Fukushima – Cabot Institute for the Environment blog

Evacuating a nuclear disaster area is (usually) a waste of time and money, says study

Posted on March 21, 2018April 5, 2023 by janet.crompton

Asahi Shimmbun/EPA

More than 110,000 people were moved from their homes following the Fukushima nuclear disaster in Japan in March 2011. Another 50,000 left of their own will, and 85,000 had still not returned four-and-a-half years later.

While this might seem like an obvious way of keeping people safe, my colleagues and I have just completed research that shows this kind of mass evacuation is unnecessary, and can even do more harm than good. We calculated that the Fukushima evacuation extended the population’s average life expectancy by less than three months.

To do this, we had to estimate how such a nuclear meltdown could affect the average remaining life expectancy of a population from the date of the event. The radiation would cause some people to get cancer and so die younger than they otherwise would have (other health effects are very unlikely because the radiation exposure is so limited). This brings down the average life expectancy of the whole group.

But the average radiation cancer victim will still live into their 60s or 70s. The loss of life expectancy from a radiation cancer will always be less than from an immediately fatal accident such as a train or car crash. These victims have their lives cut short by an average of 40 years, double the 20 years that the average sufferer of cancer caused by radiation exposure. So if you could choose your way of dying from the two, radiation exposure and cancer would on average leave you with a much longer lifespan.

How do you know if evacuation is worthwhile?

To work out how much a specific nuclear accident will affect life expectancy, we can use something called the CLEARE (Change of life expectancy from averting a radiation exposure) Programme). This tells us how much a specific dose of radiation will shorten your remaining lifespan by on average.

Yet knowing how a nuclear meltdown will affect average life expectancy isn’t enough to work out whether it is worth evacuating people. You also need to measure it against the costs of the evacuation. To do this, we have developed a method known as the judgement or J-value. This can effectively tell us how much quality of life people are willing to sacrifice to increase their remaining life expectancy, and at what point they are no longer willing to pay.

You can work out the J-value for a specific country using a measure of the average amount of money people in that country have (GDP per head) and a measure of how averse to risk they are, based on data about their work-life balance. When you put this data through the J-value model, you can effectively find the maximum amount people will on average be willing to pay for longer life expectancy.

After applying the J-value to the Fukushima scenario, we found that the amount of life expectancy preserved by moving people away was too low to justify it. If no one had been evacuated, the local population’s average life expectancy would have fallen by less than three months. The J-value data tells us that three months isn’t enough of a gain for people to be willing to sacrifice the quality of life lost through paying their share of the cost of an evacuation, which can run into billions of dollars (although the bill would actually be settled by the power company or government).

Japanese evacuation centre. Dai Kurokawa/EPA

The three month average loss suggests the number of people who will actually die from radiation-induced cancer is very small. Compare it to the average of 20 years lost when you look at all radiation cancer sufferers. In another comparison, the average inhabitant of London loses 4.5 months of life expectancy because of the city’s air pollution. Yet no one has suggested evacuating that city.
We also used the J-value to examine the decisions made after the world’s worst nuclear accident, which occurred 25 years before Fukushima at the Chernobyl nuclear power plant in Ukraine. In that case, 116,000 people were moved out in 1986, never to return, and a further 220,000 followed in 1990.

By calculating the J-value using data on people in Ukraine and Belarus in the late 1980s and early 1990s, we can work out the minimum amount of life expectancy people would have been willing to evacuate for. In this instance, people should only have been moved if their lifetime radiation exposure would have reduced their life expectancy by nine months or more.

This applied to just 31,000 people. If we took a more cautious approach and said that if one in 20 of a town’s inhabitants lost this much life expectancy, then the whole settlement should be moved, it would still only mean the evacuation of 72,500 people. The 220,000 people in the second relocation lost at most three months’ life expectancy and so none of them should have been moved. In total, only between 10% and 20% of the number relocated needed to move away.

To support our research, colleagues at the University of Manchester analysed hundreds of possible large nuclear reactor accidents across the world. They found relocation was not a sensible policy in any of the expected case scenarios they examined.

More harm than good

Some might argue that people have the right to be evacuated if their life expectancy is threatened at all. But overspending on extremely expensive evacuation can actually harm the people it is supposed to help. For example, the World Heath Organisation has documented the psychological damage done to the Chernobyl evacuees, including their conviction that they are doomed to die young.

From their perspective, this belief is entirely logical. Nuclear refugees can’t be expected to understand exactly how radiation works, but they know when huge amounts of money are being spent. These payments can come to be seen as compensation, suggesting the radiation must have left them in an awful state of health. Their governments have never lavished such amounts of money on them before, so they believe their situation must be dire.

But the reality is that, in most cases, the risk from radiation exposure if they stay in their homes is minimal. It is important that the precedents of Chernobyl and Fukushima do not establish mass relocation as the prime policy choice in the future, because this will benefit nobody.

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This blog has been written by Cabot Institute member Philip Thomas, Professor of Risk Management, University of Bristol.

Professor Philip Thomas

This article was originally published on The Conversation. Read the original article.

Is nuclear green?

Posted on September 30, 2015April 13, 2023 by janet.crompton

It may not be surprising to you that printing the question “Is nuclear green?” on two large banners at the Bristol Harbour Festival in July caused a bit of a stir, but this is exactly what Dr Tom Scott (reader in Nuclear Materials and member of the Cabot Institute at the University of Bristol) and his group of volunteers wanted to do. I joined the group at their stall next to the MShed to listen to their conversations with the public ignited by this thought provoking question.

The volunteers largely comprised of Bristol members of the South West Nuclear Hub (a joint research partnership – which Dr Scott co-directs – with Oxford University), University of Bristol physics undergraduates and some employees of Magnox Ltd a nuclear company in the South West. Together, they rolled out a wide range of activities at their marquee that invited everyone to join in and voice their opinions without judgement.

A live opinion poll with green and red plastic tokens (to vote “yes” and “no” respectively) was placed amongst the crowds along the harbour side to encourage participation and, in general, people were happy to vote publicly. We asked people to explain why they thought that way as they voted: “The sooner that they build Hinkley C the better!” one man announced as he dropped in his green token. (Hinkley C is the name of the new nuclear power station scheduled to be built at Hinkley Point in Somerset.) A red token voter proclaimed “We should go back to coal!” as he dropped his token in. Some members of the public even pretended to scoop up large numbers of tokens to demonstrate the intensity of their view.

Yes/No board to take note of people’s thoughts and feelings about nuclear energy.

The juxtaposition of the words “nuclear” and “green” in the question “Is Nuclear Green?” suggests that there is no straight-forward answer, but yet intense opinions on the matter persist. Nuclear energy, in general, suffers from a negative public opinion and there are three key reasons for this:

the perceived risk of the waste product
the potential for disasters like Chernobyl to happen again
the historical link between nuclear energy and nuclear weapons.

Dr Scott and his volunteers set about to change public opinion on nuclear energy by presenting the facts on their activities in a neutral light, such that the public would feel free to make up their own minds.

One of the activities at the stall, popular with children, had a Scalextric set (a slot car racing set) connected to a pedal generator – demonstrating how much human power was required to drive the toy cars. Further inside the marquee, you’d see a bucket of coal, 16kg of which is required to meet the electrical demands of one person per day. Many were impressed when they were then presented with a dummy pellet of nuclear waste the size of the end of their thumb that would produce enough energy for their entire lifetime.

This dummy pellet of nuclear waste shows how much nuclear material
would be needed to produce enough energy for your entire lifetime.

Meeting the energy demands of today is a pressing global issue and nuclear power provides a virtually carbon-free way of producing a large quantity of electrical power. Festival-goers were also surprised to learn that due to the large amounts of cement used to install solar and offshore wind power stations, the amount of carbon dioxide released is greater per unit of energy produced than nuclear over the lifetime of the power station.

However, people are generally fearful of the toxicity of waste that nuclear power reactors produce and how it is dealt with. By mimicking Bruce Forsyth’s TV show, Play Your Cards Right, people could learn about the relative radioactivity from different sources. For example, if you went on three transatlantic flights in a year, you would exceed the average annual occupational exposure of a nuclear power station worker.

What gives off the most radioactivity?

“But what if it all goes wrong?” said one lady from Bristol. This fear is understandable given disasters such as Chernobyl, Three Mile Island and Fukushima and it has resulted in publicly driven change. In Germany, for example, large anti-nuclear protests occurred in the wake of the Fukushima nuclear disaster in March 2011 caused by a tsunami. Partly in response to these protests, the German government have scheduled all nuclear power stations in Germany to be shut down by 2022.

It would be foolish to suggest that the effects of the Fukushima disaster are innocuous and that nothing went wrong. However, it surprised people to learn that despite the large number of fatalities caused by the tsunami directly, there were no recorded fatalities due to short term overexposure of radiation at Fukushima. Of course, the long term effects are unknown and it would be surprising if there were not any future health risks from the disaster.

Many older members of the public were concerned about the connection between nuclear power and nuclear weapons. It is a fact that the idea of using nuclear energy to generate electricity was borne out of the nuclear arms race that started during the Second World War. Nowadays though, the link between nuclear weapons and nuclear energy is unfounded in the UK because the plutonium required to make the weapons is not extracted from nuclear waste reprocessing.

The University of Bristol nuclear research group talking to
the public about nuclear energy at the Bristol Harbour Festival.

The physics of nuclear fission is very well understood by the scientists and engineers working in nuclear energy, and the risks of using this process to generate electricity are met with very strict safety standards. Despite these rigorous safety measures, nuclear power gets a bad press because the evidence for its potential to harm is clearly visible: the waste has to be specially treated before it is buried and the mass evacuations are put into place following a disaster. Nuclear power station disasters are etched into people’s memories because of their scale but the actual risk posed by a nuclear incident is much lower than maintained by the public.

On the other hand, large quantities of greenhouse gases are continuing to be released into the atmosphere from burning fossil fuels and although there is also visible evidence for climate change, the serious threat it poses to our planet it is diluted by politics. This plight is encapsulated by the most solemn of quotes from the event;

“I suppose the truth of it is, that the thing that isn’t green is humanity.”

Perhaps nuclear fission could be a necessary interim energy source before cleaner nuclear fusion takes over in 50-100 years time.
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This blog is written by Cabot Institute member and PhD student Lewis Roberts.

Read more about nuclear research at the University of Bristol by visiting the Interface Analysis Centre website.

Could Bristol drones help with Fukushima clean-up?

Posted on December 19, 2013April 19, 2023 by janet.crompton

Channel 4 News tests a special drone developed by Cabot Institute scientists at the University of Bristol which could potentially help in the Fukushima clean up.

Read the full story.

Learning lessons from Fukushima

Posted on February 2, 2012April 20, 2023 by janet.crompton

When disasters happen scientists pretty much have a duty to try to understand what happened and why, and to try to learn the lessons. This week the catastophist Gordon Woo of Risk Management Solutions gave a seminar here at the Cabot Institute and suggested that the question that we should really ask is not “why did this happen?” but “why did this not happen before?”. This is also one of the ideas that emerged from a recent exercise that we undertook to try to understand the recent events at the Fukushima nuclear power plant in Japan. The range of skills available within Cabot allowed us to take a fundamentally holistic approach to the analysis that wouldn’t have been possible for any single individual. The results of the analysis are here, but two main points emerge.

First, there is the need to tackle is “chained” or “cascaded” hazards, which, as very low probability events, have traditionally been treated as independent random events and hence have too low a likelihood of coinciding together. There may be hidden dependencies, which are not always either obvious or intuitive, requiring careful analysis to tease out or recognise. This is particularly the case for complex infrastructure like nuclear power stations.

Second, it is no longer adequate to rely on deterministic assessments of hazards and risks from natural hazards as these cannot account properly for uncertainty. Dealing with uncertainty requires a probabilistic analysis that looks at the full range of possible situations that may arise, not just a single one that a company or regulator has (perhaps somewhat arbitrarily) decided is the ‘worst case’. Probabilistic approaches should now be regarded as mandatory, and application of rigorous, structured approaches to assessing risk are needed. Such assessments must include evaluation of all credible alternative models for natural processes, rather than just adopting particular models that happen to support inherited views.