Scope of Bioassay Program - doe-std-1128-98

DOE-STD-1128-98

have been observed with regard to both highly soluble and highly insoluble forms, leading

to the good practice of performing dissolution rate (i.e., solubility) tests on standard

materials in a facility.

As plutonium ages in a residual, loose contamination form, such as might be found in old

duct work, glove boxes, or other such components, it can be expected to undergo slow

oxidation to a more insoluble form. Thus, class Y forms of plutonium may be reasonable

assumptions of what to expect during many decommissioning operations.

Particle size is an important consideration for inhalation exposures. The normal practice for

an aerosol is to identify the activity median aerodynamic diameter and its associated

particle-size distribution. Particle sizes of 10 m or less are considered respirable. The

common practice is to assume a 1-m particle size for dosimetry purposes because actual

particle size information is usually lacking. Particle size data are most readily obtainable

for chronic exposure situations.

Unless representative air sampling is performed in the immediate proximity of a worker

during abnormal working conditions, the practical likelihood of obtaining good particle-

size information is slim.

5.3

SCOPE OF BIOASSAY PROGRAM

The relatively low annual limit on intake of plutonium renders its radiation hazard

substantially more restrictive than its industrial hygiene or chemical toxicity hazard. Thus,

internal radiation dose or intake monitoring is the appropriate focus of bioassay monitoring.

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