Mühleberg nuclear power plant

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Mühleberg nuclear power plant
Mühleberg NPP
Mühleberg NPP
location
Mühleberg nuclear power plant (Canton of Bern)
Mühleberg nuclear power plant
Coordinates 587 189  /  202 210 coordinates: 46 ° 58 '15 "  N , 7 ° 16' 13"  O ; CH1903:  587,189  /  two hundred and two thousand two hundred ten
Country: Switzerland
Data
Owner: BKW Energie AG
Operator: BKW Energie AG
Project start: 1966
Commercial operation: Nov 6, 1972
Shutdown: Dec 20, 2019

Active reactors:

0

Decommissioned reactors (gross):

1 (390 MW)
Energy fed in in 2017: 2,998 GWh
Energy fed in since commissioning: 130,000 GWh
Was standing: 20th December 2019
The data source of the respective entries can be found in the documentation .
f1
Mühleberg nuclear power plant (November 2018)

The nuclear power plant Mühleberg (KKM) is a disused Swiss nuclear power plant with a 373- MW - boiling water reactor with river water cooling. The owner and operator is BKW Energie . The power plant went into operation in 1972 and is located about 2 km north of Mühleberg an der Aare directly below the Wohlensee , 14 km west of Bern .

In 2013, BKW Energie decided to take the power plant out of operation for economic reasons . A corresponding application was submitted to DETEC in December 2015 . In May 2014, the Bernese sovereign rejected the cantonal popular initiative “Mühleberg off the grid”, which would have resulted in the immediate shutdown of the power plant. On December 20, 2019, the service operation was discontinued as planned. Since January 6, 2020, the Mühleberg NPP has been safely and solidly dismantled. The fuel elements are to be brought to the interim storage facility in Würenlingen by 2024. Then all nuclear parts will be removed by 2031. Then all the buildings will be demolished. After the planned demolition, the site should be able to be used again from 2034.

The Mühleberg NPP was connected to the high-voltage network at the 220 kV voltage level.

Reactor type and cooling

The inner containment (primary containment) of the type Mark I is provided with a pear-shaped steel pressure vessel and a toroidal pressure reduction chamber ( condenser equipped). In contrast to the standard construction of General Electric , the reactor building in Mühleberg takes on the function of an external containment. This is under negative pressure and has an exhaust air system with filters that hold back dust and foreign particles. In addition, the power plant has an additional condenser, the so-called outer torus, which can reduce any pressure build-up in the outer containment. The reactor operated at a nominal pressure of 72.3 bar and contained 240 fuel elements . Only uranium dioxide was used as the nuclear fuel . The reactor output was regulated primarily via 57 cross-shaped control rods and secondarily continuously via an additional device.

Due to the comparatively low output, the system does not have a cooling tower , but was cooled with Aare water. With river water cooling, the cooling water in the condenser was heated by a maximum of three degrees Celsius and fed back into the river. The output of the reactor had to be reduced when the Aare water temperatures exceeded 18 degrees Celsius in order to protect the fish population.

Safety measures

Since the system was commissioned, retrofits and renewals have been carried out to increase safety:

  • In 1984 a hydrogen recombiner was installed in order to prevent a critical hydrogen concentration build-up inside the containment (primary containment)
  • In 1988, a nitrogen inerting system was retrofitted to prevent the formation of ignitable gas mixtures.
  • From 1986 an independent system for the removal of decay heat was set up and put into operation in 1989. The "special, independent system for dissipating the decay heat" (SUSAN) represented an additional heat sink and was able to switch off the reactor automatically and independently and to transfer it to the "cold shutdown state" (→ cold shutdown ) and this over 100 Days to hold.
  • In 1990 SUSAN was expanded to include two independent, bunkered diesel emergency power systems to secure the emergency power supply
  • 1992: Since the volume of the Mark I safety container used is relatively small and overpressure could destroy it, the system was retrofitted with a containment pressure relief system (CDS). This should prevent leakage of the containment in the event of an accident.
  • 1992: Installation of the Drywell spray and flooding system (DSFS) for flooding and cooling the containment in the event of a core meltdown
  • 1996: Due to continuously growing cracks in the core mantle, four tie rods were installed to reinforce it . However, ENSI does not accept the tie rods for long-term operation.
  • 2011: Retrofitting of a second inlet structure for the Aare water, construction of a feed with mobile fire service pumps and improvement of the flood protection for the pump house.

history

Power plant under construction (1969)
1967 start of building
1972 Start of commercial operation
1991 First discovery of cracks on the weld seams of the non-pressure core sheath
1992 Application for an unlimited operating license and increase in benefits, decision of the Federal Council : limited to a further ten years
1996 Commissioning the simulator
2005 Application for an unlimited operating license by the operator
2009 The Federal Department for the Environment, Transport, Energy and Communication (DETEC) granted the unlimited operating license based on a safety assessment by the Main Department for the Safety of Nuclear Installations (HSK) from 2007
2009 113 residents submit complaints to the Federal Administrative Court against the unlimited operating license .
2011 Letter bomb attack on Swissnuclear by left-wing extremists . A letter bomb, which was addressed to a member of the management of the nuclear power plant, led to two seriously injured people in Olten, one of whom survived only with luck. The investigators found a letter of confession from the Italian group " Federazione Anarchica Informale " in the remains of the bomb .
2012 The Federal Administrative Court is lifting the original time limit until the end of 2012, but at the same time has a new time limit until June 28, 2013 due to open questions about security.
2013 The Federal Supreme Court annuls the decision of the Federal Administrative Court and grants the unlimited operating license. Any rulings to the contrary should be issued by ENSI .
2013 BKW decides to take the nuclear power plant off the grid in 2019 for economic reasons.
2015 BKW submits a decommissioning application to DETEC.
2019 On December 20, 2019, the power operation will definitely be discontinued. The dismantling is expected to take around 15 years. The spent fuel elements will be moved to the Zwilag in Würenlingen by 2024 .

Reportable Incidents

year International event scale INES total
0 1 2 3 4th 5 6th 7th
2018 4th - - - - - - - 4th
2017 3 - - - - - - - 3
2016 3 - - - - - - - 3
2015 7th - - - - - - - 7th
2014 8th - - - - - - - 8th
2013 13 - - - - - - - 13
2012 6th - - - - - - - 6th
2011 3 1 - - - - - - 4th
2010 13 - - - - - - - 13
2009 4th - - - - - - - 4th
2008 1 - - - - - - - 1
2007 1 - - - - - - - 1
2006 2 - - - - - - - 2
2005 1 - - - - - - - 1
2004 1 - - - - - - - 1
2003 4th - - - - - - - 4th
2002 2 - - - - - - - 2
2001 1 - - - - - - - 1
2000 - - - - - - - - 0
1999 3 - - - - - - - 3
1998 - 1 - - - - - - 1
1997 3 - - - - - - - 3
1996 2 - - - - - - - 2
1995 1 - - - - - - - 1

Security concerns

Cracks in the kernmantle

In 2011, residents of the power plant asked DETEC to withdraw their operating license due to safety concerns. In their application, the applicants relied on a confidential report by TÜV Nord from 2006, which questioned whether the cracks in the core jacket known since 1990 were reliably secured by the tie rods installed in 1996 . The main department for the safety of nuclear installations (HSK) had accepted the tie rods as a provisional measure as part of a maintenance concept for the core jacket. The Department of Environment decided not to respond to the request. There are “no indications” that the Nuclear Safety Inspectorate “is not or insufficiently fulfilling its duty of supervision”. There are also no indications that the safe operation of the plant cannot be guaranteed.

Internal flooding risk

In the KKM, almost all safety-relevant pumps (emergency cooling, toroidal cooling, etc.) are housed in the so-called toroidal space. As the only NPP of this Mark 1 type from General Electric , it also has a so-called outer torus (water reservoir) instead of a separate room in which these pumps are located in all other Mark 1 systems worldwide. As early as 1990 , the Öko-Institut established in an expert report that these pumps could all fail in one fell swoop due to a major water loss accident due to flooding (common cause failure) and pointed out the associated core meltdown potential. In the meantime, so-called fire compartments have been installed in this toroidal space, which are also able to reduce the area-wide flooding risk of the room. In a 2008 edition, the supervisory authority ENSI (formerly HSK) required the operator to provide additional evidence by December 2009 that even masses of water released on floors higher up in the reactor building did not significantly impair the safety pumps.

External flood risk

The power plant is located below several dams ( Mühleberg , Schiffenen and Rossens hydropower plant ), with the Mühleberg (Wohlensee) hydropower plant only 2 km away. These could break in a strong earthquake. Such a dam break can cause a tidal wave reaching as far as the power plant and thus lead to catastrophic consequences.

During the safety review for the new building application, it turned out that the new power plant would have to be built on a pedestal, as "the results of the flooding calculations ... make it transparent ... that the (today's) KKM is flooded depending on the scenario." The latest ENSI earthquake study was received but now to the end that the Wohlensee dam would withstand a strong earthquake to be expected once every 10,000 years, which makes such a tidal wave rather unlikely.

According to the program Einstein and the Tagesschau on Swiss television, the Aare was the only way to cool the nuclear power plant. Not only a direct flooding of the power plant, but also a spillage of all water intake points with bed load poses a danger. The water intake points were added in 2011; In addition, facilities were created with which the supply of water by pumps is possible.

Radioactive emissions

In July 2013, increased cesium-137 values ​​were found in sediment samples from Lake Biel . As early as 2000, increased values ​​were measured in the water of Lake Biel. The increased values ​​correlated with increased emissions from the power plant in 1998 and 1999. According to ENSI , the radioactive emissions from the power plant via the water were, however, well below the legal limit values; Similar and sometimes higher values ​​are also found in the sediments of other Swiss lakes that are not in the lower reaches of a nuclear power plant. For example, its values ​​are many times higher in Ticino . All cesium-137 values ​​measured in the sediments of Swiss lakes are not harmful to health.

Reactor pressure vessel

After cracks in the reactor pressure vessel of Unit 3 in the Belgian nuclear power plant in Doel were discovered in mid-August 2012 , ENSI requested the manufacturing and testing documentation of the Mühleberger reactor pressure vessel, as the same company ( Rotterdamsche Droogdok Maatschappij ) had been involved in the manufacture of both vessels. In order to rule out errors in the manufacturing and monitoring processes at the time, BKW also ordered a representative area of ​​the reactor pressure vessel to be checked. The evaluation of the data showed that the reactor pressure vessel is intact and is not affected by the same type of errors as those found in Doel-3.

poll

Due to its proximity to Bern and the comparatively old age of the plant, the power plant was controversial. On May 18, 2014, the voters of the canton of Bern decided on the cantonal popular initiative “Mühleberg vom Netz”, which obliges the canton of Bern, as the majority owner of the operating company BKW Energie AG, to have the power plant shut down immediately. The initiative was rejected with 66.3% no votes. The power plant remained on the grid until December 2019.

New building Mühleberg 2

On December 4, 2008, BKW submitted a general license application for the replacement of the current power plant. A reactor with a maximum output of 1600 MW and a hybrid cooling tower was planned. Possible reactors were EPR or KERENA (until March 2009 referred to as SWR 1000) from Areva , an AP-1000, or the ESBWR from Mitsubishi . The cross-party and cross-association alliance Stop Atom announced a referendum against the planned buildings immediately after the submission was announced .

On February 13, 2011, the voters of the canton of Bern approved in a consultative vote with a majority of 51.2% (participation 51.7%) that the resolution of the Grand Council advocating the replacement of the power plant would be forwarded to the federal authorities. In the Grand Council there were 91 votes in favor of 56 votes against.

On March 14, 2011, during the series of accidents at the Japanese nuclear power plant Fukushima I , DETEC decided to freeze all licensing procedures for new nuclear power plants on Swiss soil for an indefinite period.

Reactor data

The Mühleberg nuclear power plant has one block :

Reactor block Reactor type net
power 		gross
power 		start of building Network
synchronization 		Commercialization
of essential operation 		Shutdown
Mühleberg Boiling water reactor 373 MW 390 MW March 1, 1967 July 1, 1971 November 6, 1972 20th December 2019

See also

Web links

Commons : Kernkraftwerk Mühleberg  - Collection of pictures, videos and audio files

Individual evidence

  1. ↑ Helmut Stalder: The Mühleberg nuclear power plant was once upon a time. In: Neue Zürcher Zeitung . December 20, 2019, accessed December 21, 2019 .
  2. ↑ BKW AG: This is how we shut down our nuclear power plant. Retrieved January 19, 2020 .
  3. ↑ Helmut Stalder: In Mühleberg is umgepolt nzz.ch, December 9, 2019, accessed February 29, 2020.
  4. ↑ a b BKW, EU Stress Test Kernkraftwerk Mühleberg, October 2011, p. 8 (PDF; 3.8 MB).
  5. ↑ BKW, Das Kernkraftwerk Mühleberg, p. 11 ( Memento from December 22, 2012 in the Internet Archive ) (PDF; 1.8 MB)
  6. ^ Julian Witschi: Nuclear power plant throttled because of the warm Aare. In: bernerzeitung.ch . July 25, 2019, accessed July 25, 2019 .
  7. ↑ http://www.ensi.ch/de/2011/09/26/kernmantel-muehleberg-das-ensi-verlangt-eine-langzeitloesung/
  8. ↑ http://www.ensi.ch/de/2011/08/23/ensi-erteilt-freigaben-fuer-arbeiten-an-der-kuehlwasserversorgung-des-kkw-muehleberg/
  9. ↑ Information on the Mühleberg nuclear power plant on the website of the Federal Nuclear Safety Inspectorate
  10. ↑ Mühleberg nuclear power plant receives an unlimited operating license . Swiss Confederation. December 21, 2009. Archived from the original on May 26, 2011. Retrieved on December 21, 2009.
  11. ↑ The attack was against nuclear power plant cadre. Blick.ch
  12. ↑ It is only by chance that the woman is still alive. Tages-Anzeiger Online
  13. ↑ BVger judgment A-667/2010 of March 1, 2012
  14. ↑ Berner Zeitung , March 30, 2013.
  15. ↑ Decision by BKW
  16. ↑ Simon Banholzer, Tonja Iten, Nils Epprecht: Drivers for decommissioning decisions in the Swiss nuclear industry. Swiss Energy Foundation, December 18, 2019, accessed on December 30, 2019 .
  17. ↑ BKW submits a decommissioning application for the Mühleberg nuclear power plant , accessed on December 18, 2015.
  18. ↑ Mühleberg nuclear power plant will definitely go offline on December 20, 2019 , accessed on March 2, 2016.
  19. ↑ The decommissioning order for the Mühleberg nuclear power plant is available , accessed on June 21, 2018
  20. ^ BKW: Treatment of the fuel elements
  21. ↑ Supervisory Report 2018 - ENSI-AN-10629. ENSI, accessed on December 25, 2019 .
  22. ↑ Supervisory Report 2017 - ENSI-AN-10295. ENSI, accessed on December 25, 2019 .
  23. ↑ Supervisory Report 2016 - ENSI-AN-10014. ENSI, accessed on December 25, 2019 .
  24. ↑ 2015 Supervisory Report - ENSI-AN-9671. ENSI, accessed on December 25, 2019 .
  25. ↑ Supervisory report 2014 - ENSI-AN-9252. ENSI, accessed on June 24, 2015 .
  26. ↑ Supervisory report 2013 - ENSI-AN-8800. ENSI, accessed on June 24, 2015 .
  27. ↑ Supervisory report 2012 - ENSI-AN-8300. ENSI, accessed on December 25, 2019 .
  28. ↑ Supervisory report 2011 - ENSI-AN-7870. ENSI, accessed on December 25, 2019 .
  29. ^ Supervision report 2010 - ENSI-AN-7500. ENSI, accessed on December 25, 2019 .
  30. ↑ Supervisory report 2009 - ENSI-AN-7200. ENSI, accessed on December 25, 2019 .
  31. ↑ Susan Boos: Mühleberg: What they keep silent. The WOZ publishes a secret document. (No longer available online.) The weekly newspaper , April 21, 2011, archived from the original on April 23, 2011 ; Retrieved April 23, 2011 .
  32. ↑ Thomas Angeli: The crack goes through. In: Observer . July 4, 2011, accessed January 6, 2020 .
  33. ↑ Mühleberg operating license will not be re-examined. In: Basler Zeitung . October 5, 2011, accessed January 6, 2020 .
  34. ↑ Chr. Küppers et al., Ökoinstitut Darmstadt / Freiburg: Brief statement on the BKW application to lift the time limit for the operating license for the Mühleberg nuclear power plant , 2008.
  35. ↑ Simon Thönen: BKW study raises doubts about the safety of one's own nuclear power plant . In: The Bund . November 12, 2011. Retrieved November 16, 2011.
  36. ↑ Simon Thönen: Mühleberg I: BKW disguised risk of flooding . In: The Bund . January 25, 2011. Archived from the original on May 26, 2011. Retrieved on May 26, 2011.
  37. ↑ Berner Zeitung , July 10, 2012.
  38. ↑ The future of the Mühleberg nuclear power plant is uncertain . In: Tagesschau . Swiss television. May 6, 2011. Archived from the original on May 26, 2011. Retrieved on May 26, 2011.
  39. ↑ Accidental discovery: radioactive cesium on the bottom of Lake Biel. In: SonntagsZeitung , July 14, 2013.
  40. ↑ Ensi explains increased cesium levels in Lake Biel. In: Tages-Anzeiger , July 15, 2013.
  41. ↑ Inspections planned for 22 reactor pressure vessels. www.nuklearforum.ch, August 20, 2012, accessed on August 20, 2015 .
  42. ↑ BKW checks reactor pressure vessels - Leibstadt not affected. www.nuklearforum.ch, August 27, 2012, accessed on August 20, 2015 .
  43. ^ Mühleberg: reactor pressure vessel intact. www.nuklearforum.ch, August 31, 2012, accessed on August 20, 2015 .
  44. ^ Message from the Grand Council of the Canton of Bern, accessed on April 16, 2014
  45. ↑ http://www.tagesanzeiger.ch/schweiz/Bernervolk-belaesst-Muehleberg-am-Netz/story/18405950
  46. ↑ http://www.schweiz.biz/2014/05/19/schweizerische-energie-stiftung-bedauert-nein-zu-muehleberg-vm-netz/
  47. ↑ Further requests for new nuclear power plants
  48. ↑ Requests for new nuclear power plants open up old trenches (NZZ online)
  49. ↑ Cantonal referendum of February 13, 2011 (PDF) State Chancellery of the Canton of Bern, accessed on September 2, 2019 .
  50. ↑ ( Page no longer available , search in web archives: Chancellery Bern - voting text and Grand Council vote ) (PDF)@1@ 2Template: Dead Link / www.sta.be.ch
  51. ↑ Doris Leuthard: "Security has top priority" ( Memento from March 18, 2011 in the Internet Archive )
  52. ↑ Power Reactor Information System of the IAEA : "Switzerland (Swiss Confederation): Nuclear Power Reactors" (English)
  53. ↑ Mühleberg nuclear power plant will be shut down in 2019 . In: Tages-Anzeiger , March 2, 2016, accessed on March 2, 2016.