Hinkley Point A nuclear power station
Encyclopedia
Hinkley Point A nuclear power station was a Magnox
power station
located on a 19.4 hectares (48 acre) site in Somerset
on the Bristol Channel
coast, 5 miles (8 km) west of the River Parrett
estuary.
, Babcock International Group
and Taylor Woodrow Construction, began in 1957. The reactors and the turbines were supplied by English Electric.
The power station, which is currently being decommissioned, had twin Magnox
reactors, each supplying steam to a turbine alternator set which was designed to produce 500 MWe but, after de-rating of the reactor power output due to corrosion concerns, producing 221 MWe.
The design followed the principles established by the Calder Hall nuclear power station, in that it used a reactor core of natural uranium fuel in Magnox alloy
cans within a graphite moderator, all contained in a welded steel pressure vessel. The core was cooled by CO2 pumped by six nominal 7,000 hp (5.2MW) gas circulators, which transported the hot gas from the core to the six Steam Raising Units (boilers) via steel ducts. The gas circulators could be driven by induction motors supplied with mains electricity or, when steam was available, dedicated variable speed turbo alternator sets. The design pressure of the gas circuit was 185 psig, and the temperature of the gas leaving the reactor was 378°C, although this was later reduced when the hot CO2 was found to be corroding the mild steel components of the gas circuit more quickly than had been anticipated. Like all Magnox reactors, Hinkley Point A was designed for on-load refuelling so that exhausted fuel elements could be replaced with fresh without shutting down the reactor.
In August 1963 during a hot run test on the first reactor, which had not then been loaded with nuclear fuel, problems were encountered due to noise from the single stage axial flow gas circulators. This could be heard up to five miles away, and personnel working at the station had to wear ear defenders. After unexplained drops in the mass flow rate and motor driving current in number 3 and 5 gas circulators, the hot run tests were stopped and the gas circuit opened up. Severe mechanical damage to the blading and diffuser sections of the number 3 and 5 gas circulators was observed. Large sections of the diffusers had broken away, and extensive fatigue cracking was found in the outer tapering shell and central axial cone. Large pieces of the diffuser casing had entered the gas circulator blades and caused heavy impact damage, and large amounts of debris had been transported down the gas duct. The Inlet Guide Vanes (IGVs), which were provided to enable the performance of individual gas circulators to be "trimmed," were found to be extensively damaged, and the rotor blades and outlet guide vanes also had extensive impact and fatigue damage. Large numbers of the nuts and bolts involved had been shaken loose.
The subsequent investigation determined that the noise was caused by interaction between the IGVs and the rotor blades. The sound pressure levels generated by this noise were high enough to cause rapid fatigue failure in gas circuit components, and major re-design of the gas circulators and associated components was required. The IGVs were scrapped and flow straighteners introduced to smooth the flow of gas into the gas circulator intakes. Much pioneering experimental laboratory work on resonance and sound pressure levels was performed at English Electric's Gas Turbine and Atomic Power Division (APD) facilities at Whetstone, Leicestershire, to support the redesign work, and instrumentation to measure stress and sound pressure levels in the gas circuit during testing was developed. The delay caused severe financial difficulties for the consortium and set the construction schedule back; the station began generating electricity two years late in 1965.
Hinkley Point A was one of eleven Magnox
nuclear power stations commissioned in the United Kingdom
between 1956 and 1971. During its 35 years of operation, Hinkley Point A generated more than 103 TWh
of electricity, giving a lifetime load factor against design of 34%.
There are two nuclear power
stations at Hinkley Point
, the other is Hinkley Point B
, operated by British Energy
. There are also two other power stations nearby at Oldbury
and Berkeley
on the banks of the River Severn
. A new Hinkley Point C nuclear power station
is under consideration.
Magnox
Magnox is a now obsolete type of nuclear power reactor which was designed and is still in use in the United Kingdom, and was exported to other countries, both as a power plant, and, when operated accordingly, as a producer of plutonium for nuclear weapons...
power station
Power station
A power station is an industrial facility for the generation of electric energy....
located on a 19.4 hectares (48 acre) site in Somerset
Somerset
The ceremonial and non-metropolitan county of Somerset in South West England borders Bristol and Gloucestershire to the north, Wiltshire to the east, Dorset to the south-east, and Devon to the south-west. It is partly bounded to the north and west by the Bristol Channel and the estuary of the...
on the Bristol Channel
Bristol Channel
The Bristol Channel is a major inlet in the island of Great Britain, separating South Wales from Devon and Somerset in South West England. It extends from the lower estuary of the River Severn to the North Atlantic Ocean...
coast, 5 miles (8 km) west of the River Parrett
River Parrett
The River Parrett flows through the counties of Dorset and Somerset in South West England, from its source in the Thorney Mills springs in the hills around Chedington in Dorset...
estuary.
History
The construction of the power station, which was undertaken by a consortium backed by English ElectricEnglish Electric
English Electric was a British industrial manufacturer. Founded in 1918, it initially specialised in industrial electric motors and transformers...
, Babcock International Group
Babcock International Group
Babcock International Group plc is a British-based support services company specialising in managing complex assets and infrastructure in safety-critical and mission-critical environments. Although the company has civil contracts, its main business is with public bodies, particularly the UK...
and Taylor Woodrow Construction, began in 1957. The reactors and the turbines were supplied by English Electric.
The power station, which is currently being decommissioned, had twin Magnox
Magnox
Magnox is a now obsolete type of nuclear power reactor which was designed and is still in use in the United Kingdom, and was exported to other countries, both as a power plant, and, when operated accordingly, as a producer of plutonium for nuclear weapons...
reactors, each supplying steam to a turbine alternator set which was designed to produce 500 MWe but, after de-rating of the reactor power output due to corrosion concerns, producing 221 MWe.
The design followed the principles established by the Calder Hall nuclear power station, in that it used a reactor core of natural uranium fuel in Magnox alloy
Magnox (alloy)
Magnox is an alloy—mainly of magnesium with small amounts of aluminium and other metals—used in cladding unenriched uranium metal fuel with a non-oxidising covering to contain fission products in nuclear reactors....
cans within a graphite moderator, all contained in a welded steel pressure vessel. The core was cooled by CO2 pumped by six nominal 7,000 hp (5.2MW) gas circulators, which transported the hot gas from the core to the six Steam Raising Units (boilers) via steel ducts. The gas circulators could be driven by induction motors supplied with mains electricity or, when steam was available, dedicated variable speed turbo alternator sets. The design pressure of the gas circuit was 185 psig, and the temperature of the gas leaving the reactor was 378°C, although this was later reduced when the hot CO2 was found to be corroding the mild steel components of the gas circuit more quickly than had been anticipated. Like all Magnox reactors, Hinkley Point A was designed for on-load refuelling so that exhausted fuel elements could be replaced with fresh without shutting down the reactor.
Gas circulator design problem
The subsequent investigation determined that the noise was caused by interaction between the IGVs and the rotor blades. The sound pressure levels generated by this noise were high enough to cause rapid fatigue failure in gas circuit components, and major re-design of the gas circulators and associated components was required. The IGVs were scrapped and flow straighteners introduced to smooth the flow of gas into the gas circulator intakes. Much pioneering experimental laboratory work on resonance and sound pressure levels was performed at English Electric's Gas Turbine and Atomic Power Division (APD) facilities at Whetstone, Leicestershire, to support the redesign work, and instrumentation to measure stress and sound pressure levels in the gas circuit during testing was developed. The delay caused severe financial difficulties for the consortium and set the construction schedule back; the station began generating electricity two years late in 1965.
Closure
Both reactors were shutdown in April 1999 to carry out reinforcement work following a Nuclear Installations Inspectorate Periodic Safety Review. Reactor 2 was returned to service in September 1999, but shut down on 3 December 1999 because of newly identified uncertainties in the reactor pressure vessel material properties. Because of the cost of remedying these problems, it was announced on 23 May 2000 that Hinkley Point A would be shut down.Hinkley Point A was one of eleven Magnox
Magnox
Magnox is a now obsolete type of nuclear power reactor which was designed and is still in use in the United Kingdom, and was exported to other countries, both as a power plant, and, when operated accordingly, as a producer of plutonium for nuclear weapons...
nuclear power stations commissioned in the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
between 1956 and 1971. During its 35 years of operation, Hinkley Point A generated more than 103 TWh
TWH
TWH or twh could refer to:*Tennessee Walking Horse, a breed of horse* Toronto Western Hospital, a hospital in Toronto, Canada* TWH Bus & Coach, a bus company in Romford, England* Terrawatt-hour, measure of electrical energy, 1012 watt-hours...
of electricity, giving a lifetime load factor against design of 34%.
There are two nuclear power
Nuclear power
Nuclear power is the use of sustained nuclear fission to generate heat and electricity. Nuclear power plants provide about 6% of the world's energy and 13–14% of the world's electricity, with the U.S., France, and Japan together accounting for about 50% of nuclear generated electricity...
stations at Hinkley Point
Hinkley Point
Hinkley Point is a headland on the Bristol Channel coast of Somerset, England, five miles north of Bridgwater and five miles west of Burnham-on-Sea, close to the mouth of the River Parrett....
, the other is Hinkley Point B
Hinkley Point B nuclear power station
Hinkley Point B is a nuclear power station near Bridgwater, Somerset, on the Bristol Channel coast of south west England.-History:The construction of Hinkley Point B, which was undertaken by a consortium known as The Nuclear Power Group , started in 1967. The reactors were supplied by TNPG and the...
, operated by British Energy
British Energy
British Energy was the UK's largest electricity generation company by volume, before being taken over by Électricité de France in 2009. British Energy operated eight former UK state-owned nuclear power stations and one coal fired power station....
. There are also two other power stations nearby at Oldbury
Oldbury nuclear power station
Oldbury nuclear power station is a nuclear power station located on the south bank of the River Severn close to the village of Oldbury-on-Severn in South Gloucestershire, England. It is operated by Magnox North Limited, on behalf of the Nuclear Decommissioning Authority...
and Berkeley
Berkeley nuclear power station
Berkeley nuclear power station is a disused Magnox power station situated on the bank of the River Severn in Gloucestershire, England.-History:The construction of the power station, which was undertaken by a consortium of AEI and John Thompson began in 1956....
on the banks of the River Severn
River Severn
The River Severn is the longest river in Great Britain, at about , but the second longest on the British Isles, behind the River Shannon. It rises at an altitude of on Plynlimon, Ceredigion near Llanidloes, Powys, in the Cambrian Mountains of mid Wales...
. A new Hinkley Point C nuclear power station
Hinkley Point C nuclear power station
Hinkley Point C nuclear power station is a proposed development for a new nuclear power station in Somerset, England.In September 2008 it was announced, by Electricité de France the new owners of Hinkley Point B, that a third, twin-unit European Pressurised Reactor reactor is planned for Hinkley...
is under consideration.
See also
- Energy policy of the United KingdomEnergy policy of the United KingdomThe current energy policy of the United Kingdom is set out in the Energy White Paper of May 2007 and Low Carbon Transition Plan of July 2009, building on previous work including the 2003 Energy White Paper and the Energy Review Report in 2006...
- Energy use and conservation in the United KingdomEnergy use and conservation in the United KingdomEnergy use in the United Kingdom stood at 3,894.6 kilogrammes of oil equivalent per capita in 2005 compared to a world average of 1,778.0. In 2008, total energy consumed was 9.85 exajoules - around 2% of the estimated 474 EJ worldwide total...