Construction of the power station by a consortium involving
Clarke Chapman,
Head Wrightson,
C. A. Parsons & Co.,
A. Reyrolle & Co.,
Strachan & Henshaw and
Whessoe and known as the Nuclear Power Plant Company (NPPC) began in December 1957, and electricity generation started in 1962. Bradwell had two
Magnox-design
reactors with a design output of 300
MW of net electrical output, although this was reduced to 242MW net electrical in total as a result of the discovery of breakaway oxidation of mild-steel components inside the reactor vessel. The reactors were supplied by The Nuclear Power Group (TNPG), and the nine turbines and 12 gas circulators by
C. A. Parsons & Co. (six of 52MW main turbines supplying power to the grid, three of 22.5MW auxiliaries turbines, one for each reactor for driving the gas circulators, with one standby auxiliary turbine). Each reactor contained six heat exchanger units to take the heated gas from the reactors to provide steam at pressure of 730 psi (50 bar) and temperature of at turbine. Three
Allen 6S12-DX turbocharged diesel generators were installed in 1975 to provide essential standby supplies, replacing the three original
Crossley ten-cylinder two-stroke standby diesel generators. Bradwell's peak output, achieved in the early 1960s, was nearly 10% above the design value. On a typical day it could supply enough electricity to meet the needs of towns the size of
Chelmsford,
Colchester and
Southend.
Location Bradwell was built on the edge of
RAF Bradwell Bay, a former
World War II airfield, from the Essex coastline. Its location was deliberately chosen, as the land had minimal agricultural value, offered easy access, was geologically sound and had an unlimited source of cooling water from the
North Sea. Nuclear fuel for Bradwell was delivered and removed via the nearest railhead, a loading facility adjacent to
Southminster railway station on the Crouch Valley line. This included a dedicated siding and a gantry crane. In 1969, a new
Honeywell 316 was installed as the primary reactor temperature-monitoring computer; this was in continuous use until summer 2000, when the internal 160kB disk failed. Two
PDP-11/70s, which had previously been secondary monitors, were moved to primary.
Electricity output Electricity output from Bradwell power station over the period 19641984 was as follows.
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Decommissioning In 1999, it was announced that the station would cease operation in 2002 the first UK station to be closed on a planned basis. On 28 March 2002,
Robin Neville, 10th Baron Braybrooke,
Lord Lieutenant of
Essex, unveiled a plaque to mark the cessation of electricity generation and the beginning of the decommissioning stage. Decommissioning is being carried out by
Nuclear Decommissioning Authority (NDA) subsidiary
Nuclear Restoration Services, formerly
Magnox Ltd. All
spent nuclear fuel was removed from the site by 2005, the turbine hall was demolished in 2011, and by 2016 underground waste storage vaults had been emptied and decontaminated. Demolition of all buildings except the ponds and two reactor buildings was completed in 2019. Demolition of the reactor buildings and final site clearance is planned for 2083 to 2093. ==Future plans==