Fusion Science and Technology / Volume 54 / Number 1 / July 2008 / Pages 174-177
Technical Paper / Tritium Measurement
TriathlerTM Model 425-034 single vial liquid scintillation counter (LSC) counters have been in use at the Safety and Tritium Applied Research Facility (STAR) for approximately three years. During facility setup and determination of instrumentation needs to support STAR facility operations, the Triathler was chose to assess smearable tritium contamination levels for operational conditions. The Triathler was selected due to the rapid turnaround time for obtaining tritium contamination levels versus other automated batch LSC counters currently in use at the Idaho National Laboratory (INL) and other Department of Energy (DOE) installations. Operational experience with the Triathler thus far has shown a high reliability for verifying removable contamination levels at a level of < 1,000 Disintegrations Per Minute (DPM) per 100 cm2 when compared to the PackardTM Tri-Carb 1905 AB/LA Liquid Scintillation Analyzer used by the Reactor Technologies Complex (RTC) Radiochemistry Measurements Laboratory (RML).
However, variances in the reported results for activity in DPM/vial from the Triathler versus the Packard Tri-Carb have been noted when operating in the range of 5,000 to 20,000 DPM. These variances make reliability and use of the Triathler suspect for verifying smearable contamination levels meet the release criteria identified in DOE Order 5400.5, Radiation Protection of the Public and Environment. Ensuring that removable tritium contamination levels on materials and equipment intended for free-release to the public are < 10,000 DPM per 100 cm2 is a requirement in the Idaho National Laboratory (INL) contract.
Comprehensive cross-comparisons have been ongoing to ensure the Triathler LSC reported DPM values provide sufficient detection of smearable tritium contamination when cross-compared to other automated liquid scintillation counters available at the INL.