by John Pickrell
The Earth exploded into the nuclear age on 16 July 1945.On that day, the US tested a completely new type of weapon in the New Mexico desert. Crafted from a tennis-ball-sized plutonium sphere, the Trinity bomb produced an explosion equivalent to 20,000 tonnes of TNT.
Sixty years on, tens of thousands of tonnes of plutonium and enriched uranium have been produced. The global nuclear arsenal stands at about 27,000 bombs. Nine countries very probably possess nuclear weapons, while 40 others have access to the materials and technology to make them.
But nuclear technology has also been used for peaceful means. The first nuclear reactor to provide electricity to a national grid opened in England in 1956. Now, 442 reactors in 32 nations generate 16% of the world’s electricity.
Nuclear power has been championed as a source of cheap energy. But this was undermined at the end of the 20th century by high-profile reactor accidents, the problems of radioactive waste disposal, competition from more-efficient electricity sources and unavoidable links to nuclear weapons proliferation. Nonetheless, growing evidence for global warming had led some to argue that nuclear power is the only way to generate power without emitting greenhouse gases.
However, several high profile accidents damaged public confidence in nuclear power. The worst US nuclear accident was in 1979, when a cooling system malfunctioned at Three Mile Island in Pennsylvania. The reactor melted down, releasing radioactive gas into the environment. There are now concerns about safety with other ageing US reactors.
Nuclear goes wrong
The world’s most catastrophic nuclear accident happened in 1986, at Chernobyl in Ukraine. Control rods were withdrawn from the reactor in misguided safety test, causing meltdown and massive explosions. The radiation released killed 30 people directly and spread over northern Europe.
The accident has led to radiation-induced conditions such as thyroid cancers and leukaemia, birth defects, baby deaths and contamination to lakes and forests. Three other reactors at Chernobyl began working again in 1988, but the last finally closed in 2000 after Western nations eventually paid Ukraine to close it. Similar reactors in Eastern Europe may be just as dangerous.
In 1999, 70 people were exposed to radiation in Japan’s Tokaimura uranium processing plant after workers added seven times the safe quantity of uranium to a settling tank. This triggered an uncontrolled chain reaction. Many other hazardous or lethal accidents have occurred in facilities such as Windscale, Sellafield, Mayak, Monju, Tsuruga and Mihama.
Radioactive nuclear waste – which remains dangerous for many thousands of years – is another serious drawback of the industry. Governments have considered disposing of it by reprocessing; burying it deep underground, such in Nevada’s Yucca Mountain in the US; burning it; shipping it to other countries; zapping it with giant lasers; encasing it in glass blocks and storing it on-site at nuclear facilities.
But concerns have been raised about potential flooding of repositories, secret disposal sites and the risks of transporting waste. Cleaning up decommissioned nuclear sites is also expensive and difficult.
Yet nuclear power still has one advantage that could prompt a comeback – the lack of greenhouse gas emissions. Some now tout it as a good way to reduce the emissions linked to global warming. The US government has already announced plans for a raft of new nuclear power stations – the first since 1979.
Source: NewScientist.com news service