Radioactive particles - food for thought

[George Brims]

Food for thought. Noting that the most recent radioactive particle found at Dunnet was naturally ocurring rather than coming from Dounreay, I did some searching on the web, and came across the following: http://www.edinburghgeolsoc.org/z_24_05.html

I've been trying to get a feel for the level of radioactivity of the particles that have been turning up, so the recent figures on what that particle contained compared to recent anthropogenic ones was very interesting.

[scotsboy]

George some of the surveys of beaches have turned up some superb radioactive fossils, one in particular springs to mind where you can actually see the scales on the tail of a fish.

[George Brims]

I've seen many Caithness fossils where you could see the details (striations and growth rings) on scales. But the most amazing fossil I ever saw was a specimen of Dickosteus (named after Thurso's own Robert Dick) . In shape the thing resembled a monkfish, about a yard long, and you could actually see details of the internal organs I believe it's now in one of the museums in Edinburgh.

[grmacken]

1.8kg piece of sandstone... cant really be called a particle :p

[scotsboy]

Depends on what scale you are talking ;) :lol:

[Rheghead]

Food for thought. Noting that the most recent radioactive particle found at Dunnet was naturally ocurring rather than coming from Dounreay, I did some searching on the web, and came across the following: http://www.edinburghgeolsoc.org/z_24_05.html

I've been trying to get a feel for the level of radioactivity of the particles that have been turning up, so the recent figures on what that particle contained compared to recent anthropogenic ones was very interesting.

The particles or radioactive stone like objects containing caesium 137 that were found on Dunnet are not naturally occurring. It is just impossible unless a natural reactor was running in recent times...

[jjc]

The particles or radioactive stone like objects containing caesium 137 that were found on Dunnet are not naturally occurring. It is just impossible unless a natural reactor was running in recent times...
So you are accusing UKAEA of lying (http://www.ukaea.org.uk/press/2005/01_04_05.htm) then? :roll:

[Tristan]

The particles or radioactive stone like objects containing caesium 137 that were found on Dunnet are not naturally occurring. It is just impossible unless a natural reactor was running in recent times...
So you are accusing UKAEA of lying (http://www.ukaea.org.uk/press/2005/01_04_05.htm) then? :roll:

UKAEA did not claim that the particles or the first radioactive "stone-like object" were naturally occurring, only the sandstone. Many rocks, such as the granites used in Aberdeen construction, contain natural radiation.

[scotsboy]

Radioactivity in building materials is not restricted to ABZ. The majority of the radiation exposure received by the population is from natural radiation sources - far in excess of what they receive from discharges (legal or otherwise) from the nuclear industry.

[George Brims]

Lets not forget there is Uranium ore in the ground in Caithness, out near Altnabreac I believe, and also in Orkney. So there is going to be some occurence of higher than average naturally occuring radioactivity.

[Whitewater]

I remember about the naturally occuring activity in Caithness and Orkney. When Dounreay started up a serious look was taken at the possibility of recovering the naturally occuring uranium, but it was decided against as the market at that time was saturated and a town called "Mary Kathlene" in Queensland Australia, which was one of the main suppliers had to close its mine and became a virtual ghost town

[DrSzin]

Lets not forget there is Uranium ore in the ground in Caithness, out near Altnabreac I believe, and also in Orkney. So there is going to be some occurence of higher than average naturally occuring radioactivity.
Yes, but surely this naturally-occurring uranium isn't going to fission spontaneously in sufficient quantities to produce measurable Caesium 137 in a stone or particle on Dunnet Beach. Uranium almost always alpha-decays: the branching ratio for spontaneous fission of U-238 is less than one in a million; it's even smaller for U-235.

[smee]

U-238 that was a great film Dr.Z was it submarines?

[George Brims]

Well Dr Szin they didn't actually specify what type of radiation they were detecting from the "natural" particle. I assume since you mention Cs 137 that the Dounreay-derived particles tend to contain it?

I was simply making the point here that the level of radioactivity in the natural and Dounreay produced particlesi pretty much overlaps. Certainly that would tend to reassure me that the latter aren't going to kill me instantly should I encounter one. Of course I acknowledge that in this case, less = better.

[scotsboy]

Natural nuclear reactors :eek:

http://www.ocrwm.doe.gov/factsheets/doeymp0010.shtml

[DrSzin]

Well Dr Szin they didn't actually specify what type of radiation they were detecting from the "natural" particle. I assume since you mention Cs 137 that the Dounreay-derived particles tend to contain it?
Indeed they do.



I was simply making the point here that the level of radioactivity in the natural and Dounreay produced particlesi pretty much overlaps. Certainly that would tend to reassure me that the latter aren't going to kill me instantly should I encounter one. Of course I acknowledge that in this case, less = better.
Whoops, so you were. I have been away for a few weeks and I didn't read all the articles in this thread in sufficient detail. I mistakenly thought you were responding to Rheghead's comments about a natural reactor. Mea culpa.



U-238 that was a great film Dr.Z was it submarines?
Yeah, nuclear ones. It was made in 1998 and the theme tune was by a certain Irish band. Bono was 38 at the time.



Natural nuclear reactors

http://www.ocrwm.doe.gov/factsheets/doeymp0010.shtml
Interesting. But the Cs-137 from that reactor will be long gone, even if it was somehow transported to Dunnet Beach. :)

So, perhaps the world's first reactor was a prototype PWR without enough "P" to keep it going continuously.

[scotsboy]

I was thinking more of some fissile fossils lurking below Caithness somewhere :lol: