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Radiation Exposure from Depleted Uranium Counterweights

(last updated 17 May 2002)

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Source Term

"DU counterweights have been used primarily in wide-body aircraft on rudders, outboard ailerons (wing assembly), and outboard elevators (tail assembly). Counterweights come in a variety of weights and shapes, and numerous weights and shapes are used in some aircraft. The DU counterweight can range in weight from 0.23 to 77 kg."
"Some aircraft used for military and cargo also use DU counterweights; these include the Lockheed C-130 and C-141, Jetstar, and S-3A. The Boeing Company produced helicopters utilizing DU as a rotor tip weight prior to 1979. These weights consisted of small 0.22-kg triangular weights. One to three weights were installed per blade. Virtually all of the Boeing helicopters manufactured prior to 1979 have had their blades replaced with composite blades that do not contain DU weights." [NUREG-1717]
Use of DU Counterweights in U.S. Domestic Aircraft
Aircraft TypeManufacturerAircraft Number Owned by Domestic Carriers a,bTotal Weight of Counterweights per Aircraft (kg)
DC10McDonnell-Douglas168~ 1,000 c
L1011Lockheed60~ 680 c
B747Boeing202~ 850 d
a Number of aircraft owned by domestic carriers that are members of the Air Transport Association (ATA, 1999).
b A reasonable estimate is that 50% of these aircraft still contain DU counterweights. Phone call J. Taylor, Starmet CMI, Barnwell, SC, August 1999.
c Phone call, E. Lanchester, Quality Assurance Department, Nuclear Metals, Inc., Concord, MA, August 1996.
d Phone call, D. Barbour, Project Manager, Depleted Uranium Programs, Philotechnics, Oak Ridge, TN, October 1999.
Source: [NUREG-1717] Table 3.17.1

"In many cases, tungsten alloy counterweights have replaced DU counterweights in aircraft. Since 1981, The Boeing Company has provided customers with tungsten replacement counterweights, and tungsten counterweights have been installed in new Boeing 747 aircraft. Tungsten equivalents have been sent as spares since 1981 (Gallacher, 1994). In 1988, McDonnell-Douglas discontinued using DU counterweights and began using tungsten. Tungsten counterweights are used on the MD11, MD80, and MD90 (Ford, 1994).
It is unknown how many DU counterweights are currently installed in aircraft. It is estimated that approximately 15,000 weights may be associated with the Boeing 747 fleet (based on 550, Boeing 747 aircraft produced between 1968 and 1981 and spare parts) (Gallagher, 1994). However, the number of aircraft that contain DU counterweights is decreasing. Rather than refurbishing the DU (during maintenance operations), tungsten counterweights are used as a replacement." [NUREG-1717]


Aircraft Workers

Exposure of Aircraft Workers


Aircraft Crews and Passengers

Exposure of Aircraft Crews and Passengers


References

[NUREG-1717] Systematic Radiological Assessment of Exemptions for Source and Byproduct Materials, Final Report, NUREG-1717, U.S. Nuclear Regulatory Commission, 2001
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