Tritium Capture, Contain, and Cleanup Process

DOE-HDBK-1129-99

expertise on staff. The building/systems would be designed to meet the needs of the user, and

costly retrofits after completion could be avoided.

During the first 25 years of tritium technology, the handling techniques in use were designed to

protect the worker from exposure to tritium. Worker protection was provided primarily by the use of

single-pass ventilation systems designed to rapidly remove any tritium released in the breathing

space from the area occupied by the workers. The ventilation gases were released through an

elevated stack at high velocity to massively dilute the gases before they could reach ground level.

Single-pass ventilation systems and high-velocity hoods were used extensively and quite

successfully for worker protection during these early years. These high-velocity ventilation, high-

velocity air hood, and elevated release techniques are still used for worker protection, but generally

as a supplement to improved barriers that better protect the environment.

In those early years, the room or building enclosing the tritium activity was equipped with a single-

pass ventilation system that did not recirculate the air back into the facility. Outside air was

brought in by the ventilation fans, conditioned for comfort, passed through the building spaces one

time, and was then released to the environment through an elevated stack. The room air

exchange rate generally accepted to be adequate for worker protection was 6 to 10 room air

changes per hour.

The tritium apparatus was enclosed in a high-velocity air hood, and the worker worked through

gloves in the doors or reached in through hood openings to operate the equipment. The high-

velocity air hoods were maintained at a pressure negative to the room spaces, and the natural air

flow was from the room through the hood opening and then out the ventilation duct work and up

the stack to the environment.

Tritium releases that occurred due to normal operations, component failure, and worker error were

inside the hood. The high-velocity air flowing through the hood swept any released tritium away

from the worker and out the stack to the environment where the tritium was massively diluted in

concentration. These techniques protected the worker; however, tritium was released to the

environment.

As concern for the environment increased, tritium technologists first attempted to control releases

by increasing design and material selection requirements, adding and enforcing regulations, and

increasing worker training and awareness. Time would prove that these techniques, although

helpful, were not completely successful. The tritium workers were already operating at a high

performance level and the tritium releases associated with equipment design and material

selection were not measurably decreasing as a result of the more stringent design requirements

and reviews. Tritium releases continued to occur. The expectation of faultless materials and

errorless workers was unrealistic. By the late 1960s and early 1970s, it became obvious that a

more realistic tritium culture was needed that better protected the worker, the public, and the

environment. The new culture was one of capture, containment, and cleanup.

4.1.1 Tritium Capture, Contain, and Cleanup Process

The capture, contain, and cleanup process encloses the primary or first wall tritium container inside

a secondary container such as a double-walled container, glovebox, room, or building so that any

tritium escaping from the primary container is captured in the secondary container. A tritium

removal system associated with the secondary container then removes the tritium from the

secondary by circulating the captured gases through a cleanup system.