Beznau Nuclear Power Plant
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The Beznau nuclear power plant (german: Kernkraftwerk Beznau ''KKB is a
nuclear power plant A nuclear power plant (NPP) is a thermal power station in which the heat source is a nuclear reactor. As is typical of thermal power stations, heat is used to generate steam that drives a steam turbine connected to a electric generator, generato ...
of the Swiss energy utility Axpo, located in the municipality Döttingen,
Canton of Aargau Aargau, more formally the Canton of Aargau (german: Kanton Aargau; rm, Chantun Argovia; french: Canton d'Argovie; it, Canton Argovia), is one of the 26 cantons forming the Swiss Confederation. It is composed of eleven districts and its capita ...
, Switzerland, on an artificial island in the
Aar river The Aare () or Aar () is a tributary of the High Rhine and the longest river that both rises and ends entirely within Switzerland. Its total length from its source to its junction with the Rhine comprises about , during which distance it descen ...
. The plant has been operating since September 1969.


History


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 Axpo Holding AG, headquartered in Baden, Switzerland, Baden in Cantons of Switzerland, Canton Canton of Aargau, Aargau, and its subsidiaries constitute the energy company Axpo. Axpo Holding AG was established in 2001 and is 100-per cent publicly ...
) 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 24 December 1969 Beznau 1 started commercial operation.. In German. 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 15 March 1972. Beznau 1 obtained an unlimited operating license already on 30 October 1970. On the contrary Beznau 2 operated under temporary licenses until 3 December 2004, when the
Swiss Federal Council The Federal Council (german: Bundesrat; french: Conseil fédéral; it, Consiglio federale; rm, Cussegl federal) is the executive body of the federal government of the Swiss Confederation and serves as the collective head of state and governme ...
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 The anti-nuclear movement is a social movement that opposes various nuclear technologies. Some direct action groups, environmental movements, and professional organisations have identified themselves with the movement at the local, natio ...
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 2018 no date for a definitive shutdown of the KKB has been set. From a technical point of view, similar types of reactors can probably operate safely to at least 60 years and probably until 80 years. Beznau's Unit 1 is among the oldest commercial nuclear power plants still in operations as of 31 January 2016. 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. Similar cavities, although smaller in number, size and extension, were first discovered in the Belgian Doel 3 reactor, consequently the Swiss Federal Nuclear Safety Inspectorate (ENSI) asked Beznau and Gösgen NPPs to perform adequate testing on their reactor pressure vessel. It must be said that the flaw indications in the Belgian NPPs ( Doel-3 and
Tihange Huy ( or ; nl, Hoei, ; wa, Hu) is a city and municipality of Wallonia located in the province of Liège, Belgium. Huy lies along the river Meuse, at the mouth of the small river Hoyoux. It is in the ''sillon industriel'', the former industrial ...
-2) did not cause the definitive shut down of the reactors. Indeed, both reactors resumed operations once all the needed tests were passed. Unit 1 has been shut down since the discovery of such material defects. A restart was expected in 2016 in case of positive test results, but since April 2017 no deadline for a restart was announced. ; 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 climbed over 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 Resun AG (an acronym from the French ''REmplacement SUisse Nucléaire'', Swiss nuclear replacement) is a company located in Aarau (Switzerland). Its purpose is to manage the construction of two new nuclear reactors. These are unofficially known as ...
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 Generation III reactors, or Gen III reactors, are a class of nuclear reactors designed to succeed Generation II reactors, incorporating evolutionary improvements in design. These include improved fuel technology, higher thermal efficiency, sign ...
with an electrical power of 1450 MW. The cooling is to be ensured by a hybrid
tower A tower is a tall Nonbuilding structure, structure, taller than it is wide, often by a significant factor. Towers are distinguished from guyed mast, masts by their lack of guy-wires and are therefore, along with tall buildings, self-supporting ...
. The project is on indefinite hold following decisions by the Swiss federal authorities after the
Fukushima Daiichi nuclear disaster The was a nuclear accident in 2011 at the Fukushima Daiichi Nuclear Power Plant in Ōkuma, Fukushima, Japan. The proximate cause of the disaster was the 2011 Tōhoku earthquake and tsunami, which occurred on the afternoon of 11 March 2011 and ...
in 2011 to cease constructing new nuclear power plants.


Technical specifications


Reactors and generators

The KKB is composed of two identical
pressurized water reactors A pressurized water reactor (PWR) is a type of 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 coolant (water) is ...
units (Beznau 1 and 2) delivered by
Westinghouse Electric The Westinghouse Electric Corporation was an American manufacturing company founded in 1886 by George Westinghouse. It was originally named "Westinghouse Electric & Manufacturing Company" and was renamed "Westinghouse Electric Corporation" in ...
. Both reactors are certified for the use of
MOX fuel Mixed oxide fuel, commonly referred to as MOX fuel, is nuclear fuel that contains more than one oxide of fissile material, usually consisting of plutonium blended with natural uranium, reprocessed uranium, or depleted uranium. MOX fuel is an alt ...
. Since 2013, no more MOX fuel elements are used in both Beznau units. Characterized by a thermal power of 1130 MW, each unit produces 365 MW net electricity through two
Brown Boveri Brown, Boveri & Cie. (Brown, Boveri & Company; BBC) was a Swiss group of electrical engineering companies. It was founded in Zürich, in 1891 by Charles Eugene Lancelot Brown and Walter Boveri who worked at the Maschinenfabrik Oerlikon. In 1970 ...
turbine 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 District heating (also known as heat networks or teleheating) is a system for distributing heat generated in a centralized location through a system of insulated pipes for residential and commercial heating requirements such as space heating a ...
system Refuna.


Refuna nuclear district heating

The Beznau NPP has been supplying the
district heating District heating (also known as heat networks or teleheating) is a system for distributing heat generated in a centralized location through a system of insulated pipes for residential and commercial heating requirements such as space heating a ...
system Refuna since 1984. This reduces the effect of the plant on the water temperature of the Aar river, and provides eleven surrounding municipalities with up to 150 GW·h of carbon-free heat per year. Beside Döttingen, the connected municipalities are
Bad Zurzach Bad Zurzach is a former municipality in the district of Zurzach in the canton of Aargau in Switzerland. It is the seat of the district. On 1 January 2022 the former municipalities of Bad Zurzach, Baldingen, Böbikon, Kaiserstuhl, Rekingen, Riethe ...
,
Klingnau Klingnau is a municipality in the district of Zurzach in the canton of Aargau in Switzerland. History Klingnau is first mentioned in 1239 as ''Chlingenowe''. Ulrich of Klingen acquired land from the monastery of St. Blaise in 1239 to found the ...
,
Unterendingen Unterendingen is a former municipality in the district of Zurzach in the canton of Aargau in Switzerland. On 1 January 2014 the former municipality of Unterendingen merged into the municipality of Endingen.Endingen,
Böttstein Böttstein is a municipality in the district of Zurzach in the canton of Aargau in Switzerland. History Some scattered La Tène culture items have been discovered near Böttstein. The modern village of Böttstein is first mentioned in 1087 as '' ...
,
Tegerfelden Tegerfelden is a municipality in the district of Zurzach in the canton of Aargau in Switzerland. Geography Located in the Surb river valley, Tegerfelden has an area, , of . Of this area, or 51.5% is used for agricultural purposes, while ...
, and in the bordering Baden District,
Würenlingen Würenlingen is a municipality in the district of Baden in the canton of Aargau in Switzerland. Geography Würenlingen has an area, , of . Of this area, 29.2% is used for agricultural purposes, while 49.4% is forested. Of the rest of the land, ...
and
Untersiggenthal Untersiggenthal is a municipality in the district of Baden in the canton of Aargau in Switzerland, located in the Limmat Valley (German: ''Limmattal''). Geography Untersiggenthal has an area, , of . Of this area, 33.2% is used for agricultural p ...
, and in the other bordering
Brugg District Brugg District is a district in the Canton of Aargau, Switzerland. The capital of the district is the town of Brugg. Geography Brugg District has an area, , of . Of this area, 42.6% is used for agricultural purposes, while 41.3% is forested. T ...
,
Rüfenach Rüfenach is a municipality in the district of Brugg in the canton of Aargau in Switzerland. Geography The municipality lies at the foot of the Bruggerberg and the Reinerberg, the southeast foothills of the Jura Mountains. It consists of thre ...
and
Villigen Villigen is a municipality in the district of Brugg in the canton of Aargau in Switzerland. In January 2006, Villigen incorporated the former municipality of Stilli. The Paul Scherrer Institute is primarily located in Villigen, although part is a ...
. 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 Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...
, averaging more than 5,800 m3 of natural gas consumption yearly saved for each of the 2,432 connected homes and customers.


Safety measures

Since the commissioning of the two reactors numerous upgrades have been carried out to improve safety.. In German. In the 1990s, the steam generators and the control technology of the reactor protection system were 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 electricity 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 steel and concrete. 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 Accident management 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 UPS or ups may refer to: Companies and organizations * United Parcel Service, an American shipping company ** The UPS Store, UPS subsidiary ** UPS Airlines, UPS subsidiary * Underground Press Syndicate, later ''Alternative Press Syndicate'' or ...
system can provide direct current for at least 2 h of normal operation.


Waste management

The KKB operates, 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) in
Würenlingen Würenlingen is a municipality in the district of Baden in the canton of Aargau in Switzerland. Geography Würenlingen has an area, , of . Of this area, 29.2% is used for agricultural purposes, while 49.4% is forested. Of the rest of the land, ...
. These two deposits are to ensure the storage of the plant's waste until at least 2020.


Safety events

The following is an overview of nuclear security incidents at Beznau graded 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), 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.


Level 2 events


2009

* On 31 July 2009, during the yearly revision of Beznau 2, two workers were exposed to excessive levels of radiation because of a series of organizational flaws and uncoordinated handling by another revision team. These lead to a sudden increase in radiation levels in the room where the two technicians were working. They absorbed an
equivalent dose Equivalent dose is a dose quantity '' H '' representing the stochastic health effects of low levels of ionizing radiation on the human body which represents the probability of radiation-induced cancer and genetic damage. It is derived from the ...
of 37.8 and 25.4
mSv mSv or MSV may refer to: * Maize streak virus, a plant disease * Medium-speed vehicle, US category * Medium Systems Vehicle, a class of fictional artificially intelligent starship in The Culture universe of late Scottish author Iain Banks * Mill ...
, respectively ''(see examples for radiation doses)''. Incorrect settings of personal dosimeters prevented a timely warning.


Level 1 events


2012

* An emergency diesel generator of unit 2 failed to start during a regular function test of this emergency electrical power generator.


2007

* In August, during the annual shutdown for revisions of Beznau 2, the 50 kV emergency power line was inactivated. Consequently, the diesel generator of Beznau 1 was switched on at low regime as prescribed by the security regulations. After the reconnection of the 50 kV line, the generator ran at a higher load because of technical reasons, but it eventually failed due to a defective relay. It was therefore assumed that while the 50 kV line was not active the generator would not have been able to run at full loading. Since the unit 2 generator was also unavailable due to the planned audit, the emergency power could be provided only by the hydroelectric plant or backup generators activated in case of flooding. The decrease in redundancy caused a deviation from the normal operation parameters and was therefore classified as a level 1 event (Swiss scale level B).


1997

* In the course of a periodic inspection carried out by the operating personnel, a manually operated valve, which should have been open, was found to be closed. As a result of the false position, one of three emergency cooling systems of Beznau 1 was not ready for immediate use over a period of two weeks. This breach of the technical specifications led to the incident being assessed as level 1 (Swiss scale level B).


1996

* After the revision outage, at 1 to 2% of reactor power, the new protection system for Beznau 1 and its internal power supply was to be started up with a test program. During synchronization with the new protection equipment, one of the two turbo groups inadvertently increased the load, and this caused a rise in reactor power to 12.6%. Since only the auxiliary feedwater pumps are in operation during low power, the amount of water supplied was insufficient to feed the steam generator, leading to an automatic reactor scram. The inadvertent demand on the turbo group was caused by an unforeseen reaction of the automatic turbine controller. Besides, the reactor already went critical at 251 °C instead of at the prescribed minimum temperature of 276 °C. The deviation from the operation specifications led to a level 1 assessment (Swiss scale level B).


Significant events before 1995

* In July 1992, during a revision of Beznau 1, two technicians working in the reactor
sump A sump is a low space that collects often undesirable liquids such as water or chemicals. A sump can also be an infiltration basin used to manage surface runoff water and recharge underground aquifers. Sump can also refer to an area in a cave ...
died by suffocation. This was caused by an excessive atmospheric concentration of the
argon Argon is a chemical element with the symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third-most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as abu ...
used for welding. This accident was not due to the nuclear nature of the plant and therefore didn't receive an INES assessment.


See also

*
Nuclear power in Switzerland Nuclear power in Switzerland is generated by three nuclear power plants, with a total of four operational reactors ''(see list below)''. In 2013, they produced 24.8 terawatt-hours (TWh) of electricity, down 5.8% from 2007, when 26.4 TWh w ...
*
Resun AG Resun AG (an acronym from the French ''REmplacement SUisse Nucléaire'', Swiss nuclear replacement) is a company located in Aarau (Switzerland). Its purpose is to manage the construction of two new nuclear reactors. These are unofficially known as ...


References


External links


Official power plant websiteAxpo AGResun AGRefuna AG
*[http://www.iaea.org/cgi-bin/db.page.pl/pris.prdeta.htm?country=CH&site=BEZNAU&units=&refno=3&link=HOT&sort=&sortlong=Alphabetic%20%84Switzerland%20(Swiss%20Confederation):%20Nuclear%20Power%20Reactors%93 Power Reactor Information System – Beznau 2]
International Nuclear Safety Center – Beznau 1International Nuclear Safety Center – Beznau 2
{{Authority control Nuclear power stations in Switzerland