In Process tritium measurements

DOE-HDBK-6004-99

In Process tritium measurements

The measurement of tritium within a facility has usually been by PVTC. This requires a shutdown

of the process and transferring all the gas to a volume for sampling and measurement. This is usually

a substantial disruption of the process and will take a significant time. Tritium that is "held up" in

process cannot be directly measured. This includes tritium in walls of the system, tritium in process

components such as molecular sieve, and tritium contained within the waste disposal system. It must

be estimated by difference measurements. Real time measurements of tritium amounts are done when

tritium is moved around the facility or process. These are usually done by PVTC measurements. The

laser Raman system offers advantages for the measurement of composition as tritium flows from

location to location. The use of self assaying storage beds will greatly reduce the time required to

determine the tritium in storage.

Tritium in Waste Streams

The characterization of tritium contained in waste streams is important and one of the more difficult

measurements to make. Ionization chamber measurements, calorimetry, and difference measurements

are used to determine the tritium levels.

Stack emission measurements.

Stack emissions are determined by ion chambers. The primary method used by facilities for the

reporting to the EPA is based on a passive monitoring system. A small fraction of the air stream

exhausted from a facility is passed through a system to remove the tritium. Both liquids, such as

glycol, and solids, such as molecular sieves, are used to absorb HTO. These systems can distinguish

between HTO and HT by passing the sample through a catalyst that will convert HT to HTO. The

second collection system then collects the HT as HTO.

COOLING SYSTEMS

The cooling systems include all systems, structures and components that remove heat from the facility

and transfer it to a heat sink such that:

1. Thermal, hydraulic and mechanical parameters are within design limits for the cooling system,

fusion device, confinement barriers and other safety-class equipment.

2. A leaktight barrier is maintained against uncontrolled release of fusion ash and radioactivity to

the environment.

The cooling system includes coolant makeup systems and collection and disposal systems for spilled

or drained coolant.

Fusion devices requiring cooling systems usually radiate heat to the first wall of the plasma chamber.

The first wall re-radiates the heat to the shield wall. Cooling pipes in the shield wall remove the

majority of the heat. The divertor is a secondary but significant source of heat. Components such

as the cryostat, vacuum pumps, magnetic coils may also require component cooling.