Primary Confinement System cont'd

DOE-HDBK-1132-99

Process vessels that could contain uranium should vent to the process

off-gas system, which in turn should pass through pretreatment, if

needed, and HEPA filtration.

Three types of metallurgical processes require special ventilation

considerations:

Processes that use volatile or easily entrained organic liquids should

have a ventilation system that provides sufficient air movement around

the process area to prevent exposure of personnel to the hazardous

liquid or vapor. The design should incorporate roughing filters and/or

other types of traps to remove entrained organic liquid droplets from the

process off-gas before the off-gas enters the main ventilation. As a

result, the ventilation ducts should not become coated with the organic

materials, which would create a fire hazard.

Processes that produce either finely divided particles of metal or small

metal chips should have the same kind of front-end ventilation

adaptations as for hazardous vapors and liquids to prevent metal

accumulations in the off-gas ducting or in the final filtration train(s).

Roughing filters or centrifugal separators may be sufficient to remove

metal particles from the off-gas.

Processes that use corrosive chemicals (e.g., acids, perchlorates) should

use off-gas scrubbers to preclude damage to the exhaust air cleaning

system (e.g., HEPA filtration train).

Metallurgical processing equipment should have dedicated ventilation systems

that exhaust to a common, final filtration train. If airborne particle capture is

required, a high linear velocity will be necessary to ventilate these process areas

due to the greater densities of metal particles.

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