Free-Fall Spill Experiments

DOE-HDBK-3010-94

4.0 Solids; Powders

the non-porous, reactive to water materials (flour), the effect was less

pronounced due to the absorption of the water.

The coefficients derived from analysis of variance on the data from the tests performed on

the various materials were compiled in the equation:

Gi = const(H)A(F)B(W)C(Frac i)E[D i ln(D i /25)]

(4-4)

where:

fall distance, cm

material flow, kg/s

moisture content, %

Fraci =

fraction of particles in i size range in source material

Di =

average diameter of particles collected on cascade

impactor stages

A, B, C, D & E are coefficients calculated by analysis of

variants and varied with material.

The formulae accounted for 72% to 93% of the experimental variation for the four materials

and indicates that the parameters chosen are appropriate for the purpose. The correlation

between measured and predicted size specific dust generation rates is shown in Figure 4-18.

In all cases, for drop heights ranging from 0.25- to 1.5-m, values for G were less than 2E-4

to 3E-4.

4.4.3.1.2 Free-Fall Spill Experiments. Sutter, Johnston and Mishima (December

1981) reported on experiments performed to measure the fractional airborne release of

powders (TiO2, density 4.2 g/cm3; depleted uranium oxide, density 10.96 g/cm3) during free-

fall spill. The size distribution of the two source powders was measured by liquid

sedimentation using suspensions of ultrasonically dispersed powder in water containing a

surfactant is shown in Figure 4-19 reproduced from the referenced document. Masses

ranging from 25 to 1000 g were spilled from a beaker at the ceiling of a 3.05-m (10-ft)

diameter by 3.05-m (10-ft) tall stainless steel vessel. Airborne powder was collected by high

volume total particulate and cascade impactor samplers. Material deposited on walls of the

vessel was estimated from the amount collected on aluminum foil strips on the vessel walls at

various locations. The apparatus is shown in Figure A.5 in Appendix A. The pertinent data

are tabulated in Table 4-13, with measured data reproduced in Tables A.41a, A.41b, A.41c

and A.41d in Appendix A.

The bounding ARF and RF values for the largest spill height are 2E-3 and 0.3. The median

ARF and RF values are 9E-4 and 0.4 with average values of 9E-4 and 0.5. The maximum

RF measured for spill from the greater height is 0.9 associated with the smallest ARF

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