Vessel Code or a similar code. In most cases, the materials of choice will be a
300-series stainless steel, preferably a low carbon variety (e.g., 304L or 316L).
Welding is the preferred method of construction wherever possible. Prior to
being placed into service, individual portions of the system should be certified
to a maximum leakage rate of 10 -6 to 10-7 cm3/sec (helium), at a minimum of
125 percent of the maximum expected operating pressure.
Secondary Containment Systems . The use of secondary containment
systems in the DOE tritium complex tends to vary a great deal, depending upon
when the systems were put into service and their projected use. Depending on
their use, secondary containment systems can be expected to vary in
complexity, from the relatively simple "acket concept"used to house primary
containment system plumbing and containment vessels, to much more complex
glovebox concepts, where the gloveboxes in turn are connected to specialized
cleanup systems. Depending on the amount of tritium at risk, construction
requirements for secondary containment systems can also be expected to vary
widely, from high-quality systems, to intermediate-quality systems, to low-
quality systems. An overview of each type of system is described below, along
with its intended function.
When gloveboxes are used for secondary confinement, the following design
features should be considered:
Air should not be used for the atmosphere of a recirculating tritium
glovebox because of the potential for the formation of explosive mixtures
The glovebox atmosphere should be maintained at a pressure lower than
that of the surroundings and diffusion-resistant material should be used to
the maximum extent possible to limit tritium leakage.
High-Quality Secondary Containment Systems . A typical example of a high-
quality, secondary containment system can be represented by the "acket
concept,"in which the plumbing associated with a primary containment system
is completely enclosed inside an independent secondary container. High-