Updated on February 4, 2019

After the fire we announced that we would keep the public fully informed. The following questions and answers will transparently answer possible questions and provide further information.

What exactly happened?

On the evening of December 6, 2018 a small fire with thick smoke emission was detected in one of the Advanced Nuclear Fuels GmbH (ANF) laboratory rooms in Lingen. A fire alarm was sounded. The fire was extinguished by ANF’s fire fighters and local voluntary fire brigades. Nobody was injured and there were no harmful effects on the population or the environment. The relevant authorities immediately started investigations into the causes of the fire. They will be fully supported by us.

What exactly caught fire?

An evaporator caught fire. This instrument serves to evaporate aqueous, non-flammable solutions, which are produced during laboratory operations. The size of the evaporator is approximately 2 by 3 by 1 meters (H x W x D). A 40 by 40 cm part of the device was burning at the time the emergency personnel arrived.

Which materials were affected by the fire?

Plastic components of the evaporator were set on fire. At the time of the fire a small amount of uranium was present in the evaporator. There was no release of radioactive substances into the environment. This has been confirmed by the measurements carried out by the fire brigade and the Lower Saxony Ministry of Environment, Energy, Construction and Climate Protection (NMU).

Where are the laboratory rooms located?

The laboratory affected is located in the nuclear factory building in a room that is separated from the nuclear production facilities. This part of the building has a slight negative pressure that directs the air flow into the building’s interior.   

What is the purpose of the laboratories?

In the laboratory rooms various analyses are conducted for quality inspection of fuel assemblies. Analyses of the uranium of which nuclear fuel is made require the preparation of samples and this produces aqueous, non-flammable solutions.

How exactly did this fire happen?

The Lower Saxony Ministry of Environment, Energy, Building and Climate Protection (NMU) has confirmed that the analysis of the cause of fire has been completed. The analysis corroborated previous assumptions on the cause: the fire on December 6, 2018 was caused by a technical defect in a heating element.

Due to an invisible electrical error at the connections of two heating cassettes of the heating plate of the laboratory evaporator, the metallic housing parts were heated to a high temperature. The subsequent strong heat radiation decomposed the polypropylene (PP) tabletop underneath. As a result, flammable gases were produced which ignited on the hot surfaces of the heating plate housing and led to the fire on the evening of December 6, 2018. 

Why didn’t ANF already make an earlier statement on the possible cause of fire and its consequences?

The investigations into the cause of the laboratory fire have now been completed. The Lower Saxony Ministry of Environment, Energy, Building and Climate Protection (NMU) has the sovereignty over the determination of the causes and the ministry has commissioned experts for this.

Details of the fire and an interim report on the possible cause were announced by the Lower Saxony nuclear supervisory authority in the afternoon of December 11, 2018 at a special meeting of the environmental committee of the Lower Saxony state parliament. At this meeting, the working hypothesis that an hydrogen (H2) explosion could have occurred – which was not confirmed and provisional at the time – was also presented. This working hypothesis was rejected in the course of the further investigation by new findings.

On January 16, 2019, the ministry disclosed the final results of the investigation. The results indicate that the fire was caused by a technical defect in a heating element.

The investigation of the cause of fire and its communication was coordinated together with the authorities and has our full support.

Was uranium released after the fire into the environment?

No, there was no release. On the one hand, this has been confirmed by the measurements carried out by the fire brigade directly after the fire. In addition, the Lower Saxony Ministry of Environment, Energy, Construction and Climate Protection (NMU) also confirmed these results on December 21, 2018 following independent measurements. A slight subatmospheric pressure is maintained in the nuclear facility, so that the air flow is always directed inwards. The exhaust air of the rooms passes through filters before being discharged. The exhaust air system and the filters were not affected by the fire and were therefore fully operable at all times.

How is the fire assessed and followed-up by the local authority?

The responsible regulatory and licensing authority has classified the fire as a class N reportable event. “N” means “normal reporting” which requires the operator to fully inform the authority about the event within five days. Advanced Nuclear Fuels GmbH (ANF) has completely fulfilled this duty.

What lessons does ANF learn from the fire?

The safety of people and the environment is a top priority of the Advanced Nuclear Fuels GmbH (ANF). This is why we took initiative immediately after the fire and developed a testing concept which was examined by the Lower Saxony Ministry of Environment, Energy, Construction and Climate Protection (NMU) and the TÜV. The testing concept ensures that the event cannot be transferred to other areas of fuel assembly production. The so-called transferability test was carried out together with external experts. According to the results of the finalized investigation, various measures and recommendations must be realized. These include subsequent technical and functional examinations of safety-relevant facilities as well as the precautionary replacement of materials.

Has the production been resumed?

The Lower Saxony Ministry for the Environment, Energy, Construction and Climate Protection (NMU) has granted the fuel element production of Advanced Nuclear Fuels GmbH (ANF) in Lingen permission to resume production on February 1, 2019.