Radiological Safety Traning for Uranium Facilities
Module 104 - Internal Dose Control
Radon is a radioa ctive gas that occ urs natu rally in the envir onment. It
decays by alpha emission in the first of a series of very short half-life
radionuclides that decay by alpha or beta-gamma emission.
There is a simple, inexpensive alternative to determine if the
contamination is due to radon. The effective half-life for radon
radioactive decay products is about 30 minutes, compared with the
millions of years it takes for uranium to decay. The simple way to
determine if contamination is due to radon is to wait and see if it goes
away. The sample is recounted after the radon has an opportunity to
decay to lower levels. The count rates are compared, and if the count
rates are significantly different, radon is the most likely reason for the
higher initial count rate.
Special Radiological Surveys and Techniques for Release of Materials with the
Potential for Uranium Contamination
The alpha contamination detection problems mentioned in monitoring personnel
for contamination also apply to monitoring material. An added problem is that
uranium conta mination may be loc ated in areas not accessib le to survey.
DOE requires that materials used in Contamination Areas, High Contamination
Areas, and Airborne Radioactivity Areas that are being released for unrestricted
use have accessible surfaces surveyed. Materials with inaccessible surfaces
having a potential for internal contamination shall not be released without
does not exist.
DOE values for release of uranium- contaminated material s are higher than DOE
values for rel ease of materi als contamina ted with some ot her radioac tive
nuclides found in the DOE system, such as plutonium. The difference in these