What happened in Fukushima?

On 11 March 2011 the nuclear power plant of Fukushima – Daiichi was automatically shut down due to an earthquake. The tsunami which followed it destroyed the cooling system of the reactors 1, 2 and 3. Due to overheating, the fuel rods largely melted, and explosions occurred, which caused high levels of radioactivity to be released.

Can the Fukushima accident also occur in Belgium?

The seismic activity around the Doel and Tihange sites is nothing like that in Japan. Japan lies on a fault line between major continental and oceanic plates, so it regularly experiences severe earthquakes. The Doel nuclear power plant is located in an area where earthquakes are rare; there is some seismic activity in the Tihange region, but the frequency and intensity is much lower than in Japan. Thanks to their robust buildings and safety systems, Doel and Tihange are able to withstand the type of earthquakes that can occur in Belgium.

The earthquake risk was well known in Japan. So how could a severe earthquake still lead to the Fukushima nuclear disaster? Investigations have shown that the Fukushima accident was not caused by the earthquake itself, but by the subsequent tsunami. 

The risk of a tsunami at Doel and Tihange is virtually non-existent. Floods, spring tides or tidal waves are possible, although the probability is also very low. Belgium's nuclear power plants have been fittend with the necessary protection and safety mechanisms to cope with high water levels and floods, now and in the future.

The design of the Belgian nuclear power plants is also very different from the Japanese power stations at Fukushima. The Belgian power stations are pressurized water reactors (PWR). Our power stations contain multiple barriers between the radioactive substances and the outside world. The uranium pellets are contained in sealed fuel rods which are placed in the reactor vessel. The steel reactor vessel has a thickness of 20 cm and is located in the reactor building. The reactor building is composed of 2 concrete walls, each of 1 metre thickness. 

Would you like to know more about how the safety of our Belgian nuclear power plants is guaranteed? Then click here.

What lessons were learned from these accidents?

After the disaster in Fukushima, all European sites with nuclear installations were subjected to tests by the European Union, the so-called ‘stress tests’. These tests checked to what extent the installation is resistant to extreme natural phenomena. In Belgium, security bodies also decided to examine their resistance to human acts such as terrorism and cyber attacks. The tests showed that the Belgian power stations were among the most robust in Europe. More information on these stress tests can be found on the Federal Agency for Nuclear Control website (FR).

What investments were carried out in our power stations after these Belgian Stress Tests (BEST)?

The total amount of additional investments under BEST is about 200 million euros. These investments contribute to the continuous improvement of the nuclear safety of the installations and make them resistant against the most extreme situations.

An overview of investments made:

• All reactor buildings are equipped with a special filtering system, which - in the very unlikely event of a nuclear accident - reduces the possible emission of radioactive particles to an absolute minimum.
• The stations are fitted with additional shielding to protect systems against flooding. Specifically in Tihange, a wall was built to protect against severe flooding. This structure protects the entire site from flooding during an exceptionally high water level of the Meuse River. The complex structure is 2.3 meters high and 1.8 kilometers long and is equipped with locks, drains and pumps. The wall was completed in October 2015.
• The fire safety infrastructure has been expanded.
• New earthquake-resistant buildings with additional safety features for exceptional external conditions have been constructed, consisting of both mobile (diesel generators, pumps, firefighting equipment and vehicles, etc.) and fixed equipment (e.g., additional control room in bunker). 
• The earthquake resistance of key safety systems has also been bolstered.
• Certain safety systems have been expanded, for example, those that ensure the cooling of the reactor core in accident conditions.
• At both sites, staff training programs and emergency planning organization were strengthened to manage events at several units simultaneously.