Goesgen Nuclear Power Plant
Encyclopedia
The Gösgen Nuclear Power Plant (in German Kernkraftwerk Gösgen, abbreviated in KKG) is located in the Däniken municipality (canton of Solothurn
, Switzerland) on a loop of the Aar river. It is operated by the ad hoc society Kernkraftwerk Gösgen-Däniken AG.
led the Swiss Federal Council
to order a security check on the Swiss plants that took some months. It eventually entered its commercial phase on . The unlimited operating license was issued on .
Over the years the gross plant output has been increased from the initial 970 MW to 990 MW (1992) and finally to the present 1020 MW by a series of small changes in the reactor configuration and the installation of new low pressure turbines.
The last significant change to the KKG was the construction of a new storage facility for spent rods. It entered operation in 2008.
of the Aar and Rhine waters, already used for the cooling of the Beznau
and Mühleberg
stations and in numerous hydroelectric plants. In March 1971 the Federal Council
forbade the use of river water for direct cooling of new plants. Since the KKG should also have been cooled by the Aar, the project had to be adapted by adding the cooling tower.
With the submission of the construction request in 1972 numerous formal oppositions were presented by groups and individuals at federal, cantonal, and communal level. All were rejected and construction started in 1973. In the meantime the oil crisis
and the resulting awareness of the need of an energy mix diversification decreased the resistance to nuclear power.
The confrontation revived in summer 1977. Over the Pentecost
weekend around 3000 opponents a day participated to a protest march towards the plant construction site. On 2000-3000 activists tried to occupy the accesses to the KKG and had to be dispersed by the police. The same scuffles took place two weeks later between 6000 demonstrators and 1000 policemen. Still the plant got the authorization to start operation in 1979. The continual strong opposition to the KKG induced the federal authorities in 1980 to call a hearing about the plant safety. They concluded that the plant satisfied all legal requirements and could continue operation. In April 1981 the last formal oppositions were rejected by the Federal Council, putting an end to a decade of intense confrontation.
The Chernobyl disaster
rekindled the opposition to nuclear power, which led in 1987 to a cantonal initiative for shutting down the KKG. This was eventually rejected by the Solothurn citizens with a 73% majority. Except for the 10 year building suspension for new plants of 1990, approved by the 52.5%, the same fate has been reserved by the cantonal population to all other federal initiatives proposing anticipated shutdowns or moratoria. In 2007 the cantonal parliament entrusted the government to act in order to promote the building of a new plant in the Niederamt region, between Olten
and Aarau
.
Near to its location it has been proposed to build the new Niederamt Nuclear Power Plant
. Although this is sometimes referred to as Gösgen 2, it should consist in an independent facility.
The KKG possess a pressurized water reactor
delivered by the German Kraftwerk Union AG, a then subsidiary of Siemens AG
and now part of Areva NP
. It contains 177 fuel assemblies, 48 of which are equipped with control elements. Each fuel assembly can hold up to 225 rods, but only 205 (204 for the MOX
ones) are occupied by the fuel. The remaining 20 positions are reserved to the control rods. The reactor in operation contains a total of around 76 t of uranium. It works at 324 °C and 153 bar. The thermal power output achieves 3002 MW.
Three steam generators transfer the heat to the secondary coolant loop at 65 bar and 280 °C. They are fed by three strands, with the addition of two other for start-up or emergency cases. The resulting steam is routed to the turbine, although around 1% is piped to an evaporator where is converted into pressurized process steam eventually delivered to a downstream cardboard facility. The turbine is composed of a high-pressure and three low-pressure units. It generates a net electric power of 970 MW that is delivered to the 400 kV power grid.
After having fed the turbine, the steam is condensed by the tertiary cooling loop, which water is at 22 °C. The output coolant achieves 36 °C and is therefore transferred to the 150 m tall natural draught wet-type cooling tower
that returns it to the initial temperature. 0.4-0.7 out of 31.6 m3/s leave the tower creating the typical plume.
In case of small leakages in the reactor cooling loop, four high-pressure injection pumps (one for each steam generator and a fourth as reserve) would replace the missing water. In case of fast loss of the coolant, six accumulator tanks with a total 3·100% redundancy would flood the reactor until the low-pressure injection pumps could start operation. These four pumps (one for each steam generator and a fourth as reserve) are subdivided in three loops.
If the coolant is lost from the secondary loop the feeding of the three steam generators would be entrusted to the four strands of the emergency feedwater system (one each and a reserve) with a total redundancy of 2×2·100%. In case of extreme failures the cooling would be assured by the two strands of the special emergency feedwater system.
The plant possesses an independent emergency building which purpose is, in extreme cases as plane crashes or explosions, to manage the reactor shutdown and the removal of the decay heat for at least ten hours. It contains the two strands of the special emergency feedwater system and two diesel generators. The plant possess four further emergency diesel generators in two separated building.
The low and medium radioactive operating waste is reconditioned and stored in apposite rooms on the plant site.
(15%), the Centralschweizerischen Kraftwerke (12.5%), and the Energie Wasser Bern (7.5%). The plant management is entrusted to Alpiq.
As of February 2009 no operative nuclear event (INES
level 2 or above) ever occurred. Since 1995 only one anomaly took place. The KKG is remarkable for the absence of any reactor scram
in the last 19 years.
Canton of Solothurn
Solothurn is a canton of Switzerland. It is located in the northwest of Switzerland. The capital is Solothurn.-History:The territory of the canton comprises land acquired by the capital...
, Switzerland) on a loop of the Aar river. It is operated by the ad hoc society Kernkraftwerk Gösgen-Däniken AG.
Construction
The first discussions about the construction of the third Swiss nuclear power plant started in 1966. In 1970 the formal request was submitted to the federal authorities. Initially foreseeing a river water cooling, the blueprints had to be modified in order to meet a new federal regulation that in 1971 forbade such systems for future plants. After the introduction of a cooling tower, the authorities issued the location authorization on . The construction started in summer 1973, after that a series of local permits had been granted. The commissioning was authorized on . The KKG was ready to start operation in February 1979, but the Three Mile Island accidentThree Mile Island accident
The Three Mile Island accident was a core meltdown in Unit 2 of the Three Mile Island Nuclear Generating Station in Dauphin County, Pennsylvania near Harrisburg, United States in 1979....
led the Swiss Federal Council
Swiss Federal Council
The Federal Council is the seven-member executive council which constitutes the federal government of Switzerland and serves as the Swiss collective head of state....
to order a security check on the Swiss plants that took some months. It eventually entered its commercial phase on . The unlimited operating license was issued on .
Over the years the gross plant output has been increased from the initial 970 MW to 990 MW (1992) and finally to the present 1020 MW by a series of small changes in the reactor configuration and the installation of new low pressure turbines.
The last significant change to the KKG was the construction of a new storage facility for spent rods. It entered operation in 2008.
Acceptance
In the 1970s the opposition to the construction of new plants increased in importance. Despite the accident at the Lucens Nuclear Power Plant, the debate mostly regarded technical aspects such as the construction of facilities in densely populated areas or the cooling system. Numerous were the concerns about an overexploitationOverexploitation
Overexploitation, also called overharvesting, refers to harvesting a renewable resource to the point of diminishing returns. Sustained overexploitation can lead to the destruction of the resource...
of the Aar and Rhine waters, already used for the cooling of the Beznau
Beznau Nuclear Power Plant
The Beznau Nuclear Power Plant is located in the municipality Döttingen on an artificial island in the Aar river...
and Mühleberg
Mühleberg Nuclear Power Plant
The Mühleberg Nuclear Power Plant is located in the Mühleberg municipality in the north of the village of Mühleberg and near the hydroelectric plant...
stations and in numerous hydroelectric plants. In March 1971 the Federal Council
Swiss Federal Council
The Federal Council is the seven-member executive council which constitutes the federal government of Switzerland and serves as the Swiss collective head of state....
forbade the use of river water for direct cooling of new plants. Since the KKG should also have been cooled by the Aar, the project had to be adapted by adding the cooling tower.
With the submission of the construction request in 1972 numerous formal oppositions were presented by groups and individuals at federal, cantonal, and communal level. All were rejected and construction started in 1973. In the meantime the oil crisis
1973 oil crisis
The 1973 oil crisis started in October 1973, when the members of Organization of Arab Petroleum Exporting Countries or the OAPEC proclaimed an oil embargo. This was "in response to the U.S. decision to re-supply the Israeli military" during the Yom Kippur war. It lasted until March 1974. With the...
and the resulting awareness of the need of an energy mix diversification decreased the resistance to nuclear power.
The confrontation revived in summer 1977. Over the Pentecost
Pentecost
Pentecost is a prominent feast in the calendar of Ancient Israel celebrating the giving of the Law on Sinai, and also later in the Christian liturgical year commemorating the descent of the Holy Spirit upon the disciples of Christ after the Resurrection of Jesus...
weekend around 3000 opponents a day participated to a protest march towards the plant construction site. On 2000-3000 activists tried to occupy the accesses to the KKG and had to be dispersed by the police. The same scuffles took place two weeks later between 6000 demonstrators and 1000 policemen. Still the plant got the authorization to start operation in 1979. The continual strong opposition to the KKG induced the federal authorities in 1980 to call a hearing about the plant safety. They concluded that the plant satisfied all legal requirements and could continue operation. In April 1981 the last formal oppositions were rejected by the Federal Council, putting an end to a decade of intense confrontation.
The Chernobyl disaster
Chernobyl disaster
The Chernobyl disaster was a nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukraine , which was under the direct jurisdiction of the central authorities in Moscow...
rekindled the opposition to nuclear power, which led in 1987 to a cantonal initiative for shutting down the KKG. This was eventually rejected by the Solothurn citizens with a 73% majority. Except for the 10 year building suspension for new plants of 1990, approved by the 52.5%, the same fate has been reserved by the cantonal population to all other federal initiatives proposing anticipated shutdowns or moratoria. In 2007 the cantonal parliament entrusted the government to act in order to promote the building of a new plant in the Niederamt region, between Olten
Olten
Olten is a town in the canton of Solothurn in Switzerland and capital of the district of the same name.Olten's railway station is within 30 minutes of Zurich, Bern, Basel, and Lucerne by train, and is a rail hub of Switzerland.-History:...
and Aarau
Aarau
Aarau is the capital of the northern Swiss canton of Aargau. The city is also the capital of the district of Aarau. It is German-speaking and predominantly Protestant. Aarau is situated on the Swiss plateau, in the valley of the Aar, on the river's right bank, and at the southern foot of the Jura...
.
Future
The KKG, being in the middle of its original expected lifetime run, should continue to produce clean carbon free power for some decades to come. Therefore no decision about its shutdown or possible substitution has been made.Near to its location it has been proposed to build the new Niederamt Nuclear Power Plant
Niederamt Nuclear Power Plant
The Niederamt Nuclear Power Plant is the name for a planned nuclear power plant near the existing Gösgen Nuclear Power Plant in Niederamt in the Canton of Solothurn between Olten and Aarau in Switzerland...
. Although this is sometimes referred to as Gösgen 2, it should consist in an independent facility.
Reactor and generators
Pressurized water reactor
Pressurized water reactors constitute a large majority of all western nuclear power plants and are one of three types of light water reactor , the other types being boiling water reactors and supercritical water reactors...
delivered by the German Kraftwerk Union AG, a then subsidiary of Siemens AG
Siemens AG
Siemens AG is a German multinational conglomerate company headquartered in Munich, Germany. It is the largest Europe-based electronics and electrical engineering company....
and now part of Areva NP
Areva
AREVA is a French public multinational industrial conglomerate headquartered in the Tour Areva in Courbevoie, Paris. AREVA is mainly known for nuclear power; it also has interests in other energy projects. It was created on 3 September 2001, by the merger of Framatome , Cogema and...
. It contains 177 fuel assemblies, 48 of which are equipped with control elements. Each fuel assembly can hold up to 225 rods, but only 205 (204 for the MOX
Mox
MOX might be a name or acronym for:*Malaysian Oxygen Berhad - A Malaysian company that is specializes in providing total gas solutions.*Mixed Oxide Fuel, from nuclear reprocessing*An alien race in the TimeSplitters 2 video game, the Mox...
ones) are occupied by the fuel. The remaining 20 positions are reserved to the control rods. The reactor in operation contains a total of around 76 t of uranium. It works at 324 °C and 153 bar. The thermal power output achieves 3002 MW.
Three steam generators transfer the heat to the secondary coolant loop at 65 bar and 280 °C. They are fed by three strands, with the addition of two other for start-up or emergency cases. The resulting steam is routed to the turbine, although around 1% is piped to an evaporator where is converted into pressurized process steam eventually delivered to a downstream cardboard facility. The turbine is composed of a high-pressure and three low-pressure units. It generates a net electric power of 970 MW that is delivered to the 400 kV power grid.
After having fed the turbine, the steam is condensed by the tertiary cooling loop, which water is at 22 °C. The output coolant achieves 36 °C and is therefore transferred to the 150 m tall natural draught wet-type cooling tower
Cooling tower
Cooling towers are heat removal devices used to transfer process waste heat to the atmosphere. Cooling towers may either use the evaporation of water to remove process heat and cool the working fluid to near the wet-bulb air temperature or in the case of closed circuit dry cooling towers rely...
that returns it to the initial temperature. 0.4-0.7 out of 31.6 m3/s leave the tower creating the typical plume.
| Unit | Type | Net electrical power | Gross electrical power | Construction start | Critical state | Connected to electricity grid | Commercial operation | Shutdown |
|---|---|---|---|---|---|---|---|---|
| Gösgen | PWR Pressurized water reactor Pressurized water reactors constitute a large majority of all western nuclear power plants and are one of three types of light water reactor , the other types being boiling water reactors and supercritical water reactors... |
970 MW | 1020 MW | Dec. 1973 | Jun. 1979 | Jan. 1979 | Nov. 1979 | - |
Safety measures
The core is located inside an 11 m tall and 22 cm thick cylindric vessel with an internal diameter of 4.36 m. The reactor concrete building has a wall thickness in the cylindrical part of 1.6 m (1.2 m the dome and 2.8 m the base plate). Due to the massive structures it should be able to withstand an aircraft crash.In case of small leakages in the reactor cooling loop, four high-pressure injection pumps (one for each steam generator and a fourth as reserve) would replace the missing water. In case of fast loss of the coolant, six accumulator tanks with a total 3·100% redundancy would flood the reactor until the low-pressure injection pumps could start operation. These four pumps (one for each steam generator and a fourth as reserve) are subdivided in three loops.
If the coolant is lost from the secondary loop the feeding of the three steam generators would be entrusted to the four strands of the emergency feedwater system (one each and a reserve) with a total redundancy of 2×2·100%. In case of extreme failures the cooling would be assured by the two strands of the special emergency feedwater system.
The plant possesses an independent emergency building which purpose is, in extreme cases as plane crashes or explosions, to manage the reactor shutdown and the removal of the decay heat for at least ten hours. It contains the two strands of the special emergency feedwater system and two diesel generators. The plant possess four further emergency diesel generators in two separated building.
Waste management
The spent fuel is cooled in special pools where the residual decay heat is removed. The rods are then transferred to the central interim storage facility ZWILAG where they are stored. In 2008 the second spent fuel pool started operation increasing the total capacity from 600 to 1600.The low and medium radioactive operating waste is reconditioned and stored in apposite rooms on the plant site.
Kernkraftwerk Gösgen-Däniken AG
The plant is operated by an ad hoc privately held company called Kernkraftwerk Gösgen-Däniken AG. At the moment it employs around 500 coworkers. The stocks are shared by the Alpiq Group (40%), the Axpo AG (25%), the city of ZurichZürich
Zurich is the largest city in Switzerland and the capital of the canton of Zurich. It is located in central Switzerland at the northwestern tip of Lake Zurich...
(15%), the Centralschweizerischen Kraftwerke (12.5%), and the Energie Wasser Bern (7.5%). The plant management is entrusted to Alpiq.
Nuclear events
| Year | INES International Nuclear Event Scale The International Nuclear and Radiological Event Scale was introduced in 1990 by the International Atomic Energy Agency in order to enable prompt communication of safety significance information in case of nuclear accidents.... level |
Total | |||||||
|---|---|---|---|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | ||
| 2009 | 2 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 3 |
| 2008 | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 |
| 2007 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
| 2006 | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 |
| 2005 | 5 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 5 |
| 2004 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
| 2003 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 |
| 2002 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 2001 | 4 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 4 |
| 2000 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 1999 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
| 1998 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 1997 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
| 1996 | 5 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 5 |
| 1995 | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 |
| Total | 31 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 32 |
As of February 2009 no operative nuclear event (INES
International Nuclear Event Scale
The International Nuclear and Radiological Event Scale was introduced in 1990 by the International Atomic Energy Agency in order to enable prompt communication of safety significance information in case of nuclear accidents....
level 2 or above) ever occurred. Since 1995 only one anomaly took place. The KKG is remarkable for the absence of any reactor scram
Scram
A scram or SCRAM is an emergency shutdown of a nuclear reactor – though the term has been extended to cover shutdowns of other complex operations, such as server farms and even large model railroads...
in the last 19 years.
2009
- In March the KKG announced to the federal authorities an event that took place after the 2008 revision. Four of the redundant power lines supplying the emergency system failed during a test due to a faulty protective circuit. In case of a real emergency this could cause troubles only in case of malfunctioning of the other safety mechanisms, but since the same problem occurred to multiple strands, the event has been assessed as level 1.