Facility Measurement Recommendations

DOE-STD-6003-96

can be used to determine high concentrations of tritium. Ion chambers will measure

any radioactive material that can cause ion pairs. They are also susceptible to con-

tamination from materials that adsorb on surfaces and can only be used for gas.

4.4.8.4 Facility Measurement Recommendations

a. Measurement of tritium input/output to facility. The primary method used historically

for the measurements of the tritium shipment has been the PVTC measurement with

the composition determined by either a mass spectrometer or beta scintillation

counter. A calorimeter can be used for the measurement of tritium absorbed on solid

storage beds that are designed to be used as primary shipping containers and also

be placed in the calorimeter.

b. 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 of all

the gas to a volume for sampling and measurement. This is usually a substantial dis-

ruption of the process and will take a significant time. Tritium that is "held up" in pro-

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

in process components such as a 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 offered 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.

c. 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.

d. 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 pas-

sive 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 sieve are used to absorb HTO. These system 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.