Example 2

DOE-STD-1136-2004

Guide of Good Practices for Occupational Radiological Protection in Uranium Facilities

Example 2

239

One gram of natural uranium contains Pu contamination to the extent that the Pu activity is

0.1% of the uranium alpha activity. The relative inhalation hazards of the two materials are

determined by dividing each material's relative activity by its derived air concentration.

U-Nat relative activity = 1

239

Pu relative activity = 0.001

U-Nat derived air concentration (W) = 3 x 10-10 Ci/mL

239

Pu derived air concentration (W) = 2 x 10-12 Ci/mL

These values represent the relative hazards of the two materials in the mixture.

239

Therefore, Pu at 0.1% of the U-Nat activity represents 14% of the potential inhalation dose.

The activity of 1 gram of U-Nat = 2.5 x 104 dps

239

Therefore, 0.001 x 2.5 x 10 = 2.5 x 10 dps = the Pu activity in the 1 gram of U-Nat.

239

The specific activity of Pu is 2.27 dps/nanogram:

239

Therefore, 0.1%

Pu activity fraction corresponds to 11 parts per billion on a mass basis.

2-14