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> One of the byproducts of their operation was a highly radioactive substance known as Thorium. As a nuclear engineer, I find the use of "highly radioactive" t

> One of the byproducts of their operation was a highly radioactive substance known as Thorium. As a nuclear engineer, I find the use of "highly radioactive" to be an overstatement. Thorium and other TENORM [1] (and their secular equilibrium products) are among the lowest activity kind of radioactive thing there is. Otherwise, it would have all decayed away billions of years ago. More radioactive = less stable = short half-life Less radioactive = more stable = longer half-life [1] https://www.epa.gov/radiation/technologically-enhanced-naturally-occurring-radioactive-materials-tenorm https://www.epa.gov/radiation/technologically-enhanced-natur...

HarryHirsch 4y ago
It sounds like typical sloppy journalism, CHinese whispers if you will. What might have happened is this: monazite contains rare earth elements, thorium, small amounts of uranium and trace radium from radioactive decay. Once you have separated the rare earths and thorium you are left with the really good stuff, especially Ra-226. It's an alpha emitter with a halflife of 1600 years, it's no joke at all. An establishment unaware of the radiation risks contamination at Marie Curie level.
- acidburnNSA 4y ago
  These dose rates are many orders of magnitude less than "Marie Curie level"
  - HarryHirsch 4y ago
    It's stuff from undergraduate chemistry. I don't remember which fraction the radium ends up in, but the activity gets concentrated by many orders of magnitude. The problem with alpha emitters is always fine dust that settles in the lungs.
nubinetwork 4y ago
What are your thoughts on thorium gas mantles?
- acidburnNSA 4y ago
  I have a few in my collection. They are good check sources for radiation detectors. Don't eat them.
  - Alan_Dillman 4y ago
    Lick 'em and stick 'em, got it.
- hilbert42 4y ago
  When I was a kid I used to get into an inordinate amount of trouble by touching and pushing my fingers through these gas mantles after they were 'fired'. I suppose the fact that they could be handled beforehand and not afterwards appealed to me at about the age of five. Anyway, many decades later I'm still here to tell the story (big bad Thorium hasn't gotten me yet). :-)
  - phkahler 4y ago
    Why not after?
    - londons_explore 4y ago
      Imagine burning a bit of paper. Before you burn it, paper is quite sturdy. When it's burnt, the ash is super fragile. Thorium coated gas lamps were similar. The fragile ash is what made the lamp work - it glowed brightly when heated by a gas flame. But if you touch it, it crumbles to dust. Thorium dust. Ready to breathe in.
      - hilbert42 4y ago
        "Thorium dust. Ready to breathe in." Not nice nor recommended—hence my earlier comment about the use of masks whilst cleaning up the remains of broken thoriated tungsten filaments. Of course, a child of five or younger doesn't understand that when he/she sticks a finger on a gas mantle, nor I'd suggest would parents back then. As a young child, I was lots of trouble, sticking knives and forks into power sockets, eating little bags of washing 'blue' and excreting a blue/green mess for days, eating dog excreta from the street and mother rushing me to hospital out of fright, eating poisoned flowers containing scopolamine and so on, so destroying gas mantles wasn't an unusual occurrence. Back then, gas lighting was an important backup because there was a great deal of industrial trouble with power station and electricity workers and rolling strikes and blackouts were often a nightly occurrence, they'd occur just at the most inconvenient time of the evening, so gas lighting usage was commonplace. Trouble was I'd somehow climb up on a chair or table and reach up to the gaslight fitting on the wall and touch and break the mantle, knowing I did something wrong I didn't tell my parents. Come the blackout there was no light without a lot of scrambling about with flashlights whilst a new one was fitted.
hilbert42 4y ago
Right, you know it's somewhat of a beat-up when 'highly radioactive' and 'substance' are bound together. Whenever I see the word substance used instead of the more appropriate element then one has to be wary. Incidentally, as I write, I can see an historic 100TH vacuum tube in a box on a shelf, it uses a thoriated tungsten filament: http://www.r-type.org/exhib/aaq0385.htm http://www.r-type.org/exhib/aaq0385.htm. I've no qualms about being near it but if it got broken then I'd take care to clean the mess up and dispose of it carefully, I'd even use an N90 mask whilst sweeping the bits up (but then I've always used masks in industrial/dusty environments—even before COVID).

HarryHirsch 4y ago

It sounds like typical sloppy journalism, CHinese whispers if you will. What might have happened is this: monazite contains rare earth elements, thorium, small amounts of uranium and trace radium from radioactive decay. Once you have separated the rare earths and thorium you are left with the really good stuff, especially Ra-226. It's an alpha emitter with a halflife of 1600 years, it's no joke at all. An establishment unaware of the radiation risks contamination at Marie Curie level.

acidburnNSA 4y ago
These dose rates are many orders of magnitude less than "Marie Curie level"
- HarryHirsch 4y ago
  It's stuff from undergraduate chemistry. I don't remember which fraction the radium ends up in, but the activity gets concentrated by many orders of magnitude. The problem with alpha emitters is always fine dust that settles in the lungs.

nubinetwork 4y ago

What are your thoughts on thorium gas mantles?

acidburnNSA 4y ago
I have a few in my collection. They are good check sources for radiation detectors. Don't eat them.
- Alan_Dillman 4y ago
  Lick 'em and stick 'em, got it.
hilbert42 4y ago
When I was a kid I used to get into an inordinate amount of trouble by touching and pushing my fingers through these gas mantles after they were 'fired'. I suppose the fact that they could be handled beforehand and not afterwards appealed to me at about the age of five. Anyway, many decades later I'm still here to tell the story (big bad Thorium hasn't gotten me yet). :-)
- phkahler 4y ago
  Why not after?
  - londons_explore 4y ago
    Imagine burning a bit of paper. Before you burn it, paper is quite sturdy. When it's burnt, the ash is super fragile. Thorium coated gas lamps were similar. The fragile ash is what made the lamp work - it glowed brightly when heated by a gas flame. But if you touch it, it crumbles to dust. Thorium dust. Ready to breathe in.
    - hilbert42 4y ago
      "Thorium dust. Ready to breathe in." Not nice nor recommended—hence my earlier comment about the use of masks whilst cleaning up the remains of broken thoriated tungsten filaments. Of course, a child of five or younger doesn't understand that when he/she sticks a finger on a gas mantle, nor I'd suggest would parents back then. As a young child, I was lots of trouble, sticking knives and forks into power sockets, eating little bags of washing 'blue' and excreting a blue/green mess for days, eating dog excreta from the street and mother rushing me to hospital out of fright, eating poisoned flowers containing scopolamine and so on, so destroying gas mantles wasn't an unusual occurrence. Back then, gas lighting was an important backup because there was a great deal of industrial trouble with power station and electricity workers and rolling strikes and blackouts were often a nightly occurrence, they'd occur just at the most inconvenient time of the evening, so gas lighting usage was commonplace. Trouble was I'd somehow climb up on a chair or table and reach up to the gaslight fitting on the wall and touch and break the mantle, knowing I did something wrong I didn't tell my parents. Come the blackout there was no light without a lot of scrambling about with flashlights whilst a new one was fitted.

hilbert42 4y ago

Right, you know it's somewhat of a beat-up when 'highly radioactive' and 'substance' are bound together. Whenever I see the word substance used instead of the more appropriate element then one has to be wary. Incidentally, as I write, I can see an historic 100TH vacuum tube in a box on a shelf, it uses a thoriated tungsten filament: http://www.r-type.org/exhib/aaq0385.htm http://www.r-type.org/exhib/aaq0385.htm. I've no qualms about being near it but if it got broken then I'd take care to clean the mess up and dispose of it carefully, I'd even use an N90 mask whilst sweeping the bits up (but then I've always used masks in industrial/dusty environments—even before COVID).