Venting of Pressurized Gases Over Solids

DOE-HDBK-3010-94

4.0

Solids; Nonmetallic or Composite Solids

4.3.2.3

V en tin g of P ressurized G ases O ver S olid s

No significant airborne release is postulated. The potential releases for loose surface

contamination on the solid are covered in Chapter 5.

4.3.3

F ree-F all S p ill an d I mp action S tres s

Brittle materials (e.g. glass, aggregate such as mechanically-compacted UO2, concrete,

limestone) can be fragmented when impacted or crushed. Jardine et al. (1982) performed

experiments to measure the fraction and size distribution generated by the impact of various

materials resting on a unyielding surface. Figure 4-12 reproduced from the reference

documents illustrates that the size distribution of UO2 pellets to an impact energy density of

1.2 J/cm3 is linear. Note that both the sieve and Coulter Counter data shown are physical

diameters and must be corrected by the square of the material density (10.96 g/cm3). Thus

the average grain size shown corresponds to a particle ~ 29 m AED. The degree of

fragmentation and the size distribution are a function of the material, the strength/age of the

material, and the energy input per volume (Mecham et al., October 1981). The fraction in

the size range 10 m AED and less is relatively uniform as shown in Figure 4-13 reproduced

from the reference document and was empirically correlated with the energy input (J/cu-cm)

in subsection 5.1.3, Appendix F in Vol. 4 of SAND (September 1987) as:

ARF X RF = (A)(P)(g)(h)

(4-1)

where:

ARF X RF = (Airborne Release Fraction)(Respirable Fraction)

= empirical correlation, 2E-11 cm3 per g-cm2/s2

= specimen density, g/cm3

= gravitational acceleration, 980 cm/s2 at sea level

= fall height, cm.

Use of this correlation to estimate the ARF x RF value is considered very conservative, and

may be excessively so if large debris from substantial heights is considered.

4.3.4

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

No significant airborne release is postulated. Potential releases for loose surface

contamination on metal are covered in Chapter 5.

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