Transuranics

DOE-STD-1136-2004

Guide of Good Practices for Occupational Radiation Protection in Uranium Facilities

The following text discusses the environmental, safety, and health challenges presented by the

introduction of recycled uranium into the DOE system for enrichment.

2.1.4.1 Transuranics

Transuranics (neptunium and plutonium isotopes) exist in small quantities in reclaimed or

recycled feed materials. In most cases, a regimen of radiological controls based on uranium hazards is

adequate to control the additional activity. However, because of their higher specific activities

(compared to uranium isotopes), transuranics can represent a significant internal dose concern even at

very low mass concentrations. As a result, the ALIs for transuranics are lower than those for uranium

isotopes. For example, for a moderately soluble transportability mixture, if 239Pu contamination

contributes 0.1% of the total alpha activity in uranium, then it will contribute roughly 14% of the total

inhalation dose equivalent (see Example 2). Example 2 illustrates that it takes only 11 parts of 239Pu

per billion parts of natural uranium to attain an activity fraction of 0.1%.

Radiological controls based solely on uranium content may provide insufficient protection with

increases in the TRU concentration. Processes to recover uranium from by-product streams recover

a portion of the impurities as well and may require additional controls to adequately protect

individuals when the TRU concentration exceeds 0.1%.

2-12