Monitoring Requirements and Selection of Employees

DOE-STD-1128-98

Guide of Good Practices for Occupational Radiological Protection in Plutonium Facilities

which measurements are not expected to show detectable activity and when any

detection whatsoever is likely to initiate investigation and special bioassay.

5.3.2 Monitoring Requirements and Selection of Employees

Workers who are considered likely to have intakes resulting in excess of 100-mrem CEDE

are required to participate in a bioassay program. However, because of the extensive

radiological control practices for plutonium facilities, including a high degree of engineered

barrier containment, no typical plutonium worker is likely to have intakes of 100-mrem

CEDE or more. However, this should not be used as an excuse to exclude workers from

routine bioassay. Although no one should be considered likely to have intakes resulting in

100-mrem CEDE, some workers are at significantly higher risk for incurring an intake than

others and should be on routine bioassay.

The workers at highest risk of incurring an intake are the ones in closest contact with the

material. Typically, these are the operators, maintenance, and health physics personnel

handling plutonium or plutonium-contaminated objects in the course of routine glove-box,

maintenance, or decommissioning operations. In the event of containment system failure, or

failure respiratory protection devices, it is these workers who will most likely incur

exposure and subsequent intake. These workers should be on a routine bioassay program

designed to meet the requirements of 10 CFR 835 (DOE, 1998a) as a kind of safety net to

identify intakes which might have gone undetected by workplace monitoring.

Other workers (e.g., supervisors, inspectors, observers, guards, and tour groups) who work

in or visit a plutonium facility but are not directly working with the material or contaminated

objects are at a substantially lower risk for incurring an intake. Although these people may

not need to be on a routine bioassay program, they should be subject to participation in a

special bioassay program if workplace indications suggest loss of control or containment.

5.3.3 Selection of Bioassay Monitoring Techniques

Bioassay monitoring techniques fall into two broad categories, direct measurement of

radioactive materials in the body (in vivo counting) and analysis of material removed from

the body for laboratory in vitro analysis. In vivo counting includes measurements of the

chest, lung, skeleton, liver, and wounds. In vitro measurements include urinalysis, fecal

analysis, and occasionally analysis of tissue, sputum, or blood samples. Methods for in

vitro analysis include liquid scintillation counting, fluorescence measurements, gamma

spectrometry, chemical separation followed by electrodeposition, and counting with

radiation detectors. Selby et al. (1994) provide a brief overview of bioassay techniques and

capabilities. Further discussion of the techniques is provided below.

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