In Australia, the search for radium had resulted in discoveries of uranium ores at Radium Hill and Mount Painter in South Australia, but no significant mining activities existed prior to the Second World War. Even the great Lord Rutherford, to the day he died in 1937, foresaw no practical applications deriving from his nuclear researches -'The energy produced by the breaking down of the atom is a very poor kind of thing. Anyone who expects a source of power from the transformation of these atoms is talking moonshine' (despite having said in 1904 'If it were ever possible to control at will the rate of disintegration of the radio-elements an enormous amount of energy could be obtained from a small amount of matter').

The missing links were the discoveries of the neutron (Chadwick, 1932), of artificial radioactivity (Curie and Joliot, 1934), the phenomenon of fission (Hahn and Strassman, 1939) and particularly the fact that two to three additional neutrons were released from each uranium fission (Joliot-Curie, 1939). Coming at a time when war-clouds hung over Europe, there was immediate recognition that a chain-reaction would be possible and could proceed with explosive force. The well-known story of the Manhattan Project, ending with the dropping of the atom bombs on Hiroshima and Nagasaki in 1945, remains possibly the most significant development in technology in the history of man. It also explains the controversial nature of nuclear energy in today's society, despite efforts to identify clearly and distinguish between military and peaceful applications of this new source of energy.

Prior to the atom bombs, a controlled chain reaction in uranium had first been achieved by Fermi at Chicago University in December, 1942. Following several days operation at a fraction of a watt, the pile was shut down -no protective shielding had been provided, as it was by no means certain the pile would work, nor was it envisaged as a permanent installation. It made possible, however, the design of the Hanford Plutonium-producing reactors, even though the heat released in them was an inconvenient by-product requiring vast amounts of cooling water from the nearby Columbia River.

The use of this heat for generating electricity was first demonstrated in 1951 at Idaho Falls with molten sodium as the reactor coolant. The first industrial-scale nuclear power generation took place in Britain in 1956, with the commissioning of the Calder Hall reactors (40 MW electrical). An earlier demonstration unit of 5 MW commenced in Russia in 1954, and in 1957 the 60 MW Shippingport reactor marked the US entry into significant nuclear electricity generation. By the mid 1960s, world-wide installed nuclear electricity totalled some 5,000 MW (electrical) with individual units of capacity from 100-200 MW.

The next decade saw many countries introducing nuclear power and the capacity of individual units increased to around 1200 MW (electrical). However, it also saw the steady growth of an anti-nuclear movement, making its introduction progressively more difficult and expensive. The Middle East oil crisis of 1973 persuaded many countries of the desirability of diversifying into nuclear power, but the events of Three Mile Island (1979) and Chernobyl (1986) were clear set-backs to the nuclear industry. Nevertheless a country like France is now generating more than half its electricity by nuclear means.

Australian Academy of Technological Sciences and Engineering