Beznau Nuclear Power Plant

Beznau Nuclear Power Plant

Beznau Nuclear Power Plant
Location of Beznau Nuclear Power Plant in Switzerland
Official name Kernkraftwerk Beznau
Country Switzerland
Location Döttingen AG, Zurzach
Coordinates 47°33′08″N 8°13′43″E / 47.552107°N 8.228492°E / 47.552107; 8.228492Coordinates: 47°33′08″N 8°13′43″E / 47.552107°N 8.228492°E / 47.552107; 8.228492
Status Operational
Construction began 1965
Commission date 1 September 1969 (1969-09-01)
Owner(s) Axpo Holding
Nuclear power station
Reactor type PWR
Reactor supplier Westinghouse Electric
Cogeneration? Yes (150 GW·ht/y)
Cooling source Aare
Power generation
Units operational 2 × 365 MW
Nameplate capacity 730 MWe
Capacity factor 91.8 %
Average generation 5,826 GW·h
Switzerland Nuclear power plants (view)
 Active plants
 Closed plants

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.[1]


Beznau 1 and 2

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.[2]

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.[2]

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.[3]

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,[4] 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.[5] Finally, in 2007 the cantonal parliament entrusted the government to act in order to promote the building of a new reactor.[6]

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.[1]

Newspaper Tages Anzeiger commented in October 2015 that two independent sources have confirmed that the reactor 1 pressure vessel contains around 1,000 holes of half a centimetre in diameter.[7]

Greenpeace protest

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 plans

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.[8] 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.[9][10]

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.

Technical specifications

Reactors and generators

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).[11]

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.[12] 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.

Unit Type Net electrical power Gross electrical power Construction start Critical state Connected to electricity grid Commercial operation Shutdown
Beznau 1 PWR 365 MW 380 MW Sep. 1965 Jun. 1969 Jul. 1969 Sep. 1969
Beznau 2 PWR 365 MW 380 MW Jan. 1968 Oct. 1971 Oct. 1971 Dec. 1971

Refuna nuclear district heating

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.[13][14]

Safety measures

An emergency switch-off button at Beznau.

Since the commissioning of the two reactors numerous upgrades have been carried out to improve safety.[15][16] 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.[17][18] The at least 1.5 m thick concrete-steel housings protect the critical systems from external agents like earthquakes or plane crashes.[19] 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 management

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.[16]

Nuclear events

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.

Year INES level Total
0 1 2 3 4 5 6 7
2015 TBA
2014 5 5
2013 7 7
2012 13 1 14
2009 10 1 11
2008 4 4
2007 7 1 8
2006 2 2
2005 2 2
2004 2 2
2003 4 4
2002 2 2
2001 5 5
2000 4 4
1999 5 5
1998 2 2
1997 6 1 7
1996 3 1 4
1995 3 3
Total 86 4 1 86
Sources: 2014[20] · 2013[21] · 2012[22] · others[23]

Level 2 events


Level 1 events





Significant events before 1995

See also

Wikimedia Commons has media related to Beznau Nuclear Power Plant.


  1. 1 2 "Bald läuft das älteste AKW der Welt in der Schweiz". Badische Zeitung (in German). 23 February 2012. Retrieved 7 March 2012.
  2. 1 2 Swiss Federal Office of Energy (2006-01-23), Authorizations for nuclear installations, retrieved 2010-10-28. In German.
  3. "The Federal Council issues authorizations regarding the Nuclear Energy Act" (Press release). Swiss Federal Office of Energy. 2004-12-03. Retrieved 2010-10-28. In German.
  4. Nuklearforum Schweiz. "Chronic of nuclear energy in Switzerland". Retrieved 2010-10-28. In German.
  5. "Results of the initiative Für eine Zukunft ohne weitere Atomkraftwerke". 1984-09-23. Retrieved 2010-10-28. "Results of the initiative Für den Ausstieg aus der Atomenergie". 1990-09-23. Retrieved 2010-10-28. "Results of the initiative Stopp dem Atomkraftwerkbau (Moratorium)". 1990-09-23. Retrieved 2010-10-28. "Results of the initiative Strom ohne Atom – Für eine Energiewende und schrittweise Stilllegung der Atomkraftwerke (Strom ohne Atom)". 2003-05-18. Retrieved 2010-10-28. "Results of the initiative Moratorium Plus – Für die Verlängerung des Atomkraftwerk-Baustopps und die Begrenzung des Atomrisikos (MoratoriumPlus)". 2003-05-18. Retrieved 2010-10-28. In German, French, or Italian.
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  9. "Operation Beznau replacement nuclear power plant". Axpo AG. Retrieved 2010-10-28.
  10. "Adaptation of the structure plan; Decisions on the nuclear power plants". Canton of Aargau. Retrieved 2010-11-01.
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  13. Handl, K.H. (1998). "75 MW heat extraction from Beznau nuclear power plant" (PDF). International Atomic Energy Agency. Retrieved 15 September 2016.
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  16. 1 2 Swiss Federal Nuclear Safety Inspectorate (2004-03-01), KKW Beznau II: Opinion regarding the request of the NOK for the removal of the operating license limitation (PDF), retrieved 2010-10-28. In German.
  17. The Notstand building, a bunkered facility which could support all of the plant systems for at least 72 hours. I asked Martin Richner, the head of risk assessment, why Beznau spent so much money on the Notstand building when there was no regulation or government directive to do so. Martin answered me, “Woody, we live here.”
  18. "A PRA Practioner [sic] Looks at the Fukushima Daiichi Accident (learns lessons from Beznau)" (PDF). Archived from the original (PDF) on 1 November 2016.
  19. Swiss Federal Nuclear Safety Inspectorate (2003-04-03), Position of the Swiss Federal Nuclear Safety Inspectorate regarding the safety of the Swiss nuclear power plants in the event of an intentional aircraft crash (PDF), retrieved 2010-10-28. In German.
  20. "2014 ENSI Oversight Report – ENSI-AN-9252". Swiss Federal Nuclear Safety Inspectorate ENSI. 24 June 2015.
  21. "2013 ENSI Oversight Report – ENSI-AN-8800". Swiss Federal Nuclear Safety Inspectorate ENSI. 30 June 2014.
  22. 1 2 "Regulatory Oversight Report 2012 concerning nuclear safety in Swiss nuclear installations" (PDF). June 2013. p. 20. ENSI rated one event as INES Level 1 — This related to an incident at Unit 2 of the Beznau nuclear power plant where a generator failed to start during a regular function test of the energy diesel generator
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  28. Swiss Federal Nuclear Safety Inspectorate (1998-04-01), ENSI annual report 1997 (PDF), retrieved 2010-10-28. In German.
  29. Swiss Federal Nuclear Safety Inspectorate (1997-04-01), ENSI annual report 1996 (PDF), retrieved 2010-10-28. In German.
  30. Aargauer Tagblatt, 1992-07-18 Missing or empty |title= (help)

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