Dismantling of a nuclear power plant Source: BASE / Michael Meier

In Germany, the decision to gradually phase out nuclear power had already been taken about 10 years before the Fukushima reactor accident. Following a wide public debate, the Atomic Energy Act was amended accordingly on April 22, 2002.

The aim was to phase out nuclear energy for the commercial generation of electricity in an orderly manner. To this end, each nuclear power plant was assigned a residual electricity volume such that the total output of the respective plant corresponded to an average 32 year lifetime. The construction of new nuclear power plants was banned altogether.

In the following years, the first plants were shut down as their output had reached the assigned electricity volume. The Stade nuclear power plant, for example, was shut down on November 14, 2003, and the Obrigheim nuclear power plant was finally decommissioned on May 11, 2005.

Lifetime extension

At the time, however, the 2002 decision to gradually phase out nuclear power was not based on a sustainable political consensus. A few years later, in September 2010, a new German government presented a new energy concept. Although this new concept remained, in principle, committed to the 2002 nuclear phase-out, it now classified nuclear power a necessary ‘bridging technology’ toward a renewables-based energy system.

As a result, in December 2010, a further amendment to the Atomic Energy Act extended the lifespans of Germany's nuclear power plants and expanded the electricity volumes specified in 2002. All other stipulations from the 2002 Atomic Energy Act - such as the ban on the new construction of nuclear power plants - remained in place.

The U-turn after Fukushima

Germany saw another U-turn immediately after the Fukushima nuclear disaster on March 11, 2011.

Just three days after the catastrophic accident - on March 14, 2011 - the German government made a series of political decisions that became known as the "nuclear moratorium."

All nuclear power plants (and eventually all other types of nuclear facilities) had to undergo an extensive safety and robustness screening - the so-called stress test. The risks of nuclear energy dominated the public debate at this time.

Renewed amendment of the Atomic Energy Act

The German government convened an ethics commission to advise on the future of nuclear energy in Germany. The ethics commission concluded that it was possible to phase out nuclear energy completely within a decade.

Based on this assessment, another amendment to the Atomic Energy Act was made on August 6, 2011: The December 2010 lifetime extension was cancelled and the electricity volumes originally assigned in 2002 were reinstated.

Eight nuclear power plants were not granted authorization for further power operation when the new Atomic Energy Act came into force on August 6, 2011. This concerned the nuclear power plants Biblis A, Neckarwestheim 1, Biblis B, Brunsbüttel, Isar 1, Unterweser, Philippsburg 1 and Krümmel. The Grafenrheinfeld, Gundremmingen B and Philippsburg 2 nuclear power plants were also shut down permanently in 2015, 2017 and 2019 respectively.

Ten years after the Fukushima reactor accident, by March 11, 2021, the nuclear phase-out in Germany was be almost fully completed. Only three nuclear power plants are still authorized to operate at full capacity. The Grohnde, Gundremmingen C and Brokdorf nuclear power plants were shut down by the end of 2021, and the Isar 2, Emsland and Neckarwestheim 2 nuclear power plants, currently still in operation, are to be shut down by the end of 2022 at the latest.

Further details on Germany’s nuclear phase-out can be found in BASE's technical report "10 Years after Fukushima - Rethinking Safety".

The Grohnde nuclear power plant was shut down on 31 December 2021 Source: BGZ mbH

The events at Fukushima triggered a sequence of investigations regarding the safety and robustness of nuclear power plants in Germany.

Nuclear regulatory authorities worldwide were very interested in the root cause analysis of the Fukushima Daiichi accident, not just to understand and evaluate the developments in Japan but also the radiological consequences for their own countries. The question of the potential safety of nuclear power plants in the respective countries also needed clarifying. The Fukushima Daiichi accident was the first of such severity in a light-water reactor of Western design.

Procedure in Germany

An initial plant-specific safety review of German nuclear power plants by the Reactor Safety Commission (RSK) - an advisory body to the German Federal Ministry for the Environment - was followed by further investigations regarding the robustness of German nuclear power plants: the so-called stress test was carried out. This was integrated into the European procedure for examining the safety of nuclear power plants in the EU.

The investigations in Germany were based on the recommendations of the RSK and the expert organization for facility and reactor safety, Gesellschaft für Anlagen- und Reaktorsicherheit (GRS), among others.

Results for Germany

The German report on the EU stress test showed that the German nuclear power plants possessed a high degree of robustness with regard to the following key issues:

1. external events;
2. failures of safety functions;
3. emergency measures in case of severe accidents.

This was due to their original design and to previous retrofitting measures, especially in the field of emergency measures. However, the report also identified further possible improvements in the area of emergency preparedness, which the regulators subsequently followed up on.

In addition to these three main topics, the German report dealt with the mutual influence of accidents between neighbouring plants. Furthermore, it also considered the RSK's statements on civilizational impacts such as aircraft crashes, off-site gas explosions and terrorist attacks.

Corresponding stress tests were also carried out for other nuclear facilities in Germany, such as research reactors, nuclear fuel supply facilities and interim and final storage facilities for radioactive waste. The tests confirmed a high level of robustness for those facilities as well.

Further details on the safety and robustness screenings of nuclear facilities can be found in BASE’s technical report "10 Years after Fukushima: Rethinking Safety."

Nuclear safety in Germany is ensured by numerous legal provisions and technical regulations that license holders of German nuclear power plants are obliged to comply with. Licensing and supervisory authorities work with expert organizations to verify compliance and implementation.

The legal basis for German nuclear power plants is the hierarchically structured set of nuclear regulations. The Atomic Energy Act and the Radiation Protection Act are superordinate and binding. They are supplemented by ordinances and general administrative regulations.

The subordinate nuclear regulatory guidelines specify the legal requirements and include, among other things

• Safety requirements for nuclear power plants
• Announcements of the BMU/BMI
• Recommendations of the RSK, Nuclear Waste Management Commission (ESK) and the Commission on Radiological Protection (SSK) and
• Rules of the Nuclear Safety Standards Commission (KTA).

In 2021, the safety requirements for nuclear power plants marked the beginning of a modernisation and revision of the existing nuclear regulatory guidelines. The plant-internal emergency protection and the so-called staggered safety concept were implemented in the subordinate regulatory framework, taking into account findings from the catastrophic accident at the Fukushima Daiichi nuclear power plant. Emergency protection was also incorporated into the Atomic Energy Act and the Radiation Protection Act.
RSK recommendations to increase robustness were also included in the German nuclear regulatory guidelines, e.g. in KTA safety standards. Many aspects had already been considered after the accidents at the Three Miles Island (USA) and Chernobyl (Ukraine) nuclear power plants and the nuclear regulatory guidelines only needed minor adaptations. The focus was on earthquakes, floods, the waterproofing of buildings and on energy and media supply. No significant changes to the content of the KTA safety standards were necessary.

BASE’s technical report on the 10th anniversary of the Fukushima nuclear disaster provides further information on the adaptation of the nuclear regulatory guidelines in Germany.