View Full Version : Depleted Uranium used as ballast in 747

15th Mar 2012, 09:44
Is it true?
A National Geographic docymentary tried to light up a 747 Corean cargo plane that crashed just outside Stansted airport a few minutes after take off.
The reason I am reporting this is that NTSB restricted the area not for the usual reasons only but additionally to another one.
That reason had to do with the depleted uranium used to rudder and wings as ballast.
Even though there was no leakage then I have to ask ...
Why do they use depleted uranium in public transportation? What is the purpose?
Is it safe from the point of radioactivity even though it is depleted uranium?
What about the safety of the crue which fly the planes around the clock?

15th Mar 2012, 09:50
Extensively used as elavator balance weights, certainly nothing new.

15th Mar 2012, 09:55
Why do they use depleted uranium in public transportation? What is the purpose?

Various components need to have weights to balance other bits. The smaller the size of a given weight the better, you can have better aerodynamics or more fuel or whatever. Depleted Uranium (DU) is very very dense (so very heavy for a given area). More recently other materials that are nearly as heavy but not so risky are used.

Is it safe from the point of radioactivity even though it is depleted uranium?

Yes, the material is depleted as in not as radioactive as natural uranium. That said there is a reasonable argument that any radiation is bad but in normal use it is a long way from people.
However...it is highly toxic so, in the simplest terms, if it breaks up or burns you don't want to be near it.

What about the safety of the crue which fly the planes around the clock?

The DU is safely locked away in the structure of the plane and as long as they don't crash they have nothing to worry about. If they do crash and it's bad enough to liberate the DU, then they are probably beyond caring anyway.

More interestingly is what happens to the fire crews and others who respond to the accident.

Al Murdoch
15th Mar 2012, 09:59
As long as the DU is not allowed into the environment (i.e. in a fire or crash) it is perfectly safe. Even if it is allowed into the environment, the effects of it are controversial as it is only very weakly radioactive. I think the emissions are mostly alpha particles and very, very low gamma rays, so you would need to ingest it for it to be dangerous.
It is used because its density is much, much higher than lead (by about 70% I think).

15th Mar 2012, 10:06
When did the B747 Classic first fly RPT? Early 1970 I think. Not really a new discovery.

Spent uranium - properly protected, meaning kept away from the environment and intact rather than dust - is quite benign. It is very useful in the area of flight control mass balance due to its high density.

15th Mar 2012, 10:10
Thank you all for your replies,
As for the 747 being a very old plane yes it is true but the corean 747 that crashed was a very modern 747 which means that DU is still being used today as it used to.
I had no idea about its density but it is clear now.
Thank you again all for your input.

15th Mar 2012, 10:12
I wouldn't be surprised of it was lurking near the bottom of the list of things to worry about in the case of a 747 going up in flames.

gas path
15th Mar 2012, 14:15
We had a visit from the NRPB, CAA and the AAIB (mob handed!) following the loss of PA103 asking how much DU could possibly be fitted. The answer being no idea! It was used to mass balance the elevators, outb'd ailerons IIRC upper rudder and could also be found bolted inside the outb'd nacelles to stop or rather damp out 'pod nod'. The latter depending on the mod state because the other option, would be to do away with the nacelle weights and fit a damn great block of Ti at the back of the exhaust plug.
I don't think it was ever recovered, more than likely scattered over several thousand square miles of Scotland.:(

15th Mar 2012, 17:50
An acquaintance of mine (Bob Lutz of GM/Chrysler fame) landed his L-39 Albatros gear-up several years ago. It was a particularly expensive gear-up because the L-39 has somewhere on its underside an ice-detection mechanism that uses strontium 90 as an active element. The strontium was spread for 1,500 feet down the runway, which required the involvement of a major hazmat team from the EPA.

15th Mar 2012, 18:08
In 1966 I was working on a laboratory scale process using Uranium Oxide as a catalyst. It came in small lumps which I cheerfully broke up into smaller lumps using a hammer, and generating dust. I never thought much about it, still don't to be honest. On the other hand the glass jars in which it was delivered were contained in metal cans and packed with cotton wool to reduce risk of breakage. No ill effects so far. :hmm:

15th Mar 2012, 21:12
During my time in the USAF I was based at Davis-Monthan. Every now and then, the local anti-war protesters would protest outside the main gate, particularly our use of depleted uranium rounds in the GAU-8. When the depleted uranium rounds are used against tanks and other armored vehicles, it would leave a dust cloud of depleted uranium, and soldiers who go looking for war trophies in the vehicles shortly after they are neutralized end up with long term /permanent illnesses.

15th Mar 2012, 21:34
The reason I am reporting this is that NTSB restricted the area not for the usual reasons only but additionally to another one.

Mes amis on the other side of la Manche wouldn't be very pleased to read that!

17th Mar 2012, 08:00
It is not just those looking for war trophies. Someone has to clear up the mess. We had to clear the road to Basra of burnt out armour holding up our advance. As you might imagine, it is not easy to shift dead MBTs out of the way without stirring up a fair amount of dust.

11th Dec 2017, 17:01

Provides some pictures.

12th Dec 2017, 04:00
Widely used, C-130, Jetstar, S-3, C-141, 747, 1011, DC-10, helicopter rotor blades. Since 1981 Boeing has supplied tungsten weights as replacements. Rescued the crews of two Wessex helos that clipped blades during formation flight, and finding the DU weights which had been spread about the countryside was of some concern to management. Wessex was a licence built H-34 which came into production in 1954, presumably they used DU since that time.

12th Dec 2017, 04:47
I believe the use of DU was discontinued for new commercial aircraft designs by Boeing back in the 1980's. Tungsten works just as well. But probably costs more.

12th Dec 2017, 21:09
I've worked around Boron, DU and composite structures all my life and the medical profession has yet to find a link within me.

I use to be nervous and jerky.

I'm not nervous anymore

12th Dec 2017, 21:32
Boeing switched to tungsten counterweights in 1981. They also provided updated tungsten weights for aircraft manufactured prior to 1981, although replacement of the DU weights was up to the aircraft owners and operators.

According to the NRC, a fire burning in excess of 600C is required to cause the DU weights to become a serious danger to firefighters.

12th Dec 2017, 23:20
As a very young apprentice I found some very heavy weights lieing around the hangar many years ago. The upholsterers used them to hold down glued joints on the furniture.
We used them as blocker bars when riveting. :eek:

12th Dec 2017, 23:24
Depleted uranium is not "spent" uranium. Depleted uranium is what's left of natural uranium when much of the fissile isotope, U-235 is removed while producing enriched uranium. Uranium is a natural element that appears in the earth's crust. Relax.

13th Dec 2017, 00:06
DU is not a radiation hazard. It is rather toxic and carcinogenic (which is why they feel the need to clean up battlefields), but then the same is true to a greater or lesser extent of quite a lot of the materials used in aviation and weaponry.

Dan Winterland
13th Dec 2017, 04:06
DU is about twice as heavy as lead.

13th Dec 2017, 05:52
They broke up some L-1011-200 at KGSO years back. I took it upon myself to go over to the scene and give them a heads up on the DU balance weights. The salvagers were completely unaware of the presence of DU. There were also not happy when they had to pay for special disposal. Considering all the scrapped-out aircraft, one wonders how much toxic material has been spread around. Certainly a greater threat than crashes as salvagers, in some cases, tend to be rather reckless.

14th Dec 2017, 06:05
DU is about twice as heavy as lead.

Didn't you mean density rather than weight? Actually DU is about 68% denser than lead.

14th Dec 2017, 06:33
tonytales, your story reminds me of the Goi‚nia accident (https://en.wikipedia.org/wiki/Goi‚nia_accident) "scavenging" accident involving abandoned hospital equipment, and a radioactive source (Caesium-137):
The Goi‚nia accident was a radioactive contamination accident that occurred on September 13, 1987, at Goi‚nia, in the Brazilian state of GoiŠs, after an old radiotherapy source was stolen from an abandoned hospital site in the city. It was subsequently handled by many people, resulting in four deaths. About 112,000 people were examined for radioactive contamination and 249 were found to have significant levels of radioactive material in or on their bodies

Source is partially broken
On September 16, Alves succeeded in puncturing the capsule's aperture window with a screwdriver, allowing him to see a deep blue light coming from the tiny opening he had created.[1] He inserted the screwdriver and successfully scooped out some of the glowing substance. Thinking it was perhaps a type of gunpowder, he tried to light it, but the powder would not ignite. The exact mechanism by which the light was generated was not known at the time the IAEA report was written, though it was thought to be either ionized air glow, fluorescence or Cherenkov radiation associated with the absorption of moisture by the source; similar blue light was observed in 1988 at Oak Ridge National Laboratory during the disencapsulation of a 137Cs source.[citation needed]

Source is sold and dismantled
On September 18, Alves sold the items to a nearby scrapyard. That night, Devair Alves Ferreira (the owner of the scrapyard) noticed the blue glow from the punctured capsule. Thinking the capsule's contents were valuable or even supernatural, he immediately brought it into his house. Over the next three days, he invited friends and family to view the strange glowing substance.

On September 21 at the scrapyard, one of Ferreira's friends (given as EF1 in the IAEA report) succeeded in freeing several rice-sized grains of the glowing material from the capsule using a screwdriver. Alves Ferreira began to share some of them with various friends and family members. That same day, his wife, 37-year-old Gabriela Maria Ferreira, began to fall ill. On September 25, 1987, Devair Alves Ferreira sold the scrap metal to a second scrapyard.

Mac the Knife
15th Dec 2017, 04:14
Another ridiculous thread about DU. Stupid scaremongering.

In significant doses DU is toxic, like many heavy metals (lead, arsenic etc.).

Radioactivity is minimal, much less than natural uranium.

Mercury is a lot more toxic, yet nobody gets their panties in a wad about it.

Bringing up the Goi‚nia accident is like comparing guppies to elephants and simply mischievous.

15th Dec 2017, 05:06
Mac, no nefarious or mischievous intent in my post, just thought it was an interesting aside after having my memory jogged by tonytales story, as it quite a rare and unusual set of circumstances.

I also agree that there are many far more common dangerous substance lurking in our environment compared to DU, both natural and man made.

Please forgive my frivolousness.

Ex Cargo Clown
17th Dec 2017, 01:55
Mercury is OK if it's in it's (0) oxidation state. I wouldn't drink it though , but have used it on an electrode, works lovely.

DU is normally OK, not really radioactive, unless you ingest a load of the dust, I think you'd be fine.

If worried keep a batch of EDTA on you.

17th Dec 2017, 13:17
DU is dangerous because of its Radiation. The so called Alpha Radiation does not Penetrate very well and it has not a significant reach, you can cut off Alpha Rays with a simple piece of Paper.
Problem ist when alpha radiating material gets into your body through any way, e.g. cuts in the palm. Then it does enriche at your bone marrow, depleting production of red blood cells.
Thats why it is to worry about this in cases of accidents with it (burning over 600 degees celsius effects it to spread, a chain reaction in any case is very unlikely due to missing of a moderator), beta and gamma radiation are at insatisfying [low] numbers anyway.


17th Dec 2017, 15:35
The warning notice provided in the maintenance manual for the Lockheed Jetstar with respect to the DU mass balance weights warns against cutting, grinding, drilling or otherwise disturbing the weights or their lead coating. Or words to that effect. I have always interpreted that as an admonition not to allow myself to be exposed to lead or DU particulates which may be associated with such activities.

I have heard that US customs has on occasion detected the radiation emanating from from DU balance weights and possibly certain smoke detector sensors during routine aircraft border entry inspections, but haven't experienced that myself. Apparently their equipment must be capable of detecting very low levels of radioactivity!

Despite any assurances to the contrary, depleted doesn't necessarily mean depleted completely! Get this stuff inside your body and I doubt it does one any good. In any case, I won't be knowingly exposing myself to DU or lead dust if I can help it.

17th Dec 2017, 19:06
Can anyone comment on the price of tungsten vs. DU? We used to use both in the oilfield business. Tungsten is even denser. I assume it is much more expensive otherwise it would be more commonly used. It is very inert.

17th Dec 2017, 22:57
DU cheaper to buy, but maybe not to produce end user products like counterweights. I suppose the cost analysis could possibly be skewed by how much government contractors like Boeing and Lockheed actually paid for the stuff! Cessna and Piper use lead.

I know that several if not most top-series NASCAR teams use tungsten for ballast in their race car frames and some still use lead. With what they're spending to go racing for dollars, what's a few hundred bucks for some tungsten ballast weights if it helps them if even only a little?

17th Dec 2017, 23:21
I know that several if not most top-series NASCAR teams use tungsten for ballast in their race car frames and some still use lead. With what they're spending to go racing for dollars, what's a few hundred bucks for some tungsten ballast weights if it helps them if even only a little? Latest spot price for Tungsten is about $2,000 per ounce - significantly more than gold - so you're not talking "a few hundred bucks" for tungsten ballast. Especially since NASCAR ballast is usually measured in tens (or even hundreds) of pounds. In other words, even the best funded NASCAR teams would be hard pressed to justify tungsten as simple ballast. Tungsten is however very, very strong so it's use can be justified for other reasons.
Back when I was still racing, the trick set-up in one class was to use tungsten weights in the clutch - it allowed the use of stronger springs for better clutch engagement. A clutch set of tungsten clutch weights - less than an ounce of the stuff - cost more than the clutch itself...
I wasn't able to find anything meaningful on the cost of DU, but since it is basically a byproduct with limited commercial usage I suspect it is relatively inexpensive.

18th Dec 2017, 00:22
No, tungsten is not quite that expensive! Machining it might be if you don't already have the necessary tools and equipment. Maybe you're thinking of that notoriously difficult to procure metal known a Unobtainium? :)


Product Description:
The Tungsten that we offer is used primarily in the NASCAR Racing Series. Our Tungsten is offered in block form and is used as ballast in the Frame Rails of Race Cars. In confined spaces where mass is required for balance, tungsten-based high density metals are often specified. Race cars can be given just the right "feel" or balance to maximize performance. Our Tungsten-based chassis weights are more than twice the density of steel and 50% heavier than lead. Tungsten based Race Car Ballast can be used to lower the center of gravity and/or be used to adjust the balance between the front and the rear. Our Tungsten based ballast block is machined to move easily into a NASCAR Frame Rail with threaded holes on both ends for easy movement and attachment to the Frame Rail. The Standard Block is 2-5/8" x 3-5/8" x 6" and weighs 35 lbs. Stock Car Steel & Aluminum is the leading supplier of Tungsten Block to the NASCAR Racing Series.

Tungsten Block: 2-5/8" x 3-5/8" x 6"
/ pc

18th Dec 2017, 00:55
Whoops, yes I stand corrected - when I looked at the price chart again it was per ton, not per pound - I guess I should have used my glasses :ugh:.
But I stand by the clutch weight statement - although much of that may have been due to the machining required...

18th Dec 2017, 02:31
Latest spot price for Tungsten is about $2,000 per ounce - significantly more than gold
Wow, really wish this were true as I've got a box full of old dart barrels (75-95% Wolfram) that I could use to buy a new flying toy or two....

(I appreciate your mistake upon reflection)

18th Dec 2017, 03:38
But I stand by the clutch weight statement - although much of that may have been due to the machining required...

Yeah, machining custom parts on a small scale is gonna get expensive. The NASCAR ballast weights could be cut from standard bar stock, then milled to the final dimensions and tapped for attachment to the NASCAR specified standard sized frame rails. It appears that suppliers of these weights only add a bit more than 100% above the bulk price of tungsten alloy to each ready to install unit. Prices vary somewhat, but bar stock seems to sell for around 50 bucks a kilo. At 16 kilos, each 35 lb ballast weight would seem to have about a thousand dollars of margin available for procurement, handling, machining and profit. If I was Gene Haas, Jack Roush or Rick Hendrick, I think I might buy the bar stock in bulk and have the machining done by my own people. But only if the tax guy says it's okay!

galaxy flyer
18th Dec 2017, 16:31

I have a passing acquaintance with Hendrick’s and, if there’s a way to make money, Rick knows it. Fascinating guy, wonderful collection of Corvettes.

19th Dec 2017, 04:17
I find the stories of how some of the NASCAR team owners rose to prominence rather inspiring. Hendrick has been through allot, both good and bad.

I wouln't mind seeing the 'vettes myself.

galaxy flyer
19th Dec 2017, 04:32
I think he has one model, usually unique in some way, of each year. Flight department is very nice and quite profitable. If only my wife would move!

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