Topic 10 Bombs and breakthroughs: A history

The discovery of radioactivity at the end of the 19th century began a revolution in the scientific understanding of matter. The idea that matter must be made up of indivisible units – atoms – had first been proposed by the Greek philosopher Democritus in about 400 BC! But our current understanding of atoms and elements had to wait until the 18th century, when alchemy began to be replaced by modern chemistry. The ancient belief in 'fire, water, earth and air' was slowly abandoned as modern elements - oxygen, nitrogen and others – were discovered. A scientific understanding of atoms was finally emerging. Democritus had been right, or so it seemed.

Smaller than atoms?

With the discovery of radioactivity in 1896, a new world opened up to science: the subatomic world. Scientific experiments using radioactive substances revealed that, in fact, atoms are not the smallest particles. A growing understanding of the nucleus, the proton and the electron began to profoundly change our understanding of matter and energy. It led to our present understanding of the cosmos, its origin in the Big Bang, and the reason our sun and the stars shine.

Fission and the bomb

It was the discovery of the neutron in 1932 that had the deepest technological implications for society. On the eve of World War II, it was discovered that bombardment with neutrons could cause a very large nucleus such as uranium to split in two – the process of nuclear fission. According to Einstein's new maths (E = mc²), this should release energy in quantities previously unimagined by humans. Energy to rival the sun – with its benefits and consequences.

The result of the Manhattan Project, the top secret research project in the USA that followed, was revealed to the world in 1945 at Hiroshima and Nagasaki. Australia and the other allies celebrated the end of the war with Japan, but another transformation had occurred. ‘We knew the world would not be the same’ recalled Oppenheimer, the head scientist developing the bomb. Watching the first-ever atomic test, he had recalled a line from Hindu scripture: ‘Now I am become Death – the destroyer of worlds.’ Our technological power had reached a new level, one which would trouble many in the decades to come.

Figure 10.1 The 1945 ‘Trinity Test’. US Government image.

Figure 10.1 The ‘Trinity Test’ in 1945 was the world's first ever nuclear explosion.

The cold war

The end of World War II brought peace and prosperity for many. It also marked the beginning of the cold war between communist USSR (the former soviet states that included Russia) and democratic USA, and their allies. The cold war spanned 50 years of tension and secrecy, during which nuclear weapons become much more powerful, especially with the development in 1952 of the hydrogen bomb. Other countries slowly acquired nuclear weapons. With the USSR and the USA locked in an arms race, each side built enough nuclear weapons to destroy the population of the other country many times over. The impossibility of victory led to a tense stalemate known as the doctrine of ‘Mutually Assured Destruction’: MAD.

Figure 10.2 Earth from space. Image courtesy of NASA.

Figure 10.2 In the 20th century, the development of nuclear weapons and our first whole view of Earth both contributed to a sense of the fragility of life on our planet.

Many people around the world were deeply affected by this uncertain existence. Amid the calls for nuclear disarmament – or at least for non-proliferation – international agencies helped negotiate treaties to control nuclear weapons. In 1974 Australia signed the Nuclear Non-Proliferation Treaty and abandoned any aspiration to acquire nuclear weapons.

Atoms for peace

In 1953 US President Eisenhower addressed the newly formed United Nations at a conference on ‘Atoms for Peace’. Promising to turn ‘swords into ploughshares’, he pledged to put nuclear fission to work in peaceful applications, as well as for defence. Scientists and governments were excited about the potential for nuclear power, which some thought would make electricity 'too cheap to meter'. Incredible and grand projects seemed possible for the future! In 1967 Britain opened the world's first nuclear power station for civil electricity. Since then, nearly 30 other countries have come to use nuclear power to supply some of their electricity. These include the USA, Germany, France, Switzerland, Russia, China, Japan, India, Argentina and South Africa. Today, there are more than 400 nuclear power reactors operating around the world. In addition there are thousands of small reactors used in countries such as Australia for research and the production of radioisotopes.

Fallout

Despite the potential and enthusiasm of the developing nuclear power industry, it attracted considerable public debate. Some early power reactors also produced weapons-grade plutonium, and so public concerns about the increasing ‘MAD’ threat of weapons proliferation sometimes extended to the developing nuclear power industry. Controversy escalated dramatically in the 1970s, when new environmental groups began to oppose every part of the nuclear fuel cycle, from uranium mining to waste disposal. The escalation was fuelled by emerging concern about the long-term health effects of even small doses of radiation. Initially, the small doses in question were from radioactive fallout produced by atmospheric weapons testing. Later, other sources of contamination came under scrutiny: radioactive waste, mining, and then the dramatic accidents at nuclear power reactors, first at Three Mile Island in 1979, then at Chernobyl in 1986.

Through these developments, the early grand optimism over nuclear technologies has been restrained by public doubts, and sometimes outright hostility.

Quiet benefits

Almost as soon as radioactive substances and radiation were discovered, they began to be put to good use in research, medicine, industry, the environment and other areas of society. In the 1930s scientists learnt how to make radioisotopes for use in medical imaging and scientific research. These days, most Australians benefit from nuclear medicine at some stage in their lives. Early basic research also led to the development of increasingly powerful radiation beams of neutrons, protons, electrons, ions, gamma rays and X-rays, and many different lasers. These are used to study and modify different substances for research and industry, or in radiotherapy to treat difficult-to-reach cancers. All these developments have occurred as part of the international development of radiation science and technology. Australian scientists have contributed to this international effort, and the benefits have been returned to Australian society. The contributions of nuclear technology are made every day, in hospitals, laboratories, and workshops around the country.