Example 5.3. Circumstances Not Requiring Routine Individual Monitoring

DOE-STD-1121-98

Example 5.3. Circumstances Not Requiring Routine Individual Monitoring

Radioactive materials are in a sealed source or special form.

Radioactive materials are packaged in accordance with Department of Transportation

specifications.

Quantities of radioactive material in process are less than 2% of an ALI.

The requirement in 10 CFR 835 is that monitoring be provided for workers who are likely to receive

a potential alpha energy exposure (PAEE) above background that would lead to a committed effective

dose equivalent HE,50 of 100 mrem in a year. The corresponding exposures are 0.08 WLM for 222Rn

progeny and 0.24 WLM for 220Rn progeny. Monitoring would normally include breathing zone air

sampling using lapel air samplers or etched-track detectors, or fixed air monitors with records of stay

times.

Because of compelling special circumstances, a few contractors have been able to get regulatory

relief under 10 CFR 820.62. The problem arises from the inability at these sites to distinguish between

natural and occupational sources of radon and thoron exposure. At these sites, monitoring is provided for

workers who are likely to receive a PAEE including background that would lead to a committed effective

dose equivalent HE,50 of 500 mrem in a year: this is 0.4 WLM for 222Rn progeny and 1.2 WLM for 220Rn

progeny. Monitoring would normally include breathing zone air sampling using lapel air samplers or

etched-track detectors, or fixed air monitors with records of stay times.

Both approaches to a monitoring are based on exposure, which includes both air concentration and

amount of time breathing the air. It is important to point out that workers may be permitted to work in

significant concentrations of potential alpha energy for short periods of time with no personnel

monitoring, providing they don't exceed the likelihood of receiving an HE,50 of 100 mrem or 500 mrem

(depending on whether the site has obtained an exemption from 10 CFR 835 for radon).

5.4 SPECIAL BIOASSAY PROGRAM

Special bioassay should be initiated when off-normal conditions occur or there are indications that

an intake needing assessment may have occurred. Criteria for identifying those conditions typically can

include personal contamination, high air sample results, uncontrolled spread of contamination, or

expressed worker concerns. The response to these conditions is the performance of bioassay

measurements outside the envelope of routinely performed baseline, scheduled periodic, and termination

or ending work measurements. The reason for and interpretation of these special measurements should be

clearly identified. The role of special measurements is to confirm or rule out the initial indication of an

intake, to determine the radiological significance of confirmed intakes, to indicate the need for work

restriction or dose reduction therapy, and to begin the dose assessment process.

Special bioassay measurements may include the same types of measurements as those performed for

routine monitoring (e.g., in vivo measurement, urinalysis) and may also include additional types of

measurements (e.g., fecal analysis, wound counting).