When I knew I would be visiting the site of the Fukushima Daiichi nuclear power plants, I prepared myself to be humbled. I expected to learn that things were worse than I realised. I expected sombre reflections on how we need to manage the great power that is nuclear power.
That isn’t what happened. The accident was a very serious one. But the disaster? The disaster was the response. That disaster continues to this day and as we approach the next round of international climate negotiations, it may cost us all more dearly than we could have ever imagined.
In part 1 of this post I will discuss the experience of visiting Nahara town and hearing from local officials. In part 2 I will cover the visit to deep in the exclusion zone and the Fukushima site itself.
While I travelled with a group, heard information from local officials and discussed many of the concepts raised below with the experts who joined me, these thoughts and conclusions are my own. I am speaking for no one else.
From 17-20 May, 2015, I was privileged to join an international delegation to Japan to participate in a nuclear symposium, meet relevant Japanese organisations and undertake a site visit to the Fukushima Daiichi nuclear power station.
I officially changed my tune about nuclear power in November 2010, but really went public with it at a presentation on 8 March 2011. That was just three days before the great eastern Japan earthquake, tsunami and subsequent triple reactor meltdown. Like many others I remember watching the horrible footage of that black wave rolling inland and following the news that the Fukushima Daiichi reactors were stricken. It was a test of my revised stance to say the very least, and it took effort to prepare my initial article calling for rationality in the response. This happened on our watch, in an OECD nuclear nation. This was just about as bad as nuclear could possibly get.
So I approached the prospect of a site visit with great interest and also professional trepidation. It’s one thing to comment from afar. It’s quite another to visit a location to learn and see for yourself. I prepared myself to be humbled by the experience. I expected my support for nuclear technology to be tempered. Part of me thought that’s what should happen.
It didn’t turn out that way.
The group left Tokyo early by bus to reach Fukushima prefecture by lunchtime, where we were briefed by local officials at Nahara town. Nahara was a town of about 7500 people, sitting at the southernmost coastal boundary of the exclusion zone, approximately 20 km from the Daiichi nuclear power plant. The 10.2 metre tsunami exceeded the local 6.2 metre seawall and inundated 2.5 % of the town area, killing 13 people. As the situation at Fukushima Daiichi worsened and emergency was also declared at the nearer Daiini reactors, Nahara town gave its own evacuation order about 10 hours earlier than the central Japanese government.
The evacuation was undertaken in a situation of limited information and, presumably, considerable haste. The use of private vehicles led to serious traffic jams. About 5000 people were moved from this town to become refugees in nearby Iwaki City and Aizumisato Town, during late-winter conditions that were still very cold. Given the great strain the nation was already under from the quake and tsunami, it is evident that this was a high stakes decision with considerable risks involved.
It is easy to understand why this decision was made: the town officials wanted to protect people from harm. They regard the fact that their decision pre-empted that of the central government as partial vindication that it was the right one; at least they got moving earlier than they would have otherwise been forced. There is another possibility of course: both levels of government were altogether wrong. It’s an unpleasant line of enquiry. I don’t wish to criticise decisions made under great pressure. But criticise we must for how else do we learn? Was this the right decision?
(Lengthy) Aside: Units of radiation. What are they? What matters and what doesn’t?
To understand the following, readers will need to understand a little about doses of radiation.
Different types of radiation, exposed to different parts of the body, provide differing “equivalent doses” i.e. the raw dose adjusted for the relative biological impact. To account for this I am using the unit “Sievert”. This unit takes account of the various factors that determine whether a dose is harmful and weights it for the potential for damage to be caused to the body. So it’s the right comparison unit to talk about health effects from lower levels of radiation received from the environment. In summary, Sievert measures the “dose equivalent”: the raw dose corrected for the biological effect.
For radiotherapy purposes, the unit used is the Gray. This is a more direct, raw unit of the energy received per kilogram of tissue. This is appropriate when much higher doses than are found either in nature or in occupational exposure are being targeted to specific parts of the body for the purposes of treatment. In these situations specialists know exactly how much of exactly what type of radiation is being targeted to exactly which part of the body. It’s typically a very large amount compared to environmental radiation. So I won’t be referring to Grays.
One Sievert all at once is a heck of a big dose. A sievert in a short amount of time will make you sick, 2 Sv will make you very sick, 8 Sv will kill about half of all people and 20 sieverts will kill anyone unless they get serious help, pronto. So mostly, you hear talk of millisieverts (mSv, one one-thousandth of a Sievert) or even microsieverts (µSv, one one-millionth of a Sievert).
When we are in circumstances of using mSv and µSv to consider health risks we will almost always be talking about stochastic risk, not deterministic risk. Stochastic risk refer to an increased likelihood of a future outcome (in this case, the development of cancer) from exposure to a hazard(in this case, radiation). But the outcome (cancer) will be no different in type, or severity, than might occur anyway i.e. there is a background rate of cancer in humans, influenced by a great many factors, varying hugely with location and lifestyle all over the world. Should a cancer occur, there is no way of attributing it to a single hazard factor. Deterministic risks come from much larger exposures causing direct effects very close to the time of exposure, and the size of the effect can be clearly related to the size of exposure e.g. exposure of unprotected skin to UV light will result in sunburn, and more time in the sun will worsen the sunburn in a direct way.
It’s not just the equivalent dose that matters for human health but also the equivalent dose-rate. That’s the time period over which you receive the dose. Consider the difference between a bucket of water being tipped over your head, and the same amount of water being misted onto your head over the course of a week. The impact is very different. Our bodies have multi-layered mechanisms to respond to cell damage from radiation (and other causes) that are in use all the time. Problems can occur if our cellular defence mechanisms are overwhelmed by too much damage in too little time. So for that we need to talk about mSv per hour or µSv per hour.
The largest cohort of evidence relating to human health impacts from low doses of radiation comes from survivors of the atomic bomb explosions in Japan. This evidence suggests that at a dose of 100 mSv, in a short period of time, an increase in cancer risk can begin to be detected. This finding is published by the International Council of Radiological Protection (publication 103) and reinforced in work by Zhang et al. At less than this level, there is no empirical evidence of increased risk of cancer. Any possible effect is lost in the noise in a world where we are bathed in natural levels of radiation, and we have background rates of cancer from a wide range of causes.
Furthermore what we can see is that the age-corrected rates of cancer vary markedly from country to country, and the variation has nothing to do with the differences in low-level radiation. Lifestyle and dietary differences appear to affect baseline cancer outcomes in a measurable way.
Nonetheless, in setting guidelines and regulations, the major radiological protection agencies continue to apply assumptions that exposures below this 100 mSv level result in an increased stochastic risk of cancer, all the way down to near-zero exposure. This model of harm (and it is a model, not a body of evidence) is known as linear, non-threshold (LNT). The United Nations Scientific Committee on the Effect of Atomic Radiation has recently made clear that the LNT model does not have application in determining population-wide impacts of exposure to low-levels of radiation.
So, finally, what are normal rates of exposure? Global average radiation exposure is 2.4 millisieverts per year. However the background rate varies a lot depending on location and occupation. International air crew receive an extra 4 mSv per year. Occupational exposure limits are 20 mSv per year. Doses from nature have been recorded of up to 202 mSv per year in Ramsar, Iran. Despite no epidemiological evidence of harm, some authors still prosecute the case for the protection of people in such areas, well, just because! Fortunately other authors push back against such notions, highlighting the lack of empirical evidence supporting the LNT model. End aside.
During this trip I was lucky enough to have the ear and attached brain of Professor Gerry Thomas of the Imperial College in London, one of the world’s foremost experts on the impacts of radiation on human health. She has long been one of my credible hulks, so I did the sensible thing and asked Gerry. What was the right response? She gave a sensible answer.
In light of the situation at the nuclear plant being out of control, Professor Thomas suggests it is hard to argue against the evacuation in the first instance. From there, Professor Thomas argues that it would be worth maintaining exclusion for the three months required for radioactive iodine to decay to harmless levels, and instituting other known, effective measures to prevent uptake of radioactive iodine.
I contend that, if clearly communicated, three months is a period of time away from home that most people can steel themselves for and manage, with appropriate support and compensation. I also contend that an evacuation in such circumstances can and should be calm and orderly in order to protect people from the direct risks of evacuating. Since the risk being avoided is a stochastic one that requires prolonged exposure for even theoretical increase in risk of harm, running away from it at great speed and in large numbers is just far more dangerous than it’s worth.
During that three month period, some remediation should occur and physical infrastructure needs to be repaired and replaced. Areas identified as being in need of further specific remediation should be cordoned off and dealt with in due course. Citizens should have the opportunity to return to their homes with all appropriate support and information.
This is NOT what happened
The radiation plume from Fukushima Daiichi concentrated to the north-west of the plant, with Nahara Town on the very southern border. This early map of contamination (May 2011) suggests even at the outset, Nahara was in the range of 1-2 microsieverts per hour (8-18 mSv per year). A more localised map provided by the officials in a handout suggests the town was in the range of 5-10 mSv per year by November 2011. These levels may have be higher than prior to the accident, but it is an entirely harmless level of exposure with no evidence of ill effects; in the range of the occupational dose of an international pilot. Furthermore, as shown in the subsequent figure, thanks to the behaviour of radioactive half-lives, this swiftly declines with the passage of time. Recall that there is evidence of some small increase in the background risk of cancer at 100 mSv equivalent dose, received in a short amount of time. A declining dose rate of 5-18 mSv per year would have harmed no-one.
Yet total exclusion was maintained for nearly 18 months to August 2012. At this point, daytime entry was for residents permitted. This year, officials from the town have received permission to stay, and are doing so in a bid to give confidence to other residents. But the radiation exclusion zone has resulted in a failure of timely remediation of the essential infrastructure that would have been damaged by the tsunami. A terrible, self-reinforcing spiral is underway. Failure to be rational in the face of low levels of radiation has led to prolonged absence. This prolonged absence has excused a failure to repair the infrastructure upon which the settlements depend. This in turn reinforces the absence. In absence, decay sets in making return ever-less appealing. Vermin have infested homes and shops. Looting and robbery occurred. With people unwilling to return, there is little pressure to repair the infrastructure, and so on…
Now, the dose rate in the residential areas of Nahara is 0.3 µSv per hour (2.6 mSv per year). That’s bang on globally normal. Yet former residents remain anxious about radiation.
Nahara has been a victim of fear and the perils of over-protection, not radiation. This seems to be a product of the way the nuclear industry itself has regulated itself for decades, and the way nuclear opponents amplify this approach to spread fear.
Nuclear risk management faces as perfect storm of acronyms. Firstly there is LNT, or the linear, no-threshold model of harm for radiation. This model posits that any level of radiation will do some harm, no matter how low the level. There is “no threshold” beneath which radiation is harmless. It is by this logic that some authors seriously consider “protecting” people from the environments they have occupied for centuries despite no epidemiological evidence of harm. It’s nuts, in other words, or at least it’s a nutty basis for decision making.
To LNT we can add “ALARA”, which stands for “as low as reasonably achievable”. This is one of the guiding principles for radiation protection: make exposure as low as you can. Note, at this point evidence-based safety has gone completely out of the window. We are not undertaking protective actions because we know it matters, we are not attempting to meet a regulated limit, we are doing it because LNT says we should.
The kicker in all of this is the nature of radiation itself as a brilliant tracer. We can detect radiation down to incredibly small levels, and we can even tell where it came from. So, if you can see something down to a very fine resolution and the rules say you have to keep lowering wherever “reasonably” possible it even though there is no evidence of harm, then you have a problem. Suddenly, you are neck deep in a professional culture with the potential to protect people to death.
I wish I was exaggerating.
Nahara Town lost 13 people in the tsunami. To date, they have recorded 110 premature deaths as a result of the dislocation caused by the prolonged evacuation, or as they said, “attributed to life in shelter”.
This is all willingly aided and abetted by our environmental ENGOs who expend much time and energy putting a megaphone on the message of the radiation protection industry that radiation is the most terrible hazard imaginable. This is led by some individuals who are particularly unhinged (Helen Caldicott) or outrightly venal (Chris Busby), but let’s be frank: there is no serious pushback from industry and Government. There is little courage to stand with the data about what does and doesn’t hurt people. Four years on from March 11 2011 and the results have been severe. As well as the deaths, the town and region continues to suffer from the effects of “unfounded rumours” impacting their food production and tourism. Once more it is fear, not radiation, that is preventing a return to normality.
I hope for a successful and prosperous future for Nahara Town. I applaud the courage of the officials who have made the return and shown the way. It was a pleasure to visit, eat good food and learn about the situation first hand.
However I am angered that such a situation was allowed to happen. Great pain, suffering and tragedy could have been avoided.
We have to be honest and smart about this. Delivering decarbonised energy for a large and growing world is going to require a massive build-out of nuclear power. Even acknowledging the vast improvements in reactor design and nuclear regulation, it’s just wise to assume that something will go wrong again in future.
It’s not enough to obsessively focus on lowering the likelihood of an event through design, defense and regulation, only to completely ignore the nature of societal response when something does happen. For it appears to be the response, not the radiation, that is killing and hurting people. In Nahara no one died from radiation and likely no one will. Fifteen people died from a tsunami and 110 people died from the consequences of evacuation, relocation and forced estrangement from their homes.
We have to learn and plan together, globally, based on evidence. We may be subjected to radiation events in future. It won’t be of our choosing, however we will get to choose how to respond. I hope we learn from Nahara and choose wisely.
As I will discuss in part two where I recount my visit to the nuclear site itself, we can punish companies for doing the wrong thing. But we must take care to avoid the folly of punishing ourselves in the process.