Radioisotopes Are Your Friends

[Benm]

Rules are rules indeed, and there is a perfectly fine level for occupational hazard to radiation over longer periods of time. For radiological workers in europe this is 20 mSv/year, in the US i believe it's 50 mSv/year.

So wear a dosimeter whilst at work and have that read out on a regular basis.

The results from this can be quite funny though. I remember a case of a company that worked with radiolabeled compounds and all staff were to wear such dosimeters when at work. The person that got the highest dose was the CEO of the company that never did any work with the materials, but happened to fly around quite a bit wearing the dosimeter.

This dosimeter-check idea works really well, unless you are at risk of ingesting or inhaling radioactive substances. When it comes to that i'd rather move around a well documented big angry cobalt source than some radium-painted dials that are broken with chips coming off. The worst thing about the latter is that it can be very difficult to assess the actual exposure even in hindsight.

 

[Seoul_lasers]

Rules are rules indeed, and there is a perfectly fine level for occupational hazard to radiation over longer periods of time. For radiological workers in europe this is 20 mSv/year, in the US i believe it's 50 mSv/year.

So wear a dosimeter whilst at work and have that read out on a regular basis.

The results from this can be quite funny though. I remember a case of a company that worked with radiolabeled compounds and all staff were to wear such dosimeters when at work. The person that got the highest dose was the CEO of the company that never did any work with the materials, but happened to fly around quite a bit wearing the dosimeter.

This dosimeter-check idea works really well, unless you are at risk of ingesting or inhaling radioactive substances. When it comes to that i'd rather move around a well documented big angry cobalt source than some radium-painted dials that are broken with chips coming off. The worst thing about the latter is that it can be very difficult to assess the actual exposure even in hindsight.

Having had my gamma scout on an aircraft before it's quit amazing how activity increases as you go up. On one transpacific flight from Chubu-kokusai Intl. (Nagoya) to San Francisco Intl. Readings were 300-400CPM steadily at normal cruising altitude.

Depending on where you sit in the aircraft the readings could be skewed a bit by the 2 large counter weights that are made from DU on the plane.

True about the Radium paint... it's nasty stuff and easy comes off due to it's intense Alpha emissions which break down the ZnS(Cu/Ag) crystal structure.

 

[Benm]

That mostly shows how safe radiological work often is.

The exposure from a few dozen flights a year will not harm you, but staff that didn't fly at all managed to say even below those levels just doing their work.

One issue is that we really don't know much about the effects of chronic exposure. The effects of acute exposure to doses in the order of 1 sievert are fairly well documented and generally not good news. But we don't have much human data on how, for example, exposure to 1 sievert a year gradually spread out over that year would affect someone.

There would be no acute radiation poisoning at all, but there probably would be some loss of life expectancy in the long run. To what degree is actually unknown since we don't put large numbers of people under such circumstances so there simply is a lack of data.

Animal test data aren't that useful either since they don't compare very well. Things like lab rats have a very short natural lifespan compared to humans. If something were to kill a rat in 10 years you would not see it because they'd all have died of other/natural causes well before that period of time elapsed.

 

[Seoul_lasers]

That mostly shows how safe radiological work often is.

The exposure from a few dozen flights a year will not harm you, but staff that didn't fly at all managed to say even below those levels just doing their work.

One issue is that we really don't know much about the effects of chronic exposure. The effects of acute exposure to doses in the order of 1 sievert are fairly well documented and generally not good news. But we don't have much human data on how, for example, exposure to 1 sievert a year gradually spread out over that year would affect someone.

There would be no acute radiation poisoning at all, but there probably would be some loss of life expectancy in the long run. To what degree is actually unknown since we don't put large numbers of people under such circumstances so there simply is a lack of data.

Animal test data aren't that useful either since they don't compare very well. Things like lab rats have a very short natural lifespan compared to humans. If something were to kill a rat in 10 years you would not see it because they'd all have died of other/natural causes well before that period of time elapsed.

Taken directly from NRC (US Nuclear regulatory body)

Natural and man-made radiation may come from different sources, but both affect us in the same way. The NRC does not regulate background radiation. But the NRC does require its licensees to limit exposure to members of the public to 100 mrem (1 mSv) per year above background. Exposure to adults working with radioactive materials must be below 5,000 mrem (50 mSv) per year. NRC regulations and radiation exposure limits are contained in Title 10 of the Code of Federal Regulations, Part 20.

In Canada I believe it is same dose rate for public as it is in the US. I think not too long ago we were 2mSv/annum when I worked as an FSWEP at dockyard.


Our average in Canada for general public is 1.77mSv/annum

Video below shows how powerful a large Co60 source can be even from over 1m distance.

 

[paul1598419]

Just saw this, Mac. Thanks for bringing the whole article to our attention. I always learn a little more every time you post.

 

[Benm]

Taken directly from NRC (US Nuclear regulatory body)



In Canada I believe it is same dose rate for public as it is in the US. I think not too long ago we were 2mSv/annum when I worked as an FSWEP at dockyard.


Our average in Canada for general public is 1.77mSv/annum

Video below shows how powerful a large Co60 source can be even from over 1m distance.

Well, it demonstrates how radioactivity causes camera pixels to go hot, and usually this means you are in a very dangerous situation. It's not quanititative though, and probably depends on the camera as well.

If you are ever filming something that causes this phenomenon get the heck out of there regardless. It could be .1 sV/hr, it could 100 sV/hour, but it all cases reason to leave unless you have to be there and know what you're doing (which you are not when you rely on camera noise to gauge radiation levels).

Acceptable additonal exposure for the general public will vary by country, but also by how necessary the application and exposure actually are. A -very rough- estimate of the relation between radiation exposure and death of cancer later on is 1 sievert (deliverd slowly, say over a year) increases the risk by 5 percent.

So for 1 mSv that would be something around 0.0005 percent or 50 per million. So explosing an entire towns population to an additional 1 mSv of radiation over background for a full year would basically kill 5 people in that town.

That's what you get for large numbers. Radiological workers are permitted to receive 20 or 50 mSv/yr depending on where they work. This would give a risk of something like 0.25% of killing that worker at the upper level, but most radiological workers receive far lower doses. Actually, most receive nothing detectable above the natural background at all.

To put it in a bit of perspective: one full body CT scan would give you in the order of 20 mSv. So woud staying aboard the ISS for 6 weeks.

Then again there are places with very high background radiation. In western Iran there is a town with a background of 130 mSv/year, mostly from isotopes bubbling up there and also being used in construction materials and such. Living there is roughly as dangerous that on the ISS in terms of radiation exposure, and about 5 times worse than spending you life at cruise altitude in a jet (i'm not sure if anyone does, but if you plan on, perhaps reconsider ).

 

[Seoul_lasers]

Well, it demonstrates how radioactivity causes camera pixels to go hot, and usually this means you are in a very dangerous situation. It's not quanititative though, and probably depends on the camera as well.

If you are ever filming something that causes this phenomenon get the heck out of there regardless. It could be .1 sV/hr, it could 100 sV/hour, but it all cases reason to leave unless you have to be there and know what you're doing (which you are not when you rely on camera noise to gauge radiation levels).

Acceptable additonal exposure for the general public will vary by country, but also by how necessary the application and exposure actually are. A -very rough- estimate of the relation between radiation exposure and death of cancer later on is 1 sievert (deliverd slowly, say over a year) increases the risk by 5 percent.

So for 1 mSv that would be something around 0.0005 percent or 50 per million. So explosing an entire towns population to an additional 1 mSv of radiation over background for a full year would basically kill 5 people in that town.

That's what you get for large numbers. Radiological workers are permitted to receive 20 or 50 mSv/yr depending on where they work. This would give a risk of something like 0.25% of killing that worker at the upper level, but most radiological workers receive far lower doses. Actually, most receive nothing detectable above the natural background at all.

To put it in a bit of perspective: one full body CT scan would give you in the order of 20 mSv. So woud staying aboard the ISS for 6 weeks.

Then again there are places with very high background radiation. In western Iran there is a town with a background of 130 mSv/year, mostly from isotopes bubbling up there and also being used in construction materials and such. Living there is roughly as dangerous that on the ISS in terms of radiation exposure, and about 5 times worse than spending you life at cruise altitude in a jet (i'm not sure if anyone does, but if you plan on, perhaps reconsider ).

Yup, point of video was to show a big angry Co60 source irradiating a camera.
The camera died after the video was recorded.
The source in question was from a gamma irradiator used to
Irradiate food and boxes. Activity of the given source is about 200TBq, not something you'd survive.
About that town in Iran, people who live there have developed a natural immunity to the high background. The town sits on a large natural deposit of Uranium.

 

[Benm]

Yeah, that cobalt source is intended to kill. If it's used in food or goods processing it's likely designed to kill insects or even bacteria when it comes to food. Those are pretty hardy when it comes to radiation exposure, afaik doses in the order of a kGy are used.

I'm not even sure you'd live long enough to tell, but it would probably be so intense you could litterally feel the heat at that point. Also, your eyes might actually pick up hot spots like the camera does.

As far as immunity goes i'm not overly convinced yet, but that's mostly due to lack of a control group. It's not the richest place in the world by any measure and medical care probably is sub-standard to western countries. Life expectency is no measure for those reason.

It's not so insanely radioactive that visiting the region would be very dangerous either - staying there for a few days or weeks would probably not give you cancer. Even staying there for a couple of years would only yield a few percent of causing cancer, but i suspect it's not that popular a destination for expats regardless of what the geiger counter screams

 

[Seoul_lasers]

It's a bit old I know...

Just found a video clip showing a density meter using 100mCi of Cs137.
This is used to gauge rock thickness.

Notice the detector the technician is using. That's an Ion chamber detector.
These are typically used when the radiation fields are over a few mSv/hr or greater. (R/hr).

 

[paul1598419]

That was interesting. Thank you for bringing to us. I would have like to have seen what happened after it was inserted into the well and the measurement taken.

 

[weirdmeister]

uh ..how sad...david hahn passed away ..haven´t noticed this :yabbem:

ive got a vintage counter dp63a ..that has a radium paint dial , i measure 10mr/h behind the thick glas..havent dissassembled yet

also inside: B-8 Sr90 source (100mrad/h)

another source: DP-2 , Sr-90 as well, ~6 rad/h

(hi mac )

 

[Seoul_lasers]

Diving in a University research nuclear reactor while it's running.

No, this is not a new extreme sport. :wave:

This video is by far the best video footage I've seen of a Nuclear reactor on startup, EVER. Note the white flashes as high energy Gamma photons strike the Gopro's CCD sensor.

 

[paul1598419]

Are you sure there was a diver involved in this video? I got the impression it was a remote set up as the stability of the camera was much better than a person would be able to accomplish. I noticed that even after the initial start up, the core continued to become brighter over time. This was obvious if you advance the video a minute at a time further into the reactor's running. It is pretty cool watching even this small reactor start and run.

 

[Seoul_lasers]

Are you sure there was a diver involved in this video? I got the impression it was a remote set up as the stability of the camera was much better than a person would be able to accomplish. I noticed that even after the initial start up, the core continued to become brighter over time. This was obvious if you advance the video a minute at a time further into the reactor's running. It is pretty cool watching even this small reactor start and run.

Right you are. But it is a pretty clear video. Amazingly clear.
This is just a GoPro on a telescopic pole (sigh) . Though there are Nuclear divers this video is not to do with them. :yabbem:

 

[Jhop]

David Charles Hahn Obituary – "The Radioactive Boy Scout" Dead at 39
October 30, 1976 - September 27, 2016 Shelby Township, Michigan


David Hahn From Wikipedia


The Radioactive Boy Scout - When a teenager attempts to build a breeder reactor
Article From the November 1998 issue of Harper’s Magazine By Ken Silverstein


Radioactive Boy lives! Student who sparked panic in 1996 after he built a nuclear reactor in his shed survived and now wants to invent a 100-year light bulb... out of 'safe' irradiated paint
By Laura Collins In Utica, Michigan
Published: 15:15 EST, 13 November 2013 | UPDATED: 11:33 EST, 14 November 2013

Published on Nov 26, 2013
Nucleaire scouting boy Part 1 from David Hahn

Published on Nov 26, 2013
Nucleaire scouting boy Part 2 from David Hahn

This was a very interesting read! The radioactive Boy Scout. What a fascinating guy that David Hahn was. So sad he was cut short at 39

 

[WizardG]

uh ..how sad...david hahn passed away ..haven´t noticed this :yabbem:

ive got a vintage counter dp63a ..that has a radium paint dial , i measure 10mr/h behind the thick glas..havent dissassembled yet

also inside: B-8 Sr90 source (100mrad/h)

another source: DP-2 , Sr-90 as well, ~6 rad/h

(hi mac )

6 rad/hr? Be careful with that one!