[quote author="pdf27" date="1330865186"][quote author="Stovensen" date="1330831053"][quote author="pdf27" date="1330827235"]I'm a vacuum engineer working on a nuclear fusion reactor.[/quote]
pdf27, please read this:
https://www.hearth.com/econtent/index.php/forums/viewthread/38966/
Perhaps you have the knowledge to enlighten some worried minds over here.
The pellets I've burnt for the last four seasons are all made in eastern Europe. Right now I'm burning some pellets from Poland ( Barlinek). In fact these Barlinek pellets have the highest heat output and lowest ash I've experienced so far. But, if they contain even the smallest amount of Caesium 137, then I certainly WILL change to some of the pellets made here in DK ( more expensive, though ).[/quote]
The original article's long since expired, so I can't get any quantitative numbers to go on. A couple of things I can say though:
1) As isotopes go, it's relatively nasty - the salts are water-soluble and in the UK at least notification to the appropriate government agency is required for relatively small quantities (~3ng)
2) The actual concentration in Polish soil and in the pellets is likely to be massively below the legal limit*.
3) Any Caesium in the pellets (and I guarantee you that any pellets you buy WILL contain some Caesium, if in extremely low quantities) will be concentrated in the ash, with next to nothing going up the chimney.
Personally, I wouldn't worry about it at all - your ionising radiation dose rate from medical X-rays and cosmic rays when flying will dwarf any dose rate you get from a wood stove unless you're buying pellets made in Chernobyl. However, if you're worried there are two things you can do that will reduce your dose rate from incredibly insignificant to too small to measure:
1) Don't eat the ash
2) Don't spread the ash on any part of the garden you're growing things you intend to eat in.
In reality, Brazil Nuts are a far greater radiation risk than your wood pellets are likely to be (no joke - we've had a discussion at work recently where we decided that by the rules we work to if you've been eating Brazil Nuts and use a toilet, then technically you can't flush it without permission from Health Physics. We're thinking of waiting until the 1st of April to try explaining that one to them
)
* The legal limit is almost certainly many times below the safe limit. Legal limits are set by taking cancer rates in those whose exposure rate is known - in reality almost exclusively atom bomb survivors - and assuming that cancer rates drop off linearly with dose. We're almost certain that this isn't true and that human beings can cope quite well with low radiation doses - witness the fact that cancer rates in areas with high natural radiation levels are much the same as those with low levels - but it's a sensible precaution. This suspected safe level is divided by ~10 to give dose rates for registered radiation workers (whose health is followed for the rest of their lives - when I signed up for my current job I had to let them have full access to my medical records for the rest of my life). The radiation worker dose rate is divided by 20 in the UK to arrive at the permitted dose rate to the public.[/quote]
pdf27, first of all thanks for taking the time to answer the questions above. However, in order not to disturb this fine thread: "What is/was your occupation?" :zip: , I've made this new thread :coolsmile:
Did a little home work on this topic today, but nuclear physics is an exact science, so new questions pop up all the time... it's like diving into a very deep ocean of information :ahhh:
Let us try to focus then: How do I measure/monitor the amount of Becquerels/g in the ash produced by my Whitfield stove? A professional high precision Geiger-Müller counter is way too expensive for me, but in my search it turned out that perhaps less can do...
I searched on the name of the unit of radioactivity: Becquerel, named after the french physicist Henri Becquerel. In 1903, Becquerel shared the Nobel Prize in Physics with Pierre and Marie Curie "in recognition of the extraordinary services he has rendered by his discovery of spontaneous radioactivity".
As often happens in science, radioactivity came close to being discovered NEARLY FOUR DECADES EARLIER when the french photographer Abel Niepce de Saint-Victor observed that uranium salts exposed to light emitted penetrating radiation able to darken photographic emulsions. Like Becquerel, Niepce de Saint-Victor believed he was observing a kind of phosphorescence, but unlike Becquerel he never gave up that belief, nor did he succeed in persuading other scientists that the effect was important enough to warrant thorough investigation.
Bottomline: It was the invention of photography that led to the discovery of radioactivity. Without this "photo eye" that could sense and record the rays from a hitherto mysterious hidden world, mankind would most likely never have entered the atom age as we know it today.
So, if radioactivity could be discovered by means of photography, then it also must be possible to monitor the radiation level of my pellet ash by a simple dosimeter made of some black and white negativestrips put in a small opaque plastic box.
On the developed negative, the alpha particles leave some traces that are clearly visible in a microscope. It should be possible to count them, thus getting a rather exact information of the radiation level. However, some sort of calibration, based on a known source of radiation, is needed. The faculty of physics on a nearby university may be helpful in this matter.
How to make a simple dosimeter:
http://www.instructables.com/id/Quick-and-Dirty-Film-Badge-Dosimeter/
Is the radiation from Caesium 137 only particle radiation, or is it also gamma radiation? and is the negative based dosimeter capable of sensing/recording gamma rays as well? I don't know.
BTW, interesting info about the brazil nuts. I've ate a lot of these through the years. Now I'm sceptic... I've just read that the radiation level of brazil nuts is about 1000 times higher than that of normal food :ahhh:
pdf27, please read this:
https://www.hearth.com/econtent/index.php/forums/viewthread/38966/
Perhaps you have the knowledge to enlighten some worried minds over here.
The pellets I've burnt for the last four seasons are all made in eastern Europe. Right now I'm burning some pellets from Poland ( Barlinek). In fact these Barlinek pellets have the highest heat output and lowest ash I've experienced so far. But, if they contain even the smallest amount of Caesium 137, then I certainly WILL change to some of the pellets made here in DK ( more expensive, though ).[/quote]
The original article's long since expired, so I can't get any quantitative numbers to go on. A couple of things I can say though:
1) As isotopes go, it's relatively nasty - the salts are water-soluble and in the UK at least notification to the appropriate government agency is required for relatively small quantities (~3ng)
2) The actual concentration in Polish soil and in the pellets is likely to be massively below the legal limit*.
3) Any Caesium in the pellets (and I guarantee you that any pellets you buy WILL contain some Caesium, if in extremely low quantities) will be concentrated in the ash, with next to nothing going up the chimney.
Personally, I wouldn't worry about it at all - your ionising radiation dose rate from medical X-rays and cosmic rays when flying will dwarf any dose rate you get from a wood stove unless you're buying pellets made in Chernobyl. However, if you're worried there are two things you can do that will reduce your dose rate from incredibly insignificant to too small to measure:
1) Don't eat the ash
2) Don't spread the ash on any part of the garden you're growing things you intend to eat in.
In reality, Brazil Nuts are a far greater radiation risk than your wood pellets are likely to be (no joke - we've had a discussion at work recently where we decided that by the rules we work to if you've been eating Brazil Nuts and use a toilet, then technically you can't flush it without permission from Health Physics. We're thinking of waiting until the 1st of April to try explaining that one to them
)* The legal limit is almost certainly many times below the safe limit. Legal limits are set by taking cancer rates in those whose exposure rate is known - in reality almost exclusively atom bomb survivors - and assuming that cancer rates drop off linearly with dose. We're almost certain that this isn't true and that human beings can cope quite well with low radiation doses - witness the fact that cancer rates in areas with high natural radiation levels are much the same as those with low levels - but it's a sensible precaution. This suspected safe level is divided by ~10 to give dose rates for registered radiation workers (whose health is followed for the rest of their lives - when I signed up for my current job I had to let them have full access to my medical records for the rest of my life). The radiation worker dose rate is divided by 20 in the UK to arrive at the permitted dose rate to the public.[/quote]
pdf27, first of all thanks for taking the time to answer the questions above. However, in order not to disturb this fine thread: "What is/was your occupation?" :zip: , I've made this new thread :coolsmile:
Did a little home work on this topic today, but nuclear physics is an exact science, so new questions pop up all the time... it's like diving into a very deep ocean of information :ahhh:
Let us try to focus then: How do I measure/monitor the amount of Becquerels/g in the ash produced by my Whitfield stove? A professional high precision Geiger-Müller counter is way too expensive for me, but in my search it turned out that perhaps less can do...
I searched on the name of the unit of radioactivity: Becquerel, named after the french physicist Henri Becquerel. In 1903, Becquerel shared the Nobel Prize in Physics with Pierre and Marie Curie "in recognition of the extraordinary services he has rendered by his discovery of spontaneous radioactivity".
As often happens in science, radioactivity came close to being discovered NEARLY FOUR DECADES EARLIER when the french photographer Abel Niepce de Saint-Victor observed that uranium salts exposed to light emitted penetrating radiation able to darken photographic emulsions. Like Becquerel, Niepce de Saint-Victor believed he was observing a kind of phosphorescence, but unlike Becquerel he never gave up that belief, nor did he succeed in persuading other scientists that the effect was important enough to warrant thorough investigation.
Bottomline: It was the invention of photography that led to the discovery of radioactivity. Without this "photo eye" that could sense and record the rays from a hitherto mysterious hidden world, mankind would most likely never have entered the atom age as we know it today.
So, if radioactivity could be discovered by means of photography, then it also must be possible to monitor the radiation level of my pellet ash by a simple dosimeter made of some black and white negativestrips put in a small opaque plastic box.
On the developed negative, the alpha particles leave some traces that are clearly visible in a microscope. It should be possible to count them, thus getting a rather exact information of the radiation level. However, some sort of calibration, based on a known source of radiation, is needed. The faculty of physics on a nearby university may be helpful in this matter.
How to make a simple dosimeter:
http://www.instructables.com/id/Quick-and-Dirty-Film-Badge-Dosimeter/
Is the radiation from Caesium 137 only particle radiation, or is it also gamma radiation? and is the negative based dosimeter capable of sensing/recording gamma rays as well? I don't know.
BTW, interesting info about the brazil nuts.
I've ate a lot of these through the years. Now I'm sceptic... I've just read that the radiation level of brazil nuts is about 1000 times higher than that of normal food :ahhh:
