Chemically Nonreactive Compounds

DOE-HDBK-3010-94

4.0 Solids; Powders

initial activity collected on the glass fiber filter during the experiment. In some experiments,

portions of the material passing through the chimney were collected on a membrane filter

and sized by optical microscopy using a graticule to determine the size distribution of the

airborne materials. Particles were grouped into seven categories - <5, 5-8, 8-12.5, 12.5-20,

20-32, 32-50 and >50 m equivalent spheres. The size quoted in the text must be

multiplied by the square root of the density of Pu oxide (11.46 g/cm3) to approximate the

AED. These measurements are the basis for the RFs quoted in the tables. In the case of

compounds that were oxidized, the time required to convert all the powder to oxide is not

known. This introduces an additional source of uncertainty into the use of these

measurements for ARFs during the heating and oxidation of the powders. In most cases,

microscopic examination of the residual materials after the heating indicated that for the

conditions under which the higher releases were measured (higher temperatures and air

velocities), the oxidation was relatively complete. Furthermore, the airborne materials were

entrained in an induced flow that probably exceeds that anticipated for convective flow and

bounds the entrainment for convective flow. The pertinent data from these tables for the two

situations are listed in Tables 4-10 and 4-11.

4.4.1.1

Chemically Nonreactive Compounds

The measured ARFs for heating nonreactive PuO2 particles are tabulated in Table 4-10.

Table 4-10. Airborne Release from Nonreactive Powder During Heating

in Flowing Air

(Table V - Mishima, Schwendiman and Radasch, July 1968)

Temperature, oC

Airflow, m/s

ARF

Ambient

0.1

6.1E-6

1.17

5.6E-3

800-900

0.1

5.3E-6

1.17

2.5E-4

The source material for these experiments was oxide nominally in the size range of 15 to 150

m AED (the upper value is given as 44 m but is the fraction passing through a 325 mesh

screen and is LLD rather than AED for the lower value), although some respirable particles

may have been present. The two values at each separate air velocity appear to be relatively

consistent with the ARF for the higher temperature lower than that at ambient temperature.

Since the lower air velocity (0.1 m/s) is calculated to carry particles as large as 17 m that is

barely above the lower size of the powder used (although it was noted during the oxidation

experiments that the oxide formed was friable), the low ARF value would be anticipated.

Particles as large as 300 m could be carried by the higher velocity (1.17 m/s) and the ARF

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