Greenpeace airship says "Nuclear energy never safe!"

Belgium's nuclear crisis continued this week with a fire and explosion at the Tihange nuclear power plant. The fire began in the electrical substation transformer building at approximately 10.30am on Sunday, December 1 and led to an emergency shutdown of reactor unit 3. The 29 year old Tihange nuclear reactor is located near Liege and is 70 kilometers west of the city of Aachen. The fire was put out by the local fire service. The reactor restarted at 5.00am on December 2.

Fires at nuclear power plants pose significant risks to reactor safety due to the potential disruption of the electrical supply to vital reactor safety functions. (In 2008, Jack Grobe, Associate Director for Engineering and Safety Systems, Office of Nuclear Reactor Regulatory, Nuclear Regulatory Commission, said: "Approximately one-half of the core damage risk at operating reactors results from accident sequences that initiate with fire events.")

The transformer at a power plant converts the electricity current generated before it enters the main electrical grid. There have been numerous fires at nuclear power plants in recent years, including at the Krummel plant in Germany and at the Arkansas reactor in the United States. A fire of an oil-cooled transformer that contains several thousand litres of combustible insulating oil can result in severe damage to nearby power plant structural components such as concrete walls, and damage or destroy electrical components.

Tihange's operator Electrabel stressed that the cause of the fire was a technical failure rather than sabotage. The Belgium nuclear industry was shaken in August 2014 when it was revealed that sabotage had caused major damage at the Doel nuclear power plant. Doel's reactor 4 remains shutdown and is undergoing repairs.

The nuclear industry is in crisis in Belgium. The Tihange reactor 2 and Doel reactor 3 have been shutdown since March 2014 due to the discovery of thousands of serious cracks in their reactor core pressure vessels. Investigations are on-going into the extent and cause of the cracks, while Greenpeace has been demanding the release of research tests results on the reactors.

The remaining operating reactors are the oldest in Belgium. In July 2013, Belgium's Council of Ministers made an agreement to close the twin Doel 1 and 2 reactors in 2015, but the nuclear industry is pushing to have their lives extended due in part to the crisis with their newer reactors.

Action at Tihange Nuclear Power Plant in Belgium. Climbers from Greenpeace Belgium hang a banner with the slogan "The End" from a cooling tower during a protest at the Tihange power plant in Belgium. Greenpeace activists are protesting against ageing nuclear power plants in Europe. 03/05/2014 © Nick Hannes / GreenpeaceAction at Tihange Nuclear Power Plant in Belgium (03/05/2014 © Nick Hannes / Greenpeace)

Greenpeace has been demanding a complete phase out of nuclear power in Belgium due to the accident risks from their ageing reactors, including protests at Tihange earlier this year.

Shaun Burnie is a senior nuclear campaigner with Greenpeace Germany.