How do you lose a radioactive capsule? Australian researchers are wondering the same thing

Brisbane, Australia

The discovery of a small lost radioactive capsule next to a remote highway in Western Australia raises many questions – not least how it escaped layers of radiation-resistant packaging loaded onto a moving truck.

It’s one of many puzzling aspects of a case that researchers will investigate in the coming weeks as they try to piece together the timeline of the capsule’s movements from Jan. 12, when it was packed for transport, to Feb. 1, when a salvage team found him. by the side of the road.

The capsule — just 8 millimeters by 6 millimeters — was used in a density meter mounted on a pipe at Rio Tinto’s Gudai-Darri iron ore mine to measure material flow through the feeder.

Rio Tinto said in a statement Monday that the capsule was packed for transit to Perth, 1,400 kilometers (870 miles) away, with its presence in the package confirmed by a Geiger counter before being transported by a third-party contractor.

Normally the journey would take more than 12 hours by road, but after about two hours the capsule got out of the vehicle as it headed south and somehow crossed a lane, ending up at two meters (6 .5 feet) from the north side of the dual carriageway.

Lauren Steen, managing director of Radiation Services WA, a consultancy that writes plans for radiation management, said industry insiders were as stunned as the public when they learned the capsule had disappeared.

“The whole team scratched our heads. We couldn’t find out what had happened,” says Steen, whose company was not involved in the disappearance.

“If the source was placed in certified packaging and transported according to all requirements of the code of practice, then it is an extremely unlikely event – one in a million,” she said.

The truck that was to carry the capsule arrived in Perth on January 16, four days after it left the Gudai-Darri iron ore mine. But it wasn’t until January 25, when workers from SGS Australia went to unpack the meter for inspection, that it was discovered missing.

In a statement, SGS Australia said it was hired by Rio Tinto to package the capsule but had nothing to do with the transport, which was carried out by a “specialist carrier”.

“We performed the contracted service to pack and unpack the equipment at the mine site after transportation using qualified personnel for our client in compliance with all standards and regulations,” it said.

“The transport of the package, organized by our customer and delegated to a specialist carrier, was not part of the services of SGS. Our staff noticed the loss of the source in our Perth lab upon opening the package and immediately reported the incident.”

The name of the company contracted to transport the package has not been released.

The missing capsule sparked a six-day search along a stretch of the Great Northern Highway. On Wednesday morning, a car equipped with special equipment driving south of the small town of Newman detected a higher radiation reading. Handheld devices were then used to sharpen the capsule in the dirt.

The capsule was about the size of a pen nib.

In Australia, each state has its own laws regarding the handling of radioactive materials and codes of practice that conform to the guidelines of the Australian Radiation and Nuclear Safety Agency (ARPANSA), a government body that works closely with the International Atomic Energy Agency (IAEA). ) and the World Health Organization (WHO).

In Western Australia, the rules are governed by the Radiation Safety Act 1975, which Steen says is long overdue for revision. “It hasn’t been rewritten since the 1970s, so I think that speaks for itself,” she said.

Steen said technological advances in recent decades have made the use of radiation sources in mining equipment much safer — and because it was safer, devices were used more often. According to the state’s Chamber of Minerals and Energy, by 2021 more than 150 projects were operating in Western Australia, the center of the country’s mining exports.

Under the Radiation Safety Act 1975, only specially trained and licensed operators are allowed to pack radioactive materials, but different rules apply to contractors hired to transport it, Steen said.

“Any transport company can transport radioactive material, provided they have the license to do so,” she said.

Under the law, that license can be obtained by attending a one-day course and passing a test certified and approved by the regulator.

The permit holder must supervise a transport plan submitted to the regulator, but does not have to personally supervise the journey. There are no rules about the type of vehicles used for transportation.

Steen clearly says something has gone wrong — and she hopes the results of the research will be shared with the radiation community so they can avoid such problems in the future.

Discussion has already begun about the need for tougher penalties – in WA, mishandling radioactive materials carries a fine of just AUD 1,000 ($714) – an amount that Australian Prime Minister Anthony Albanese described to reporters on Wednesday as “ridiculously low.” ” is described.

At least 100 people, including police and firefighters, joined the search for the capsule.

The rules surrounding the packaging of radiation sources depend on how much radiation they emit. In some cases, the device can be wrapped in three layers. In the case of the capsule, the meter could be considered one layer of protection before being placed in an “overwrap”, a container that was likely bolted shut.

In a statement, DFES said that when the package was opened, the meter was found to be broken, with one of its four mounting bolts missing. Referring to the capsule, the statement added, “the source itself and all the screws on the gauge were also missing.”

One theory researchers can investigate is whether the meter broke and the capsule fell out of the overwrap through a hole used to secure the lid.

It is expected to take several weeks for the Radiological Board to submit its report to the WA Minister of Health. Meanwhile, Rio Tinto conducts its own investigation.

CEO Simon Trott said the company would be willing to reimburse the government for costs associated with the search – if requested.

Stephen Dawson, WA’s emergency services minister, said the offer was appreciated but the government would wait for the outcome of the inquiry to pinpoint blame.

He said he did not know how much the search had cost, but at least 100 people were involved, including police, firefighters, health department and defense personnel.

Employees from the National Emergency Management Agency, the Australian Nuclear and Science Technology Organization and the Australian Radiation Protection and Nuclear Safety Agency also participated.

On Thursday, relieved DFES officials released new footage of the capsule being taken to Perth, where it will be kept safe in a facility.

This time it traveled in a convoy of closed white vehicles – with large stickers warning of the presence of a radioactive substance.

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