Fessenheim Nuclear Power Plant

Fessenheim Nuclear Power Station
Company type	Nuclear power plant
Industry	Energy
Founded	1970
Headquarters	Fessenheim, France
Products	Electricity generation (nuclear)
Number of employees	700

The Fessenheim Nuclear Power Station is situated within the commune of Fessenheim in the Haut-Rhin department of the Grand Est region in northeastern France. It lies roughly northeast of Mulhouse, less than from the German frontier, and about away from Switzerland. Unit 1 ceased operations in February 2020, followed by Unit 2 on June 29, 2020.

Description

The facility consisted of two pressurized water reactor units, each with an output capacity of 920 MWe. Construction commenced in 1970, and the plant began operation in 1977. It utilized approximately of cooling water annually drawn from the nearby Grand Canal d'Alsace, which channels water from the Upper Rhine river.

Approximately 700 employees worked at the plant alongside 200 contractors, with an additional 600 to 2,000 personnel indirectly involved during maintenance activities. The plant contributed nearly €16 million each year in local taxes, accounting for 70% of the revenue for the Fessenheim commune.

In October 2009, Reactor 1 underwent its third decennial inspection prior to a decision on extending its operational life. Authorization was granted in 2011 to continue running Reactor 1 until its definitive shutdown on February 22, 2020. Reactor 2 was inspected in April 2011 and permanently closed on June 29, 2020. The local Information and Oversight Commission commissioned GSIEN to perform an independent parallel review alongside the formal assessment conducted by the Nuclear Safety Authority.

Technical data

Unit	Type / Model	Net Capacity	Gross Capacity	Thermal Capacity	Construction Start	First Criticality	Grid Connection	Commercial Operation	Permanent Shutdown
Fessen- heim 1	PWR / CP0	880 MW	920 MW	2785 MW	1971-09-01	1977-02-07	1977-04-06	1978-01-01	2020-02-22
Fessen- heim 2	PWR / CP0	880 MW	920 MW	2785 MW	1972-02-01	1977-06-27	1977-10-07	1978-04-01	2020-06-30

Selected incidents and accidents

On April 9, 2014, overfilling of a tank within the non-nuclear cooling circuit caused water to spill into zones adjacent to Unit 1's control room, damaging electrical equipment associated with nuclear control systems. This incident disabled one of two redundant reactor protection systems as well as the visual indicators for reactor control rods, necessitating a shutdown via boron injection. By April 11, the reactor had reached a maintenance cold shutdown state. The event was classified as 'level 1' on the International Nuclear Event Scale (INES). Following repairs, Unit 1 was reconnected to the grid on May 28, 2014.
On September 5, 2012, steam release during a minor chemical incident caused mild injuries to two employees and triggered fire alarms.
An operator error on April 10, 2011 led to an automatic reactor shutdown without further consequences; this was also rated 'level 1' on INES.
On December 27, 2009, plant debris partially obstructed flow at the Essential Service Water System intake; however, flow rates remained adequate to ensure safety standards. This incident received a 'level 1' INES rating.
Radioactive resin contamination occurred in Unit 1's primary circuit water on January 24, 2004. This clogged filters and threatened pump joint integrity. During filter replacement and cleanup operations, seven EDF workers inhaled radioactive dust; one experienced minor radiation exposure. The event was rated 'level 1' on INES.

Risks

The Fessenheim nuclear facility is subject to particular hazards related to earthquakes and flooding, which have continuously raised questions about the sufficiency of its original design.

Seismicity

The majority of the Haut-Rhin département, including the area around Fessenheim, is classified within a moderate seismic risk zone, with the southern portion designated as medium-risk. Notable seismic occurrences in the region include a 3.9 magnitude tremor near Flaxlanden in September 2022 and a 4.7 magnitude quake at Sierentz dating back to 1980. The most significant historical earthquake in the vicinity was the 1356 Basel earthquake, estimated to have reached a magnitude as high as 7.1.

A 2007 analysis commissioned by Basel-Stadt challenged earlier seismic hazard evaluations conducted by EDF and the Institut de radioprotection et de sûreté nucléaire (IRSN), suggesting they underestimated the risks involved. The report emphasized inadequate precision in pinpointing the fault responsible for the 1356 quake, which impacts localized risk assessments for the site. Scientific opinions vary regarding which faults were implicated, the earthquake’s strength (ranging from 6.0 to 7.1), and their proximity to Fessenheim (between 2 km and 40 km), differing from EDF and IRSN’s estimation of approximately 29–34 km. The critique also highlighted EDF’s omission of moderate local earthquakes that could pose greater threats than more distant but larger events, and it questioned certain elements of the RFS 2001-01 regulations. Although the plant was engineered to withstand seismic activity comparable to that considered for public buildings at the time of construction, uncertainties remain regarding safety margins under revised seismic criteria.

On March 11, 2011, following the Fukushima disaster, the local Information and Oversight Commission commissioned two independent assessments: one evaluating plant resilience against a magnitude 7.2 earthquake, reflecting updated Swiss expert standards, and another examining redundancy in cooling systems during flooding events. The GSIEN was assigned responsibility for one of these evaluations.

Flood

Situated approximately below the neighboring Grand Canal d'Alsace, it is uncertain whether design methodologies from the 1960s fully addressed potential consequences of a canal breach. After the 1999 Blayais Nuclear Power Plant flood, the Institute for Nuclear Protection and Safety recommended a reassessment of Fessenheim’s flood vulnerability due to its proximity to this waterway.

On March 11, 2011, an urgent report was commissioned by the local Information and Oversight Commission concerning cooling system redundancy under flooding conditions. Additionally, an investigation was initiated to determine necessary safety enhancements against possible canal breaches, with results anticipated by June 2011.

Aquifer

The facility is constructed atop the extensive Fossé rhénan (Oberrhein Aquifer), where any contamination would have severe consequences. To safeguard this vital water resource, a concrete slab was installed beneath the reactor structure as a protective barrier.

Cooling water

In August 2018, during an intense heatwave, operations were temporarily halted to avoid excessive warming of cooling water discharged into the adjacent river.

Opposition

Resistance to the Fessenheim plant began alongside its initial proposal in the 1970s; notably, in June 1977, the pirate radio station Radio Verte Fessenheim commenced broadcasts opposing it.

Concerns over seismic safety escalated following the 2011 Fukushima nuclear incident. The local Information and Oversight Commission advocated for re-examining seismic risks based on a magnitude 7.2 earthquake scenario, whereas original designs accounted for up to magnitude 6.7. The Swiss cantons of Basel-Stadt, Basel-Landschaft, and Jura called on France to suspend plant operations pending thorough safety reviews. Similarly, Baden-Württemberg in Germany urged temporary closure, consistent with Germany’s policy of shutting down reactors built before 1981.

On March 29, the Franche-Comté Regional Council became the first French regional authority to vote in favor of closure. Subsequently, Basel-Stadt’s Grand Council and Strasbourg’s city council also endorsed shutting down Fessenheim. Members of the European Parliament affiliated with Green parties supported closure initiatives and referred concerns to the European Commission. Large-scale protests near the site attracted thousands of participants; meanwhile, Stop Fessenheim gathered over 63,000 signatures demanding shutdown and organized a continuous fasting relay lasting 366 days outside Colmar’s préfecture.

Although designed for a four-decade operational life span, anti-nuclear organization Sortir du nucléaire pressed for immediate closure upon reaching its thirtieth anniversary. The Tri-national Nuclear Protection Action Group (ATPN), representing interests from France, Germany, and Switzerland, campaigned against continued operation and unsuccessfully sought judicial orders for closure in both 2008 and March 2011 on grounds related to seismic and flood hazards.

The formal establishment of Stop Fessenheim occurred in 2005 after informal activism since 2004.

Fessenheim is among several French nuclear facilities opposed by neighboring countries, alongside others such as Cattenom and Bugey.

Attacks and sabotage

During the construction phase on May 3, 1975, two explosive devices detonated at the Fessenheim Nuclear Power Station, inflicting damage and postponing its completion. Fortunately, no one was harmed. The responsibility for this assault was claimed by the group known as "Commando Puig Antich – Ulrike Meinhof".

On June 2, 1980, unknown assailants discharged firearms at security personnel guarding the facility; no injuries were reported.

Closure announcements

After winning the presidency in 2012, François Hollande confirmed intentions to shut down Fessenheim by 2017. Later that year, an official directive set the closure deadline for the end of 2016. By September 2015, Minister Ségolène Royal expressed a goal to complete the shutdown before Hollande’s presidential term concluded in May 2017, additionally proposing to convert the site into a Tesla manufacturing plant.

In June 2016, EDF requested financial compensation from the government; by August, a settlement amounting to €400 million had been agreed upon. On April 9, 2017, a formal closure order was issued contingent upon activation of the Flamanville 3 reactor (originally scheduled for late 2018 but subsequently postponed to 2019), ensuring that France’s nuclear capacity stayed below the legal cap of 63.2 GWe.

In November 2018, President Emmanuel Macron declared that both reactors would cease operations by early 2020. This timeline was later refined in 2019, setting unit 1’s closure for February and unit 2’s for June of that year.

Opposition to the plant’s shutdown came from industry stakeholders. Both the World Nuclear Association and the Director General of the Société française d’énergie nucléaire cautioned that phasing out this low-carbon energy source would lead to increased reliance on fossil fuels. Estimates indicate that closing Fessenheim will result in an annual rise of approximately 10 million tonnes of CO2 emissions due to substitution with gas-fired power plants rather than renewables.

Popular culture

The 1976 American movie The Enforcer, part of the Dirty Harry franchise, features a scene portraying two bomb explosions at the Fessenheim Nuclear Power Plant.

External links

Fessenheim, Nuclear Engineering International wall chart, September 1975
France 24: The nuclear plant that Germans want to shut down – in France (video)