Aerodynamic Entrainment and Resuspension

DOE-HDBK-3010-94

4.0 Solids; Metals

4.2.4

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

Aerodynamic entrainment from a coherent, bulk solid would be limited to the surface dust

unless the solid is eroded by the airflow. The phenomenon would be similar to suspension of

a powder from a hard, unyielding surface. For large pieces that project beyond the boundary

layer, entrainment due to "wake effect" may be a significant process. The only experimental

data for the resuspension/aerodynamic entrainment from a coherent monolith of material that

have been reported are found in Stewart (1963). It is assumed that the airborne release of Pu

during oxidation at room temperature is the aerodynamic entrainment (resuspension) of the

corrosion products (oxides) from the metal surface and that the bounding values measured for

that configuration would bound the aerodynamic entrainment from the metal (see subsection

4.2.1.1.1). It would be conservative in that it is assumed that sufficient corrosion product

exists for material that is normal stored under conditions to minimize corrosion and is

contained. The ARR and RF values previously quoted for this configuration are assessed to

be bounding:

ARR (dry air) 2E-6 g Pu/cm2-hr; RF 0.7

unalloyed metal

ARR (100% RH) 7E-3 g Pu/cm2-hr; RF 0.7

ARR (dry air) 7E-8 g Pu/cm2-hr; RF 0.7

delta-phase metal

ARR(100% RH) 6E-4 g Pu/cm2-hr; RF 0.7.

No experimental data for the aerodynamic entrainment of uranium metal were uncovered.

The data reported for the oxidation of uranium in air (Mishima March 1985) did not show

rates for temperatures less than ~ 400 oC. Since the oxidation of uranium is inhibited by

the formation of an adherent oxide layer at the metal-atmosphere interface, the values

reported above for plutonium are conservative for uranium.

4.3

N O N M E T A L L I C O R C O M P O S I TE S O L I DS

Examples of the types of solids in nonreactor facilities other than simple metals or powders

are aggregates such as concrete/cement, limestone/sandstone; glasses such as vitrified high-

level waste and products of slagging pyrolosis; and spent nuclear fuel, including clad,

irradiated, and compacted ceramic oxide.

4.3.1

T h erm al S tres s

The types of materials discussed in this section behave differently under thermal stress and

are discussed individually below. All the materials are normally contained (overburden,

container, equipment or cladding) when holding/incorporating radionuclides and this barrier

must be breached before the material is directly exposed to the ambient environment. The

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