Nuclear Engineering and Technology

Korean Nuclear Society (한국원자력학회)
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Tritium radioactivity estimation in cement mortar by heat-extraction and liquid scintillation counting

  • Kang, Ki Joon (Department of Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST)) ;
  • Bae, Jun Woo (Department of Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST)) ;
  • Kim, Hee Reyoung (Department of Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST))
  • Received : 2020.08.29
  • Accepted : 2021.06.03
  • Published : 2021.11.25
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Abstract

Tritium extraction from radioactively contaminated cement mortar samples was performed using heating and liquid scintillation counting methods. Tritiated water molecules (HTO) can be present in contaminated water along with water molecules (H2O). Water is one of the primary constituents of cement mortar dough. Therefore, if tritium is present in cement mortar, the buildings and structures using this cement mortar would be contaminated by tritium. The radioactivity level of the materials in the environment exposed to tritium contamination should be determined for their disposal in accordance with the criteria of low-level radioactive waste disposal facility. For our experiments, the cement mortar samples were heated at different temperature conditions using a high-temperature combustion furnace, and the extracted tritium was collected into a 0.1 M nitric acid solution, which was then mixed with a liquid scintillator to be analyzed in a liquid scintillation counter (LSC). The tritium extraction rate from the cement mortar sample was calculated to be 90.91% and 98.54% corresponding to 9 h of heating at temperatures of 200 ℃ and 400 ℃, respectively. The tritium extraction rate was close to 100% at 400 ℃, although the bulk of cement mortar sample was contaminated by tritium.

Keywords

Acknowledgement

This study was supported by the Industrial Technology Innovation Program (20191510301210, Development of Dismantling Technology for the Volume Reduction of Radioactively Contaminated Tanks) funded by the Korea Energy Technology Evaluation and Planning (KETEP, South Korea).

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