The Saint-Laurent

Nuclear Power Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions. Presently, the vast majority of electricity from nuclear power is produced b ...

Station is located in the commune of

Saint-Laurent-Nouan Saint-Laurent-Nouan (, ) is a commune in the Loir-et-Cher department, central France. History Saint-Laurent-Nouan was formed in 1972 from the merger of the two former communes, Saint-Laurent-des-Eaux and Nouan-sur-Loire. Population See als ...

Loir-et-Cher Loir-et-Cher (, ) is a department in the Centre-Val de Loire region of France. Its name is originated from two rivers which cross it, the Loir in its northern part and the Cher in its southern part. Its prefecture is Blois. The INSEE and La P ...

on the

Loire The Loire (, also ; ; oc, Léger, ; la, Liger) is the longest river in France and the 171st longest in the world. With a length of , it drains , more than a fifth of France's land, while its average discharge is only half that of the Rhône ...

– 28 km upstream from

Blois Blois ( ; ) is a commune and the capital city of Loir-et-Cher department, in Centre-Val de Loire, France, on the banks of the lower Loire river between Orléans and Tours. With 45,898 inhabitants by 2019, Blois is the most populated city of the ...

and 30 km downstream from

Orléans Orléans (;"Orleans"
(US) and pressurized water reactor A pressurized water reactor (PWR) is a type of light-water reactor, light-water nuclear reactor. PWRs constitute the large majority of the world's nuclear power plants (with notable exceptions being the UK, Japan and Canada). In a PWR, the primary ...

s (each 900MWe), which began operation in 1983. They are cooled by the water of the Loire River. Two other

UNGG reactor The UNGG (''Uranium Naturel Graphite Gaz'') is an obsolete nuclear power reactor design developed in France. It was graphite neutron moderator, moderated, cooled by carbon dioxide, and fueled with natural uranium metal. The first generation of ...

s used to exist at the site, which were brought into service in 1969 and 1971 and were retired in April 1990 and June 1992. The site employs approximately 670 regular workers.

Incidents

On 17 October 1969, 50 kg of

uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...

in one of the gas-cooled reactors began to melt. This event was classified at 4 on the

International Nuclear Event Scale The International Nuclear and Radiological Event Scale (INES) was introduced in 1990 by the International Atomic Energy Agency (IAEA) in order to enable prompt communication of safety significant information in case of nuclear accidents. The s ...

(INES), and is, as of December 2011, the most severe civil nuclear power accident in France.Les Echos - 18/03/11 - A Saint-Laurent, EDF a renoncé à construire une digue contre les inondations
Les Echos, published 2011-03-18, accessed 30 March 2011 On 13 March 1980, there was some annealing that occurred in the

graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on large ...

of one of the reactors, causing a brief heat excursion. This was also classified as 4 on the INES and has been called another worst nuclear accident in France. Much later, the Institute of Marine Geochemistry at the ''École normale supérieure'' claimed that they found traces of

plutonium Plutonium is a radioactive chemical element with the symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibi ...

in the river they believed was released in the 1980 or 1969 accident. However, tests conducted in 1993 by the

IPSN IPSN, the IEEE/ACM International Conference on Information Processing in Sensor Networks, is an academic conference on sensor networks with its main focus on information processing aspects of sensor networks. IPSN draws upon many disciplines incl ...

and in 2003 by the IRSN determined that the levels of plutonium measured upstream and downstream from the power plant were similar and of the same order of magnitude, concluding that the presence of the plutonium was due to the fallout of aerial nuclear tests and not due to either the 1980 or 1969 accidents. On the morning of 12 January 1987 at 9 h 30, due to the exceptional frost of Loire, ice-clogged the water intakes from the central A1 (GCR) and resulted in the loss of normal cooling. This caused the automatic shutdown of the gas-graphite reactor. The cooling system needed to remove the residual power failed as the diesel generators failed to start. It was necessary to feed it by the western power grid of France. The generators were eventually returned to service, just before the collapse of the power grid which took place around noon after a failure of the thermal power Cordemais. The army was then called in to use explosives and destroy the ice blocking the water intakes. On 12 May 2004, radioactive sodium was released into the atmosphere during a leak test of new steam generators of one of the reactors at the B plant. The incident, which resulted in the automatic shutdown of the reactor, was of no consequence for the environment according to

EDF EDF may refer to: Organisations * Eclaireurs de France, a French Scouting association * Education for Development Foundation, a Thai charity * Électricité de France, a French energy company ** EDF Energy, their British subsidiary ** EDF Luminus, ...

. Sortir du nucléaire noted however that when the automatic shutdown of the reactor happened, the control rods remained blocked for unknown reasons. On 19 August 2011, reactor #1 stopped after a failure. '' unexpected shutdown of the reactor 1 of the St-Laurent-des-Eaux ''
Trading on Sat 19 August 2011

Flood risk

The initial report following the

1999 Blayais Nuclear Power Plant flood The 1999 Blayais Nuclear Power Plant flood was a flood that took place on the evening of December 27, 1999. It was caused when a combination of the tide and high winds from the extratropical storm Martin led to the seawalls of the Blayais Nucl ...

, identified the Saint-Laurent plant as being at risk of flooding, and called for its safety measures to be re-examined.Rapport sur l'inondation du site du Blayais survenue le 27 décembre 1999
Institute for Nuclear Protection and Safety, published 2000-01-17, accessed 21 March 2011 Plans to build a

flood wall A flood wall (or floodwall) is a primarily vertical artificial barrier designed to temporarily contain the waters of a river or other waterway which may rise to unusual levels during seasonal or extreme weather events. Flood walls are mainly u ...

around the site were made but abandoned, it is thought, due to the cost.

Gallery

Image:Centrale-nucleaire-Saint-Laurent-des-Eaux.jpg,

Sunflowers ''Helianthus'' () is a genus comprising about 70 species of annual and perennial flowering plants in the daisy family Asteraceae commonly known as sunflowers. Except for three South American species, the species of ''Helianthus'' are native to N ...

and the nuclear power station Image:A1 A2 saint laurent.JPG, The two GGRs Image:Saint-Laurent des Eaux Centrale (2).jpg, The two GGRs Image:Saint-Laurent des Eaux Centrale (1).jpg, The nuclear power plant

References

External links

St Laurent des eaux (UNGG reactors)
Nuclear Engineering International wall chart, August 1969 {{Authority control Nuclear power stations in France Nuclear power stations using pressurized water reactors Graphite moderated reactors Nuclear power stations with closed reactors