The Saint-Laurent-des-Eaux nuclear power plant is an operating nuclear power facility located in the heart of France, in the Centre-Loire Valley region.
This plant has been the site of two significant nuclear accidents, both classified as level 4 on the INES (International Nuclear Event Scale), which occurred in 1969 and 1980. These incidents marked a turning point in both public perception and nuclear energy policy in France, influencing nuclear safety policies and the management of nuclear power plants across the country.
Location and characteristics of the plant
The nuclear power plant is located in the commune of Saint-Laurent-Noin, in the Loire-et-Cher department, on the banks of the Loire River, approximately 30 km southwest of Orleans, a key city in the region. Nearby, approximately 70 km to the east, is the Dampierre nuclear power plant, another major energy facility in the region.
The plant has four power units, two of which are shut down. The two operating units feature Framatome-designed pressurized light water reactors (PWRs), each with a capacity of 965 megawatts.
The decommissioned units, using UNGG (uranium-graphite-gas) technology, were in operation during the plant's early years, and were later replaced by more modern pressurized water reactors.
Nuclear accident of 1969
On March 24, 1969, the Saint-Laurent-des-Eaux nuclear power plant launched its first UNGG reactor, a pioneering model in French nuclear energy. However, just six months after its activation, the plant suffered one of the most serious accidents in the history of nuclear energy, both in France and worldwide.
On the night of October 17, 1969, during refueling, a system failure combined with human error caused a partial meltdown of the reactor core. The result was 50 kg of uranium, 47 kg of which was later recovered, including manually by the employees involved in the cleanup.
Classification on the INES scale
This incident was classified as level 4 on the INES scale, making it one of the most serious nuclear accidents in the history of French nuclear power plants.
Despite the magnitude of the event, there was no significant leakage of radiation into the surroundings.
Consequences
After an exhaustive repair and overhaul process, the A-1 reactor was restarted on October 16, 1970, although the accident left an indelible mark on France's nuclear industry and its energy policies.
Public opinion on the risks of nuclear energy was seriously challenged, fueling a national debate about the pros and cons of this energy source.
Nuclear accident of 1980
More than a decade later, on March 13, 1980, the Saint-Laurent-des-Eaux nuclear power plant again suffered a nuclear accident. This time, the A-2 reactor suffered an uncontrolled increase in nuclear fission activity.
The increase in thermal energy in the reactor reached dangerous levels, leading to a meltdown of the reactor core. As a result of this incident, 20 kg of nuclear fuel melted, representing another serious event for the French nuclear industry.
The accident was again classified as level 4 on the INES scale, the same as the one that occurred in 1969.
Classification on the INES scale
In this case, the cause was a failure in the reactor's own components, which caused two fuel rods to melt. Although safety measures, such as the control rods, were in place, they were not sufficient to prevent the disaster.
Consequences of the accident
As a result, plant personnel had to release radioactive iodine into the atmosphere from March 22 to 26, 1980, in an attempt to prevent radioactivity levels in the cooling system from reaching dangerous levels.
Following the accident, a grueling 29-month cleanup of the affected reactor began. More than 500 specialists worked to remove the molten uranium residue.
In addition to radioactive iodine, radioactive particles were suspected of leaking into the atmosphere and the Loire River, raising additional concerns about the environmental consequences.
The A-2 reactor was finally restored in 1983, but continued to operate until its final closure in 1992.
Impact and repercussions
These two accidents at the Saint-Laurent-des-Eaux nuclear power plant had a profound impact on the French nuclear industry and on public perceptions of nuclear plant safety. The plant underwent numerous revisions to its safety protocols and technological improvements to prevent future incidents.
Furthermore, the series of incidents contributed to the tightening of nuclear safety regulations in France and increased scrutiny of nuclear power plant operations across the country.
The debate over nuclear energy in France has remained a hot topic over the years, especially after the accidents, although the nuclear industry remains a pillar of national energy policy.
Current status of the Saint-Laurent-des-Eaux power station
The Saint-Laurent-des-Eaux nuclear power plant, located in the Centre-Loire Valley region, remains in operation with two of its four units active.
These operating units feature Framatome-designed pressurized light water reactors (PWRs), each with a capacity of 965 MW. These more modern reactors replaced the older UNGG reactors, which were decommissioned due to their obsolescence and safety concerns arising from accidents at the plant.
The plant's two oldest units, which used UNGG (uranium-graphite-gas) technology, were shut down in the 1980s and 1990s. These reactors were subject to several serious incidents, leading to their permanent closure.
The plant is currently focusing on its more efficient and safer light water reactors, although power output has decreased compared to its previous capacity due to the closure of older units.
Despite these changes, Saint-Laurent-des-Eaux remains a vital part of France's electricity grid. The plant is undergoing strict reviews and improvements to its safety systems, in line with national nuclear energy regulations.
In the future, further adjustments to the plant's infrastructure are likely as France moves toward greater sustainability and diversification in its energy mix.