Executive Summary
The large quantity of radioactive material released by the Fukushima incident has swayed public sentiment against nuclear energy. It did not only cause loss of livelihood but it has also rendered large stretches of land uninhabitable. The effects also extended outside Japan affecting countries as far as Russia and the US.
A collection of evidence point out that the Fukushima accident was preventable. Had Tokyo Electric Power Company (TEPCO) and Japan’s regulator, the Nuclear and Industrial Safety Agency (NISA), followed international best practices, heed to tell-tale signs of danger, and carefully crafted a methodology that would assess the hazards involved, the Fukushima plant would have withstood being struck by a massive tsunami.
The methods used by TEPCO and NISA to assess the risk from tsunamis lagged behind international standards in at least three important respects:
- Insufficient attention was paid to evidence of large tsunamis inundating the region surrounding the plant about once every thousand years.
- Preliminary simulations conducted in 2008 that suggested the tsunami risk to the plant had been seriously underestimated were not followed up and were only reported to NISA on March 7, 2011.
Finally, the Fukushima accident does not reveal a previously unknown fatal flaw associated with nuclear power. Rather, it underscores the importance of periodically re-evaluating plant safety in light of dynamic external threats and of evolving best practices, as well as the need for an effective regulator to oversee this process.
Introduction
The 2011 Fukushima Daiichi Nuclear Power Station accident sparked an ever-contentious debate about nuclear energy. With large quantities of radioactivity leaked into the environment, and hundreds of thousands of residents in the area displaced, and a clean-up operation that will take decades and will cost billions of dollars, critics have argued that nuclear power is too dangerous to be considered.
Are they right? Is nuclear power too dangerous? Or can nuclear power be made significantly safer? The answer depends on whether nuclear power plants are inherently susceptible to worst case scenarios and/or whether it is possible to predict such hazards and defend against them.
The International Atomic Energy Agency’s (IAEA’s) International Nuclear Safety Group believes that if best practices are implemented, major releases of radiation from existing nuclear power plants should occur about fifteen times less frequently (International Nuclear Safety Advisory Group 1999) True enough, improvement on this scale is probably necessary for nuclear power to gain widespread social and political acceptance.
The Fukushima plant was a unique case in history as it was hit by a massive earthquake and then a tsunami, triggering a chain of events that led to fuel melting and a significant off-site leak of radiation.
One year after the Fukushima accident, however, a picture is emerging that suggests that the incident was easily preventable. There is also a growing body of evidence that suggests the accident was the result of failures in regulation, plant design and that it failed to follow international best practices and standards. Had these been considered and promptly applied, the accident in the Fukushima Daiichi Nuclear Power Station would likely have been prevented.
Facts of the Case
On March 11, 2011, at 02:46 local time, a record magnitude 9 earthquake struck Japan, setting a powerful 14-15 meter tsunami in motion which devastated the Tohoku coastline in the country. This event claimed around 20,000 lives and inundated the Fukushima Daiichi Nuclear Power Plant in Fukushima, Japan, creating disastrous environmental effects in the area.
The extreme seismic events led to the loss of electricity and the failure of backup generators in the said power plant, which was operated and maintained by Tokyo Electric Power Company (TEPCO). Japan has 54 nuclear reactors and the plant was made up of six boiling reactors, which purpose was to generate electricity from the steam produced by the fission reaction’s heat. Nuclear fission happens in the nuclear reactor core and cooling systems were set up, as part of risk management, to prevent core meltdowns.
However, when a reactor is shut down for maintenance or refuelling, the radioactivity in the core of the reactor still produces heat for a period of time. This means that the reactor, even when not in use, still needs to be cooled. This is where diesel generators, DC batteries, or other operating reactors are used to power cooling pumps when a reactor is not working.
On the day of the incident, specifically within the first 80 hours, three reactors were already refuelling and were turned off as part of protocol. The other three active reactors were shut down as part of a safety procedure mandated by the Government (IAEA 2011). Since all six reactors were no longer active to generate their own cooling pumps, diesel generators were turned on to compensate for the power loss.
However, almost an hour subsequently after the earthquake, a 13-metre high tsunami hit Fukushima, engulfing the 10-metre plant seawall. Water flooded the low-lying location of these diesel generators that caused the generators of five reactors to stop functioning (Lipscy, Kushida, and Incerti 2013). These generators were located in the turbine building’s basements.
Despite all these, the sixth reactor’s generator that was capable of powering two cooling systems was left unharmed, thus, keeping the cooling systems of two reactors running. The next alternative generators called the DC batteries were then used to avoid overheating problems. But after a day, the batteries ran out resulting into core meltdowns for three reactors from short supply of cooling (Strickland 2011). Hydrogen-air chemical explosions occurred, even while workers were still in the facility trying to restore power and keep the cooling pumps on. Plumes of radiation were released, spreading radioactive contamination in the nearby areas. Strong spring winds also brought these further afield.
Radioactive material contaminated the sea water spreading to the Pacific Ocean. Radioactive releases went as far as Russia and The United States of America that stretched to a global scale covering the entire Northern and Southern Hemisphere in a month (Buesler et al. 2012). Although there was no death related to radiation exposure from the catastrophe, an estimated hundreds of people are expected to have cancer-related fatalities due to the accident (Brumfiel 2012). High thyroid cases were reported after the event and an increasing number of the population are at risk of deaths from benign thyroid growths if left undetected (Russia Times 2013).
In addition, around 80,000 residents within the 20-km evacuation zone around the reactors were displaced. Moreover, a wider economic fallout occurred as bans on Japanese product were imposed overseas and overall inbound tourism declined by 25% in 2011.
The Government wasn’t well-equipped for such a disaster even though Japan is in the active seismic zone, giving it higher vulnerability to earthquakes. The tsunami could have been foreseeable as well but the lack of clear organisational structure in terms of proper coordination and communication in TEPCO and the Government agencies made the Nuclear industry in Japan more susceptible to such catastrophic events (Funabashi & Kitazawa 2012). The Government was also to blame for not providing adequate safety regulations to the nuclear power plants. Its emergency responses and its disaster risk management weren’t adequate causing additional 1700 deaths from the situation of evacuation (Smith 2013). The Fukushima Nuclear Accident Independent Investigation (NAIIC) find the Government regulators and energy utilities caused the technical failures (Massey 2012). In an interview, Japan’s Prime Minister Yoshihiko Yoda said, “The government, operator and the academic world were all too steeped in a safety myth”.
TEPCO is expected to lose 7 trillion yen for compensation while the Government is expected to shell out 12 trillion yet for stabilising the situation such as decontamination and clean-up (Harding 2016).
Risk Management Issues
This paper identifies two key risk management issues. First, the management underestimated the threats identified in the location of the said plant. Second, there were significant flaws identified in the methodology used by the management to assess the hazards involved. According to Acton and Hibbs (2012):
“The management failed to meet basic safety requirement because they underestimated the threats involved.”
Three widely cited investigations of the Fukushima disaster — one by the Japanese government, one by an independent team of experts in Japan and a third by The Carnegie Endowment for International Peace — have concluded that the nuclear disaster of March 2011 was preventable.
“It was a profoundly man-made disaster that could and should have been foreseen and prevented,” said Kiyoshi Kurokawa, chairman of the Fukushima Nuclear Accident Independent Investigation Commission, established by the National Diet of Japan” (Wharton 2013).
The Carnegie Endowment for International Peace study found that the Fukushima Daiichi Power Station was not designed to withstand a tsunami even half the size of the one that ultimately struck the Japanese coast.
According to the official licensing documents, Fukushima Daiichi’s design basis tsunami was estimated to have a maximum height of 3.1 meters above mean sea level. (IAEA 2012) Given this, TEPCO decided to locate the seawater intake buildings at 4 meters above sea level and the main plant buildings at the top of a slope 10 meters about sea level. In 2002, TEPCO voluntarily re-evaluated the tsunami hazard and adopted a revised design-basis tsunami height of 5.7 meters.
The maximum height of the tsunami that actually hit the plant is not known exactly since the sea-level gauge at the plant was destroyed. However, TEPCO and the Japan Society of Civil Engineers, using computer modelling to re-create the observed pattern of flooding at the plant, have estimated that just before it made landfall, the tsunami had a height of 13.1 meters, over twice the revised design basis. Once the tsunami had “run up” the slope on which the main buildings of the plant sit, it reached 14–15 meters above sea level in many areas and, in a few places, more than 17 meters.
TEPCO, the regulatory bodies (the Nuclear and Industrial Safety Agency and Nuclear Safety Commission of Japan) and the government body promoting the nuclear power industry (Ministry of Economy, Trade and Industry), all failed to correctly develop the most basic safety requirements—such as assessing the probability of damage, preparing for containing collateral damage from such a disaster, and developing evacuation plans for the public in the case of a serious radiation release. Moreover, a separate study by Stanford researchers also found that Japanese plants operated by the largest utility companies were particularly unprotected against potential tsunami.
TEPCO admitted that the reason why it failed to take the necessary measures to prevent the disaster was for fear of inviting lawsuits or protests against its nuclear plants (CNN Wire Staff 2012). TEPCO added that taking such measures could add to public anxiety and add momentum to anti-nuclear movements. This is the reason why communities with low levels of social capital are specifically chosen in order to reduce the risk of local opposition and because their marginal socio-economic situation makes them more inclined to accept financial inducements (Kingston 2012).
The fact that Japan suffers 20% of the world’s >6 magnitude earthquakes and invented the word tsunami, it may seem surprising that the government decided to place such a big bet on nuclear energy and decided to construct clusters of multiple reactors that amplifies the risks. This behaviour could be related to the oil embargoes and price hikes of the 1970s which reinforced perceptions that Japan had no choice but to pursue the nuclear fuel cycle because it offered the hope of eliminating Japan’s dependence on energy imports (Kingston 2012). This created an environment where social cost is underestimated due to the perceived social benefit of running these nuclear reactors. Like Kingston (2012) said, “There were significant flaws in the methodology used to assess the hazards involved.”
An earthquake offshore of the Miyagi region, where the epicentre of the March 11 earthquake was located, had been long anticipated. For example, as recently as January 11, 2011, the Headquarters for Earthquake Research Promotion (a Japanese government–funded organization set up after the 1995 Kobe earthquake to improve seismic modelling) repeated a long-standing prediction that in that region there was a 99% probability of a magnitude 7.5 earthquake within thirty years. But when the earthquake actually arrived, its magnitude caught seismologists by surprise. The Great East Japan Earthquake on March 11, 2011, was actually a magnitude 9.0 event. This significant underestimation, in spite of Japan’s considerable investments in seismology, is a sobering warning against overconfidence in hazard prediction.
Notwithstanding the intrinsic difficulties of hazard prediction, the approach to hazard prediction for Fukushima Daiichi appears to have been at variance with both international best practices and, in some cases, with Japanese best practices.
First, there appears to have been insufficient attention given by TEPCO and NISA to historical evidence of large earthquakes and tsunamis. Best practice, as promulgated by the IAEA, requires the collection of data on prehistorical and historical earthquakes and tsunamis in the region of a nuclear power plant in order to protect the plant against rare extreme seismic events that may occur only once every ten thousand years. Historical data was used in assessing plant safety. The original design-basis tsunami for Fukushima Daiichi of 3.1 meters was chosen because a 1960 earthquake off the coast of Chile created a tsunami of that height on the Fukushima coast. However, greater attention should have been paid to evidence from further back in history. Over the last decade or so, evidence of much larger tsunamis in and around Miyagi has emerged. Japanese researchers have discovered layers of sediment that appear to have been deposited by tsunamis and have concluded that the region had been inundated by massive tsunamis about once every one thousand years. The sifting through and evaluation of the stream of potentially relevant geophysical studies to extract data important to nuclear power plant safety was said to be underestimated (Acton and Hibbs 2012).
Second, there appear to have been deficiencies in tsunami modelling procedures, resulting in an insufficient margin of safety at Fukushima Daiichi. A nuclear power plant built on a slope by the sea must be designed so that it is not damaged as a tsunami runs up the slope. In 2002, the Japan Society of Civil Engineers developed a detailed methodology for determining the maximum run-up of a tsunami. This methodology prompted TEPCO, voluntarily, to revise the design-basis tsunami at Fukushima Daiichi from 3.1 meters to 5.7 meters. However, in at least one important respect, TEPCO does not appear to have implemented the relevant procedures in full (Acton and Hibbs 2012).
In the view of some Japanese experts, the accident at Fukushima Daiichi was an expression of supreme overconfidence by decision-makers that Japan’s nuclear power program would never suffer a severe accident. Broadly speaking, Japanese nuclear officials and executives said the reluctance of authorities to re-evaluate tsunami risk may reflect a more general Japanese cultural bias against open discussion of worst-case scenarios or contingencies for which Japanese society and its authorities may be unprepared (Acton and Hibbs 2012).
Conclusion and Recommendation
Prepare for the worst
Accurate hazard prediction is extremely challenging. It is always possible, after the fact, to spot indicators of an impending disaster that, in this case, included evidence for massive tsunamis inundating the region once every one thousand years. This calls for an identification of engineering design attributes that would prepare nuclear reactor for the worst. Such attributes includes protection against natural hazards. A design that would enforce that structure to withstand strong earthquakes even that of magnitude 9 earthquake and would be protected against a 14-15 meter tsunami, and a plant capability against a station blackout.
The following modifications can be implemented to ensure the reactors are safe and protected:
- Moving emergency diesel generators and other emergency power sources to higher ground on the plant site
- Establishing watertight connections between emergency power supplies and the plant
- Building dikes and seawalls to protect against a severe tsunami
- Installing emergency power equipment and cooling pumps in dedicated, bunkered, watertight buildings or compartments
- Assuring that seawater-supply infrastructure is robust and providing additional robust sources to serve as the plants’ ultimate heat sink.
The value of taking such action was demonstrated by upgrades that one Japanese utility, Japan Atomic Power Company (JAPC), was in the process of carrying out when the tsunami struck Japan’s east coast. JAPC’s Tokai-2 plant is located about 100 miles south of Fukushima, and the tsunami that ravaged Fukushima also caused flooding at Tokai-2. Prior to the tsunami, JAPC had partially implemented plans to erect a wall to prevent tsunami water from flooding two pits at the plant where seawater pumps were located and to make the pump rooms watertight. The wall was erected before the tsunami occurred. Water entered one of the pits because spaces where pipes penetrated into the pit had not yet been made watertight before the accident. In that pit, a seawater pump that provided cooling for an emergency diesel generator was damaged and unable to function, forcing JAPC to shut down the generator. But no flooding occurred at the other pit where pipe penetrations had been made watertight. This saved the cooling pumps for two more diesel generators. Had JAPC not carried out these upgrades, it would almost certainly have lost all three emergency diesel generators, potentially resulting in a much more serious accident.
More than the enhancement of safety, a consistency in the maintenance of safety in nuclear power plants must also be emphasized. To compare, European regulators undergo expensive engineering modifications to enhance and maintain safety. If needed, the government should take into account the social harm in case safety is not upheld. The perceived harm could offset, if not justify, the perceived cost of maintaining safety.
The reason why this is important is not only because this entire incident was caused by oversight, but because we are dealing with lives of people and the environment- not only of the Japanese but of the world. Preparing for the worst allows for the prevention of unnecessary deaths, loss of livelihoods, displacement, and radiation leaks, in case a nuclear power plant fails. More than that, it also manages secondary risks such as the economic effects of exports being banned and the reduction of in-bound tourism.
Promote a culture of safety
Evidently, TEPCO did not make safety its priority and oversight by the government allowed this culture of complacency to persist long. Most of the world’s greatest disasters have tell-tale signs. Authorities should heed to these signs and err on the side of caution when making judgments. In Japan, for example, given the risks associated with operating nuclear power plants in a seismically active, densely populated country, evacuation procedures should be regularly and consistently practiced in reactor- hosting communities. Procedures and guidelines should be outlined and practiced in awareness programs that could be conducted in schools and communities for all ages. This helps prepare communities of the worst-case scenario. This also allows farmers and fisherman – who often comprise a large portion of the population in these communities – to prepare a contingency in case of loss of livelihood.
Moreover, the Japanese industry and government should be familiar with, and in some cases be participants in, international efforts to review the safety of nuclear power plants concerning severe externally caused events. This allows TEPCO and Japanese regulators to take well-understood and straightforward engineering measures to better protect the Fukushima Daiichi Nuclear Power Station.
Uphold transparency
The claim of fear that communities will oppose nuclear power plant projects is no excuse for the government to conduct a program that would fully inform nuclear-hosting communities of the risks involved in the program. Not only is this the government’s moral obligation, but this allows for a mitigation of a public uproar in case of incidents. This also allows for fully-informed decisions within the community.
More importantly, a fully-informed community creates a check-and-balance system in the government. This will help increase the standard of safety that the government and its regulating bodies must adhere to. Communities often would prioritize safety over anything else. This would rectify the Japanese cultural bias against open discussion of worst-case scenarios or contingencies for which Japanese society and its authorities may be unprepared.
Find alternatives to energy
The risks of nuclear power plants are higher than other alternatives to energy such as solar and hydro power plants. Japan should explore other alternatives as other countries have. This could directly address the issues and concerns to having a nuclear energy source.