Primary Confinement System

DOE-HDBK-1132-99

Generally, UCRFs have used two confinement systems. The primary

confinement system encloses or confines the uranium materials being

processed and the materials 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

operating areas include those areas that are not normally expected to become

contaminated. 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. The actual confinement system

requirements for a specific UCRF should be determined on a case-by-case

basis.

Primary Confinement System. The primary confinement system consists of

barriers, enclosures (including their associated ventilation or atmosphere control

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

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

following considerations should be addressed in the design of primary

confinement systems for UCRFs:

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 function

should be ensured by adequate airflow and appropriate process

equipment design.

If needed, conveyors should be used to interconnect gloveboxes 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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