Sizewell nuclear power stations

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Sizewell A & B nuclear power stations

The Sizewell nuclear site consists of two nuclear power stations, one of which is still operational, located near the small fishing village of Sizewell in Suffolk, England. Sizewell A, with two magnox reactors, is now in the process of being decommissioned. Sizewell B has a single pressurised water reactor and is the UK's newest nuclear power station. A third power station, to consist of twin EPR reactors, is planned to be built as Sizewell C.

Sizewell A[edit]

Sizewell A nuclear power station
Sizewell A.jpg
Sizewell A
CountryUnited Kingdom
LocationSuffolk, East of England
Coordinates52°12′54″N 1°37′11″E / 52.215°N 1.61972°E / 52.215; 1.61972
StatusOperational
Commission date1966
Decommission date2006
Operator(s)Magnox Ltd
Nuclear power station
Reactor typeMagnox
Cooling sourceNorth Sea
Power generation
Nameplate capacity490 MWe (gross)
420 MWe (net)[1]
External links
Websitewww.british-energy.com/pagetemplate.php?pid=96
CommonsRelated media on Commons

grid reference TM473633

Site[edit]

The site of Sizewell A occupies 245 acres (99 hectares) north of Sizewell. It is on a low plateau above flood level. The geological foundation comprises Norwich Crag Formation and Red Crag Formation bedrock of Pleistocene age above Eocene London Clay. The Crag deposits predominantly consist of medium dense and dense sands with thin layers of clay and silt and fossiliferous shelly horizons. The Crag strata extend to a depth of 200 feet (60 metres) below ground level. In 1972/73 Sizewell A was awarded the Christopher Hinton trophy in recognition of good housekeeping

Hinton Cup

The site is reached by road, with the nearest railhead about one mile inland at Sizewell Halt. Sidings were installed at the railhead primarily to transport irradiated elements to the United Kingdom Atomic Energy Authority plant at Sellafield, Cumbria. Nuclear fuel was handled by a crane loading facility at the end of the five-mile Leiston/Sizewell branch railway. This is connected to the East Suffolk line via a south-facing junction to the north of Saxmundham station. The line was extended and used for the delivery of construction materials for Sizewell B power station in the 1980s. The line is now only rarely used for transportation of spent fuels from Sizewell B since the completion of decommissioning of Sizewell A in 2006. A new branch line off the Leiston branch has been proposed for rail terminals for the construction of Sizewell C power station to the north of the existing B power station.[2]

Construction[edit]

The Midlands Project Group of the Central Electricity Generating Board (CEGB) planned and managed the project. The main contract was placed in November 1960 and construction work on Sizewell A began on 1 April 1961. The main construction contract was awarded to British Nuclear Design and Construction Ltd ('BNDC'), a consortium of English Electric, Babcock & Wilcox and Taylor Woodrow Construction,[3] The initial budget was £56 million, but due to inflation this figure rose to £65 million.[4] During its 40-year operational lifetime, it had produced 110 TWh (400 PJ) of electricity, which would have been sufficient to meet the domestic needs of England and Wales for six months.[5] Unit 1 was commissioned on 21 March 1966, and Unit 2 on 15 September. The station was officially opened on 7 April 1967 by the Lord Lieutenant of Suffolk, the Earl of Stradbroke.

Design[edit]

The designed net electrical output of the station was 652 MWe. The power station originally had a single 324.75 MW turbo-alternator, and a gross generating capability of 327.7 MW. In 1967 a second turbo-alternator was commissioned with a rating of 275 MW.[6] The total generating capacity was reduced to 490 MW in 1969, and then 420 MWe in 1973, to arrest the rate of oxidation of internal reactor-core components. At full load, 70 MWe were used in providing works power from the gross electrical output of 490 MWe.[1]

The main plant consisted of two 1,010 MW (thermal) Magnox reactors,[1] which were natural uranium, carbon dioxide gas cooled, graphite moderated units. These supplied heat to eight boiler units, four associated with each reactor. The steam produced by the boilers was fed to two turbo-generators each rated at 325 MW, but which operated at a reduced capacity of 250 MW from 1969.

The reactors and turbines were both supplied by English Electric.[7]

Building specification[edit]

The foundations for the reactors and associated boilers are provided by a reinforced concrete raft 8 feet (2.4 metres) thick, founded on the sand with a designed net bearing pressure of 3.5 tons per square foot. The biological shields are 100 feet (30.5 metres) high and vary between 10 and 14 feet (3 and 4.3 metres) thick. The composite steel and reinforced concrete cap above each reactor is 12 feet (3.7 metres) thick. Both reactors were housed in a single building to achieve savings in building costs.

The turbine house is a steel-framed, aluminium clad building 380 feet (115.8 metres) long, 160 feet (48.8 metres) wide and 90 feet (27.4 metres) high, with a reinforced concrete basement 26 feet (7.9 metres) deep. The foundations are provided by isolated bases and strip footings with a designed maximum bearing pressure of 3 tons per square foot.

The pumphouse which supplied the main turbines with 27 million gallons of cooling water per hour drew sea water from an intake structure about 1,350 feet (410 metres) offshore via twin 10 feet (3 metres) diameter tunnels. This water was returned to the sea through similar tunnels discharging 350 feet (107 metres) offshore.

Electricity output[edit]

Electricity output from Sizewell A power station over the period 1966-84 was as follows.[6]

Sizewell A annual electricity output GWh.

Decommissioning[edit]

The power station was shut down on 31 December 2006.[4] The Nuclear Decommissioning Authority (NDA) is responsible for placing contracts for the decommissioning of Sizewell A, at a budgeted cost of £1.2 billion. Defuelling and removal of most buildings is expected to take until 2034, followed by a care and maintenance phase from 2034 to 2092. Demolition of reactor buildings and final site clearance is planned for 2088 to 2098 [8]

On 7 January 2007 a contractor working on the decommissioning of the station noticed water leaking on to the floor of the laundry where he was washing his clothes. The water was found to be cooling water from the pond that holds the reactor's spent nuclear fuel which had dropped more than 1 foot (0.30 m) without activating any of the alarms. It is estimated that up to 40,000 gallons (151,500 litres) of radioactive water had leaked from a 15 ft (4.6 m) split in a pipe, with some spilling into the North Sea. According to the HM Nuclear Installation Inspectorate's report of the incident, without the chance intervention of the contractor, the pond could have drained before the next scheduled plant inspection. If the exposed irradiated fuel had caught fire, it would have resulted in an airborne off-site release of radiation.[9]

In popular media[edit]

Sizewell A was the location where Thomas Dolby shot the music video to Europa and The Pirate Twins.

Sizewell B[edit]

Sizewell B nuclear power station
Sizewell B.jpg
Sizewell B
CountryEngland
LocationSuffolk, East of England
Coordinates52°12′54″N 1°37′11″E / 52.215°N 1.61972°E / 52.215; 1.61972
StatusOperational
Commission date1995
Operator(s)EDF Energy,
Nuclear power station
Reactor typePWR
Reactor supplierWestinghouse
Cooling sourceNorth Sea
Power generation
Make and modelGEC-Alsthom
Nameplate capacity1,250 MWe (gross)
1,195 MWe (net)[10]
External links
Websitewww.british-energy.com/pagetemplate.php?pid=96
CommonsRelated media on Commons

grid reference TM473633

Sizewell B is the UK's only commercial pressurised water reactor (PWR) power station. Its single reactor was built and commissioned between 1987 and 1995, and first synchronised with the national grid on 14 February 1995. The main civil engineering contractor was John Laing.[7] The power station is operated by EDF Energy. The architectural design was carried out by Yorke Rosenberg Mardall.[11]

EDF's strategic target is for 20 year life extension for Sizewell B PWR, beyond the current accounting closure date of 2035.[12] This would mean the plant remaining in operation until 2055.

Design[edit]

The 'nuclear island' at Sizewell B is based on a Westinghouse '4-loop' plant known as SNUPPS (Standard Nuclear Unit Power Plant System) initially designed in the 1970s and used at Wolf Creek and Callaway but with additional redundancy and diversity in the safety systems, and other modifications such as the addition of a passive Emergency Boration System. The containment design was not based on SNUPPS however, but was designed by NNC (National Nuclear Corporation – bought by Amec Foster Wheeler in 2005) in conjunction with Bechtel.

The Wolf Creek and Callaway plants each have single half speed, 1,800 RPM (60 Hz), steam turbine-alternator sets which use the steam produced from the heat generated in the reactor to produce about 1,200 MW of electricity at the US grid frequency of 60 Hz. Such large turbo-alternator sets were not available in the UK at the time Sizewell B was designed. So that orders could be given to UK manufacturers, and to avoid project risk in dealing with what were at the time newly designed very large turbo-alternator sets, Sizewell B uses two full-speed, 3,000 RPM (50 Hz), nominal 660 MW turbo-alternator sets similar to those used at Drax coal-fired power station, and at the last of the AGRs Heysham 2, but adapted to cope with the wetter steam conditions produced by the PWR steam supply system. PWR steam supply systems produce saturated steam at lower temperature and pressure than the dry superheated steam produced by AGR reactors or coal-fired power stations, and the high- and intermediate-pressure stages of the steam turbines have to be designed cope with this[13] Sizewell B can run at half power using one turbo-alternator.[14]

The major components were supplied by:[15]

A distinctive white hemisphere envelopes the outer shell of the twin-walled containment building that protects the pressurised water reactor and its steam generators.

History[edit]

First announced in 1969 as an advanced gas-cooled reactor (AGR) based power station,[17][18] and then in 1974 as a steam-generating heavy water reactor (SGHWR), Sizewell B was eventually announced as a PWR power station in 1980.[19] The initial design submissions to the CEGB and NII were based on the design of the Trojan plant at Portland, Oregon.[20][21] Designed by Westinghouse, construction of Trojan began in 1970 and was completed in 1975. Westinghouse continued to develop the design they had used for the Trojan plant into the SNUPPS design, built first at Callaway, and SNUPPS was adopted as the basis for the design approved by the CEGB in October 1981.[22]

Before construction commenced, the design of Sizewell B was subjected to a detailed safety review by the Nuclear Installations Inspectorate (NII), and a lengthy public inquiry. The Pre-Construction Safety Case was submitted to the NII in August 1981. The public inquiry was held between 1982 and 1985, and took over 16 million words of evidence, a record at the time. The chairman of the inquiry, Sir Frank Layfield, reported in early 1987 that, subject to a satisfactory safety case, there were no substantive reasons why the project should not proceed. The Nuclear Installations Inspectorate accepted the Pre-Construction Safety Case and issued a licence to proceed with construction in August 1987.

Sizewell B was calculated to be economically viable at a 5% discount rate and was approved financially on that basis. The project cost was revised upwards three times to 135% of the original cost, providing a cost-performance of £2,250/kW (2000 prices) not including first of a kind costs and £3,000/kW including them. A post-startup evaluation estimated generating cost at around 6p/kWh (2000 prices, which is 10.2p/kW at 2019 prices), excluding first-of-kind costs but using an 8% discount rate for the cost of capital.[23]

Sizewell B reactor dome

Sizewell B was built and commissioned between 1987 and 1995, and first synchronised with the National Grid on 14 February 1995.

The original rating was for a thermal power of 3,444 MW and gross electrical output of 1,250 MW,[10] which after house load of 62 MW gave a net output to the grid of 1,188 MWe, equivalent to 8.7 TWh (31 PJ) in the year of 2005. It was uprated by 1% in 2013 with a thermal power of 3,479 MW and an electrical output of 1,195 MWe,[10] though this is dependent on seawater temperature.

As with many other PWRs, Sizewell B operates on an 18-month operating cycle, i.e. at or near 100% output continuously for around 18 months, followed by a month's shutdown for maintenance and refuelling. Sizewell B was designed for a commercial life of 40 years (i.e. to around 2035) but similar stations elsewhere have been granted extensions to 60 years.

On 27 May 2008 Sizewell B had an unplanned shutdown, cutting off its supply to the National Grid.[24] A British Energy spokesman said that the fault involved conventional equipment at the plant rather than any part of the nuclear reactor.[24]

On 17 March 2010 Sizewell B was taken offline for an extended period because of high moisture levels in the containment building due to a pressuriser electrical heater fault, requiring difficult repairs.[25] On 2 July 2010 just before 21:00, while still offline, a minor fire broke out on the second floor of the building housing the charcoal adsorber at Sizewell B. Numerous emergency services were called to the scene and the fire was brought under control by 3:30 the following day when the charcoal adsorber was flooded.[26]

On 2 March 2012 Sizewell B had an unplanned shutdown due to an electrical fault. One and a half weeks later it was restarted at half capacity.[27] As of June 2012, conditions improved and Sizewell B continued under carefully controlled operation.

In 2013 a new remote Emergency Response Centre was inaugurated near the power station, following recommendations made after the Fukushima Daiichi nuclear disaster. The centre provides remote controls and a back-up plant.[28]

In January 2014 the building of a dry spent nuclear fuel store began. The existing spent fuel pool, which stores spent fuel under water, was expected to reach full capacity in 2015.[29] In April 2016 the building was inaugurated. This will enable spent nuclear fuel produced from autumn 2016 until at least 2035 to be stored until a deep geological repository is available.[30] In March 2017 the first cask containing spent nuclear fuel was installed.[31]

In 2021 Sizewell B had an extended outage for maintenance and safety related issues. The Times reported that excessive wear on some stainless steel "thermal sleeves" in the control rod mechanisms had been discovered. The maintenance period was extended to over four months to evaluate the cause and extent of the wear to decide how many to replace.[32]

Sizewell C[edit]

A view of the Sizewell A & B nuclear power stations

Since the sale of British Energy to Électricité de France (EDF) in February 2009, plans for a further twin-unit reactor to be built at Sizewell have looked increasingly likely.[33] Sizewell already has a connection agreement in place for a new nuclear power plant to be built.[34] The government revealed that the 1,600 MW projected units, to be called Sizewell C, would, together with the planned units at Hinkley Point C, contribute 13% of UK electricity in the early 2020s.[33] EDF plans to use Framatome's EPR design for any new-build reactors in the UK, this being the design of reactors currently being built in Finland, France and China.[33]

On 18 October 2010 the British government announced that Sizewell was one of the eight sites which it considered suitable for future nuclear power stations.[35]

On 21 October 2015, it was reported that Britain and China had reached Strategic Investment Agreements for three nuclear power plants, including one at Sizewell,[36] though no specific financing plans for Sizewell are agreed.[37] The final investment decision for Sizewell C is only likely to take place after the Hinkley Point C build has started.[38]

In May 2020 the NGO Energy for Humanity issued an open letter calling for the Department of Business, Energy and Industrial Strategy to support the project as without nuclear the "action on climate will be more difficult, more expensive, and more likely to fail". It also called for lessons to be drawn from Hinkley Point C as well as the UK's offshore wind programme to ensure a timely procurement schedule.[39]

Concerns have been expressed[40][41] regarding one of the shareholders in the consortium, China General Nuclear Power Group. CGN is owned by the Chinese government and has been blacklisted by the US Department of Commerce for attempting to acquire advanced U.S. nuclear technology and material for diversion to military use.[42][43]

EDF submitted its planning application in May 2020, declaring 25,000 job opportunities and 70% of investment being spent in UK. The plant will largely replicate Hinkley Point C design to reuse experience, lower cost and ensure high levels of safety.[44] The proposal was welcomed by Unite the Union.[45]

On 27 May 2020, EDF Energy announced that it had submitted a development consent order application.[46] However EDF have yet to organise financing, and cannot take on more construction risk in the UK. EDF is looking to the UK government to assist on financing either by offering a regulated asset base (RAB) model used on less risky infrastructure, though that puts an immediate cost burden on end consumers or through other approaches such as a government equity stake in the development.[47]

On 30 June 2020, EDF Energy announced that it had applied to the Office for Nuclear Regulation (ONR) for a licence to build and operate Sizewell C. The ONR is responsible for the safe operation of nuclear sites in the UK and for permitting new nuclear site licences – one of the key regulatory requirements for building and operating a new power station.[48]

See also[edit]

References[edit]

  1. ^ a b c "Sizewell A". Power Reactor Information System. IAEA. 22 June 2015. Retrieved 23 June 2015.
  2. ^ Scotchman, Iain C. (February 2019). "Sizewell-C could generate freight". Modern Railways. 76: 17.
  3. ^ "Nuclear Development in the United Kingdom". World Nuclear Association. October 2016.
  4. ^ a b "Night falls on Sizewell A". Nuclear Engineering International. 2 April 2007. Archived from the original on 27 September 2007.
  5. ^ "Magnox South Sites: Sizewell A". Magnox South Ltd. Archived from the original on 11 December 2008. Retrieved 2 November 2008.
  6. ^ a b CEGB Statistical Yearbook (various dates). CEGB, London.
  7. ^ a b "Nuclear Power Plants in the UK". Archived from the original on 19 July 2009.
  8. ^ "The 2010 UK Radioactive Waste Inventory: Main Report" (PDF). Nuclear Decommissioning Agency/Department of Energy & Climate Change. February 2011. Archived from the original (PDF) on 25 March 2012. Retrieved 22 May 2012.
  9. ^ Gould, Mark (11 June 2009). "Sizewell nuclear disaster averted by dirty laundry, says official report]". The Guardian.
  10. ^ a b c "Sizewell B". Power Reactor Information System. IAEA. 22 June 2015. Retrieved 23 June 2015.
  11. ^ "Sizewell Stories". Building. 2006. Retrieved 30 March 2016.
  12. ^ "EDF plans longer life extensions for UK AGRs". Nuclear Engineering International. 20 February 2012. Archived from the original on 13 October 2013. Retrieved 16 May 2012.
  13. ^ Leyzerovich, Alexander (2005). Wet-steam Turbines for Nuclear Power Plants. PennWell. pp. 23, 24. ISBN 978-1-59370-032-4.
  14. ^ "Sizewell: Nuclear station running at half power after turbine taken offline". East Anglian Daily Times. Retrieved 13 November 2011.
  15. ^ Pick, Malcolm (9 June 2004). "United Kingdom LWR Activities (IAEA Vienna presentation)" (PDF). BNFL. Retrieved 2 August 2011.[permanent dead link]
  16. ^ Large, John (26 September 2016). Irregularities and Anomalies Relating to the Forged Components of Le Creusot Forge (PDF). Large Associates (Report). Greenpeace France. p. 24. Retrieved 27 October 2016.
  17. ^ Aldous, Tony (30 October 1969). "Government agree to £400m power stations programme". The Times (57704). p. 1.
  18. ^ "Steep penalties for drug traffickers: four power stations approved". The Times (57704). 30 October 1969. p. 5. col A.
  19. ^ Hirst, Nicholas; Wright, Pearce (2 October 1980). "Electricity board confirms that it intends to build pressurized water reactors on site in Suffolk". The Times (60739). p. 5. col A.
  20. ^ Wright, Pearce (30 July 1977). "Government advised not to develop UK-designed reactor". The Times (60069). p. 2.
  21. ^ Wright, Pearce (23 April 1981). "Safety systems are doubled in proposed new nuclear power plant". The Times (60909). p. 4.
  22. ^ Cookson, Clive (24 October 1981). "Design approved for first PWR reactor". The Times (61064). p. 15.
  23. ^ Performance and Innovation Unit (February 2002). "The Economics of Nuclear Power" (PDF). Cabinet Office. Archived from the original (PDF) on 29 December 2008. Retrieved 2 June 2009. Cite journal requires |journal= (help)
  24. ^ a b "Sizewell nuclear plant shut down". BBC News. 27 May 2008. Retrieved 27 May 2008.
  25. ^ "Sizewell B outage will extend into summer". Nuclear Engineering International. Progressive Media International. 11 June 2010. Retrieved 6 July 2010.
  26. ^ "Fire breaks out at nuclear power plant near Leiston". BBC News. 3 July 2010.
  27. ^ "Sizewell B: Nuclear plant back up and running after shut down". East Anglian Daily Times. 13 March 2012.
  28. ^ "EDF Energy inaugurates Sizewell B emergency response centre, hints about Dungeness B life extension". Nuclear Engineering International. Progressive Media International. 19 December 2013. Retrieved 21 December 2013.
  29. ^ "Sizewell builds dry spent nuclear fuel store". Nuclear Engineering International. Progressive Media International. 23 January 2013. Retrieved 26 January 2013.
  30. ^ "EDF Energy completes 'dry fuel store' at Sizewell B". World Nuclear News. World Nuclear Association. 5 April 2016. Retrieved 6 April 2016.
  31. ^ "First cask emplaced at Sizewell B fuel store". World Nuclear News. World Nuclear Association. 23 March 2017. Retrieved 23 March 2017.
  32. ^ Gosden, Emily (17 May 2021). "Sizewell B nuclear plant forced to stay shut over safety concerns". The Times. London. Retrieved 17 May 2021.
  33. ^ a b c "New dawn for UK nuclear power". WNN. 24 September 2008. Retrieved 25 September 2008.
  34. ^ "EDF confirms £12.5bn offer for British Energy". New Energy Focus. 24 September 2008. Archived from the original on 30 June 2016. Retrieved 25 September 2008.
  35. ^ "Nuclear power: Eight sites identified for future plants". BBC News. BBC. 18 October 2010. Retrieved 18 October 2010.
  36. ^ "Hinkley Point nuclear agreement reached". BBC News. 21 October 2015.
  37. ^ Leroux, Marcus (16 September 2016). "Hinkley is no pointer to funding for Sizewell". Sunday Times. London. Retrieved 30 October 2016.
  38. ^ Cornwell, Richard (15 September 2016). "Hinkley Point nuclear energy plant approved – but still doubts over Sizewell C as new controls on foreign investment agreed". Ipswich Star. Retrieved 27 October 2016.
  39. ^ "Open letter to Secretary of State for Business, Energy and Industrial Strategy". Energy For Humanity. 27 May 2020. Retrieved 27 May 2020.
  40. ^ Wood, Vincent (25 October 2018). "Spy warning on Chinese nuclear company". The Times.
  41. ^ Pagnamenta, Robin (24 January 2019). "Britain's nuclear industry is falling inexorably into Chinese hands". The Daily Telegraph.
  42. ^ Ng, Eric (11 August 2016). "China General Nuclear Power accused of espionage with its adviser in the US". South China Morning Post.
  43. ^ Teplinsky, Elina; Leidich, Anne; Hutman, Aaron R. (15 August 2019). "Four China Nuclear Industry Companies Added to "Entity List"". Pillsbury Insights. Pillsbury Winthrop Shaw Pittman.
  44. ^ "Sizewell C submits planning application". Nuclear AMRC. 27 May 2020. Retrieved 27 May 2020.
  45. ^ "25,000 jobs to build new Suffolk nuclear power station a boost for post-pandemic economy, says Unite". Unite the Union. 28 May 2020. Retrieved 28 May 2020.
  46. ^ "Sizewell C submits planning application". EDF Energy. 27 May 2020. Retrieved 2 June 2020.
  47. ^ Thomas, Nathalie; Pickard, Jim (2 June 2020). "Plan for new UK nuclear plant under intense scrutiny". Financial Times. Retrieved 4 June 2020.
  48. ^ "Sizewell C applies for a licence to build and operate in Suffolk". EDF Energy. 30 June 2020. Retrieved 8 July 2020.

Further reading[edit]

External links[edit]