This International Standard specifies the conditions for determining the activity concentration of tritium in environmental water samples or tritiated water ([3H]H2O) using a liquid scintillation counter. The selection of the analytical method, whether with or without distillation of the water sample before the determination, depends on the aim of the measurement and the properties of the sample. When directly measuring raw water samples using the liquid scintillation meter, the potential presence of beta-emitting radionuclides must be taken into account. In order to avoid interference with such radionuclides when they are detected, tritium quantification is carried out by distillation after sample treatment. Three distillation processes are described in Appendices B, D and E. This procedure is not suitable for the analysis of organically bound tritium. This determination requires further chemical processing (such as chemical oxidation or combustion). Under suitable technical conditions, the detection limit can be 1 Bq l-1. Activity concentrations of tritium below 106 Bq l-1 can be determined without sample dilution. Prior enrichment can significantly reduce the detection limit.
EN ISO 9698:2015 Referenced Document
ASTM D4107-08 Standard Test Method for Tritium in Drinking Water*， 2024-04-20 Update
ISO 11929:2010 Determination of the characteristic limits (decision threshold, detection limit and limits of the confidence interval) for measurements of ionizing radiation - Fundamentals and application
ISO 5667-14:2014 Water quality - Sampling - Part 14: Guidance on quality assurance and quality control of environmental water sampling and handling
ISO 5667-1:2006 Water quality - Sampling - Part 1: Guidance on the design of sampling programmes and sampling techniques
ISO 5667-3:2012 Water quality - Sampling - Part 3: Preservation and handling of water samples
ISO 80000-10:2009 Quantities and units - Part 10: Atomic and nuclear physics