Tritium Measurement Methods

DOE-HDBK-6004-99

Tritium Measurement Methods

There are two primary categories of tritium measurements that are made at fusion facilitates. The

first category of measurements determine the quantity and the location of tritium within the facility.

These measurements are generally of large quantities of tritium in high concentrations. The second

category is for environmental or safety determinations. These are generally lower concentrations and

small quantities.

This section will discuss methods for both categories. The measurements techniques for tritium can

be grouped in the three general areas:

1. Composition measurements,

2. Thermal measurements, and

3. Tritium concentration measurement.

Composition measurements determine the actual concentration determination for each atomic /

molecular species. This method can be used for gases only.

Thermal methods (calorimetry) rely on the radioactive heat of decay of tritium. For one gram of

tritium approximately 0.333 watts is generated by decay. The temperature increase or heat

generation is measured. Calorimetry can be used for tritium in any form; either solid, liquid or gas.

The only radioactive material present must be tritium since other radioactive materials will contribute

to the thermal properties of the sample.

The final method determined the total tritium concentration by the measurement of the products or

the effects of the products of the radioactive decay. The beta particle can cause scintillation effects

or ionization effects. These effects can be measured and the concentration of tritium determined.

The following is a listing of methods that are used or proposed to be used for measurement of tritium:

1. Pressure/Volume/Temperature/Composition, using either Mass Spectrometer or laser Raman

spectrometer for the composition measurement,

2. Beta scintillation counter,

3. Self assaying tritium storage beds,

4. Scintillation counting, and

5. Ion Chamber.

Most of the techniques discussed here are batch samples, however as noted some techniques can be

used for "on-line / real time" measurements.