Opened in 1967, it had two Magnoxreactors producing 424megawatts (MWe) in total[1][2] – enough electricity on a typical day to serve an urban area twice the size of Bristol. Reactor 1 went critical on 18 September 1967 and first generated electricity on 9 November 1967. Reactor 2 started generating electricity in April 1968.[3]
The construction was undertaken by a consortium known as The Nuclear Power Group ('TNPG').[4] The reactors were supplied by TNPG and the turbines by AEI and C. A. Parsons & Co.[2] The main civil engineering contractor was Sir Robert McAlpine.[2] Construction on the site began in 1961.[3]
Oldbury was the first nuclear power station in the UK to use prestressed concrete pressure vessels, earlier Magnox reactors having used steel pressure vessels more suited to smaller reactors.[5]
The design net power output of the station was 626MWe, but due to steel corrosion problems from the hot carbon dioxide coolant within the reactor, operating temperature had to be reduced soon after operation started causing a large drop in power output. Initially, the power output was set at 424MWe, dropping to 400MWe by 1973. Then as remedial measures were adopted, power was progressively increased to 434MWe by 1983 with a gas outlet temperature of 365 °C (689 °F), compared to the 412 °C (774 °F) design temperature, which was maintained as the normal operational output.[1][6]
The station had two 216MW turbo-alternator generators giving a gross electrical capability of 439.5MW and a net capability of 416MW.[7] The steam conditions at the turbine stop valves was 43.0bar at 389 °C (732 °F).
The generating capacity, electricity output, load factor and thermal efficiency were as shown in the table.[8]
Year
Net capability, MW
Electricity supplied, GWh
Load as percent of capability, %
Thermal efficiency, %
1972
633.5
3,069.722
87.4
28.3
1979
439.4
3,044.545
83.5
27.98
1981
439.5
3,288.453
90.2
26.8
1982
439.5
3,339.707
91.6
27.09
1984
434
2,945.387
77.3
27.61
In 1976/77, Oldbury was presented with the Hinton Cup, the CEGB's "good house keeping trophy". The award was commissioned by Sir Christopher Hinton, the first chairman of the CEGB.
In 1992, Reactor one set a world record for the longest continuous period of power generation from a commercial nuclear reactor, of 713days 21hours and 32minutes.[9]Hinkley Point A Nuclear Power Station held the previous world record of 700days and 7hours, set in 1988.
From 2005 until 2012, the power station was protected by armed officers from the Civil Nuclear Constabulary.
Closure and decommissioning
The station was originally to cease generating at the end of 2008, however continued use was licensed in various stages; an additional 2.5years in the case of reactor 2, and four years for reactor 1.
[10][11][12][13]
Reactor 2 ceased operating permanently on 30 June 2011,[14] followed by Reactor 1 on 29 February 2012.[15]
Defuelling and removal of most buildings is expected to take until 2027, followed by a care and maintenance phase from 2027 to 2095. Demolition of reactor buildings and final site clearance is planned for 2096 to 2101.[16]
Incidents
On 30 May 2007, only a few days after reopening after safety checks, the power station was shut down as part of standard emergency procedure when a fire broke out on one of the generator transformer HV bushings. No-one was injured in the fire and no radiation was released. Information suggests an insulator overheated, causing it to fail. Minor damage ensued resulting in a standard shutdown. All emergency procedures were commenced, and by 11:30am the situation was stabilised.[17][18]
The power station resumed production for a few days in June then shut down again. Production eventually resumed on 24 August 2007, at which point it had only produced electricity for eight days since August 2006.[19]
On 17 March 2011 at 10:40am, Reactor 2 was automatically shut down after an electrical problem.[20]
Magnox stated that workers had been carrying out routine maintenance when a small relay overheated (this failure caused the turbine to shut down). Their spokesman went on to say, "Because the turbine tripped the steam produced in the boilers couldn't be sent to the turbine as it would normally and so was released through relief valves on top of the building." and "To reduce the amount of steam being produced, and in accordance with expectations, the reactor automatically tripped and was safely shut down."[21]
On 14 July 2011, Reactor 1 was automatically shut down after 'problems with the refuelling machinery.' Again steam was released to remove the decay heat.[22]
Horizon Nuclear Power, an E.ON and RWE joint venture, announced in 2009 intentions to install up to 3,300MWe of new nuclear plant at Oldbury. Horizon were considering building up to either two 1,650MWe Areva EPR reactors, or three 1,100MWe Westinghouse AP1000 reactors. As the Severn estuary water supply would be inadequate to cool these larger reactors, cooling towers would be built.[24][25]
On 18 October 2010, the British government announced that Oldbury was one of the eight sites it considered suitable for future nuclear power stations.[26]
On 29 March 2012, E.ON and RWE npower announced that their plans to build the new power station had been shelved.[27]
In late 2012, it was announced that Hitachi had bought the UK Nuclear project from E.ON & RWE. It planned to build ABWR (Advanced Boiling Water Reactors) at this site along with Wylfa Newydd, the lead site. Construction would not have started until Wylfa Newydd was operational, in order to learn from experience and correct problematic aspects that arose during construction. However, Hitachi suspended work on Wylfa and Oldbury in January 2019.[28]
In September 2020, Hitachi announced its withdrawal from the Oldbury and Wylfa projects. It will close down its development activities, but will work with the UK government and other stakeholders to facilitate future options for the two sites.[29]
In April 2022, it was announced that Oldbury and Wylfa sites are candidates for two sets of EPR reactors to be constructed as the UK Plans to construct up to eight new reactors this decade. These sites would be part of the next set of plants with the first being Hinkley Point C and Sizewell C. The Oldbury and Wylfa sites are likely to begin construction next parliament.[clarification needed][30][31][32]
^ abc"Arquivo.pt". arquivo.pt. Archived from the original on 19 July 2009. Retrieved 7 April 2022.((cite web)): CS1 maint: bot: original URL status unknown (link)
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