Figure 11. Typical tritium removal system flow schematic

DOE-HDBK-1132-99

(3)

The cleanup system removes the tritium from the gas stream by breaking

down the hydrogen (i.e., H, D, and T) containing molecules on a hot,

precious metal catalyst.

(4)

The free H, D, and T atoms are recombined with oxygen in the catalytic

reactor to form water vapor.

(5)

The hot water vapor is cooled to a suitable temperature by passing the

gas stream through one or more heat exchangers.

(6)

The water is removed from the gas stream by passing the gas stream

through molecular sieve traps. A typical example of this type of cleanup

system is shown schematically in Figure 11.

Catalyst/molecular sieve tritium removal systems of this type can be very

effective. Depending on the tritiated species, the reduction in tritium

concentration for such systems has been measured at ratios of 10 6:1 to108:1

when operated in a once-through flow mode, in which the gas stream passes

from the glovebox, through the cleanup system, and out the stack to the

environment. In most situations, these types of cleanup systems are operated

in the continuous flow mode, where the gas stream is moved from the

glovebox, through the cleanup system, and back to the glovebox. When

Glovebox, Room, or Buidling

To Be Cleaned Up

Circulation

Gas To Gas

Gas

Catalysts

Blower

Heat Exchanger

Heater

Bed

Molecular

Water To Gas

Sieve Trap

Heat Exchanger

FIGURE 11. Typical tritium removal system flow schematic.

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