Around 8,000 km and 25 years separate the catastrophic Chernobyl and Fukushima nuclear disasters. There are clear differences between the Ukraine and Japan-based catastrophes, but what are some of the more subtle distinctions? And how were they similar?
Both power stations opened in the 1970s; Fukushima in 1971 and Chernobyl six years later. The Japanese plant was, then, operating for 40 years before the disaster and the Ukrainian just nine. At the time of each disaster, six reactors were running at Fukushima and four at Chernobyl.
At a first glance, the incidents appear to have different causes. The Chernobyl reactor explosion on April 26, 1986, was the result of an experiment carried out by plant personnel. The Fukushima meltdown, meanwhile, was triggered by an earthquake and subsequent tsunami on March 11, 2011.
However, construction mistakes and negligence have since been cited as being behind both catastrophes.
So, what actually happened?
At Fukushima, the potential dangers of a large tsunami had already been raised, but ultimately ignored. The March 2011 ‘quake destroyed power lines and back-up generators, meaning the plant’s reactors could not be cooled. This caused severe damage, including meltdowns and an explosion.
Operators at Chernobyl made mistakes during the experiment they were carrying out and these errors were initially considered to be the main cause of the catastrophe But the International Atomic Energy Agency (IAEA) later amended its conclusion.
The construction of the RBMK reactor (High Power Channel-type Reactor) used at the station is deemed one of the main reasons behind the accident. The reactor’s developers thought that a certain, disastrous combination of events could not possibly happen at the same time, so the protective systems to prevent such a situation were not created. But this chain of events did occur on the night of April 26; namely the deliberate disabling of the emergency protection equipment and breaking of operating rules. This resulted in a steam explosion inside of the reactor, a raging graphite fire and core meltdown.
Both Chernobyl and Fukushima were ranked level seven events on the IAEA’s international nuclear radiological scale – its highest rating. It was concluded that both accidents caused a major release of radioactive material, which adversely affected people’s health and the environment.
But this does not necessarily mean that the Japanese catastrophe was as dangerous for humanity and the environment as Chernobyl, which remains the worst nuclear disaster of our era.
Due to its location, the explosion at Chernobyl caused significant contamination in countries neighbouring Ukraine, such as Belarus and Russia (all were Soviet republics at that time). It reached the whole of Europe in some form, except Portugal.
Radiation from Fukushima continues to seep into the ocean via ground waters – radionuclides have been found in seawater throughout the Pacific – but the contamination consequences for other countries are relatively insignificant. The new system to contain the leaking water was recently approved.
Partially cleaned water from the reactors will also be released into the ocean deliberately later in 2016.