Tritium Apparatus, Isolation Valves, and Purge Ports

DOE-HDBK-1129-99

If the port connection is leaking, the leak is repaired, and the leak test is rerun.

The first hand valve is opened and then closed to allow tritium from the container to enter the

void space between the two valves.

The second hand valve is opened and then closed to allow the trapped tritium to expand into

the port volume.

The outside of the port connection area can be sniffed with a tritium monitor. The containment

system tritium monitor may be observed for an increase in tritium concentration to detect a

tritium leak from the port connection into the containment volume.

If no leak is detected, then the two series valves may be opened, and the reconnection is

complete.

6.3.1 Tritium Apparatus, Isolation Valves, and Purge Ports

A "purge port" is a capped, sealed port connected through a valve to a potentially tritium-

contaminated volume. The purpose of a purge port is to provide a path, which can be used to

remove tritium-contaminated gases from the isolation volume prior to making a line break at the

component flanges to remove a component. If the tritium-contaminated gases are not removed

from the isolation volume, they will be released into the containment system when the flange is

unsealed. The released gases and outgassing from the isolation volume surfaces will contaminate

the containment volume gases. Following removal and replacement of a component, the port is

used to leak test the new component and flange seals prior to placing the component in service.

Figure 6-2 is an illustration of two purge ports installed to allow evacuation of the volume and leak

testing of the flanges between two sets of valves, thus allowing isolation and removal of a tritium-

contaminated component. Note that the purge ports are part of the permanently installed system,

and are not part of the component.

IsolationVal ves

Component to be

Connected

removed/repaired

to the rest of

the T2

system

Purge Ports

Evacuate

port volume;

check for

leaks

Air

Component to be

purge

removed/repaired

val ve

Component flanges

Evacuate

isolation

val ve

volume

Component to be

removed/repaired

Backfill with

Purge

air; repeat

with

evacuate

air

backfill cycle

necessary

FIGURE 6-2. Purge ports and isolation valves