Calder Hall nuclear power station

Year:1956

Duration:3 years

Cost:Unknown

Country: Sellafield, UK

What did this project achieve?

Build the world’s first commercial nuclear power station

Calder Hall was the first nuclear power station in the world to produce electricity for domestic use. Designed to last 20 years it was operational for 47 years before closing in 2003.

Work began on the station in 1953 with the first electricity transmitted to the National Grid three years later. 24km away the town of Workington was the first in the world to receive electricity produced by nuclear power.

Although the station was promoted as generating electricity too cheap to meter, it produced relatively little during its working life. Calder Hall’s capacity of 1,96MW was far less than the 1,200MW output of the Sizewell B modern reactor.

Calder Hall was in fact primarily intended to produce plutonium for the UK’s atomic weapons programme. Producing electricity for the domestic market was a sideline for the plant.

The station had 4 Magnox reactors. Magnox (from the phrase ‘magnesium no oxidation’) refers to the metal content of the nuclear fuel containers. In a Magnox reactor, magnesium alloy is wrapped around each uranium fuel rod.

By the time Calder Hall generated its last electricity in 2003 it was the oldest Magnox power station in the world.

Difference the power station has made

The lessons learned from Calder Hall led to more successful nuclear power stations able to produce far more electricity.

Calder Hall was the first of 10 nuclear power stations built in the UK. Nuclear technology now supplies about a quarter of the UK’s electricity.

The plant produced plutonium for the British nuclear weapons programme.

How the work was done

When it opened in 1956 Calder Hall had 2 reactors, 2 cooling towers and a turbine house. Another 2 reactors and cooling towers were added to the site later.

Engineers housed each reactor in casing made from mild steel. Each cylindrical casing was 215m high and 11m in diameter.

The reactors weighed 33,000 tonnes each and contained 1,696 nuclear fuel channels. Each reactor also had 4 heat exchangers, generating high and low pressure steam at the same time.

Engineers installed 8 x 3,000rpm turbines in the plant to generate the electricity. The turbines were 75m long, 25m high and 20m wide.

The project team also built 4 concrete cooling towers, each 90m high. Cooling towers use evaporation to remove heat from water produced in an industrial process.

The Calder Hall cooling towers were demolished using explosives in September 2007 as part of the plant’s decommissioning process.

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Nothing that comes after will be able to detract from the importance of this first great step forward.

Sir Edwin Plowden

Atomic Energy Authority chair on the opening of Calder Hall.

Fascinating facts

Decommissioning of Calder Hall started in 2005. As with all nuclear power stations the process will take many years. Removal of the spent fuel rods began in 2011 and is planned to finish in 2019.

It will be at least 100 years before the land on the site can be re-used.

According to the British Nuclear Group, Calder Hall generated enough power in its lifetime to run a 3 bar radiator for almost 3m years.

People who made it happen

  • Designer: engineer Christopher Hinton
  • Contractors: Taylor Woodrow

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