Official name Kernkraftwerk Beznau Reactor type PWR Phone +41 56 266 71 11 | Status Operational Construction began 1965 | |
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Commission date 1 September 1969 (1969-09-01) Address Beznau, 5312 Döttingen, Switzerland Similar | ||
The Beznau nuclear power plant (German: Kernkraftwerk Beznau, abbreviated KKB) is a nuclear power plant of the Swiss energy utility Axpo, located in the municipality Döttingen, Canton of Aargau, Switzerland, on an artificial island in the Aar river. Producing energy since September 1969, it can claim to be the world's oldest nuclear power plant in commercial operation.
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Beznau 1 and 2Edit
Beznau 1 is the first commercial nuclear power reactor in Switzerland.
Putting an end to the traditional predilection of the Swiss power utilities for hydroelectric power, in the beginning of the 1960s the then Nordostschweizerische Kraftwerke AG (NOK, now part of Axpo Holding) started to take into account the construction of a nuclear power plant. On 23 December 1964 the Swiss Federal Office of Energy recognized the artificial island in Beznau as potential location for a reactor. The corresponding construction permit was issued on 2 November 1965 and, after only four years, on 12 May 1969 commissioning was authorized. On 1 September 1969 Beznau 1 started commercial operation.
In the meantime the procedure for the construction of the identical reactor Beznau 2 had begun. The location and a first construction permit were approved on 17 November 1967, followed on 21 September 1970 by the final one. The commissioning started on 16 July 1971 and the reactor finally entered the commercial operation phase on 1 December 1971.
Beznau 1 obtained an unlimited operating license already on 30 October 1970. On the contrary Beznau 2 received temporary licenses until 3 December 2004, when the Swiss Federal Council removed the limitation.
The power plant was built in the 1960s, when little opposition to nuclear projects was present. Over the years Beznau has been the scene of some anti-nuclear protests, but such opposition never widespread among the majority of the local population. The cantonal citizens systematically rejected all votes on early shutdown of existing plants and on building suspension of new ones. Finally, in 2007 the cantonal parliament entrusted the government to act in order to promote the building of a new reactor.
As of 2008 no date for a definitive shutdown of the KKB has been set. From a technical point of view, it is expected to become necessary in the 2020s, when the two reactors will be 50–60 years old. After the decommissioning of Oldbury Nuclear Power Station's Reactor 1 on 29 February 2012, Beznau 1 is the oldest operating nuclear power station in the world.
Newspaper Tages Anzeiger commented in October 2015 that two independent sources have confirmed that the reactor 1 pressure vessel contains around 1,000 cavities of half a centimetre in diameter.
At dawn on 5 March 2014, Greenpeace activists broke into Beznau, urging European governments to close down the reactors on safety grounds. Some 100 protesters dressed in orange jumpsuits scaled the boundary fence and hoisted large banners with images of cracking reactors and announcing "The End" of nuclear power at the 45-year-old Beznau nuclear plant.
40 activists were arrested by cantonal police before noon and the others in the evening. 58 activists were reported to the Public Prosecutor for trespassing. The nuclear operator Axpo submitted a criminal complaint for trespassing.
Beznau 3 plansEdit
In view of the substitution of the plant, Resun AG submitted a framework permit application for a third reactor to the federal authorities on 4 December 2008, designated "EKKB" (Ersatzkernkraftwerk Beznau, Beznau replacement nuclear power plant) or Beznau 3. Although the technical specifications are to be defined later, the reactor of choice is to be a light water type Generation III reactor with an electrical power of 1450 MW. The cooling is to be ensured by an hybrid tower.
The project is on indefinite hold following decisions by the Swiss federal authorities after the Fukushima Daiichi nuclear disaster in 2011 to cease constructing new nuclear power plants.
Reactors and generatorsEdit
The KKB is composed of two identical pressurized water reactors units (Beznau 1 and 2) delivered by Westinghouse Electric.
Both reactors are certified for the use of MOX fuel. As for October 2008 (39th operational cycle) Beznau 1 hosted 12 bars out of 121 contain MOX, while for Beznau 2 this ratio increased to 32 of 121 (37th cycle).
Characterized by a thermal power of 1130 MW, each unit produces 365 MW net electricity through two Brown Boveri steam generators. Over the years the net electric power produced has been increased twice: it was 350 MW until 30 September 1996 and 357 MW until 2 January 2000. The energy is delivered to the 220 kV grid.
The plant is cooled using the water of the Aar river and through the district heating system Refuna.
Refuna nuclear district heatingEdit
The cooling water load on the Aar river is reduced by the district heating system Refuna, that provides eleven surrounding municipalities with up to 150 GW·h/y. Beside Döttingen, the connected municipalities are Bad Zurzach, Klingnau, Unterendingen, Endingen, Böttstein, Tegerfelden, and in the bordering Baden District, Würenlingen and Untersiggenthal, and in the other bordering Brugg District, Rüfenach and Villigen. The heat extraction, at a supply temperature from 125 °C in winter down to 80 °C in summer, induces a loss of electric power, but less than 18 GW·he/year at 2 MWe average electric power loss. The energy content of the average 142 GW·h/y provided heat, is about the same as of 14,200,000 m3 of natural gas, averaging more than 5,800 m3 of natural gas consumption yearly saved for each of the 2,432 connected homes and customers.
Safety measuresEdit
Since the commissioning of the two reactors numerous upgrades have been carried out to improve safety. In the 1990s the steam generators and the control technology of the reactor protecting system have been replaced. The control rooms were consequently adapted and new turbine controls installed.
Furthermore, each reactor unit has been equipped with an emergency building (NANO, NAchrüstung NOtstandsystem). These contain additional safety systems for the reactor emergency shutdown and for the feeding of the steam generators, a 50 kV emergency power line, and a diesel generator. They are heavily protected (bunkerised) from external hazards and, if needed, are able to cool and shut down the power plant without human intervention for 72 hours. The at least 1.5 m thick concrete-steel housings protect the critical systems from external agents like earthquakes or plane crashes. Each unit of the KKB has a large dry type containment in concrete and steel.
The emergency core cooling (ECCS) is performed by a redundant high-pressure safety injection system with a total of three strands (one in the NANO). The two steam generators are provided with water by two main feeding pumps. If they fail, feeding is taken over by one of the security systems: a double-stranded auxiliary feedwater system or one of the two emergency feedwater systems, one of which part of the bunkerised NANO. Finally, in case of problems with the cooling, two containment spray systems are entrusted with the removal of excessive heat and pressure by condensation of the resulting steam.
The power plant is connected through five strands to the external power grid. Two of them are mainly used to deliver the power plant output to the 220 kV grid. They are nevertheless equipped with an emergency diesel generator each. Two other strands provide emergency power and are connected to the nearby hydroelectric power plant and the 50 kV grid. Further, two diesel generators expressly equipped to be able to work in case of flood are also available. The NANO is connected through the fifth strand to the 50 kV grid and contains a fifth generator. The plant main UPS system can provide direct current for at least 2 h of normal operation.
Waste managementEdit
The KKB possesses since 1993 a separate interim radioactive waste storage facility (ZWIBEZ). It is composed of a hall for low level operational waste and a second one for the dry storage of spent fuel. The waste needing conditioning is stored in the central interim storage facility (ZZL). These two deposits are to ensure the storage of the plant's waste until at least 2020.
Nuclear eventsEdit
The following is an overview of nuclear security incidents at Beznau graded on the International Nuclear Event Scale (INES), which ranges from 0 (least severe) to 7 (most severe). In the plant's history there has been one level 2 event and four level 1 events.