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.