Why is there depleted uranium on a commercial aircraft?

Question

I was watching a show about disassembling a 747 and they briefly stated that they had to carefully remove the depleted uranium. What use does the uranium have on a commercial aircraft?

Answer 1

For many years, aircraft manufacturers have used "depleted" uranium to balance ailerons, rudders, and elevators on certain jet aircraft and rotor blades on certain helicopters.  Uranium is 1 1/2 times as dense as lead and is the heaviest naturally occurring metal.  According to a 1983 McDonnell Douglas Customer Service First Quarter publication, only "depleted" uranium is used, which means it has been processed to remove most of its uranium 235, the most highly radioactive form used in nuclear powerplants.  The remaining uranium 238 emits only low-level alpha radiation.  While the depleted uranium normally poses no danger, it is to be handled with caution.  The main hazard associated with depleted uranium is the harmful effect the material could have if it enters the body.  If particles are inhaled or digested, they can be chemically toxic and cause a significant and long-lasting irradiation of internal tissue.  Depleted uranium is slightly radioactive.  To minimize radiation hazards, depleted uranium balance weights are 100 percent cadmium plated during the manufacturing process.  If the cadmium plating is intact, normal handling of the parts is considered to be non-hazardous and no special precautions are recommended.  The use of radioactive materials in many every day applications is not at all unusual.  For example, tritium, a radioactive form of hydrogen, is used in self-luminous signs, such as exit signs, and watches.  Thorium, which has a radiation activity level comparable to depleted uranium, is used in making gas mantels for lanterns, electronic equipment, and high-quality optical lenses for cameras and overhead projectors.  Also, smoke detectors contain americium 241, a radioactive material.

On arrival at accident scenes of aircraft suspected of containing balance weights made of depleted uranium, determine if balance weights have been damaged or lost their cadmium plating coating.  Request specialized assistance if balance weights have been damaged or lost their cadmium plating.  No penetration of the plating is allowed.

Answer 2

as i think for the thunderstoms

Answer 3

I saw it too and was surprised they used it on a commercial aircraft.  It was obviously used in this case for balancing the weight of outer wingtips when it was extended during an upgrade of the original wing.  The B-47 had wingtips made of solid lead.  

Although it's depleted of most of it's radioactivity, it's not all that dangerous.  It's used for bullets on the warthog aircraft because it the densist substance known. It can be readily handled without special equipt.. It's high weight for it's size is probably why it was used on the 747.  It's probably the ideal substance to use when you need to add a lot of weight while taking up a minumum amount of room.

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Answer 4

Such planes have as much as 3300 pounds of depleted uranium. It's used as counterweights on the wing flaps and rudders.  Depleted uranium is used for this purpose because it's very heavy and dense, so it does its job with a tiny volume of material.

It would take a very large hunk of steel, taking up valuable scarce space, to be as heavy as uranium.

The second reason is that depleted uranium was very cheap back then (these planes were built decades ago).  The government was giving the stuff away like candy to get rid of it.

Boeing now uses tungston instead of urnaium, because tungston is even heavier than uranium, and much safer to handle.

Answer 5

I agree with the answer from PS, except that uranium is heavier than tungsten!  Uranium is the heaviest naturally occurring element.

Depleted uranium is essentially U-238 remaining after the isotope U-235 has been separated from the naturally occuring "blend" of 99.7% 238 and 0.7% 235.  235 is fissionable and therefore used in nuclear reactors, leaving 238 as a by-product.  The half life of U-238 is 4.5 billion years so its barely radioactive.