Confinement Systems vs. Containment Systems

DOE-HDBK-1132-99

Confinement Systems vs. Containment Systems . Within DOE, the term

2.10.8

" onfinement"has been used to describe the generic use of barriers, systems,

and structures that have been specifically designed to limit the dispersion of

radioactive materials within a given facility. Typical examples of confinement

barriers and systems include the use of fume hoods, ventilated gloveboxes, air

locks, etc.

Because most DOE facilities have, over the years, been associated with the

handling of solid or particulate materials, HEPA filters have long been used on

ventilation exhaust systems to minimize or eliminate the release of radioactive

materials to the environment.

For tritium, however, the concept of " onfinement"has little meaning because

(1) tritium is a gas, (2) the use of HEPA filters on exhaust systems can do nothing

to prevent the release of tritium to the environment, and (3) the classic concept of

confinement, from the perspective of the facility, reduces back to the use of the

high volume airflow, single pass ventilation systems described above. Thus,

standard terminology has evolved that clearly differentiates between the use of

" onfinement"systems and the use of " ontainment"systems.

Primary Containment Systems. The innermost barrier that separates tritium

from its immediate outside environment, primary containment systems for

tritium handling typically consist of piping, valves, containment vessels, pumps,

transducers, etc. Because these components can be expected to have their

interior surfaces fully wetted with high concentrations of tritium gas under

vacuum conditions and/or at high pressures, materials considerations become

important, as do the methods of construction.

Because the primary containment system in question may or may not be

situated in a secondary containment environment, the rule-of-thumb for modern

primary tritium containment systems is to assume that there is no secondary

containment system, and that the primary containment system is the only

barrier between the tritium and the outside environment. The materials and

construction issues associated with primary containment systems for tritium

handling should follow the guidance set forth in the ASME Boiler and Pressure

I-112