Internal Dose Evaluation Program

DOE-STD-1128-98

Guide of Good Practices for Occupational Radiological Protection in Plutonium Facilities

which incorporate assumed biokinetic models, or by an appropriate computer code. Intake-to-dose

conversion factors can be found in Federal Guidance Report No. 11 (EPA, 1988b) or ICRP

Publication 30 (ICRP, 1979, 1988b). Further discussion on intake and dose assessment is provided

in Section 5.8. DOE is currently evaluating its internal dosimetry methodology and considering

updating it to adopt newer models.

Participation in internal dose evaluation programs is required by DOE for conditions identified in

10 CFR 835.402(c) (DOE, 1998a). The internal dose evaluation program must address both general

workplace conditions and individual intakes.

Workplace conditions are monitored through air sampling programs as well as contamination

surveys. For work that can have variable or changing conditions, more intensive surveillance may

be required, using supplemental portable air samplers, continuous air monitors, or personal air

samplers.

Individual worker monitoring for intakes is commonly performed using bioassay procedures.

Bioassay monitoring includes both direct (in vivo) measurements of radioactivity in the body and

indirect (in vitro) measurements of material excreted or removed from the body. Refer to

Section 5.7.4 for information on assessing interanl exposurese from air supply data.

10 CFR 835.402(c) (DOE, 1998a) specifies the requirements for participation in a radiological

bioassay program Because most plutonium facilities have a high degree of radiological control and

containment for plutonium, chronic exposure to levels of occupational concern is unlikely and it is

not considered likely that a worker would incur more than one unplanned intake in a year. Thus,

participation in a bioassay program is generally based on the possibility that a single intake causing

a dose in excess of 100-mrem committed effective dose equivalent (CEDE) might occur. Bioassay

is also required if an intake is suspected for any reason.

Indications of intake include (but are not limited to) detection of facial or nasal contamination, air

monitoring or sampling that indicates internal exposure, or any wound in which contamination is

detected or suspected (See Section 5-9 for internal dosimetry recommended indicator and action

levels.) The most common internal exposure monitoring program for workers is the bioassay

monitoring program, which must be designed for the specific nuclides and forms of material at a

particular facility. Likely candidates for internal exposure monitoring include personnel who may

be routinely exposed to surface or airborne contamination, or those identified by the foregoing

workplace indicators.

Workplace monitoring for potential internal exposures is performed to verify the adequacy of

containment and work practices. This monitoring includes air sampling, continuous air monitoring,

personal contamination surveys, and workplace contamination surveys. Facilities are to be

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