The Radioactive Source Missing In Australian Desert Has Been Found

Nuclear material is relatively safe when used, stored, and managed properly. This generally applies to a broad range of situations, from nuclear medicine to nuclear power generation. Some may argue it’s impossible to use nuclear weapons safely. In any case, stringent rules exist to manage nuclear material for good reason.

Sometimes, though, things go wrong, mistakes are made, and that nuclear material ends up going AWOL. That’s the situation that faced authorities in Australia, as they scoured over a thousand kilometers of desert highway for a tiny missing radioactive source with the potential to cause serious harm. Thankfully, authorities were able to track it down.

A Screw Loose

Authorities had to search a 1,400 km stretch of road between the mine site and Perth. Credit: EmergencyWA, screenshot

The situation concerned a tiny radioactive source, roughly 6 mm in diameter and 8 mm tall. The round silver pellet contains the radioactive isotope Cesium-137, and puts out harmful quantities of both gamma and beta radiation. The pellet was part of a gauge used for measuring the density of iron ore feed running through mining equipment.

The gauge itself had been transported from a Rio Tinto mining site in Western Australia on January 12, and had made a 1,400 km journey, ending up in Perth on January 16. The capsule was first reported as missing on January 25, when the gauge it was a part of was unpacked for inspection. The gauge was found broken, with a mounting bolt missing along with multiple screws. Authorities concluded that vibrations from the truck caused the screws and bolt to loosen, with the radioactive capsule then falling out of the gauge and off of the vehicle.

Government authority Radiation Services WA has released a statement on the incident. It notes that typically, radioactive sources of this type are usually protected in secure housings in equipment. They are intended to be safe in regards to corrosion and vibration, as well as being able to withstand drops from nine meters high, and even high temperatures of up to 800 °C for 30 minutes without danger. Transporting such materials also requires strict controls, including the use of trained personnel and meeting certain packaging requirements. The fact that the source was able to literally fall off the back of a truck suggests these controls were not met.

The Danger

The loss spawned an urgent hunt for the tiny radioactive source. Despite its diminutive size, the source does pose a significant health risk. According to authorities, the source’s original radioactivity was 18.5 GBq. At this level, a human would receive roughly 1.665 mSv/hr (milliSieverts per hour) standing at a distance of 1 meter from the source. This is equivalent to roughly 17 normal chest x-rays, or a year’s worth of background radiation in Australia. For further perspective, a 2 mSv dose increases cancer risk by 1 in 10,000.

Unfortunately, getting closer to the source greatly increases the harm. Getting within 1 cm of the capsule would deliver a dose rate of 16.65 Sv/hr (Sieverts per hour), a full 10,000 times higher thanks to the inverse square law – note the unit change. Picking up the source would increase the dose rate ever higher, on the order of 1,665 Sv/hr. The device is radioactive enough that holding it would cause serious damage to the tissues of the hand, including burns. (Editor’s note: If you want to learn a lot more about the biological specifics, check out Dan’s awesome article.)

Some radioactive sources are labelled with the phrase “Drop And Run,” and that action would certainly apply in this case. This tiny Cesium-137 source is far less radioactive than the Cobalt-60 sources this message usually applies to. However, it’s still radioactive enough that you don’t want to be anywhere near it.

Those numbers indicate the severe risk the source poses. If you spotted the tiny source from a distance, you could remain five meters away as recommended by authorities, and you would be relatively safe. Alternatively, if you picked up the source, or it perhaps became lodged in the tread of your shoe, you could be exposed at close range for a great deal of time. An exposure to a double-digit dose of Sieverts tends to be fatal in most cases, so the risk is extreme if it comes into contact with humans.

On the flipside, if the source remains in an isolated area, far from human contact, its impact may be minimal. The Cesium-137 itself is sealed in the capsule, and thus is unlikely to contaminate ground water sources or the soil itself. With a half-life of roughly 30 years, the source is expected to remain meaningfully radioactive for approximately 300 years or so. As the decades pass, though, it becomes less and less radioactive, posing a lower risk over time.

A Hot Needle in a Haystack

The capsule most likely went missing somewhere between the Gudai-Darri mine site operated by Rio Tinto, and Perth. The capsule is potentially still sitting somewhere along the desolate desert roads of Western Australia. Credit: Calistemon,CC-BY-SA-4.0

Trying to find a tiny capsule smaller than a coin on 1,400 km of highway is a difficult task. It’s akin to trying to find the proverbial needle in the haystack, but much harder. Thankfully, though, tools existed to assist authorities in their search. The radiation output by the capsule can be detected at some range by radiation-detecting equipment. This means authorities didn’t just have to rely on keeping their eyes peeled. If they were able to get in the general vicinity of the object, their radiation detectors would help them track down its precise location.

Authorities used vehicles outfitted with radiation-detecting equipment. The vehicles made making slow passes up and down the highway at a speed of just 50 km/h. Travelling at the prevailing highway speed of 100 km/h would be too fast, as any spike caused by the capsule would probably be missed. Going slow and steady was key to finding the capsule.

Of course, there was a risk that the capsule is no longer directly on the highway route where it was lost. Weather or local animal life could have moved the capsule, potentially carrying it a great distance away. Alternatively, the capsule may have become lodged in another vehicle’s tire and carried away. This would be a particular risk, as it would leave the capsule in regular proximity to people. Worse, it could later be removed from the tire by hand, causing a significant radiation exposure in the process.

Just as we’re writing this, thankfully, the source was found by authorities before any calamity came to pass.

Overall, though, There’s also clearly a need to figure out how the source came to be lost in the first place. It would appear that the gauge containing the source was clearly not transported properly, or not transported in the proper condition, if the source was able to get loose in the first place. There are many questions to be answered to ensure that this never happens again.

66 thoughts on “The Radioactive Source Missing In Australian Desert Has Been Found

  1. “It’s akin to trying to find the proverbial needle in the haystack, but much harder.” ….. Just trying to think what equipment would be needed to actually find an actual needle in an actual haystack. Would make a great Youtube video for people with nothing better to watch. Anybody gonna try it?

    1. I’m not actually sure it’d be as exciting as you think if we’re talking a run of the mill ferromagnetic needle. Heck I wouldn’t be shocked to learn that hay bailers already have a magnet bar built in to grab stray metal bits before they get rolled up in the bail and eaten by some animal. If I was going to overkill it, I’d take the hay to a junk yard and let them use the big magnet on it, otherwise I’d just spread out the hay and use a magnet drag bar like they use to clean up nails and screws at work sites.

      Even if the needle was aluminum or something non-ferromagnetic you could take a cattle trough, have water flowing through with it propped at an angle and dump the hay in slowly on the high side and let the hay wash out the low side and once you’re done, the needle will be in the bottom assuming you didn’t leave it on the ground, in which case you do a pass with a shop vac or maybe nice metal detector to find it.

    2. Mythbusters did it. They also tried a bone needle to foil the use of magnets and metal detectors.

      Burn it, blow it in the air, or float it in water – the needle separates from the hay eventually.

    3. Mythbusters ahead of the game, again!

      They made two machines to do exactly this – one used a special rotating burning cylinder thing to burn off all the hay, the other a water tank and some agitators to break up clumps. The hay floated, needles sank. If I recall both of them found all the needles.

    4. I’d give it a go. I’d probably go with fire, the magnets and stratification by density. Maybe add some pulverization in there. Fire makes the volume to be searched much lower, and ash and hay charcoal are much less dense than a needle.

      Back on topic.. :-)

      My guess is that the gage was being transported for repair. Could that account for the missing screws? Is there a requirement for a secondary container for anything containing a radiation source?

    5. Without being destructive (= not burning the hay away) I’d assume some sort of RF technique could be used.
      RF sender at resonate frequency of needle (varying a bit) and multiple antennas to get an idea of the general location and then powerful (electro-)magnets.

  2. The parts of this article do not add up well.
    First it seems very unlikely that multiple screws vibrated loose during transport. You would have thought that putting on some thread locker or safety wire would common for stuff like this. From the descipton, a deliberate opening seems more plausible.

    Second, It states the pellet has been found (but not where), but how does “being found” match with “The capsule most likely went missing somewhere between …”

    1. You’re right, I was confused too – is it found or not? A quick Google search gave the answer:
      – Officials said the capsule, about the size of a pea, was found south of the mining town of Newman on the Great Northern Highway. It was detected by a search vehicle traveling at more than 40 mph when specialist equipment picked up radiation being emitted by the capsule.

    2. Bolts can vibrate out like that, although I agree it does sound suspect. My 1985 VW Golf Diesel had 2 bolts fall completely out and 1 was halfway out of the alternator… which is used as the front engine mount in this car… the engine tilted out of contact with the drive shaft and I lost all power while driving. Wedging it back in place with a 2×4 allowed my Dad to get it home and he was able to replace the bolts, this time with some locktite.

      1. Having owned a dozen of these I am not sure the alternator bracket is part of the engine mount. The starter most definitely is. And they are within 6/8 inches of each other.

        The diesel does not need anything more than a fuel cut off solenoid energized and possibly a fuel lift pump. With its generous battery the alternator wouldn’t make a difference for most trips, it would easily run for a day without.

        Since an alternator doesn’t have a driveshaft or an engine mount bolt I would guess it was the starter at fault. Glad your dad made it home with a block of wood! 80s diesels are one vehicle that could run with no electricity at all given a hill to start the engine and a mechanical fuel shut off.

        On subject: I don’t expect mining equipment to have this level of radioactive material inside. At least not without 2 levels of protection and a tamper proof inner one at that so the freed (sealed) inner part would not be capable of causing death.

        Story seems fishy, suspect people tried to steal it.

    3. Because the device was sent for maintenance, maybe some well-meaning DIY person opened it up, breaking up the thread-locker in process. Then after being told to stop or realizing that they shouldn’t tinker with devices bearing radiation warnings, the bolts were put back but without thread-locker and at insufficient torque.

  3. For those interested in what 93 grams of caesium-137 may cause on a city, just search for “Goiania Accident”, that happened in Goiânia city, Brazil, in 1987. It started with a radiotherapy equipment dismantled by a junkyard, and ended as one of the worst radiological incidents.

    Yes, they broke the container. Yes, people literally played with “a bluish glowing powder” bare handed.

    Reports says that when a Geiger counter was brought to the hospital, the technician thought that the equipment was broken, as it went totally nuts. And the poor guy wasn’t even inside the building.

    1. Atomic Adventures by James Mahaffay has a whole chapter about the many, many incidents of this nature. One that stands out is abandoned facilities with sources left in place where looters break in, ignore the warning signs and loot the fancy shiny machined devices then irradiate a whole bunch of people. Then sometimes yes the physicians instantly recognize radiation poisoning but it’s rare enough that usually they don’t.

    1. I sued to work for a company making density meters. If you wanted to ship a source, you needed to triple pack it. Three boxes with three layers of tape at a minimum with QA paperwork at both ends to be singed.

      Gauges were never shipped with sources inside and the manuals stated this.

      Some radiation safety officer now has some serious explaining to do!

      1. I seriously considered for several seconds why anyone in their right mind would want to brute force himself into a job by employing attorneys, before I realized two letters were simply swapped in that sentence…

        1. Or why the QA paperwork had to be slightly burned, or was it the tape, at both ends?
          Instead of burning it, could professional vocalists using lyrics and melody convey make a recording of the paperwork on a long, spooled, flexible, magnetic, media?

  4. Same thing (almost) happened in Hiway Patrol; s1 e8 RadioActive (nov.,’55 for those with short memories).
    Disgruntled employee walk off with an oil well drillhead…(radioactive, of course) Dan starts
    chasing thief in Bell Ranger… suspect tosses it from car to be picked up by a hobo (can we still say ‘hobo’?) Hobo brings it to scrapyard, gets $.75 for it. Ham operator buys it for $1.75. He’s on a tight budget since his wife is expecting. Dan has ’emergency warning’ broadcast on ham frequencies…but ham doesn’t hear message because he has to remove laundry from washingmachine for wife. Neighbor visits ham and recognises device and calls hiway patrol.

  5. Meh it was 2 meters off the side of the road in the middle of nowhere and the chances of it been found by accident before nature buried it are very very low, it would have gone through enough half lives before it was found to not be a great threat to anyone. The truth is they were worried that it was not lost but stolen, and therefore could be weaponized. It isn’t the first one that has gone missing either, I don’t recall if they ever found the last one which was actually stolen from the back of a truck.

    1. *Now* we know that it was off the side of the road, but that’s only because it was found.

      As mentioned in the article, there was a *very real* chance that the source could have gotten stuck in the tyre treads of another vehicle and carried into a populated area.

      1. It that part of the world nothing stands in the sun for more than a few minutes, or you will die of heatstroke. It is a very nasty environment even without small radiation sources.

    1. …I was about to go on a rant about how the /one thing/ that Imperial and Metric should have agreed on is which punctuation means what (the objectively correct answer, for the record, is Commas for Thousands, Periods for Decimals), but then I reread and noticed the article did in fact say that picking it up would give you “sixteen hundred and change” Sv/hr. That’s half a sievert per SECOND.

      And I thought Cobalt-60 was the poster child for DROP & RUN…

  6. I have lots of radioactive tritium for my nuclear battery. There are lots of radioactive rocks I have anyone can get on eBay or mine for it using water soil and a curtifuge. You can get radioactive rocks by mining for it using a diy nuclear reactor that I have at home.

  7. I found what might have been an orphan source a while back. It appears that somehow it got mixed in with a bunch of electronics stuff, but was quite clearly part of a gold/radium needle. Handed it in. My counter went absolutely berserk near it, up to 30-40* a smoke alarm source. Also found some 137Cs once that had seemingly been used in a 1970s vintage smoke alarm by mistake. Also handed in.
    Its quite common to find things like hot clocks, but 137Cs has no business being near civilians.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.