Did History Actually Teach Us Anything? – Episode 18 Fukushima Nuclear Explosion Laura: Welcome to "Did History Actually Teach Us Anything?". The podcast where we unravel the most well-known tales of calamity, mishap, and unforeseen consequences that have shaped the course of history. And consider whether we've actually learned anything from them all these years later... In this podcast, we examine the historical events that you may think you know about already and the causes that led to them, be they icebergs or bakers ovens. We will consider whether these tragedies could have been avoided, and some of the surprising things we do differently now as a result. But this podcast, isn't just about dates and events. It's about learning from the past, drawing insights from hindsight, and gaining a deeper appreciation for the complexities of what really happened in these events we think we know so well. So get ready to encounter remarkable individuals, pivotal moments and fascinating insights that will make you appreciate health and safety and environmental management as far more than just red tape. On March the 11th, 2011, Japan faced an unprecedented disaster when a massive nine magnitude earthquake struck off its northeastern coast, triggering a devastating tsunami. This catastrophe caused a meltdown at the Fukushima Daiichi nuclear power plant, leading to one of the worst nuclear accidents in history. Over the following days, explosions, radiation leaks, and mass evacuations gripped the world's attention as Japan grappled with the crisis. In this episode, we'll explore the events that unfolded, the monumental challenges of the cleanup, and the lasting impact on people, the environment and nuclear energy policy worldwide. But first John, our environmental management expert, is going to give us an overview of what actually happened on that fateful day. John: On March the 11th, 2011, a nine magnitude earthquake struck off Japan's northeastern coast, triggering a massive tsunami that devastated the Fukushima Daiichi nuclear power plant built in the 1970s. The plant housed six boiling water reactors, three of which were operational at the time. Although the reactors automatically shut down as designed, residual heat caused the fuel rods to overheat leading to partial meltdowns. In reactors one, two, and three, explosions from pressurized hydrogen gas damaged containment structures and radiation was released further exacerbated by a fire in reactor four. Emergency crews were tirelessly to stabilize the situation by pumping boric acid and seawater into the reactors, using helicopters and water cannons to cool the overheating cores. By December, the reactors were declared safe after a cold shutdown, but the disaster left behind a legacy of contaminated water, radiation exposure, and a monumental cleanup challenge that continues to this day. Laura: Clearly there was a lot that contributed to this event, so can you talk us through the timeline of what happened? John: It all began on 11th March 2011 with the earthquake and tsunami. At 2:46 PM JST, a magnitude 9.0 earthquake strikes off the northeastern coast of Honshu, Japan. The quake is one of the largest ever recorded. Automatic shutdown systems activate at the Fukushima Daiichi Nuclear Power Plant, stopping the three reactors that were operational (Units 1, 2, and 3). At 3:27 PM JST, a massive tsunami follows, with waves over 14 meters high. The plant’s seawall, designed to handle waves up to 5.7 meters, is overwhelmed, and the tsunami floods the emergency diesel generators located in basements, knocking out power to the cooling systems. Over the 11th and 12th March, without power, the cooling systems for reactors 1, 2, and 3 fail, causing the reactor cores to overheat. At 11:00 PM JST on March 11th, the pressure begins to build in the containment vessels due to steam and hydrogen generation from overheated fuel rods. On the morning of 12th March, radiation levels rise, prompting evacuations within a 20-kilometer radius. Then at 3:36 PM JST on March 12, a hydrogen explosion occurs in Reactor 1, blowing off the outer building’s roof but not breaching the containment vessel. On March 13, Reactor 3 shows signs of trouble, with the cooling systems failing. And at 11:01 AM JST on 14th March, Reactor 3 experiences a hydrogen explosion, similar to Reactor 1. The following day, at 6:14 AM JST (on March 15th), Reactor 2's containment vessel suffers damage, likely from a hydrogen explosion, leading to significant radioactive releases. And then a fire breaks out at Reactor 4’s spent fuel pool due to overheating. Between the 16th and 20th March, efforts are made to stabilize reactors including water injection using helicopters and fire trucks. Workers attempt to restore power to cooling systems, battling extreme radiation levels. Seawater is pumped into reactors as a cooling measure between the 21st and 31st March, a desperate action with long-term consequences, and radioactive water leaks into the Pacific Ocean, raising international concerns. The disaster is officially classified as a Level 7 event on the International Nuclear Event Scale, the highest level (equivalent to the Chernobyl disaster of 1986) in April. The aftermath and long-term impacts of the event were severe. Over 150,000 residents were displaced, many permanently; and there was significant contamination of land and water, with ongoing maintenance and cleanup. The Tokyo Electric Power Company began decommissioning the plant, a process expected to take decades, meaning completion is anticipated in the 2050s or beyond. Laura: So John, can you run us through the actual causes of the disaster? John: The initial cause of the Fukushima nuclear disaster was a combination of an earthquake of a magnitude level of 9 (this is extremely high on the scale and only occurs around 2 or 3 times on average per year around the world), and a 15 metre tsunami that overcame the 8 metre seawall built to protect the nuclear plant. The seafloor, extending 650km from the north – to the south of Japan, moved 10-20 metres horizontally, this was a huge change in the earth's crust! The tsunami itself inundated 560 km2 and led to around 19,500 deaths and much damage to property with over a million buildings destroyed or partially collapsed. The reactors coped with the seismic activity with no significant damage reported, but proved vulnerable to the tsunami. The tsunami waves generated by the earthquake caused cessation of power from the grid and damaged backup electrical generators of the plant, causing cooling systems (reactor cooling and water circulation functions) to fail in each of the three reactors that were operating at the time. The response after the accident was centered around restoring cooling systems to the reactors and dealing with spent fuel ponds. Although all three reactors were successfully shut down, the power loss caused the cooling systems to fail within the first few days of the disaster. Rising residual heat within each reactor’s core caused the fuel rods to overheat and partially melt down, leading to the release of radiation, and explosions resulting from the buildup of pressurised hydrogen gas (produced from a reaction of steam and extremely hot zirconium cladding) which blew off the roofs of reactors 1 and 3. Explosions occurred as the hydrogen mixed with air, and ignited. Laura: What was the impact of the accident on the workers and the residents of the local area? John: Imagine at the time of the incident a huge tidal wave passing over the area and causing death and destruction on a massive scale. Many people's lives were ended on that day, and the survivors had to cope with trying to survive in the carnage caused by the tsunami, only to have to deal with the worry of being exposed to radiation leakage from the plant, and the impacts this might have on their health as well. In the days that followed the accident, around 47,000 people had to leave their homes as a 20km evacuation zone was declared. Warnings about the consumption of local food and water supplies were issued. By the end of March, the evacuation zone was expanded to 30km. On the 12th April, the severity level was raised from 5 to 7 – the top of the scale created by the Internal Atomic Energy Agency and at the same level of the Chernobyl accident that occurred in 1986. Radiation doses on local people had been low and as such very few diseases associated with radiation exposure are expected to have occurred from the incident. At its peak, around 164,000 people were evacuated from the site. The stress of relocation is said to have caused many impacts such as mental health problems, an increase in suicides and alcholism that have significantly lowered life expectancy of evacuees. In fact, the evacuation impacts are expected to have had a much bigger impact on people's health than the radiation exposure from the disaster. At least 16 workers were injured in the explosions, while dozens more were exposed to radiation as they worked to cool the reactors. Luckily no deaths were reported in the immediate aftermath of the explosion. Laura: If the event was caused by a natural disaster, is there any way that the meltdown could have been avoided? John: TEPCO had been aware for many years prior to the incident that there would be a lack of cooling and a blackout in the event that the plant flooded. There was a significant lack of planning and training for mitigating these issues as the emergency progressed. Plans and processes for manual operation of the cooling system and venting were also incomplete, as such their implementation at the time of the emergency was poor. Implementation of a robust management system, including a valid assessment of the risk of the damage flooding may cause, and adequate emergency procedures and training surrounding flooding, would have severely reduced the impact of the incident. Regulators were aware of the issues that would occur surrounding flooding of the site but chose to take no enforcement action. According to an independent commission investigating the Fukushima nuclear disaster, long-standing collusion between Japan's regulators and industry set the stage for the tragedy that could and should have been avoided. The report states that those parties "effectively betrayed the nation's right to be safe from nuclear accidents" and that the accident was clearly man-made. Official Japanese reports into the causes of the disaster also identified significant weaknesses in the country's structures and systems for governing nuclear safety. TEPCO had known safety improvements were needed before the disaster but had failed to implement them. For example, scientists warned that critical backup generators built in low-lying areas were at significant risk from tsunami damage. The pre-event tsunami hazards study, if done properly, would have identified the diesel generators as the linchpin of a future disaster. The tsunami hazard at Fukushima Daiichi was dramatically underestimated, and changes in plant design resulting from effective safety reviews could have prevented a severe accident. Laura: What was the impact of the event on TEPCO? John: TEPCO has acknowledged that it could have avoided the disaster that crippled the Fukushima Daiichi power plant as the accident was the result of failures in regulation, nuclear plant design, and hazard prediction. The company has faced significant financial pressure to provide compensation for businesses and individuals affected. This is expected to exceed 3 billion yen. This amount of compensation would've bankrupted the company, and as such resulted in a massive 1 trillion yen bail out by the Japanese government effectively nationalizing the company. As a condition of the bailout, TEPCO is forced to cut its costs significantly by restructuring its workforce and operations. Laura: So what lessons have been learned as a result of this event and has there been another nuclear disaster as severe since? John: Following the emergency, corporate governance improvements have been made by TEPCO. For example, the company has established a nuclear reform special task force that has led to improvements in TEPCO’s safety culture, safety measures, disaster prevention measures, risk/crisis control protocol, information release and risk communication techniques. A nuclear reform monitoring committee was also put together of global and local experts who act as an advisory body to the organisation's board of directors on nuclear safety. More specifically, additional backup sources of electrical power and supplies of water have been installed at the plant, and the protection of plant against extreme external events has been strengthened. Generally, one of the overarching lessons is that nuclear safety is a continuous process that requires constant vigilance and improvement. The disaster highlighted the importance of proper hazard prediction, building backup generators in safe areas, and implementing safety improvements. The tragedy also revealed the need for better communication and co-ordination between government agencies, industry, and the public during emergencies. Moreover, the disaster has highlighted the importance of mental health support for affected communities. Fukushima has led to significant changes in the nuclear industry. Regulations were developed that identified a need for nuclear power stations to be able to withstand extreme natural events, such as earthquakes and tsunamis. They also require nuclear plants to have measures for dealing with the maintenance of key safety functions in the event of a severe accident, and improve emergency preparedness and response such as evacuation procedures in the event of a nuclear accident. The Fukushima disaster has also led to advances in earthquake science and influenced strategies for tsunami defence and local warning systems. And “stress tests” are now carried out to reassess the design of nuclear power plants against site-specific extreme natural hazards. As such, there has not been another nuclear disaster as severe as the Fukushima Daiichi disaster since it occurred in 2011. In fact, Fukushima and the 1986 Chernobyl disaster (which will be covered in a different episode of this podcast) remain the only nuclear accidents classified as Level 7 on the International Nuclear Event Scale: the highest level. Laura: Thanks for joining us on this episode of "Did History Actually Teach Us Anything?". 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