Environmental Remediation cont'd

DOE-HDBK-1132-99

Confinement of hazardous particles can be achieved with systems varying

from general ground cover (soil cleanup) to a complex structure with

multistage ventilation (stationary cleanup "treatment" center). The

confinement system needed for a specific cleanup activity should consider the

work to be performed, the hazard, the complexity of the activity (multiple

activities simultaneously conducted at a single location), energies available,

and, if the energies are present continuously or only during actual work, the

cleanup rate (hazard decrease rate), and several other factors.

General soil cleanup releases are usually chronic rather than acute. For this

type of activity, wind and cleanup equipment movement provide the

predominant energy sources leading to the airborne dispersion of

contaminants. Barriers designed to inhibit the generation of dust (wetting or

fixatives) during operations and to separate the energy from the contaminants

(ground cover) during nonwork periods are among the simplest forms of

confinement.

Retrieval or recovery of buried waste has the potential for acute releases.

Accumulation of retrieved items and in some cases individual items can

contain sufficient materials to represent an accident hazard. Confinement for

this type of activity could involve a vented overpack, portable hot cell, or a tent

of plastic or metal construction with an associated ventilation system. Vented

overpacks and hot cells provide confinement for the unusual or anticipated

small percentage of packages that are uncharacteristic of the normal retrieved

items. Tent confinement provides control where packages may have lost their

integrity and pockets of contamination are possible or expected. Tents may

also be used as weather covers for normal operation and to provide

confinement only for accident conditions. The specific type of confinement

used depends on the method of recovery, the type of hazard, and the

confidence in the knowledge of inventory and package condition.

In cases where ER projects involve temporary structures for process

confinement, especially when potentially high-activity buried waste is involved,

some design considerations are common to both environmental restoration

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