Primary Containers

DOE-HDBK-1129-99

4.1.1.a(1) Primary Containers

Operations are conducted with tritium enclosed inside leak tight primary containers consisting of

parts such as valves, tubing, pipe, components, transducers, pumps, and vessels. The leak rate of

these primary containers, at operating pressure, is generally certified to be less than 10-6 to 10-7

cm3 of helium per second (cm3 He/sec). The quantity of tritium released during all normal

operations is extremely small and can be estimated from the engineering specifications. Many

primary tritium systems are designed with pressure relief protection. These devices should not

relieve directly into the environment, but rather into holding tanks designed with sufficient capacity

to retain the entire contents of the primary system.

4.1.1.a(2) Secondary Containers

In modern tritium operations, the primary container is enclosed inside a secondary barrier such as

a glovebox. The secondary system is only exposed to the tritium, which is released from the

primary barrier.

Secondary containers in the DOE complex vary in size, shape, leak rate, and quality depending

upon the age, projected use, and the quantity of tritium at risk.

4.1.1.a(2)(a) High-Quality Secondary Containers

Some operations are equipped with high quality, double-walled pressure vessels. The outer

pressure vessel is the secondary containment system, and the inner container is the primary

container. This type of secondary containment system is generally used for storage of large

quantities of tritium of very high quality, and is certified at operating pressure to leak rates of less

than 10-6 to 10-7 cm3 He/s.

These high-quality secondary containment systems safely store any tritium released from the

primary container for several days or weeks without a significant release to the environment. The

maximum quantity of tritium released from these high-quality systems during a significant primary

container leak can be accurately estimated from the secondary containment system engineering

specifications.

The space between the primary vessel and the secondary container in these systems is usually

evacuated during service. If tritium is released into these spaces, there are no dilution gases

present, and the gas leaking from the secondary container is in the same form as the gas in the

primary container. If the gas released into this high-quality secondary is 90 percent tritium, less

than 1 Ci of tritium will be released to the surrounding area for each four to 40 storage days.

Following a release into a high-quality secondary container, the tritium can be recovered in almost

the original purity by pumping it from the secondary container into another primary container.

Several days can elapse during the recovery process without a significant release of tritium to the

environment.

4.1.1.a(2)(b) Medium-Quality Secondary Container

It is not practical or possible to enclose all primary tritium containers inside high-quality, non-

diluting, evacuated secondary containers. Gloveboxes, as discussed in 4.1.1.a, can be utilized in

both secondary containment and secondary confinement systems. Most primary containers can