by People were told to stay away from the tiny capsule containing cesium-137, which emits radiation equal to 10 x-rays per hour.
Australia’s nuclear security agency has joined the search for a tiny missing radioactive capsule somewhere in the outback, sending a team with specialized portable and car-mounted detection equipment.
The loss of the radioactive capsule, which is believed to have fallen from a lorry that traveled some 1,400 km (870 miles) through Western Australia, sparked a week-long search and radiation alert for large parts of State.
On Tuesday, the Australian Radiation and Nuclear Safety Agency said it was working with the Western Australian government to locate the capsule. The Australian Nuclear Science and Technology Organization also sent radiation service specialists as well as detection and imaging equipment.
The capsule, part of a gauge used to measure the density of iron ore, had been entrusted by Rio Tinto Ltd to a specialist contractor for transport. Rio apologized Monday for the loss, which occurred over the past two weeks. The truck had traveled from the north of Newman, a small town in the remote Kimberley region, to a storage facility in the northeast suburbs of Perth – a distance longer than the length of Britain.
Western Australia’s Chief Health Officer, Andrew Robertson, said under strict regulations radioactive material is regularly transported into Western Australia.
“It is extremely rare for a source to be lost,” he said in a statement.
State emergency officials on Tuesday issued a new alert to motorists along Australia’s longest highway to be careful of approaching capsule search teams, as vehicles carrying the detectors radiation move at low speed along the highway.
“It will take approximately five days to complete the original route, approximately 1400km, with crews traveling north to south along the Great Northern Highway,” said the Department of Fire and Emergency Services Incident Controller. (DFES), Darryl Ray, in a statement. Monday.
The capsule was recovered from Rio Tinto’s Gudai-Darri mine site on January 12. When unpacked for inspection on January 25, the gauge was found broken, with one of the four mounting bolts missing, and the gauge screws also missing.
Authorities suspect the vibrations from the truck caused the screws and bolt to loosen, and the capsule to fall out of the packaging and then out of a gap in the truck.
The silver capsule, just 6 mm (0.24 inch) wide and 8 mm (0.31 inch) long, contains cesium-137 which emits radiation equal to 10 x-rays per hour. People were told to stay at least 5 meters (16.5 feet) away as exposure could cause radiation burns or radiation sickness, although experts said walking past the capsule would present a relatively low risk, similar to an X-ray.
The capsule does not pose a hazard to passers-by who do not linger, said Edward Obbard, senior lecturer in nuclear engineering at the University of New South Wales, Sydney.
“If you stood three feet away from him for an hour, you would receive a radiation dose of about 1 millisievert. This is about one-twentieth the dose that people who work with radiation are allowed to receive in a year,” Obbard wrote in The Conversation.
“If you were much closer to the capsule, say about 10cm, you would get about 100 millisieverts per hour, which could do some real damage to you,” he said.
If the capsule remains missing, it will pose a danger for “the next century or so”, according to Obbard. The concern is that such a threat may be forgotten over time.
“Will anyone remember that?” Obbard asked
“If you encountered a small cylinder on the road today, you would know how to keep your distance – but what if you found it five years from now or 20 years from now?”
