Primary Confinement System

DOE-HDBK-1132-99

system. The actual confinement system requirements for a specific UPHF

should be determined on a case-by-case basis.

Generally, facilities that process and handle UEU have used two confinement

systems. The primary confinement system encloses or confines the uranium

materials being fabricated and the equipment used to process the uranium. The

secondary confinement consists of the structures and associated ventilation

systems that surround the operating areas that house the primary confinement

system. The secondary confinement system barriers are those that separate

the outside environment and free access areas, such as offices and lunch

rooms, from potential contamination.

Primary Confinement System. The primary confinement system includes

barriers, enclosures (including their associated ventilation or atmosphere control

systems), and process piping and vessels. Its principal function is to prevent

the release of hazardous substances into the operating areas. The following

features should be considered in the design:

Breaches of the primary confinement barrier (e.g., due to glove or seal

failure) are acceptable if the off-gas treatment system is capable of

maintaining an adequate inflow of air for the specified breach size and

location. Some portions of the primary confinement may not form a

complete physical enclosure. For these, primary confinement should be

ensured by adequate airflow and appropriate process equipment design.

If needed, conveyors should be used to interconnect glove holes or other

primary confinement enclosures to minimize introduction and removal of

materials from the system. The primary confinement system criteria

should be applied to these interconnections.

Special design features should be considered to safely introduce and

remove materials from process confinements.

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