Hinkley Point B is a nuclear power station near Bridgwater, Somerset, on the Bristol Channel coast of south west England. It was the first commercial Advanced Gas Cooled reactor to generate power to the National Grid in 1976 and shares its design with sister station Hunterston B nuclear power station.
The construction of Hinkley Point B, which was undertaken by a consortium known as The Nuclear Power Group (TNPG), started in 1967. The reactors vessels were supplied by Whessoe, reactor machinery was supplied by Strachan & Henshaw and the turbines by GEC.
In March 1971 it was announced that there would be a six-month delay in completion due to problems with the insulation of the concrete pressure vessel. In place of the stainless steel mesh and foil insulation that had been used on previous Magnox stations, a fibrous type of insulation supplied by Delaney Gallay, part of the Lindustries Group, had been used for the first time. During pre-operational trials, before the nuclear fuel was loaded, high levels of acoustic vibration in the gas circuit were found to be damaging the insulation tiles, and the retention plates which held the insulation in place had to be redesigned and modified within the reactor.
During further pre-operational testing, severe vibration of the fuel channel gags was detected. The fuel channel gags are valves which are gradually closed to restrict the flow of gas through a fuel channel in order to maintain the channel gas outlet temperature as the nuclear fuel is used up. Modifications to produce a fluidically generated bias force to stop the gags vibrating took time to design, test and implement, delaying the planned start up date. The station began generating electricity on 5 February 1976.
It was taken over by Nuclear Electric as part of the privatisation of the UK Electricity Supply Industry in 1990, though remaining in public ownership at that time. In 1996, the AGR and PWR assets of Nuclear Electric and Scottish Nuclear were privatised as part of British Energy.
In 2006 the station's reactors were shut down in order to inspect the boilers for microscopic weld defects that had been found in power stations using similar boiler designs. While it was implied in the media that these were major holes gushing steam, had this been the case the loss of pressure would lead to an automatic shut down to prevent damage. Due to its age, on 16 August 2006 the company warned that until a decision was made over whether to extend its usable life it would operate at a maximum of 70 per cent load. Both reactors were subsequently restarted generating 420 MW each, roughly 70% of full capacity. The number 4 reactor was cleared for restart by the Nuclear Installations Inspectorate on 11 May 2007. The power station's current accounting closure date is 2023.
In July 2013, EDF Energy announced that the load on both of the station reactors had been increased to 80 per cent, resulting in an output of around 485-500MWe per reactor up from 70 per cent load, where it had been generating around 420MWe per reactor since 2006.
Hinkley Point B is the only one of four nuclear power stations in the area which is operational, the others being decommissioned are the adjacent Hinkley Point A together with Oldbury and Berkeley on the banks of the River Severn.
In October 2016 it was announced that super-articulated control rods would be installed in the reactor because of concerns about the stability of the reactors' graphite cores. The Office for Nuclear Regulation (ONR) had raised concerns over the number of fractures in keyways that lock together the graphite bricks in the core. An unusual event, such as an earthquake, might destabilise the graphite so that ordinary control rods that shut the reactor down could not be inserted. Super-articulated control rods should be insertable even into a destabilised core.
The station is of the advanced gas-cooled reactor (AGR) type with two 1600 MWt reactors, each with their own 660 MWe steam turbine generator set giving a combined maximum design generating capacity of 1250 MW. As of 2013 it provided over 1% of the UK's total power output.
The current estimated decommissioning date for the station is set for 2023, which was established in 2012 when the station's owner EDF Energy announced a seven year extension, taking the decommissioning date from 2016 up to 2023.
A new 3,260 MW Hinkley Point C nuclear power station, consisting of two EPR reactors, was given planning consent on 19 March 2013. A guaranteed "strike price" of £92.50 per megawatt-hour (to be indexed for inflation over 45 years) was announced on 21 October 2013. The new power station would see Hinkley's contribution to the country's power supply rise to 7%. At the time of the planning consent, the price for electric energy on the wholesale market was around £45 per megawatt-hour while the new power plant was expected to need earnings of £90 per megawatt-hour in order to break even.
The EU gave (8 October 2014) its consent to the 'Contract for Difference (CFD)' that guarantees the "strike price". Greenpeace Energy have announced that they have mandated 'Becker Büttner Held' to file a lawsuit against the EU commission.