Abstract

Quantitative analysis of radioactive nuclides is essential for the disposal of radioactive waste generated during the operation and decommissioning of nuclear facilities. Among these, tritium (³H), carbon-14 (¹⁴C), and iodine-129 (¹²⁹I) are representative target volatile nuclides requiring strict management due to their significance in radioactive waste handling. This study established optimal conditions for simultaneous separation and quantification of ³H, ¹⁴C, and ¹²⁹I in various waste matrices using high-temperature thermal decomposition and wet digestion methods. The pretreatment conditions were optimized by comparing the recovery rates of ³H, ¹⁴C, and ¹²⁹I under varying temperature and flow rate conditions during high-temperature decomposition. Additionally, selective application of liquid scintillation counting (LSC) and inductively coupled plasma mass spectrometry (ICP-MS) was proposed for precise measurement of the target nuclides. The established pretreatment methods (high-temperature decomposition and wet digestion) and measurement techniques (LSC and ICP-MS) were applied to various waste samples, including soil, concrete, sludge, resin, metal, plastic, rubber, and paper, to evaluate the effectiveness of the methods.