Hunterston has two reactors, A and B, each of which is housed in a building more than 200 ft in height and with a weight of 75,000 tons.
In the centre of each building enclosed within a steel sphere and surrounded by protective concrete sheilding is the reactor - and it is the reactor of course which is set at the very heart of the matter.
The core of each reactor is constructed from a mass of graphite, 28 ft high and about 50 ft in diameter, built up from accurately machined blocks in which more than 3000 channels are formed to accommodate the fuel. The uranium fuel elements - 32,880 in all - are loaded into these channels, 10 elements end to end in each channel. Each element is separately contained in a finned magnesium alloy can.
The chain reaction of the fissile materials in the fuel, a reaction made possible by the surrounding graphite which acts as a moderator, releases energy in the form of heat and this heat passes to the finned alloy cans.
Carbon-dioxide gas (CO2) flowing over the surface of the cans in a continious cycle carries away the heat from the alloy cans and in turn gives it up in its passage through eight steam raising units, or boilers, before returning to the reactor core to repeat the cycle of operations.
From the point at which the steam is raised the plant on the station is on conventional power station lines.
Hunterston produced enough electricity to supply the size of Edinburgh and it did at a fuel cost which was far below that of any coal or oil-fired station built or even contemplated. Its demands on transport and storage for fuel were almost non-existant. There was no railway sidings, no chimneys, no problems of ash disposal.
Instead of burning 73,000 tons of coal per month which would be the case if Hunterston were a coal fired station. It used 10 tonnes of uranium fuel - a single load for a single lorry.