Special Radiological Surveys and Techniques for Release of Materials

DOE-HDBK-1113-98

Radiological Safety Training for Uranium Facilities

Module 104 Internal Dose Control

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 contamination may be located in areas not

accessible 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 evaluating the material on a case-by-case

basis to ensure internal contamination does not exist.

DOE values for release of uranium- contaminated materials are higher

than DOE values for release of materials contaminated with some other

radioactive nuclides found in the DOE system, such as plutonium. The

difference in these values is due to the relative health risk from exposure

to uranium contamination compared with these other nuclides.