Subject: 3.17 Uranium in Counterweights

NUREG-1717

Draft Report for Comment
Date Published: December 1999

Division of Risk Analysis and Applications
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001

Summary
Full report 3.1 MB

----------------
The following excerpts are taken from the PDF file:
----------------

3.17 Uranium in Counterweights [...]

3.17.2.4 Production Information

The National Lead Company was the primary U.S. manufacturer of DU counterweights; however, this company is no longer in business and stopped manufacturing new counterweights in 1986 (Phone call, D. Barbour, Project Manager, Depleted Uranium Programs, Philotechnics, Oak Ridge TN, October 1999). A company called Eldorado Resources Ltd. (currently known as Cameco Corporation), located in Canada, is the only known North American manufacturer of DU counterweights for nonmilitary applications (Phone call, E. Lanchester, Quality Assurance Department, Nuclear Metals, Inc., Concord, MA, September 1994). Nuclear Metals, Inc. is the only refurbishing facility in the United States (Phone call, E. Lanchester, Quality Assurance Department, Nuclear Metals, Inc., Concord, MA, September 1994).

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 MD–11, MD–80, and MD–90 (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 (Phone call, D. Barbour, Project Manager, Depleted Uranium Programs, Philotechnics, Oak Ridge, TN, October 1999). [...]

3.17.4.4.1 Aircraft Accident Involving Fire

In the event of a fire involving DU counterweights the generic modeling of Appendix A.1 has been used, where it has been assumed that the transportation accident would reasonably approximate the exposures from an aircraft fire. The amount of material involved is 850 kg of DU, which is that on a typical Boeing 747 aircraft. For the fireman, the EDE is estimated to be 0.3 mSv (30 mrem) and for the clean-up worker, the EDE is estimated to be 4 mSv (400 mrem). [...]

Table 3.17.1 Use of DU Counterweights in Domestic Aircraft

Aircraft Type;
Manufacturer;
Number Aircraft Owned by Domestic Carriers (kg)a;
Total Weight of Counterweights per Aircraft

DC–10;
McDonnell-Douglas;
168;
~ 1,000 b

L–1011;
Lockheed;
60;
~ 680 b

B–747;
Boeing;
202;
~ 850 c

========

a Number of aircraft owned by domestic carriers that are members of the Air Transport Association (ATA, 1999).

b Phone call, E. Lanchester, Quality Assurance Department, Nuclear Metals, Inc., Concord, MA, August 1996.

c Phone call, D. Barbour, Project Manager, Depleted Uranium Programs, Philotechnics, Oak Ridge, TN, October 1999.