But the greatest danger comes from fragments of raw plutonium which are like fine particles of dust. Each one is potentially lethal. However during the series of test explosions at Maralinga, South Australia in the 1950s the plutonium core never fully exploded. Special sealed vehicles track the lumps of most radioactive material and once located another vehicle is called out to helps to sweep up the plutonium. To protect the operators the excavator cabs are airtight and checked for contamination before every tea or meal break.
Special walkways keep their boots off the potentially contaminated earth.
Effectively the plutonium is then locked up inside the newly formed rock, rendering it safe. This is not the first time a clean up has been attempted - and it is proving more complicated than first anticipated. Meanwhile in the Kakadu National Park in the Northern Territory, Australian police arrested nine people on Tuesday in a dawn raid on a group of protesters at the Jabiluka mine site. Tactical response police scuffled with protesters at a blockade outside the mine, which has been picketed since March by up to 100 environmentalists and the traditional Mirrar Aboriginal land owners. Environmentalists and Aborigines oppose the development of the mine in the Kakadu National Park in the Northern Territory, warning it risks destroying the fragile ecosystem of the vast wetland park.