Fukushima Daiichi Accident
11 March 2021
Ten years ago the most powerful earthquake ever to have struck Japan triggered a 15-metre tsunami, inundating around 560 km². It resulted in around 19,000 deaths, with extensive damage to coastal towns, and over a million buildings destroyed or partially collapsed. At the Fukushima Daiichi plant water surged over defences and disabled the power supply and cooling system of three reactors, causing a nuclear accident.
Below, we detail the events themselves, why the accident would not happen in the UK, and the consequences of Japan’s decision to shut down its nuclear reactors.
The Earthquake and Accident
- The Tōhoku earthquake was the most powerful earthquake ever recorded in Japan, triggered a 15 metre tsunami, which resulted in around 19,000 deaths.
- The tsunami overcame the sea wall at Fukushima Daiichi and flooded back-up generators for cooling the reactors, which had properly shut down immediately on detecting seismic activity.
- Heat from fission product decay created hydrogen which exploded in units 1-4, although containment structures prevent dispersal of most radioactivity.
- 1 person died in 2018 from radiation effects.
Why the Accident Would Not Happen in the UK
- The initial earthquake in Japan was 1000 times stronger than the strongest in the UK, which is not at high risk of seismic activity.
- The UK’s Office for Nuclear Regulation (ONR) has a global reputation for rigorous and independent oversight.
- The ONR’s Chief Inspector was chosen to lead the International Atomic Energy Agency mission to Japan, which found in Fukushima that the sea defence wall was not sufficient to protect against predictable events, and the Japanese regulator admitted lax standards and poor oversight.
- The ONR found no shortfalls in UK reactor operational safety in rigorous stress tests conducted after Fukushima.
- The UK nuclear industry nonetheless undertook an extensive programme to add further layers of safety to nuclear stations anyway.
- These included actions such as deploying extra water pumps and coolers for reactor fuel cooling, trailer-mounted diesel generators, and specialised support vehicles at strategic locations around the country, away from stations themselves that might be affected by a natural disaster.
Effects of Nuclear Shutdown in Japan
- A Columbia University study found that by 2017 alone Japan emitted 480 million tonnes more CO2 and caused another 2300 indirect deaths.
- The study further found that Japan could have prevented up to 21,000 (UR: 10,500–27,300) premature air pollution-related deaths and 1700 MtCO2 cumulative emissions from coal burning between 2011 and 2017.
- Japan has 23 GW of idle nuclear capacity. Nuclear generation is now only 6% of generation, compared to around 30% before the accident.
- Japan is the largest importer of Liquefied Natural Gas (LNG) in the world. Coal is the second most important power source.
- Japanese Energy Minister has said that “I think nuclear power will be indispensable” after January 2021 price spikes to $2,500/MWh and blackout warnings as grid reached 99% capacity. The Japanese Prime Minister has said that Japan will “advance our nuclear energy policy”.
Tom Greatrex, Chief Executive of the Nuclear Industry Association, said:
“The Fukushima Daiichi accident was completely preventable, and would not happen in the UK because of our strict regulatory oversight and significantly lower risk of natural disasters. Indeed, an independent review in the aftermath of the accident found no shortfalls in UK operational reactor safety. Huge efforts were made nonetheless to add further layers of safety to UK nuclear sites and their supporting systems.
“Nuclear power, as the Japanese Government itself has recognised, will be indispensable in cutting carbon emissions, as turning off reactors has led to alarming spikes in coal and gas use. The UK should be confident that nuclear power can provide the firm, zero-carbon nuclear capacity we need to end our dependency on fossil fuels and hit Net Zero.”