Aerodynamic Entrainment and Resuspension

DOE-HDBK-3010-94

4.0 Solids; Summary

Suspension of bulk powder by debris impact and air turbulence from falling

objects.

Median

ARF 4E-4/RF 0.2

Bounding

ARF 1E-2/RF 0.2

A erod yn am ic E n train m en t an d R esus pen sion

Based upon the information on resuspension factors and rates found in the articles reviewed

and the outdoor rates, the long-term ARR suggested by Sehmel and Lloyd (1976a,b) of

4E-5/hr appears to be a reasonable bound. Although ARRs appear to decrease with time,

use of the initial ARR measured is conservative. Not including MAR depletion with time

tends to overestimate the release. The resuspension tends to fluctuate as the level of stress

fluctuates and the surface conditions respond to the previous stresses. The bounding ARF

and RF for aerodynamic entrainment is due to the passage of vehicular traffic.

Use of the values given above for short time frames (<100 hours) would not introduce

serious error due to the severe depletion of the source. For time periods exceeding

100 hours, the reduction of the source can be accounted for from the entrainment of

material. In general, these values are intended for immediate post-accident conditions and

freshly deposited material. They would overestimate releases from long-term contamination

(i.e., months to years) and are not appropriate for such use.

Homogeneous bed of powder exposed to ambient conditions (normal process

facility ventilation flow or less, or nominal atmospheric windspeeds <2 m/s

with gusts up to 20 m/sec) following an event.

Bounding

ARR 4E-5/hr, RF 1.0

Homogeneous bed of powder buried under structural debris exposed to

ambient conditions or under static conditions within structure following an

event.

Bounding

ARR 4E-6/hr, RF 1.0

Entrainment of powders from road surface by passage of vehicular traffic.

Bounding

ARR 1E-2/passage, RF 1.0

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