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Heysham 2 Nuclear Power Station
Heysham, near Morecambe, Lancashire, UK
associated engineer
Not known
date  1979 - 23rd June 1988
era  Modern  |  category  Power Generation  |  reference  SD400595
Like Heysham 1 at the same site, Heysham 2 is an Advanced Gas-Cooled reactor power station. This type of reactor is unique to the UK and the pair of reactors at Heysham 2 were the last to be commissioned.
The two equal reactors at Heysham 2 have a combined net capacity of 1,230MW, which supplies electricity to more than 1.5 million homes. Total output for the year ended 31st March 2007 was 9.45 million MW-hours.
Reactor 1 achieved criticality on 23rd June 1988 and was connected to the National Grid on 12th July. Reactor 2 went critical on 1st November 1988 with grid connection on 11th November. Both reactors began supplying electricity commercially on 1st April 1989 — as did the reactors at Heysham 1.
The design of the reactor containment vessel was developed from the first such concrete vessel, used at Oldbury, and the later Hinkley Point B vessel. Its general design is similar to those at Torness.
The concrete pressure vessel, which contains the core and the boiler, is cast around a gas tight 13mm thick carbon steel liner. The prestressed concrete is 5.5m thick and acts as a biological shield. It has an external cooling water system and internal insulation to stop the concrete overheating. Cooling water is abstracted from Morecambe Bay.
The reactor core is constructed from interlocking graphite bricks, with 332 fuel channels and 89 control rod channels built in.
The fuel channels contain a row of ‘fuel stringers’ — vertical stacks of eight fuel elements. A fuel element is a group of 36 fuel pins — each consisting of hollow uranium dioxide pellets stacked inside stainless steel tubes — inside a cylinder of graphite.
If the reactor needs to be shut down, rods of boronated steel enter the control channels. Nitrogen is injected into the core and, if required, boron beads are added to the core.
A large domed cylinder of carbon manganese steel — the gas baffle — encloses the core and separates the gas coolant (pressurised carbon dioxide) from the hot gas from the fuel channels. This hot exhaust gas passes through the boiler, and drives a turbine generator unit. Each generating set has six exhausts.
Strong winds depositing sea-borne salt on the transmission lines between Heysham 2 and the National Grid sub-station resulted in loss of grid connection in December 1997 and December 1998.
Heysham 2 was built by the Central Electricity Generating Board. Management passed to Nuclear Electric Ltd, then to the present operator British Energy plc (part of EDF Energy since January 2009). Its likely decommissioning date is 2023.
On 9th November 2009, the government announced their intention to build ten new nuclear power stations. Heysham was one of the sites selected.
Main contractor: Parsons Engineering
Reactor installations: National Nuclear Corporation
Turbine and generator supply: NEI
Research: ECPK
"Going Critical — An Unofficial History of British Nuclear Power"
by Walter C. Patterson, Paladin Books, 1985
"Heysham 2 and Torness Nuclear Power Stations — the findings of NII’s assessment of British Energy’s periodic safety review"
Health and Safety Executive, February 2001, document in PDF available at www.hse.gov.uk

Heysham 2 Nuclear Power Station