An impressive find : That tiny radioactive capsule

Apparently there were three buckets of uranium at the Grand Canyon visitor centre for years until somebody noticed

Links to https://eu.usatoday.com/story/travel/news/2019/02/18/grand-canyon-tourists-exposed-radiation-safety-manager-says/2905358002/

Rob

Hi, like a lot of people, I've had a few watches with luminous hands and the main five minute positions. The photo below shows the remains of one that I had many many years ago. The luminous parts will still glow for a couple of moments when exposed to the light on my phone camera for about a minute, but it took a few shoots to capture an image, as the luminous glow disappeared as quick as a flash, and the bottom photo shows them at about half the brightness from when I switched the camera light off.

My younger brother and I were given a Crucifix with a luminous figure, by one of our parents friends when I was about eight, and these would glow quite brightly, longer than it took for us to fall asleep, it still will glow for a while after shining an LED array battery hand held light on for about a minute, although it has been stored in different boxes/draws for most of my life.

Regards Nick.

That incident is very bizzare. Uranium is not much of a radiation hazard, it's toxcity as a heavy metal is as much of a concern. Some ore in a storeroom was unlikely to pose a hazard to visitors. The incident, which I'd heard of before, sounded like some kind of retaliation by an employee or at best over-zelous health and safety action.

In the UK there is no restriction on possession of up to 15kg of natural or depleted Uranium metal. I have a couple of samples including some rare pre-WWII Uranium oxide which is made from natural uranium. It's great for spectrographic calibration. All the modern Uranium chemicals are made from depleted Uranium which has different isotopic ratio and is less radioactive. As mentioned earlier it is actually used to shield the radiation from large gamma sources.
Also used for balance weights in aircraft flying controls. Early Boeing 747's had a load of it. There is still a weight somewhere in a field near Stansted from a 747 freighter that crshed in 1999 (Korean Air HL7451). See page 25/26 of this AAIB report. https://assets.publishing.service.gov.uk/media/5422f0a5ed915d13710002fb/3-2003_HL-7451.pdf

Robert.

Nicholas

Your watch dial doesn't use radium but uses the "milder" Tritium based luminescence indicated by the "T" either side of the Swiss Made legend.

CS

Here on Light Straw, we have a little article on Trimphone dial disposal
https://www.lightstraw.uk/ate/tao/trimphones/radiation1.html

"Light Straw" is the cream coloured paint used after battleship Grey on telephones and transmission equipment in GPO/BT; also coincidentally the colour of the rood of my Landrover, as I found a tin after I'd retired.

Bill

Edited By peak4 on 03/02/2023 01:10:46

Hi Clive, never really thought much about the two "T's" so that's something I've learnt today.

Regards Nick.

There is uranium and there is uranium ore. And in the middle there is "yellow cake", the concentrated ore that is shipped around the world in 44 gallon drums for final processing. The radiation level of the ore is not very high. Yellow cake a bit higher. The buckets in the Grand Canyon contained ore, not finished uranium.

I worked in the 1970s on the construction of a uranium ore treatment plant at the mining site in the Northern Territory (Australia) and it was just the same as any treatment plant used for iron or gold or any other mineral. All open conveyors, crushers, ball mills, settling tanks etc etc. No special precautions taken that I could see, other than the incoming operatiing staff at the end of construction all wore radiation badges that were checked weekly to make sure they had not been over-exposed that week. So I don't think the ore itself is considered particularly dangerous. (or it wasn't in 1979!).

Nonetheless, I got out of there before they started putting the ore through the machinery,

Thanks for the extra info, chaps.

Rob