Abstract: Nuclear facilities are equipped with continuous sampling and on-line monitoring systems for measuring airborne radioactivity discharged from the stacks to determine if airborne effluent emissions would meet the regulatory requirements. These systems are also used for timely detection and alarm of abnormal releases. However, measurement accuracy would be directly affected by the representativeness of sampling from airborne effluents. Both the ISO standard ISO 2899—2010 and ANSI/HPS N13.1—2011 standard have established specific quantitative criteria on the performance of sampling and monitoring systems for airborne effluents from nuclear facilities. In this paper, technical background for the preparation of the above standards and the relevant work conducted both at home and abroad are reviewed. The quantitative criteria and validation methods recommended in these standards are analyzed. This can provide guidance for demonstration and implementation of sampling representativeness of airborne effluents. Meanwhile, the study can also provide references for the design of vents and sampling systems of airborne effluents in nuclear facilities.

Key words: sampling representativeness, airborne effluents, mixing homogeneity, qualification tests, deposition loss