External Dose Measurements cont'd

DOE-HDBK-1113-98

Module 103 External Dose Control

Lesson Plan

Instructor's Notes

radiological conditions to change. There are two general

categories of measurement used for external exposure

associateed with uranium, portable survey instruments and

personnel dosimeters.

Gamma radiation from uranium is normally not the

controlling problem. For example, the contact beta

radiation field from depleted uranium is approximately 240

millirem per hour, while the contact gamma radiation field

is less than 10 millirem per hour. However, significant

gamma fields can exist in areas where large quantities of

uranium are stored, such as a storage area for uranium

contaminated soil. The accuracy and precision of survey

instruments used for measurement of beta radiation fields

depend on many factors which must be addressed, such as

energy response and geometry factors. Accordingly, these

surveys are typically conducted by Radiological Control

personnel. Neutron fields from enriched uranium fluoride

compounds can also add to this area of concern. Depending

on the magnitude of neutron fields generated, periodic

neutron dose rate measurements are made, typically by

Radiological Control personnel.

Discuss the facility specific

Personnel dosimeters produce the data which becomes the

methods for measuring external

formal or "legal" record of personnel exposure,

exposure and dose.

thermoluminescent dosimeters, used in most DOE uranium

facilities, provides the most accurate and precise means of

measuring doses received by workers.