back to article Watch tiny swimming magnetic robots suck up uranium in a droplet of radioactive wastewater

Scientists have built microscopic primitive robots that can swim in wastewater and remove radioactive uranium, in the hopes that they can one day be used to clean up nuclear spills for humans. The team of researchers at the University of Chemistry and Technology and the Institute of Organic Chemistry and Biochemistry in Prague …

  1. Elledan

    How would uranium be the dangerous part? In a nuclear disaster, it are strontium-90 and cesium-137 in addition to radioactive iodine which are the threat. Uranium is harmless unless swallowed.

    A much better use for these little critters would be to recover uranium fuel from seawater, to economically recover it.

    1. diodesign (Written by Reg staff) Silver badge

      "Uranium is harmless unless swallowed"

      Yes, yes, and it's a good thing this article isn't about uranium in water, that hard to swallow, easy to contain, non-spilling water.

      C.

      1. Robert Sneddon

        Re: "Uranium is harmless unless swallowed"

        What water sources are noticeably contaminated with uranium? I know that seawater has about 3mg of uranium in each cubic metre and I presume there are rivers fed from rocky uplands that might have noticeable levels of uranium but are those levels considered harmful in drinking water?

  2. robidy

    "Uranium is harmless unless swallowed" - please don't spead fake news, please check with someone who understands nuclear physics before making a fool of yourself.

    1. TechnicalBen Silver badge

      Do they possibly mean, this concentration of uranium while in [this] water? As the water would be a partial radiation shield/mitigation/etc, plus it's a very small concentration (though a large amount of concentrated water).

      So this particular contamination of uranium is only harmful if swallowed/digested where it will accumulate. However, as it's also a lot of contaminated water, that's a big risk still, so needs cleaning up!

    2. imanidiot Silver badge
      Boffin

      You need quite a lot of pure uranium for it to be dangerous/harmful. They were handling pure chunks of the stuff in Los Alamos without too many ill effects (discounting the one where Slotin dropped a hemisphere and created a prompt critical mass, that is bad). Just a low concentration of uranium in water isn't really all that dangerous unless swallowed. And then it's mostly because Uranium is more poisonous than lead, it's biological half time (how fast the body removes it again) isn't long enough to give you a fatal dose either.

      The actinides and fission products really ARE the main concern in a nuclear accident, not the uranium (long term you want to get rid of it, mostly because of the poisonous nature of it). Look at what they've been dealing with in Fukushima, you'll find it's the Strontium that is the main concern right now outside the reactor.

      Edit to add:

      Uranics are harmful if you STAY in the environment and don't go to a place that isn't contaminated. Obviously then the body can't get rid of the stuff because it keeps getting replenished.Uranium however isn't the acute danger that other radioactive elements present.

      1. phuzz Silver badge

        Slight correction, the core that Slotin was messing about with was made of plutonium, not uranium.

        It was the exact same core that had killed Harry Daghlian 1945 (he dropped a neutron reflector onto it, which caused it to go critical). It was still kept for experimentation (because refined plutonium was/is worth more than gold).

        At least after Slotin killed himself, they stared doing the experiments with remote control, rather than an (un)steady hand and a screwdriver.

        The core was then nicknamed "The Demon Core", and eventually melted down. Parts of it probably ended up in multiple nuclear weapons.

      2. bombastic bob Silver badge
        Boffin

        certain areas in Mexico apparently have yellow clay that has occasionally been used for things like pottery... and the yellow is from the Uranium.

        Radiation poisoning etc. is a non-simple thing. MANY factors, from the type of emitter and nature of exposure, to biological half life and decay rate and energy levels of the emitted particles.

        The one thing that struck ME is to have these bots go out and MINE FOR MORE URANIUM. That, and recycle spent fuel. how about going through spent fuel rods to extract all of the remaining uranium so it can be reprocessed and turned into MORE FUEL???

        THAT would be AWESOME!

    3. phuzz Silver badge
      Boffin

      "Uranium is harmless unless swallowed"

      Well, that depends a lot on the exact form of the uranium. I also assume we're talking about it's radioactive properties, (if I dropped 10kg of uranium on your foot it would cause you harm but that's not the point).

      If it's mostly U238 (which is likely, as it's the vastly more common isotope), then yes, it's pretty safe to hold a chunk in your hand. It's primary decay releases an alpha particle, which won't penetrate skin. I probably wouldn't keep some in my pants, but I'd be happy to hold a chunk of uranium in my hand all day.

      If it gets inside you however, bad things will occur. Not only will the alpha particles have a much easier time of causing radiation damage once they're inside your skin, but uranium is also a toxic heavy metal, with all the unpleasant side effects that implies.

      tl/dr "Uranium is harmless unless ingested" is a (broadly) true statement.

      1. Robert Sneddon

        Heavy metal

        uranium is also a toxic heavy metal,

        It's not actually very toxic since there aren't many biological pathways to absorption for the most common form of the metal, the oxides (nuclear fuel is formulated into a ceramic oxide form). As for "heavy" metals, a lot of the higher-number and denser metals are pretty much inert biologically speaking -- gold, for example and tungsten. The really nasty poisons are light low-atomic number metals like beryllium and lithium and arsenic. Lead, mercury and thallium are the only really stand-out heavy/dense metals with noticeable toxicity.

  3. Jemma Silver badge

    Bite..

    My tiny metal ass...

    Uranics are harmful if ingested but also from skin contact or from being breathed in - although you really don't want them floating around in the digestive tract, that's probably the most dangerous place for it to end up.

    Radioactivity is pretty much bad anywhere in or on or around the body.

    1. Oh Matron!

      Re: Bite..

      Upvote for the Futurama reference

    2. Robert Sneddon

      Re: Bite..

      Uranium isn't particularly (geddit?) radioactive. Both common isotopes have very long half-lives so they don't emit a lot of radioactivity -- U-235 half-life is 700 million years, U-238 half-life is 4 billion years. In comparison a radioactive isotope like potassium-40, commonly found in food and drink has a half-life of 1.3 billion years. The typical human body contains about 16 milligrams of potassium-40.

      As for chemical toxicity uranium is not as dangerous as, say, arsenic or mercury or many other metallic substances. The most common oxide forms of uranium are nearly insoluble which means they have limited biological uptake. The only known biological downside to uranium poisoning in human beings is kidney damage.

      1. Jemma Silver badge

        Re: Bite..

        Any unnatural radioactivity inside the body is bad radioactivity. It's a simple principle.

        Uranics aren't anywhere near as dangerous as strontium and cobalt isotopes but they are still radioactive. Even Radium paint can merrily dissolve a person given time (The Radium Girls, which you can find on Kindle, not a good way to die*).

        *not for the squeamish. And if your vintage guns have a luminous nightsight - don't lick it..

        1. Anonymous Coward
          Anonymous Coward

          Re: Bite..

          "Any unnatural radioactivity inside the body is bad radioactivity. It's a simple principle."

          This is simply nonsense. There is no difference between a natural source and an "unnatural" one, if the absorbed dosages are similar.

          There are plenty of life saving medical imaging, techniques using radioactive isotypes that are 'unnatural', many of which can only be produced in a nuclear reactor (and risked a major shortage of when all the reactors where these were being produced went into maintenance at similar times). Here, the negligible negative effects of the radiosources are judged far less than the utility of the imaging which can be produced from them. While perfectly natural radon gas being released from underground decay of natural and wholesome granite is a major cause of lung cancer in affected areas.

          As with all things, the difference between poison and medicine is the dosage.

          So if you happen to have a vintage gun with a luminous nightsight, you should be alright licking it a few times, so long as you aren't doing so continually throughout a long working day for a few months or years.

        2. Loyal Commenter Silver badge
          Headmaster

          Re: Bite..

          Any unnatural radioactivity inside the body is bad radioactivity. It's a simple principle.

          A pure pedant point, admittedly, but all Uranium is "natural", in the sense that it comes from the natural environment, not from ghosts.

        3. Loyal Commenter Silver badge

          Re: Bite..

          The Radium Girls, which you can find on Kindle, not a good way to die

          See also "fossy jaw". In general, it's not a good idea to lick the chemicals you work with, be they radioactive, or not.

        4. swm Bronze badge

          Re: Bite..

          Radium is a high-energy gamma ray emitter. This is far more dangerous than an alpha emitter.

          I have a radium dial wrist watch. In college physics lab they tried to demonstrate saturation effects in a geiger counter but none of the radiation sources available in the lab were strong enough to demonstrate the effect. My watch had no problem demonstrating the effect. People started edging away from me for some reason.

        5. Paul Hovnanian Silver badge

          Re: Bite..

          "Any unnatural radioactivity inside the body is bad radioactivity."

          Natural or otherwise, it depends on the half-life of the isotope in question. Many Radium and Strontium isotopes have half-lifes measured in days. That means they are breaking down and releasing particles at a high rate. Uranium isotope half-lives range in the hundred thousand to billion year range.

          1. Loyal Commenter Silver badge

            Re: Bite..

            Natural or otherwise, it depends on the half-life of the isotope in question.

            More strictly accurately, it depends on the half-life, the decay type and decay energy.

            Radiactive decay typically involces one or more of electron emission (beta radiation), alpha particle emission (alpha radiation), high-energy photon emission (gamma radiation), and neutron emission.

            Ionised particles (alpha and beta emission) cause damage by basically smashing into other atoms, alpha moreso, because an alpha particle consists of a positively charged combination of two protons and two neutrons (some 8000 times more massive than the electron released in beta decay and with twice the electric charge).

            The amount of damage such particles can cause is pretty much directly related to the amount of energy they hold when they are emitted, which is specific to the isotope that is decaying, but for alpha particle is usually around 5 MeV.

            Gamma radiation depends very much on the energy of the photon in how harmful it can be. They typically cause damage by ionising the atoms they pass by.

            Neutrons can hit other nuclei and make them into unstable isotopes. This requires a direct-hit on the nucleus, and the vast majority of every atom is empty space, so neutron flux has to be quite high for this to be hazardous. A single decay has a very low chance of being harmful, compared to the potential of an alpha particle. Neutrons, however, being uncharged, can travel a lot further, so the safe distance from a neutron source is a lot more than the safe distance from an alpha source - alpha particles typically don't get more than a few cm, but neutrons will travel many metres. Free neutrons also have a half-life of around fifteen minutes before decaying into ionised particles (a proton and electron) and a neutrino. If it does so when it's inside you, that proton and electron are going to cause damage to whatever is around them.

    3. Dusty

      Re: Bite..

      "Radioactivity is pretty much bad anywhere in or on or around the body."

      Unless "Radiation Hormesis" is actually a thing after all.

      1. swm Bronze badge

        Re: Bite..

        There is some evidence that small amounts of radiation might train the body in repair mechanisms of DNA. I don't know how true this is.

        1. Dusty

          Re: Bite..

          Its the old, what I believe to have been called, Hippocratic principle "That which is used grows, that which is not used wastes away" (Or words to that effect) The immune system and cellular repair mechanisms seem to work better if they are given something to chew on. Being too sterile is implicated in all sorts of health problems. Being under exposed may well be an issue too.

          I recall reading of a proposed "Ultra Low radiation exposure" experiment where test animals are excluded from as much radiation as possible (Including being fed specially processed food from which the K40 has been removed) to see how their health compares with normal control subjects, but I don't know if there has been progress on this. The results would be interesting.

  4. Chris G Silver badge

    It seems to me, that this technology would be more useful if it could be adapted to sweep up a range of other heavy metals that are commonly emitted in industrial effluents as a part of inline treatment prior to discharge.

    1. TechnicalBen Silver badge

      I'd assume you'd not need these in those circumstances, as much easier to use other contained methods. Once it leaks out though. :(

    2. swm Bronze badge

      There are some aquatic creatures that preferentially select radioactive isotopes.

  5. Chris 239
    Boffin

    Seems a bit arse backward to me.

    If these collect the uranium by it simply sticking to them as they randomly move about would it not be simpler/more effective/economic to just coat some sort of surface or filter with the stuff the uranium sticks to and move the water rather making zillions of these robots which I presume would be dificult.

    1. AdamT

      Re: Seems a bit arse backward to me.

      I'd say the interesting bit was the mechanism to have them move around under their own power. As you suggest, there are probably easier ways to extract uranium from contaminated water. Could be that this is one of those situations where the research is rather academic (but worthwhile!) then it gets jazzed up a bit for the publicity with a token "it could be used for <X>!"

    2. Draco
      Meh

      Re: Seems a bit arse backward to me.

      Exactly what I thought. Far more efficient to filter the water through a sieve which attracts the uranium than introducing a gadjillion nano-particles, adding hydrogen peroxide to get them to go on a random swim, attract the spent nano-particles with a magnet, filter them out of the water, clean the particles up, rinse and repeat.

      In a "real" environment, H2O2 + nano-particles may be toxic / hazardous to the flora and fauna.

  6. Paul Johnston
    Black Helicopters

    Biology beats Robotics

    If you need loads get them to replicate!

    https://phys.org/news/2015-06-scientists-bacterium-uranium-immobile.html

  7. Anonymous Coward
    Anonymous Coward

    Drop them in the ocean. Sea water is loaded with uranium, more than enough to supply our energy needs for centuries. It's just very dilute.

    1. Julian Bradfield

      I'm not sure that turning the sea into a 1% solution of H₂O₂ is a very good idea.

      1. Ken Moorhouse Silver badge

        Re: I'm not sure that turning the sea into a 1% solution of H₂O₂ is a very good idea.

        Calling it a "blonde moment" will probably provoke some criticism of political correctness.

      2. Anonymous Coward
        Anonymous Coward

        It's one way to clean up the environment.

  8. Ragarath
    Joke

    Iron?

    Since they’re partly made out of iron

    They're gonna rust like, you know, real quick.

  9. Crisp Silver badge

    Teeny Tiny Robots and radiation

    What could possibly go wrong?

    I'm thankful the little buggers can't replicate.

  10. RGE_Master

    That's fast

    OK,

    I'm 6"5, I've done the math, 6ft5 x 60 is 390, 390 feet per second into miles per hour is 265.9091 MPH.

    I could run from London to Edinburgh in less than 2 hours, I could make it from my house to work in 5 minutes rather than an hour on the train.

    it's a stupid comparison but helps you to see how fast they really are.

  11. Unep Eurobats

    Clever stuff, but practical?

    This sounds like it will work best for open stretches of still or slow-moving contaminated water. It's going to be harder to deploy in other scenarios - where spillage leaks into the ground, for example.

    1. diodesign (Written by Reg staff) Silver badge

      "Clever stuff, but practical?"

      It's a lab experiment right now - where all* good ideas begin.

      C.

      * YMMV

  12. Anonymous Coward
    Anonymous Coward

    Off and on topic ...

    but I was listening to a Radio 4 podcast - (possibly the usually excellent "Infinite Monkey Cage") recently, and one of the non-science guests made the classic faux-pax of thinking "radioactive for billions of years" was somehow the "bad" radiation.

    I waited till the end, but not one of the panel (which was two guest chemists, but surely Prof. Cox could have interjected) pointed out that the longer the half-life, the more stable an isotope is and less harmful.

    It's not the stuff with a half life of 1,000,000 years that worries me as much as the stuff with a half life of 1 year.

    Just grated as it means there will be some folk that will continue in their wrong thinking and stand in the way of the UK being powered by nuclear forever ...

    As you were.

  13. HobartTas

    Distillation not an option?

    I would have thought that distillation in a specialized multi-stage flash unit like the Arabs use to make fresh water from sea water would be the best way to go as you can boil off whatever remaining water is left and all you're left with is solid residue which could be a large mix of radioactive elements and then you can just simply bury it somewhere like you do other contaminated nuclear waste. I believe that you only need a high single digit of kWh's to make one kiloliter of fresh water using this method so even a swimming pools worth of contaminated water would need less energy than that required to make one tonne of Aluminum which is about 14,000 kWh's. These robots would probably only be useful for a contaminated pond or lake with a huge amount of water.

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