Once simply a farm near the Royal Burgh of Annan, Chapelcross became the name synonymous with introducing nuclear power to Scotland. In 1955, on the former aerodrome of RAF Annan, the United Kingdom Atomic Energy Authority (UKAEA) announced plans to build the first combined military and civilian power station in Scotland, Chapelcross Nuclear Power Station. By 1959, Chapelcross had begun producing Plutonium for the British Nuclear Weapons Programme, as well as electricity for the increasingly demanding British public, and would continue production for almost 55 years into the future.

Establishing Chapelcross

In a statement to the House of Commons on 14^th June 1955, Geoffrey Lloyd, the Minster of Fuel and Power announced the UKAEA would erect four nuclear reactors near Annan, Dumfriesshire. In August 1955, the UKAEA held a meeting with representatives from local government departments to highlight the reasons why Chapelcross was chosen. These included the matter of urgency that was placed on the Authority to build a nuclear establishment, the ideal location of the 92-acre site where there was established road links, the prospect to link to the River Annan for the required seven million gallons of water per day and also the opportunity for an effluent pipe to run to the Solway Firth. Additionally, for administrative reasons, it was desirable for the new site to be relatively near to Calder Hall and the Risley HQ.

With all these factors in Chapelcross’ favour, the new project was announced to local people; the Annandale Observer reported, ‘Annan will be new A-Town’. According to the newspaper, ‘rumours had been circulating in the town for over a week, but tremendous surprise was expressed when the news was confirmed, and many people have been expressing pleasure that Annan should have been chosen’. In an article titled, ‘Atomic Age in Annan’, A.I Milton proclaimed, ‘Annan shall be host to a new population unprecedented since the Kaiser’s war and the boom days of the Gretna Ordnance Factory’, commenting on the huge influx of workers that would soon arrive to construct Chapelcross.

Building Chapelcross

Newcastle based company, Merz & McLellan were the consulting engineers commissioned by the UKAEA to oversee the work at Chapelcross. Work began in October 1955,  expected cost £40 million. Originally Chapelcross was destined to be a duplicate of Calder Hall, however due to the advances in technology and knowledge in the two years since work on the station began, the engineers had improved or modified certain aspects of construction to make Chapelcross more efficient and thus slightly more modern than Calder Hall. Whilst Calder Hall was originally designed as a two-reactor station and only later were two additional reactors constructed, Chapelcross was designed from the outset as a four-reactor station which was more compact and economically arranged.

All four reactors at Chapelcross were surrounded by a 7-foot-thick octagonal biological shield, built using thousands of tonnes of dense concrete to prevent radiation escaping from the core. Within the octagon was the cylindrical pressure vessel which contained the reactor. A heavy steel lattice called a diagrid was placed inside each pressure vessel to support the over 1000 tonnes weight of the graphite moderator. The graphite moderator was 36 feet across by 27 feet high. There were 1800 vertical channels running through the graphite moderator, 1696 of these graphite channels would contain fuel elements and the rest would accommodate graphite control rods and monitoring instruments. To avoid having too many openings in the pressure vessel, each tube was arranged to supply 16 channels. 

The fuel elements were uranium bars, 40 inches long by 2 inches in diameter, stacked six high sealed in magnesium alloy (Magnox) cans with spiral fins to assist in dissipating the heat. These spiral fins around the fuel rods were a new invention introduced at Chapelcross, thus differing slightly to those at Calder Hall. Spent uranium fuel rods would be transferred to one of the two cooling Ponds, where fuel rods would be handled and stored underwater, remaining in skips for at least 90 days to allow them to cool down to a level safe enough to transfer to Windscale, where they would be processed.

When in production, hot carbon dioxide gas would circulate continuously at a rate of one ton per second, between the pressure vessels and the heat exchangers, where this heat would transfer through boiler tubes. There were 16 heat exchangers, 4 per reactor, weighing 170 tonnes.  The turbine hall contained eight identical units, each consisting of a two-stage turbine connected to an alternator, capable of producing 23,000 kilowatts of electricity. A system of pipes was laid underneath the turbine hall to convey hot water to the cooling towers and return cool water to the condensers. In the cooling towers this water was sprayed into the upward draught of cold air and collected in the ponds at the foot of each tower, which then cooled ready for re-use. The once Provost of Annan, Thomas Dykes thought Chapelcross should be named, ‘the Vesuvius of Annandale’ due to these clouds of steam bellowing from these cooling towers.

Chapelcross in Operation

On 27^th February 1959, just over three years since the work started and two weeks ahead of schedule, the first reactor at Chapelcross began generating electricity. The remaining three reactors were to become operational the following year, with the fourth and final reactor online by 29^th March 1960.

The site was officially opened, on the 2^nd May 1959, by the Lord Lieutenant for Dumfriesshire, Sir John Crabbe, who proclaimed, ‘we are entering the threshold of a new era. It is the nuclear era. Scotland can be proud of the part she is playing in this revolution. This station is not hidden but is erected where it can be seen for miles around and is a monument to progress and the nuclear era.’

As each reactor was completed, tested and brought online, the power plant’s commercial status grew and by December 1960 it was at full capacity. Chapelcross pioneered many changes in technology in the 1960’s by testing fuel element designs which would later form the core of other power stations in Britain and abroad.