Secondary Containment Systems

DOE-HDBK-1132-99

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

of hydrogen gas. Argon or nitrogen is recommended.

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-

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