Doel Nuclear Power Station

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Doel Nuclear Power Station
Closest unit is Doel 4, furthest unit Doel 1
Doel nuclear power station, viewed from the north
Doel Nuclear Power Station is located in Belgium
Doel Nuclear Power Station
The plant sits on the west bank of the Scheldt river
Official name Kerncentrale Doel (KCD)
Country Belgium
Location Doel, East Flanders
Coordinates 51°19′29″N 04°15′31″E / 51.32472°N 4.25861°E / 51.32472; 4.25861Coordinates: 51°19′29″N 04°15′31″E / 51.32472°N 4.25861°E / 51.32472; 4.25861
Status Operational
Construction began July 1969 (1969-07) (Doel 1)
Commission date February 15, 1975 (1975-02-15) (Doel 1)
Owner(s) Engie Electrabel, EDF Luminus
Operator(s) Engie Electrabel
Nuclear power station
Reactor type PWR
Reactor supplier ACECOWEN
FRAMACEC
Fuel type UO2, MOX
Fuel supplier Areva, ENUSA
Cooling source Scheldt river
Cooling towers 2
Power generation
Units operational 2 x 454 MW
1 x 1056 MW
1 x 1090 MW
Units under const. 0
Units planned 0
Units cancelled 1
Units decommissioned 0
Thermal capacity 2 × 1312 MWt
1 × 3064 MWt
1 × 3000 MWt
Nameplate capacity 3054 MWe
Capacity factor 89,4%
Annual net output 22,789 GW·h (2011)
Website
Doel nuclear power plant

The Doel Nuclear Power Station is one of two nuclear power plants in Belgium. The plant includes 4 reactors. The site is located on the bank of the Scheldt river, near the village of Doel in the Flemish province of East Flanders. The station is operated and majority-owned by vertically-integrated Belgian energy corporation Electrabel. EDF Luminus has a 10% stake in the two newest units. It employs 963 workers and covers an area of 80 hectares (200 acres). The plant represents about 15% of Belgium's total electricity production capacity[1] and 30% of the total electricity generation.[2] Nuclear energy typically provides half of Belgium's domestically-generated electricity and is the country's lowest-cost source of power.[3]

The station is located in the most densely populated area for any power station in Europe, with 9 million inhabitants within a radius of 75 kilometres (47 mi).[4][5]

History[edit]

The powerstation was built by a public utility Ebes which merged into Electrabel in 1990 together with Intercom and Unerg. The design of the plant was made by the Belgian engineering firm Tractebel. Doel 1 and 2 are twin units that entered commercial operation in 1975. Doel 3 entered commercial operation in 1982 and Doel 4 in 1985. Doel 1, 2 and 4 were delivered by the ACECOWEN (ACEC-Cockerill-Westinghouse) consortium. While Doel 3 was delivered by FRAMACEC (Framatome-ACEC-Cockerill).[6]

Earthworks for Doel 5, a 1400MW reactor also known as N8 (8th nuclear reactor in Belgium), were stopped in 1988. The participation in the French twin plant in Chooz however was continued. The French industry was reimbursed for the already ordered components.[7]

Reactors[edit]

The plant consists of four second-generation pressurized water reactors with a total net capacity of 2,905 MWe, smaller than Belgium's other nuclear power plant at Tihange. Its four units are rated as follows:[3]

Reactor [8] Loops Supplier Thermal power Gross power Net power Start construction Criticality Grid connection Commercial operation
Doel 1 2 ACECOWEN 1312 MW 454 MW 433 MW 01.07.1969 18.07.1974 28.08.1974 15.02.1975
Doel 2 2 ACECOWEN 1312 MW 454 MW 433 MW 01.09.1971 04.08.1975 21.08.1975 01.12.1975
Doel 3 3 FRAMACEC 3064 MW 1056 MW 1006 MW 01.01.1975 14.06.1982 23.06.1982 01.10.1982
Doel 4 3 ACECOWEN 3000 MW 1090 MW 1039 MW [9] 01.12.1978 31.03.1985 08.04.1985 01.07.1985

Design[edit]

The design of the plants is reviewed completely every ten years. This so-called TJH (tienjaarlijkse herziening) is a legal obligation imposed by the Belgian state and the exploitation license of the plant. The purpose of the review is to update the plants to the most recent international safety standards.[10]

The station from the opposite bank of the Scheldt (2013).
Doel Nuclear Power Station from a commercial airliner (2010).
Doel Nuclear Power Station from the south (2012)

Meteorological conditions[edit]

Various weather conditions have been analysed including rain, seiches, tsunamis, floods, earthquakes, wind, tornados, lightning, snow, hail, extreme temperatures, cyclones, sandstorms and waterspouts.[11]

Earthquakes[edit]

Since the design of Doel 3 and 4 and the first TJH of Doel 1 and 2[11]:50 the plants are designed to be subjected to earthquakes like the one in Zulzeke-Nukerke in 1938. With an intensity of 5.6 on the Richter scale and a distance of 75 km to the epicentre this is the most significant historic earthquake for Doel. This earthquake resulted in horizontal ground accelerations of up to 0.058g [11]:51 and formed the design base for Doel 1 and 2. Doel 3 and 4 were designed for peak ground accelerations of 0.1g.[11]:50 After the Fukushima Daiichi nuclear disaster probabilistic safety studies performed by the Royal Observatory of Belgium predicted an earthquake with peak ground acceleration of up to 0.081g every 10,000 years.[11]:52 The design was subsequently analysed for earthquakes up to 0.17g[11]:70, which is equivalent to a 1 in 100,000 year earthquake.[11]:48

Floods[edit]

The Doel plant was originally designed for a 10,000 year flood of 9.13m TAW (Tweede Algemene Waterpassing).[11]:90 The highest measured level was 8.10m TAW during the North Sea flood of 1953.[11]:78 The site was filled to 8.86m TAW during construction and fitted with a seadyke of 12.08m TAW. The other dykes around the site have a height of 11m TAW.[11]:20 Probabilistic studies performed after Fukushima showed the height of a 10,000 year flood had slightly increased to 9.35m TAW, 22 cm higher than the studies performed in the 1960s.[11]:91 The highest possible tsunami is lower than 0.5m.[11]:77 During post-Fukushima stress tests a dyke failure with a water level of 10.2m was simulated. Due to the presence of bulkheads and pedestals in the buildings no safety functions were endangered.[11]:98–108

Bunker[edit]

Besides regular primary level safety systems, in common with most nuclear power plants in the world, Doel has secondary level safety systems that can autonomously keep the power plant safe during large external accidents such as the crash of an aircraft, external explosions or loss of the primary level.[11]:30[11]:14 The primary level systems have a redundancy of three or four times.:26–29 The secondary level systems are 2x100% or 3x50%.[11]:30–33 and have their own heatsink separate from the primary heatsink, the Scheldt river. Doel 1 and 2 have aircoolers [11]:32 while Doel 3 and 4 have three separate artificial cooling ponds.[11]:33

Double containment[edit]

Nuclear plants are designed with multiple physical barriers to keep fission productions from escaping into the environment. In the case of a pressurized water reactor there are three barriers: the fuel cladding which surround the fuel pallets, the primary circuit which houses the fuel rods and finally the containment building in which the primary circuit is built. In Belgium it was decided to add an extra barrier, a so-called double containment.[12] The primary containment, which is a steel sphere for Doel 1 and 2 and a pre-stressed concrete cylinder with steel liner for Doel 3 and 4, is surrounded by a secondary containment made of 1.2 to 1.3m thick reinforced concrete. The space between both containments is kept at sub-atmospheric pressure and filters are used to filter potential leaks of the primary containment.[11]:14

Filtered containment venting system[edit]

In answer to a question of die Grünen in the Bundestag, the German parliament, the German government replied that the Belgian nuclear power plants do not have filtered containment venting systems installed. In German nuclear reactors these were already built in after the nuclear disaster in Chernobyl in 1986. Other countries followed this example, latest after the Fukushima nuclear disaster. This kind of system allows for the containment pressure to be relieved in the event of a severe accident. The non-condensible gases that cause pressure within containment to rise are released through a stack (or chimney) via a filtration system that removes large quantities of fission products from the effluent.[13][14][15][16][17][18]

As part of the stress tests following the Fukushima incident, this issue had already been identified to be included in the stress-test action plan (BEST). Units Doel 3 and Doel 4 will have functional containment filter venting systems by 2017, Doel 1 and 2 by 2019.[19]

Turbo feed pump[edit]

Every reactor has at least one steam driven feedwater pump which can supply the steam generators with water to cool down the reactor. These turbine driven pumps can cool down the plant even when no electrical power is available to power the motor driven feedwater pumps during a station blackout like the Fukushima Daiichi nuclear disaster.[11]:147 In a boiling water reactor, like those in Fukushima, the heat removal capacity of the pumps is limited as the steam that drives the turbines is radioactive and thus has to be stored.[20] This is not the case with a PWR due to the use of steam generators. Steam can simply be removed via a chimney. Water supplies on site are sufficient to keep the plant safe for dozens of days.[11]:147

Nuclear waste[edit]

Light and intermediate level waste, which represents 99% of the volume of waste,[21] is treated on site in the WAB (Water and Waste Treatment Building).[22] Category A waste with half lives of less than 30 years is transported to Belgoprocess in Dessel for surface disposal.[23]

High level waste was originally recycled to MOX fuel, and re-used in the Doel 3 reactor. In 1993, the Belgian federal government placed a moratorium on the reprocessing activities in order to research other options.[24] Pending further decisions regarding the moratorium, spent fuel was stored on site in dry cask storage. Final disposal of the waste is being researched at the HADES underground laboratory 225m deep in the Boom Clay.[25] Nuclear transmutation of the waste is also being researched with the MYRRHA project.

In October 2013, NIRAS suspended Electrabel's license to treat two types of waste, concentrate and resins, after foam was discovered on previously treated waste due to an alkali–silica reaction. Electrabel has started a licensing procedure to use the process used in Tihange to process future waste. This process can take up to two years and in the meantime the waste in question is stored on site.[26]

Incidents[edit]

INES[edit]

There has been one INES-2 incident on the International Nuclear Event Scale. One of the three feedwater pumps of the first level turned out to deliver insufficient flow rates during certain circumstances.[27] The two other first level feedwater pumps and three second level feedwater pumps were still available. The incident was rated 2 on the scale rather than 1 because the licensee reported the issue late.[28] All other incidents received an INES-1 rating, an anomaly.

Level [29] 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017
INES 1 4 5 3 6 1 3 2 3 3 3 5 ? 3 3 7 9 4 2 5 3 1 3 1
INES 2 0 0 0 0 0 0 0 0 0 0 0 ? 0 0 0 0 1 0 0 0 0 0 0

2012 Doel 3 hydrogen damage[edit]

Doel 3 was shut down at the beginning of June 2012 for a planned inspection. Ultrasound inspections revealed thousands of semi-laminar flaws in the reactor vessel's steel rings forged by Rotterdam Drydocks. This was determined to be hydrogen damage, which affects steel brittleness and vessel pressure.[30] The reactor remained offline for further inspections and assessment for a year.[31][32][33] Eventually the nuclear regulator judged that the reactor could still operate safely and it was restarted on 3 June 2013.

The restart was linked to an action plan concerning further investigation of the material properties of the reactor vessel. A piece of steel from a French steam generator with hydrogen flakes was irradiated at the BR-2 materials testing reactor to simulate the lifetime of the reactor vessel. At the end of March 2014 the test results revealed a different outcome compared to what was anticipated by experts. Therefore, the operator (GDF Suez) decided to stop the affected power plant until a clarification could be found and further operation of the powerplant is declared safe.

After a re-qualification of the ultrasound equipment and additional tests on a more similar German-made piece of steel the reactor was restarted in November 2015. A separate investigation by Oak Ridge National Laboratory also justified the restart of the unit.[34]

2014 Doel 4 turbine incident[edit]

In August 2014, there was a major incident in the non-nuclear part of the plant. The main turbine overheated while operating without oil. A valve had been deliberately opened, which rapidly evacuated 65,000 litres of oil to an underground storage tank. The procedure was normally used in case of fire. The valve was normally secured by a padlock.[35] Authorities and the plant operator suspected an act of deliberate sabotage. The unit was eventually back on grid by 19 December 2014. Combined with the outage of Doel 3 and Tihange 2, blackouts were not ruled out for the winter period of 2014-2015.[36]

In December 2016, Electrabel requested that the justice department in Brussels prolong the search for the perpetrator of the turbine sabotage. Repairs cost more than 100 million euros.[37]

Other[edit]

Transmission[edit]

The Doel – Zandvliet line

The power plant has two electrical substations. Two lines depart to Zandvliet and Kallo from the 150 kV station. The 380 kV station has three lines to Avelgem, Mercator in Kruibeke and Zandvliet. The substations are exploited by Elia.

The lines departing to Zandvliet cross the Scheldt river using one of the highest transmission towers in Europe. The tower is 170 metres (560 ft) high and built on a caisson in the middle of the river. The line is part of the interconnection between the Dutch and Belgian grids.

Cooling towers[edit]

With a height of 176 metres, the two cooling towers are the most visible structures in the Port of Antwerp. Due to their proximity to the Dutch-Belgian border, the towers and the accompanying wet steam can be seen over large areas of the Dutch provinces of Zeeland and western North Brabant. Since the spring of 1996, one of the cooling towers has hosted a nest of peregrine falcons.[38]

Security[edit]

On 15 March 2016, the federal government of Belgium decided 140 soldiers would guard the nuclear sites and that Electrabel should cover the costs.[39] In late 2015 it had already been decided that a specially trained department of the federal police would guard the nuclear sites.[40] After the 2016 Brussels bombings, on March 22 the nuclear powerplants of Doel and Tihange were preventively evacuated, the standard procedure when the threat level in Belgium reaches Level 4. The powerplants continued running with minimal staff.[41]

See also[edit]

References[edit]

  1. ^ "Doel nuclear power plant". Engie Electrabel. Retrieved 26 May 2017. 
  2. ^ "CREG Nota" (PDF). CREG. Retrieved 20 August 2017. 
  3. ^ a b "Nuclear Power in Belgium". London: World Nuclear Association. February 2017. Retrieved 17 April 2017. 
  4. ^ Chrisafis, Angelique (25 March 2016). "Belgium steps up security at nuclear sites in wake of attacks". The Guardian. London. Retrieved 17 April 2017. 
  5. ^ Kerncentrale Doel in dichtstbevolkte gebied, deredactie.be
  6. ^ "Nuclear Power Reactors in the World" (PDF). IAEA. 2007. 
  7. ^ viWTA (2004). "kernenergie" (PDF) (in Flemish). VITO. Retrieved 2017-02-22. 
  8. ^ FOD Economie. "FODe" (PDF). OECD-NEA. Retrieved 2017-02-22. 
  9. ^ Elia. "Elia". Elia. Retrieved 2017-02-22. 
  10. ^ FANC (2016-03-22). "TJH". FANC. Retrieved 2017-02-22. 
  11. ^ a b c d e f g h i j k l m n o p q r s t u "Kerncentrale Doel rapport weerstandstesten. Bijkomende veiligheidsherziening van de installaties" (PDF). FANC (in Flemish). Brussels: Electrabel. 31 October 2011. Archived from the original (pdf) on 17 October 2014. Retrieved 19 April 2018. 
  12. ^ "Nucleaire veiligheid in de Belgische kerncentrales van Doel en Tihange : van de dagelijkse uitbating tot en met de tienjaarlijkse herzieningen". FANC (in Dutch). Brussels: Federaal Agentschap voor Nucleaire Controle. 18 January 2010. Archived from the original on 25 January 2010. Retrieved 19 April 2018. 
  13. ^ AD (11 maart 2016) Belgische kernreactoren missen benodigde filters
  14. ^ omroep brabant (11 maart 2016) Kernreactor Doel mist belangrijk onderdeel dat radioactieve straling filtert
  15. ^ Nu.nl (11 maart 2016) duitsland zegt dat belgische kernreactoren filters missen
  16. ^ ravage-webzine.nl (11 maart 2016) geen filters in belgische kerncentrales
  17. ^ 4nieuws.nl (11 maart 2016) duitsland zegt dat belgische kernreactoren filters missen
  18. ^ 1limburg (11 maart 2016) Duitse regering: Belgische kernreactoren missen filters
  19. ^ Seventh Meeting of the Contracting Parties to the Convention on Nuclear Safety (FANC) http://fanc.fgov.be/GED/00000000/4200/4218.pdf
  20. ^ ANS (2017-03-01). "Stresstest=Fukushima" (PDF). Retrieved 2017-02-23. 
  21. ^ NIRAS. "Soorten afval". NIRAS. Retrieved 2017-02-23. 
  22. ^ "Doelbewust 81" (pdf) (in Flemish). Brussels: Electrabel GDF Suez. December 2012. p. 6. Retrieved 28 May 2018. 
  23. ^ "Het cAt-project". NIRAS (in Flemish). Archived from the original on 28 July 2017. Retrieved 28 May 2018. 
  24. ^ FOD Economie. "Moratorium". fgov. Retrieved 2017-02-23. 
  25. ^ "HADES underground laboratory". Belgian Nuclear Research Centre. Retrieved 2017-02-23. 
  26. ^ Engie Electrabel (2017-03-01). "Doelbewust" (PDF). Electrabel. Retrieved 2017-02-25. 
  27. ^ Afwijking op Doel 4, Engie, 18 maart 2011, geraadpleegd 19 april 2017
  28. ^ Nieuw incident in Kerncentrale Doel, Het Nieuwsblad, 31 maart 2011, geraadpleegd 3 juni 2011
  29. ^ FANC. "Jaarverslagen FANC". FANC. Retrieved 2017-02-23. 
  30. ^ Doel-3 in Belgium reports possible pressure vessel flaw, ANS Nuclear Cafe
  31. ^ Doel 3 investigates potential cracks, Nuclear Engineering International
  32. ^ Incident at Doel nuclear power station, Belgian Federal Agency for Nuclear Control
  33. ^ Doel 3: Safety Authorities Meet in Brussels, Belgian Federal Agency for Nuclear Control
  34. ^ "Doel 3 & Tihange 2: foutindicaties in de stalen wanden van de reactorvaten". FANC. 2016-03-03. Retrieved 2017-04-18. 
  35. ^ "Doel 4 ligt mogelijk tot einde van het jaar uit" (in Flemish). vrtnieuws. August 12, 2014. Retrieved 10 September 2014. 
  36. ^ De Clercq, Geert (14 August 2014). "Belgian Doel 4 nuclear reactor closed till year-end". Reuters. 
  37. ^ "Engie Electrabel vraagt bijkomend onderzoek naar de sabotage van Doel 4". Gazet van Antwerpen (in Flemish). Antwerp, Belgium. 24 December 2016. Retrieved 17 April 2017. 
  38. ^ "Electrical falcons". Brussels: Royal Belgian Institute of Natural Sciences. 18 May 2016. Retrieved 17 April 2017. 
  39. ^ De Redactie (2016-03-04). "Militairen zullen ook". De Redactie. Retrieved 2017-02-25. 
  40. ^ "Beveiliging kerncentrales". FANC. 2016-08-04. Retrieved 2017-02-25. 
  41. ^ Engie Electrabel (2016-03-22). "Verhoogde waakzaamheid". Electrabel. Retrieved 2017-02-25. 

External links[edit]