Tertiary Confinement System

DOE-HDBK-1132-99

Special features (e.g., air locks, enclosed vestibules) should be

considered for access through secondary and tertiary confinement

barriers.

Tertiary Confinement System. The process building and associated

ventilation system comprise the tertiary confinement system. Penetrations of

the building confinement barriers should have positive seals to prevent the

migration of contamination.

1.2.6

Uranium Conversion and Recovery Facilities (UCRFs). To the extent

practical, the primary confinement system should be constructed of fire-resistant

materials, and the process equipment and process being confined should be

designed to prevent potential flammable or explosive conditions. Confinement

enclosures for flammable metals should be designed with self-contained fire

protection and extinguishing equipment; in some cases, inert atmospheres may

be desirable within the enclosures.

Work that could subject personnel to possible inhalation exposures should be

performed in process confinement enclosures. Gloveboxes should be the

preferred enclosure, but are not always practical. Alternative systems may have

to be considered.

When gloveboxes are used, their design and construction should allow

replacement of parts and/or relocation of the box(es) within the facility or

system(s) with a minimum of contamination or exposure.

To the extent practical, discrete processing steps should be performed in

individual process confinements to reduce the amount of hazardous material

that can be released by a single or local failure of the confinement system.

Process and auxiliary system differential pressure should be maintained to

inhibit backflow of hazardous materials into auxiliary systems.

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