into the atmosphere. The gasses quickly dispersed but women and children within a 5-mile radius were asked to leave the area as a precaution.
An additional concern was that hydrogen gas accumulated. However, as there was no oxygen in the chamber it did not burn or explode.
In spite of operator mistakes, faulty valves and signals the design of the containment building was sufficiently robust to contain the core melt down and there was no surface contamination of the area.
TMI-2 was subsequently destroyed, the site cleaned and mothballed. TMI-1 continues to operate and is licensed to operate until 2034.
Although there were no casualties from the TMI incident, the consequences for development of nuclear power were profound.
According to an expert group, the Ad Hoc Population Assessment Group, only 1 cancer death and 1-2 hereditary mutations are likely as a result of TMI-2. About 450,000 people would be expected to die from cancer (not caused by radiation) in the 2 million population living within a 50-mile radius of TMI. The average dose to the 2 million people in the 50-mile radius was about 0.01mSv and the maximum dose to a person at the boundary of TMI-2 was about 1mSv, N.B. The average dose of radiation for a person flying from London to New York is about 0.08 mSv (PHE) and the average annual dose of radiation from natural radiation in Pennsylvania is about 1 – 1.25 mSv.
Studies carried out by the Nuclear Regulatory Commission (NRC), The Department of the Environment (DOE), the EPA and Pennsylvania Health Department and independent researchers found that there were no effects on pregnancy outcome, spontaneous abortion, foetal and infant mortalities or cancer.
As a result of TMI-2 major changes were made by the NRC to the regulations and design of nuclear plants and how they are managed and training of operators. There have been no nuclear accidents in the US since TMI-2, and TMI-1 continues to operate safely to the present day.
Nonetheless, anti-nuclear protesters succeeded in blocking the development of nuclear power in the US such that, of the 129 nuclear power plants scheduled, only 53 were completed. The sad fact for climate change is that the nuclear reactors which were not built were replaced by fossil fuel power stations, mostly coal fired with millions of tonnes of CO2 being pumped into the atmosphere. Since TMI-1 the US has had 3,600 reactor-years of experience with commercial nuclear reactors with no accidents or loss of life. Thus, the risks from nuclear power are extremely small compared with the enhanced risks from global warming resulting from replacing nuclear power with fossil fuel. Nuclear power has the best safety record for all major power production in the US.
Chernobyl
This is the worst nuclear reactor disaster and occurred on April 26, 1986. The reasons this occurred have been studied and reported on internationally; see here and here.
Poorly trained workers began an unauthorised test while carrying out a scheduled shutdown on unit 4. They wanted to see how long the slowing turbine could provide power after the reactor was shut down. They decided to shut off the emergency core-cooling system since it would draw power. This was the first of several major safety violations which eventually led to the reactor becoming unstable and power surging to 100 times the operating capacity of the reactor. This caused the uranium fuel to disintegrate resulting in a huge explosion which blew the 1,000-ton lid of the reactor aside. A second explosion blew through the reactor walls resulting in a plume of radioactive debris rising 10 km into the atmosphere. In addition to these operator violations, the design of the Generation 2 reactor was at fault. This was a Soviet type RBMK, unique to the world. It was also designed, as were several other Generation 2 reactors, to produce both power and plutonium. A feature of this reactor is that it had a graphite core to slow down neutrons with channels of water to cool the core and produce steam. The RBMK reactors, which are no longer made, were the only ones in the world to have this design. An additional fault was that this reactor had no containment structure that could contain a core meltdown, such as TMI had.
It is reasonable to conclude that the Chernobyl incident was a one off caused by a combination of operator error and poor reactor design.
Generation 3 and 4 nuclear reactors are designed with sufficient safeguards to make another ‘Chernobyl’ incident extremely unlikely.
Fukushima
A huge natural disaster hit Japan on 11th March 2011 as a Force 9 earthquake occurred at sea, 95 miles from the Daiichi nuclear power plant near Fukushima.
There were six reactors at the Fukushima plant. Units 1-3 were operating and immediately shut down and went to emergency cooling with diesel generators after the earthquake caused a loss of electrical power. The units 4-6 were not operating and did not overheat.
The reactors in units 1-3 responded as they were designed to do. The problem was not the earthquake but the subsequent 45-foot wall of water, a tsunami, which overwhelmed the 20-foot wall designed to protect the reactors from the sea. This wall of water overwhelmed the diesel generators so that cooling could not take place. Consequently, the reactors overheated, which eventually caused a hydrogen explosion, partial meltdown and release of radioactivity.
Yet only 7 miles down the coast, the Daini nuclear plant units were running at full power and were able to go into full shut down in spite of their diesel engines being shut down by the tsunami.
Seventy miles north of Daiichi and even closer to the epicentre of the earthquake, three reactors were operating at the Onagawa nuclear power plant. They were protected from the tsunami as the protecting wall was 48 ft high.
Unlike the nuclear power accidents at Three Mile Island and Chernobyl, which were the result of operator error and poor design, the Fukushima accident was the result of a large natural disaster. The entire infrastructure of a large part of northern Japan was destroyed by the earthquake and subsequent tsunami. Nearly 20,000 people died as a result of the earthquake but none from the nuclear accident.
Health and environmental consequences.
In spite of the meltdown of reactor cores in units 1-3, the release of radioactivity was limited because the primary containment vessels were not destroyed.
Radioactive release was limited to three major spikes and the amount of radioactivity released was about 18% of the Iodine-131 released from Chernobyl consisting of I-131 and small amounts of Caesium-137. Unlike Chernobyl, Strontium-90 was not released into the atmosphere possibly because the core temperature did not rise sufficiently to vaporise the isotope.
Both the Chernobyl and Fukushima accidents were rated 7 on the international Nuclear and Radiological Event Scale (INES), a logarithmic scale similar to the Richter scale. However, there were large differences between them. Following Chernobyl there were 28 deaths from radiation exposure, 15 deaths from thyroid cancer, 19 deaths from unknown causes and a life time expectancy of 4,000 additional cancer deaths and wide spread contamination of the environment leading to the evacuation of 336,000 people. In contrast, for Fukushima, although the tsunami killed 20,000 people, there were no deaths from radiation exposure and a prediction of one extra cancer expected in the workers and possibly 20-30 additional cancers in the people in the fallout pathway. There was a fairly widespread area of contamination leading to the temporary evacuation of 100,000 people with the long-term effects predicted to be confined to a small area.
Although Chernobyl and Fukushima were both bad accidents, Chernobyl was worse, not only because it should not have happened as it was due to faulty reactor design and human error, but the consequences to health were much greater than Fukushima.
The Fukushima accident is the only accident due to natural causes in the history of nuclear power generation and was not due to operator error or reaction design fault. The human failure was not to build the protection wall as high as the one at the Onagawa nuclear power plant. In future, cooling reservoirs will be placed on the top of nuclear power plants if they are located near sea level.
Contributors
1. Duncan Roy, Lewes Green Party
2. Peter Vaughan, East Devon Green Party
3. Mark Yelland, Brighton & Hove Green Party
Feature image: A sign hanging on the wall of the first nuclear power plant ever built in Idaho. This plant is now a museum. Dan Myers.