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After Fukishima: Cleaning up Japan’s Nuclear Disaster

On 11th March 2011, the seabed off the eastern coast of Japan began to move – the time was 2.46 pm. The earthquake, with its hypocenter approximately 29 km (18 mi) below the surface of the water, was about to become the strongest in Japanese history and the fourth-strongest anywhere in the world since 1900. 

But this was just the start. The massive tsunami now barreling towards Japan was about to cause devastation that would see over 15,000 people lose their lives and the nearby Fukushima Daiichi nuclear power station inching towards unimaginable disaster. The most serious nuclear accident since Chernobyl was about to unfold. 

Fukushima Nuclear Power Station  

The Fukushima nuclear power station covers an area measuring 3.5 sq kilometres (1.3 sq miles), close to the towns of Ōkuma and Futaba on the eastern coast of the Japanese mainland. Construction began in 1969 and it was formally opened in 1970. The plant is composed of six boiling water nuclear reactors producing 4.7 GWe of energy, placing Fukushima in the top 15 largest nuclear power stations in the world. These reactors were opened one at a time, but by 1979, all six were in operation. 

As the investigation after the accident got underway, questions began to be asked over several aspects of the power station, not least the decision to have so many nuclear reactors so close to one another right on the coast. It’s easy of course to look back in hindsight, but generally speaking, before the accident, it was considered well run and well maintained.   

Situated on the seafront, protected by a small seawall and on a raised bluff, the power station’s location now seems like a terrible choice. As does the decision to lower the overall height of the bluff from 35 metres (114ft) to just 10 metres (32ft), which would lower the cost of seawater pumping and also allow the reactors to be built on more solid bedrock, which in theory would help to mitigate the threat of earthquakes. 

Just to give you a quick idea of how prevalent earthquakes are in this part of the world, Japan receives roughly 1,500 tremors each year. And while the earthquake that led to mayhem on 11th March 2011 was bigger than anything ever seen, tragic earthquakes are very much a part of Japanese history. In 1923, the Great Kanto earthquake killed 142,800 people and devastated the nation’s capital Tokyo. 

But this also means that the nation has developed some of the best earthquake prevention methods anywhere in the world. It’s estimated that 87% of buildings in Tokyo can withstand earthquakes. Large buildings are built with deeper than normal foundations and many come with inflated rubber or liquid-filled bases which act as shock absorbers, allowing the base to move semi-independently from the rest of the building.  

Hell Arrives

The earthquake that shook the seabed on 11th March 2011 measured 9 on the Richter scale (out of 9). This is the category of the largest earthquakes in history. What shook Sumatra in December 2004 killing over 200,000 people around the Indian Ocean was slightly more powerful than what struck Japan in 2011 – 0.1 on the Richter scale to be exact. There is some debate over whether a category 10 is ever possible, as this would equate to roughly 56.6 trillion kg (125 trillion pounds) of TNT and would likely cause devastation on an apocalyptic level. So for all our sake, let’s hope a 10 is not possible. 

The wave that stormed towards the Japanese mainland is reported to have measured up 40.5 metres (133ft) at its highest point – roughly the height of a 13 storey building – and travelled at speeds of 700 km/h (435 mph). Residents in the coastal areas had only between 8 and 10 minutes warning and for many, it wasn’t enough. 

At the Fukushima power station, as per protocol, the reactors went into automatic shutdown as a result of the initial earthquake, but a disastrous set of circumstances had been set in motion. With the reactors shutting down and with widespread electrical grid problems, power within the power station failed – which is a paradoxical situation if I’ve ever seen one. 

This power failure led to the backup generators starting, which were vital to pump cooling liquid around the reactors. For the moment the power station was safe, but as the first wave appeared on the horizon, things were about to go from bad to nuclear meltdown kind of bad. The water powered over the seawall, flooding the lower sections of reactors 1 through 4. Within minutes, the back-up generators also began to fail and the critical cooling liquid ceased circulating within the reactors.     

What came next was a 7 on the International Nuclear Event Scale – and yes, you’ve guessed it, the INEV only goes to 7. This had only occurred once before, on 26th April 1986, with the catastrophe at Chernobyl, and despite the best efforts of the staff at the plant, three of the reactors (1,2 and 3) went into meltdown and three hydrogen explosions left Fukushima a wreckage. 

In the coming days, the evacuation zone was repeatedly pushed further and further back until it stood at a 20 km (12.4 miles) radius, leading to 154,000 people being ordered to leave their homes. Radiation was released into the atmosphere, but also huge amounts seeped into the waters off the coast. 

Roughly 18,000 terabecquerel of radioactive caesium 137 leaked out through water during the accident and even by 2013, 30 gigabecquerel was still escaping from the powerplant every day. If you’re new to the world of becquerels, then you are probably not alone. Becquerel is used to measure radiation exposure, with one becquerel corresponding to a decay rate of one nucleus per second. This is an absolutely tiny amount, the human body naturally experiences about 8000 becquerels, even a banana has roughly 15 becquerels. This is far too small to be used when discussing nuclear accidents, so we use giga (1 billion) and tera (1 trillion). Therefore, what leaked out in the immediate aftermath, was about 18,000 trillion units of becquerels. That’s a lot, but pales in comparison to Chernobyl and begins to look increasingly small when compared to a nuclear bomb.   

Now that sounds terrifying, but when you consider that the ocean contains roughly 8,125,370,000 trillion becquerels, it certainly puts it all in perspective. The current Japanese legal radioactivity limit is 60,000 becquerel per litre of tritium (a radioactive isotope of hydrogen), with tests at Fukushima still currently showing levels around 1.7 million becquerel per litre – 30 times the legal amount 

There were mass reports that Tokyo was seeing levels of radiation 22 times higher than what was safe in the days of the accident, but these proved to be false. The days following the accident saw levels in Tokyo increase, but only to about twice that of a standard x-ray. 

Clean-Up Begins 

The immediate weeks after the nuclear accident were chaotic, as the Tokyo Electric Power Company (TEPCO), who was responsible for the power plant, battled to bring the disaster under control. The number of separate challenges facing the company was vast. First and foremost, radiation leaking out of the power station needed to be brought under control. Along with that, the huge amount of contaminated water accumulating at the base of reactors would also have to be carefully disposed of. Then we come to the dizzying dilemma of what the hell to do with four badly damaged nuclear reactors. These are not buildings where you simply slap a padlock on and blow up at a later date. If you need a perfect example of this, the Chernobyl disaster happened almost 35 years ago and they are still nowhere near completion. If the reactors at the Fukushima power station were to be decommissioned, this was a process that could take decades. 

But at least they had a rough of how this would be done. Away from the power station, TEPCO was faced with perhaps an even greater challenge. How can the area within the 20 km (12.4 miles) radius exclusion zone be made safe once again? Soil, trees, houses, roads – everything had to be cleaned or moved to another location before inhabitants were allowed back. This was a disaster that would eventually lead to the largest clean-up operation in history – not to mention the costliest.      

In the days following the accident, work began removing the debris that lay strewn throughout the site. This was done using remote-controlled heavy lifting equipment that cleared the debris, which was then placed into specialised containers that would be kept on site until it could all be properly disposed of. 

The most pressing concern was the radiation still leaking out of the reactors. On reactor 2 they found a 20cm (7.8 inches) crack towards the base. TEPCO first tried to block it by injecting fresh concrete, polymeric water absorbent, sawdust, and shredded newspapers into the crack – which did little to stem the flow. After further examinations, they switched to sodium silicate on April 5th and by the following day, the leak had been plugged. 

Two weeks later a clear (ish) plan was finally put forward of how TEPCO would approach the clean-up operation. This included,    

(1) a cold shutdown in about six to nine months (when the coolant system is at atmospheric pressure and a temperature below 93 °C (200°F)

(2) restoring stable cooling to the reactors and spent fuel pools in about three months.  

(3) putting special covers over Units 1, 3, and 4. 

(4) installing additional storage containers for the radioactive water gathering in the turbine basements and outside trenches

(5) using radio-controlled equipment to clean up the site 

(6) use silt fences to limit ocean contamination 

In terms of to-do lists, this was monumental and needed to be done carefully, but as quickly as possible. 

The reactors remained in a delicate state and would be until they were sufficiently cooled. Cooling liquid was injected into the battered reactors but began seeping out of the bottom, further expanding the pool of contaminated water. Normally excess water can be pumped into a holding tank known as a condenser, but the amount was far too much. 

The Japanese initially requested the use of a Russian floating water decontamination plant called the Landysh, but it quickly became clear that the Russians were in no hurry to aid Japan without tacking on plenty of conditions. The negotiations eventually broke down, and the Japanese began looking for alternatives. The funny thing about that is, while the Landysh was built by Russia, it was primarily funded by Japan. I suppose it showed who your real friends are. 

The amount of contaminated water became such a problem that on 5th April, TEPCO decided to discharge 11,500 tons of what they considered the least contaminated water into the sea. At the same time, additional water storage tanks began arriving and were quickly filled. Much of this contaminated water is still present at Fukushima, with over 1.2 million tons believed to remain on the site. 

One of the most intriguing additions at Fukushima has been the so-called ice wall, measuring 1.5 km long and situated 30 metres below the surface. Designed to prevent groundwater running from nearby mountains from entering the site area, the wall isn’t really a wall at all, but rather a series of pipers that now encircle the power plant. Coolant, set at -33C (-22F), is pumped through the pipes which in turn freezes the ground around it – hence the ice wall. This is a technique that has been around for nearly 150 years, first used to help construct mine shafts, but few, if any, can match the $300 million barricade built by the Japanese.  

Fabric covers were installed over the reactors by the end of 2011, and I know what you’re thinking, as if fabric is going to prevent nuclear contamination from billowing out. But this sturdy polyester fabric along with specialised filters was indeed able to stem much of the radioactive substances from escaping.  

Cold Shutdown 

A cold shutdown was finally achieved on 11th December 2011, making further meltdowns impossible. By this point, it had already been announced that reactors 1 through 4 would be decommissioned, a process the authorities believed could take as long as 30 years. The fate of reactors 5 and 6 are still up in the air, but most agree they will be decommissioned also. 

But if you were thinking things were over, think again. Work has progressed at an agonizingly slow pace ever since – as you probably would expect at the site of a nuclear disaster. In August 2013, officials made the extraordinary announcement that 300 tons of radioactive water was leaking out into the Pacific Ocean every single day. It was at this point that the Japanese government decided to step in and play a larger role in the clean-up operation. 

It wasn’t until 2019 that the nuclear fuel rods from reactor 3 began to be removed, a process that is expected to last for 2 years. To do this, a large dome-shaped metal cover had to be constructed over the reactor which was finished in February 2018. With reactors 1 and 2, both of which are in a much more delicate state, this process is not expected to even start until 2023. 

Cleaning the Surrounding Area

There were countless fears raised in the aftermath of the disaster at Fukushima, with one being the contamination of land around the power plant, which could, in turn, lead to contaminated crops and water sources. 

If the clean-up operation within the power station is impressive, what has been happening in the surrounding area is perhaps even more so. In the years after the disaster, as many as 70,000 people removed topsoil, tree branches and even grass from around the Fukushima plant. Quite simply they were trying to cleanse the entire area of any potential contamination – a process believed to cost in the region of ¥2.9trillion  ($27 billion) and will eventually cover 14 million cubic meters (494 million cubic feet) of soil by 2021. 

But what do you do with all this contaminated soil? Well, in truth there’s not a whole lot that can be done. The soil cannot be completely cleaned, so instead, it is being held in temporary containers until a suitable site can be found somewhere in Japan to store it. Unsurprisingly, this is proving hard to come by, with countless areas rejecting the chance to take in all this contaminated soil. But even when they do find somewhere, this soil is not expected to be completely safe for at least 3 decades, and probably much more. 

Just the Start

Considering the disaster took place nearly a decade ago, it’s shocking to think that this clean-up operation probably hasn’t even hit its mid-way point. Yes, the immediate danger has rescinded with the reactors put into a cold shutdown state, but this will be a true marathon of an operation. 

So where are we right now? Not very far to be perfectly honest. They have only just started removing fuel rods from reactor 3 – which is by far the easiest of three to address. Reactor 1 is still covered by dangerous rubble and represents a foreboding challenge for the future. Reactor 2 is in a slightly better situation, but not by much.

Nobody quite knows how much this will all eventually cost. The initial estimate after the accident of ¥1 trillion $13 billion now sounds like a joke. The most recent estimate, made in 2018, now puts that figure at ¥21.5 trillion $187 billion. 

The water remains a huge problem. As of 2020, over a million tons of contaminated water is still being kept on-site, but tanks are quickly approaching capacity. With 120 tons added per day, there has been a steadily increasing belief that eventually this water will be released into the Pacific Ocean. As you might imagine, environmental organisations have reacted with fury to this plan, but it’s not immediately clear whether a viable alternative can be found. 

But people are returning to the area, with as many as 122,000 inhabitants going back to the homes they were frantically evacuated from in 2011. But things are not the same. Many of the towns require serious reconstruction, with a ghostly aura still hanging in the air. For many, it has come down to the generous financial incentives and the prospect of brand new homes, but it will be years, perhaps even decades until this area begins to feel normal again.    

The shadow hanging over this nuclear power is not going away anytime soon. With the clean-up operation plodding painstakingly on and the slow reconstruction of the towns – and lives – completely upended by the events of 11th March 2011 – the name Fukushima is one we will be hearing for some time to come.     

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