The discovery of a tiny radioactive capsule lost alongside a lonely highway in Western Australia raises many questions, including how it escaped layers of radiation-resistant packaging loaded onto a moving truck.
It’s one of many puzzling aspects of a case that investigators will examine in the coming weeks as they try to piece together the timeline of the capsule’s movements from January 12, when it was packed for transport. , to February 1, when a recovery team found her. by the side of the road.
The capsule – just 8 millimeters by 6 millimeters – was used in a density gauge fitted to a pipe at Rio Tinto’s Gudai-Darri iron ore mine to measure the flow of material through the loader.
Rio Tinto said in a statement on Monday that the capsule was packaged for transit to Perth, 1,400 kilometers (870 miles) away, with its presence inside the package confirmed by a Geiger counter before being transported by a third party contractor.
Normally the trip would take over 12 hours by road, but about two hours later the capsule exited the vehicle as it headed south and somehow crossed a lane of traffic to end up two meters (6.5 feet) on the north side. of the two-lane highway.
Lauren Steen, chief executive of Radiation Services WA, a consultancy that drafts radiation management plans, said industry insiders were just as baffled as the public when they learned the capsule was missing.
“The whole team was scratching their heads. We couldn’t figure out what happened,” said Steen, whose company was not involved in her disappearance.
“If the source had been placed in certified packaging and transported in accordance with all code of practice requirements, then this is an extremely unlikely event – one in a million,” she said.
The truck supposed to carry the capsule arrived in Perth on January 16, four days after leaving the Gudai-Darri iron mine. But it wasn’t until January 25, when workers from SGS Australia went to unpack the gauge for inspection, that it was discovered missing.
In a statement, SGS Australia said it had been contracted by Rio Tinto to pack the capsule but that had nothing to do with its transport, which was carried out by a “specialist transporter”.
“We performed the contracted service to pack the equipment at the mine site and unpack it after transport using trained personnel for our client in accordance with all standards and regulations,” he said.
“The transport of the package, organized by our client and delegated to a specialized carrier, did not fall within the scope of SGS’s services. Our staff noticed the loss of the source in our Perth lab upon opening the packaging and immediately reported the incident.
The name of the company responsible for transporting the package was not disclosed.
The missing capsule sparked a six-day search along a stretch of the Great Northern Highway. Then on Wednesday morning, a car fitted with special equipment traveling south of the small town of Newman detected a higher radiation reading. Handheld devices were then used to focus on the capsule nestled in the earth.
In Australia, each state has its own laws regarding the handling of radioactive substances and codes of practice that follow guidelines set by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), a government agency that works closely with the International Atomic Energy Agency (IAEA) and World Health Organization (WHO).
In Western Australia, the rules are governed by the Radiation Safety Act 1975, which Steen says is long overdue for review. “It hasn’t been rewritten since the 70s, so I think it speaks for itself,” she said.
Steen said that over the decades, advances in technology had made the use of radiation sources in mining equipment much safer — and because it was safer, the devices were used more frequently. As of 2021, more than 150 projects were underway in Western Australia, the country’s mining export hub, according to the state’s Chamber of Minerals and Energy.
Under the Radiation Protection Act 1975, only specially trained and licensed operators can package radioactive substances, but different rules apply to contractors contracted to transport them, Steen said.
“Any transport company can transport radioactive materials provided they have the authorization to do so,” she said.
By law, this license can be obtained by taking a one-day course and passing a certified test approved by the regulatory body.
The permit holder must have oversight of a transportation plan submitted to the regulator but does not have to supervise the trip in person. There are no rules regarding the type of vehicles used for transport.
Steen is making it clear that something went wrong – and she hopes the results of the investigation will be shared with the radiation community so they can avoid such issues in the future.
Discussions have already started about the need for tougher penalties – in WA, the mishandling of radioactive substances results in a fine of just 1,000 Australian dollars ($714) – a figure described as “ridiculously low” by Australian Prime Minister Anthony Albanian to reporters on Wednesday.
The rules for packaging radiation sources depend on the amount of radiation they emit. In some cases, the device could be encased in three layers. In the case of the capsule, the gauge could be seen as a protective layer before being placed in an “overwrap”, a container that has probably been locked.
In a statement, DFES said when the package was opened the gauge was found to be broken, with one of the four mounting bolts missing. Referring to the capsule, the release adds that “the source itself and all gauge screws were also missing.”
One theory investigators can look into is if the dipstick broke and the capsule fell from the overwrap through a hole used to secure the lid.
It is expected to take several weeks before the Radiological Board submits its report to the WA Minister of Health. Meanwhile, Rio Tinto is carrying out its own investigation.
CEO Simon Trott said the company would be willing to reimburse the government for costs associated with the research – if requested.
WA Emergency Services Minister Stephen Dawson said the offer was appreciated, but the government would await the outcome of the investigation to assign blame.
He said he didn’t know how much the search cost, but at least 100 people were involved, including police, firefighters, health services and members of the defense force.
Staff 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 images of the capsule being transported to Perth where it will be kept safely in a facility.
This time he traveled in a convoy of closed white vehicles – with large stickers warning of the presence of a radioactive substance.