Primary Confinement System cont'd

DOE-HDBK-1132-99

Breaches in the primary confinement barrier that cannot be totally avoided or

ruled out (e.g., due to glove or seal failure) should be compensated for by

providing adequate inflow of air or safe collection of spilled liquid. Occasional

breaches required for anticipated maintenance should be made only under

carefully controlled conditions. Primary confinement should provide for storage

of in-process material elsewhere, temporary alternative barriers, and adequate

inflow of air to provide contamination control.

The supply and exhaust ventilation system should be sized to maintain in-facility

radiation doses at levels as low as reasonably achievable (ALARA) in the event

of the largest credible breach. Process equipment and the process itself should

be designed to minimize the probability of fire, explosion, or corrosion that might

breach the confinement barrier. When handling pyrophoric forms (e.g., chips,

filings, dust) of materials in the confinement enclosure, the guidance of DOE-

HDBK-1081, Primer on Spontaneous Heating and Pyrophoricity, should be

considered. Halon systems should not be used with pyrophoric metals due to

the oxidizing reaction between halon and hot metal.

Primary confinement barrier(s) should be provided between the process material

and any auxiliary system (e.g., a cooling system) to minimize risk of material

transfer to an unsafe location or introduction of an undesirable medium into the

process area. Differential pressure across the barrier(s) should be used where

appropriate.

The effectiveness of each confinement barrier should be checked analytically

against challenges it is expected to withstand without loss of function. This

applies to any form of the hazardous material (gas, liquid, or solid) and its

carrying medium (i.e., airborne or spilled in a liquid).

To protect the integrity of process confinement systems, fire protection systems

should include the following features:

Automatic and redundant fire detection devices.

A fire-extinguishing system that actuates automatically to--

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