() — What do a capsule in Australia, a cylinder in Thailand, and a camera in the United States have in common?
All three contained radioactive material and have disappeared within the past three months, in what experts say is a very rare coincidence that nonetheless raises security questions about what is a fascinating and incredibly useful array of substances.
What are radioactive isotopes?
A radioactive isotope, also known as a radioisotope, is an unstable form of a chemical element that decays over time in the form of radiation.
These chemicals can be found naturally, but many are created artificially.
The radiation emitted by these elements comes in the form of alpha, beta and gamma rays which, depending on their concentration, can be dangerous.
But their unique properties also make them useful for a host of applications, from killing cancer cells to making incredibly precise measurements.
What are these radioactive sources used for?
Radioactive sources are more common than most people realize.
“Hundreds of thousands” of these sources are “used and safely transported every day,” Lauren Steen, general manager of Radiation Services WA, a consultancy that writes about radiation management plans in Australia, told .
Radioactive materials have a variety of industrial uses, such as the cylinder that went missing in Thailand that measured ash at a coal-fired power plant.
In construction, X-ray cameras, like the one that disappeared in the US, can be used to inspect the integrity of ships, pipelines and other small spaces, according to the National Nuclear Security Administration.
Radioactive substances can also be found in meters that analyze the soil. The capsule that disappeared in Australia, for example, was used in a density meter for the Rio Tinto mining company.
In addition, radioactive substances are used in hospitals to diagnose and treat various types of cancer or to disinfect blood for transfusions, according to David McIntyre, a public affairs officer for the US Nuclear Regulatory Commission
How dangerous are the radioactive items that disappeared?
Much depends on the type of radioactive isotope inside a device and whether it is contained within a shield or open to the elements.
The risk of radiation exposure from the camera that disappeared in Texas is “very low,” especially since the radioactive material is encapsulated by multiple layers of shielding, authorities said.
But the capsule in Australia and the cylinder in Thailand contained Cesium-137, a highly radioactive substance that is potentially lethal.
Experts warn that cesium-137 can create serious health problems for people who come in contact with it: skin burns from close exposure, radiation sickness, and potentially fatal cancer risks, especially for those unknowingly exposed for long periods of time. periods of time.
Cesium-137 has a half-life of about 30 years, which means it could pose a risk to the population for decades to come, if it is not found.
The risk of radioactive material being present in an unknown area for an indefinite period of time was a particular concern in the Australian case because the radioactive capsule disappeared along a vast stretch of desert road and was not contained within. of a protective casing.
It was found after a challenging search akin to trying to find a needle in a haystack, assuaging fears that people could have been unknowingly exposed to radiation.
“If people in general (come) in contact without knowing it, the health effects will depend on the level of intensity (of radiation). If it’s high, the first thing we’ll see is skin irritation,” Pennapa Kanchana, deputy secretary general of the Office of Atoms for Peace (OAP), a government regulator for nuclear and radioactive research in Thailand, told .
The radiation intensity from the missing cylinder in Thailand should be slightly hampered by the protective shroud surrounding the radioactive source, experts suggest.
“It seems to be 100% in the casing which is lined with lead, so it’s a little bit safer than just a source that is in the size of the road,” Steen told . “The only risk comes back if the cesium source gets separated from the house.”
But that concern may now have become a reality.
Days after the cylinder was reported missing from a coal-fired power plant in Thailand, authorities detected cesium-137 radiation from iron dust at a foundry at an iron smelting factory about 6 miles (10 km ) of the plant. They are still investigating whether the missing cylinder was brought to this factory and whether the detected cesium came from the missing cylinder.
This is not the first time something like this has happened in Thailand.
In 2000, according to a report by the Congressional Research Service, two junk collectors bought canisters containing another radioactive isotope, cobalt-60, and took it to a junkyard where they cracked it open.
Some workers suffered burn-like injuries, and ultimately three people died and seven others suffered radiation injuries, according to the report. Nearly 2,000 other people who lived nearby were exposed to radiation.
But Pennapa said the canister currently missing is much less radioactive than the one that caused the incident in 2000.
How often are radioactive materials lost?
The disappearance of three radioactive items in such a short time raised concerns, but experts say the frequency of recent incidents is atypical.
“I just think it seems like a great coincidence,” Steen said.
In 15 years of working on radiation management, Steen told that he had never heard of a “missing” radioactive source until this year.
“To be honest, I’m surprised,” Steen said. “In all my years of practicing radiation safety, I have never encountered these situations before.”
The transport of radioactive capsules such as the indicator in Australia “is not an uncommon practice,” but “the loss of a source is somewhat uncommon,” Steen added.
US Nuclear Regulatory Commission press officer McIntyre said recent incidents should be seen as the exception, not the rule, when it comes to radioactive material, and should not overshadow its valuable uses.
“Although devices with radioactive sources do go missing from time to time, I would caution against concluding that there is a large amount of unsecured radioactive material,” McIntyre said.
‘s Kocha Olarn, Heather Chen and Hilary Whiteman contributed to this report.