Depleted Uranium
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From: The Daylight Saving Free Zone
Depleted Uranium
In light of past news regarding the health hazard caused by the use of Depleted Uranium in modern weaponry (secondary hazard that is).
It has occurred to me that at least one helicopter manufacturer uses DU in its M/Rotor balance weights (I’m 99% sure). Maintenance engineer/mechanics, would come into physical contact with these weights on a regular basis during the course of normal maintenance, not even including hub balancing. Also pilots, when doing their preflights would most likely come into physical contact with these weights, as well.
I guess I should first be asking, can anybody confirm that DU is in fact the material used in any of these balance weights? Then if so, how safe is it to handle?
It may be a subject that little is known, but I feel it could be an important question to ask.
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sprocket: .. No standards? Nooo problems!
[This message has been edited by sprocket (edited 19 April 2001).]
It has occurred to me that at least one helicopter manufacturer uses DU in its M/Rotor balance weights (I’m 99% sure). Maintenance engineer/mechanics, would come into physical contact with these weights on a regular basis during the course of normal maintenance, not even including hub balancing. Also pilots, when doing their preflights would most likely come into physical contact with these weights, as well.
I guess I should first be asking, can anybody confirm that DU is in fact the material used in any of these balance weights? Then if so, how safe is it to handle?
It may be a subject that little is known, but I feel it could be an important question to ask.
------------------
sprocket: .. No standards? Nooo problems!
[This message has been edited by sprocket (edited 19 April 2001).]
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I believe you are correct.
However, my understanding is that unless you ingest DU you won't have a problem because the radiation is very weak and won't penetrate human skin, especially if encased inside a blade. The problem comes where there is a dust of DU allowing ingestion to occur inadvertantly.
Don't swallow any tip weights!
However, my understanding is that unless you ingest DU you won't have a problem because the radiation is very weak and won't penetrate human skin, especially if encased inside a blade. The problem comes where there is a dust of DU allowing ingestion to occur inadvertantly.
Don't swallow any tip weights!
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Skycop, I hear what you say, but is it time to cover with a sheet of lead the old wedding tackle ? or because its nearer to our heads will it give us just a Tad of Altzimers, is there a list of Helios with this little extra somthing in their blades! could flying one of these Du types give the pilot Danger money?
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Actually I think you are safe inside the cockpit.
As you know, the massive centrifugal forces once the blades start rotating will throw all the radiation outwards. Beware of any manoeuvres causing re-circulation though.
The lead underpants might be useful if you haven't finished procreating but as you know, we helicopter pilots seldom get our leg over anyway due to the lack of a leg-opening flash uniform to wear, and the smell of AVTUR puts the ladies right off.
Hope this helps to alleviate your worries.
But keep the windows shut just in case, eh!
As you know, the massive centrifugal forces once the blades start rotating will throw all the radiation outwards. Beware of any manoeuvres causing re-circulation though.
The lead underpants might be useful if you haven't finished procreating but as you know, we helicopter pilots seldom get our leg over anyway due to the lack of a leg-opening flash uniform to wear, and the smell of AVTUR puts the ladies right off.
Hope this helps to alleviate your worries.
But keep the windows shut just in case, eh!
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I assume you mean the B412, Sprocket. I think I agree with Skycop: just don't eat it! As to other radiation hazards,I don't believe that they are significant. Why don't you get somebody to use their clever medical kit to check and reassure you all?
Meanwhile, I'll just sit here glowing in the bask of times remembered...click click...click click click....buzzzzzzzz
Meanwhile, I'll just sit here glowing in the bask of times remembered...click click...click click click....buzzzzzzzz
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Is depleted uranium also used in FLIR systems as a counter weight? Can it be dangerous if the aircraft is involved in an accident. I know that during the recent investigation into an A4 crash at Nowra NAS, Australia, the site was handed over to the scientists for a day so that DU could be found and cleaned up.
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And what about the radioactive materials in the old BIM indicators on the S61? . I'm sure all the US attorneys are licking their lips at the prospect of class action law suits. I think the best thing is for us to live in a lead shielded hyperbaric chamber just in case we get exposed to anything nasty.
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From: The Daylight Saving Free Zone
Multp, yes I was referring to the 412.
Well, I left pprune and went searching on the ‘world wide wasteland’ and come up with a lot of words on the subject. Most of it, either from military advice sites or environmental sites. Heres a few examples ….
My only concern out of that statement is, that the balance weights on the 412 don’t appear to be encased in ‘thin metal jackets”, (unless it’s in the form of what looks like cadmium plating) or “sealed inside several inches of regular steel armour”
Do any ex Mil. guys know what these thin metal jackets look like?
I have not seen any warnings/instructions regarding the disposal of the 412 balance weights.
Apparently, Boeing used DU on flight control counterweights in its earlier model 747’s, but not on later models.
I understand that DU does emit a certain amount of radioactivity. The above statement says, It is “40 percent less radioactive than natural uranium” Which means it is just over half as radioactive (60%) as natural uranium. Still sounds like a fair amount of clicking is still going to happen if the old Geiger counter comes nearby.
It seems that the general consensus is that DU, in the form of products like the 412 balance weights and ballast in airliners, is safe to be in contact with. I guess while you’re in the cockpit and the DU is outside, there would be no problems.
If, for some strange reason, your cyclic grip was made of the stuff, would you be of the same opinion? … Vfrpilotpb, a lead box wouldn’t be such a bad idea!
I know it’s a ridiculous scenario, but how safe would you feel? Remembering that DU is stated as being about 60% radioactive as Natural Uranium
I am not entirely convinced that it is completely safe to handle, but without an independent opinion apart from Military or Environmental organisations, how does one really know?
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sprocket: .. No standards? Nooo problems!
Well, I left pprune and went searching on the ‘world wide wasteland’ and come up with a lot of words on the subject. Most of it, either from military advice sites or environmental sites. Heres a few examples ….
<font face="Verdana, Arial, Helvetica" size="2">“Unfired depleted uranium munitions are encased in thin metal jackets that seal in alpha and beta particles, and allow only extremely slight gamma emissions, which fall well below regulatory health and safety limits. Similarly, depleted uranium panels used in tank armour pose no real health risk because the depleted uranium is sealed inside several inches of regular steel armour.”</font>
Do any ex Mil. guys know what these thin metal jackets look like?
<font face="Verdana, Arial, Helvetica" size="2">”Depleted uranium produced as a by-product of uranium enrichment is classified as radioactive and toxic waste and it is subjected to numerous regulations for handling and disposal.”</font>
<font face="Verdana, Arial, Helvetica" size="2">“Depleted uranium is the by-product of the process for converting ("enriching") natural uranium for use as nuclear fuel or nuclear weapons. Depleted uranium is approximately 40 percent less radioactive than natural uranium. The depleted uranium used in armour-piercing munitions is also widely used in civilian industry, primarily for stabilizers in airplanes and boats.”</font>
I understand that DU does emit a certain amount of radioactivity. The above statement says, It is “40 percent less radioactive than natural uranium” Which means it is just over half as radioactive (60%) as natural uranium. Still sounds like a fair amount of clicking is still going to happen if the old Geiger counter comes nearby.
It seems that the general consensus is that DU, in the form of products like the 412 balance weights and ballast in airliners, is safe to be in contact with. I guess while you’re in the cockpit and the DU is outside, there would be no problems.
If, for some strange reason, your cyclic grip was made of the stuff, would you be of the same opinion? … Vfrpilotpb, a lead box wouldn’t be such a bad idea!
I know it’s a ridiculous scenario, but how safe would you feel? Remembering that DU is stated as being about 60% radioactive as Natural Uranium
I am not entirely convinced that it is completely safe to handle, but without an independent opinion apart from Military or Environmental organisations, how does one really know?
------------------
sprocket: .. No standards? Nooo problems!
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Skycop
Re. your comment: "...the massive centrifugal forces once the blades start rotating will throw all the radiation outwards."
It's been a long time since my O-Level Physics but don't radioactive particles move at or near the speed of light? If so, wouldn't this be more than adequate to overcome the outward velocity caused by centrifugal force? Should this be so then a pilot will in fact be surrounded by a source constantly emitting in his (and all other) directions for the duration of the flight.
One would assume that the relatively weak emissions plus the distance of the blade tips from the canopy would combine to negate any ill effects but is there an atomic physicist or even a hospital radiologist out there who could inform all of us better?
Re. your comment: "...the massive centrifugal forces once the blades start rotating will throw all the radiation outwards."
It's been a long time since my O-Level Physics but don't radioactive particles move at or near the speed of light? If so, wouldn't this be more than adequate to overcome the outward velocity caused by centrifugal force? Should this be so then a pilot will in fact be surrounded by a source constantly emitting in his (and all other) directions for the duration of the flight.
One would assume that the relatively weak emissions plus the distance of the blade tips from the canopy would combine to negate any ill effects but is there an atomic physicist or even a hospital radiologist out there who could inform all of us better?
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EGAC,
With regard to your second paragraph of questions;
Yes, yes and....er well, yes!
Sorry but you have fallen for the spoof part of my answer.
Actually, at least if my schooling and military NBC training were correct, alpha and beta emissions have a very short range and will be stopped by human skin, paper or very definitely by any metal case including a tip cap or blade skin. The problem comes when emitting material is ingested, resulting in the emissions coming into immediate contact with the insides of the body organs. Gamma radiation is difficult to stop (requiring the lead underpants or a few metres of concrete), but it is less harmful than alpha and beta.
Hope this clears up any misunderstanding.
SC
With regard to your second paragraph of questions;
Yes, yes and....er well, yes!
Sorry but you have fallen for the spoof part of my answer.
Actually, at least if my schooling and military NBC training were correct, alpha and beta emissions have a very short range and will be stopped by human skin, paper or very definitely by any metal case including a tip cap or blade skin. The problem comes when emitting material is ingested, resulting in the emissions coming into immediate contact with the insides of the body organs. Gamma radiation is difficult to stop (requiring the lead underpants or a few metres of concrete), but it is less harmful than alpha and beta.
Hope this clears up any misunderstanding.
SC
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Depleted Uranium has a half life of about 4.5 billion years. This means that the first decay in a long decay chain goes very slowly...1/2 of the DU decays every 4.5 billion years.
What this means is there are very few radioactive particles emitted. The first decay emits alpha particles (big and slow) that are stopped with a piece of paper or a few centimeters of air.
Many people counter this argument with the fact that the elements produced in the decay are more radioactive than U238. This is true however the elements are produced very slowly as well. All the by products have a half life that is substantially smaller than that of U238 so there is no significant buildup of other materials. The decay of the by products does include beta and gamma emissions, which take more than paper or a few centimeters of air to stop, but the rates of production are so low that even completely unshielded result in negligible radiation doses.
Am I saying this stuff is safe? Not at all. With enough quantity (much more than would be used as tip weights) the radiation dose could become a concern. In small quantities DU is highly toxic, same as most heavy metals. That is the big concern.
This is where ingestion is a factor. Any dust from this is not something to inhale. Wash hands if contacting it directly. I assume most of the stuff would be coated in a safe metal, as mentioned previously so dust or contact shouldn't be a concern.
The spinning of the blades won't produce any noticeable effect on whatever gamma emmisions (high energy photons) make it to the cockpit. Very little effect on beta particles (electrons), and a very small effect on alpha particles (helium nucleii), if any are even detected at the cockpit.
If there is any dust the spinning would help keep it away from the pilot. Recirculation would be bad but with the density of Uranium and the speed of the downwash, probably not a problem. The spinning would send the dust everywhere, diluting it and making it a very very small problem for everyone else, kinda like how we treat waste from hydrocarbon combustion (the solution to pollution is through distribution).
Long story short, if you don't touch it, don't worry about it.
Matthew.
[This message has been edited by heedm (edited 26 April 2001).]
What this means is there are very few radioactive particles emitted. The first decay emits alpha particles (big and slow) that are stopped with a piece of paper or a few centimeters of air.
Many people counter this argument with the fact that the elements produced in the decay are more radioactive than U238. This is true however the elements are produced very slowly as well. All the by products have a half life that is substantially smaller than that of U238 so there is no significant buildup of other materials. The decay of the by products does include beta and gamma emissions, which take more than paper or a few centimeters of air to stop, but the rates of production are so low that even completely unshielded result in negligible radiation doses.
Am I saying this stuff is safe? Not at all. With enough quantity (much more than would be used as tip weights) the radiation dose could become a concern. In small quantities DU is highly toxic, same as most heavy metals. That is the big concern.
This is where ingestion is a factor. Any dust from this is not something to inhale. Wash hands if contacting it directly. I assume most of the stuff would be coated in a safe metal, as mentioned previously so dust or contact shouldn't be a concern.
The spinning of the blades won't produce any noticeable effect on whatever gamma emmisions (high energy photons) make it to the cockpit. Very little effect on beta particles (electrons), and a very small effect on alpha particles (helium nucleii), if any are even detected at the cockpit.
If there is any dust the spinning would help keep it away from the pilot. Recirculation would be bad but with the density of Uranium and the speed of the downwash, probably not a problem. The spinning would send the dust everywhere, diluting it and making it a very very small problem for everyone else, kinda like how we treat waste from hydrocarbon combustion (the solution to pollution is through distribution).
Long story short, if you don't touch it, don't worry about it.
Matthew.
[This message has been edited by heedm (edited 26 April 2001).]
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From: The Daylight Saving Free Zone
CTD, Thanks for that clarification,
Definitely much to my relief as those weights total over 100lbs in mass ….. But, the weights I was originally referring to, are the Hub Balance Weights. These are attached to the inboard facing lugs of the SPA brackets when required during rotor balancing. It is still my understanding that these are made from Depleted Uranium. There can be up to a couple of pounds of weight on the average 412 hub.
These weights are handled by the engineers/mechanics during balance adjustments of the main rotor and no doubt that pilots, sometimes when preflighting the rotor, will come into physical contact with these weights.
heedm, Skycop: I will heed your advice. There is no dust problem with the weights I’ve handled.
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sprocket: .. No standards? Nooo problems!
<font face="Verdana, Arial, Helvetica" size="2">The droop stop weights are made from alloy steel.
The pendulum (SPA) dampers, product balance and tail rotor balance weights are made from tungsten.</font>
The pendulum (SPA) dampers, product balance and tail rotor balance weights are made from tungsten.</font>
These weights are handled by the engineers/mechanics during balance adjustments of the main rotor and no doubt that pilots, sometimes when preflighting the rotor, will come into physical contact with these weights.
heedm, Skycop: I will heed your advice. There is no dust problem with the weights I’ve handled.
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sprocket: .. No standards? Nooo problems!
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From: The Daylight Saving Free Zone
CTD, relaxed considerably.
Now I’ll have to find the source of my DU rumour and snuff it out.
Vfr. yup, I think there are a few of Uncle Sam’s men, that got the dust as well, from “friendly fire’.
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sprocket: .. No standards? Nooo problems!
Now I’ll have to find the source of my DU rumour and snuff it out.
Vfr. yup, I think there are a few of Uncle Sam’s men, that got the dust as well, from “friendly fire’.
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sprocket: .. No standards? Nooo problems!
