These two pictures show the first of the two Hartlepool Advanced Gas Cooled Reactors, under construction around 1969. But I understand that it took until 1984 before the reactors went into service. This was typical of the building time of the AGRs, and was one reason why this British approach to nuclear energy fell out of favour. Since then the nuclear programme in Britain has been rudderless. Nevertheless the reactors at Hartlepool have been given a life extension until the mid 2020s.
The AGRs were the most efficient type of nuclear plant, turning more than 40% of the energy in nuclear fuel into electricity. But this required them to run at over 600 deg centigrade and resulted in a new form of high temperature corrosion. This was the second reason for the AGR programme being chopped.
Photographs and details courtesy of Fred Starr.