20.500.12556/DiRROS-28544 Simulation of water activation in the KATANA activation loop of the TRIGA reactor Water is widely used as a coolant in both fission and fusion nuclear reactors. However, when exposed to neutrons, it becomes activated and can turn into a significant radiation source especially in fusion reactors operating with deuterium–tritium plasma. This effect influences reactor design and requires accurate modeling to ensure safe and reliable operation. During the development of the ITER fusion reactor, methods and codes were created to simulate the process of water activation and its flow through the cooling system. However, lack of relevant experiments needed for experimental validation of these codes was highlighted. In 2024, the KATANA water activation facility began operating at the TRIGA Mark II reactor at the Jožef Stefan Institute with the aim to improve understanding of water activation and to validate computational tools used for simulating it. This paper presents an analysis of water activation in the KATANA loop using the open-source FLUNED code, which integrates fluid dynamics with neutron and gamma-ray transport simulations. The analysis focuses on activation calculations based on the latest loop design. Additionally, we examine how uncertainties in some of the main input parameters, i.e. flow rate and the total volume of the loop components, influence the overall uncertainty in the determined activity of water. water activation KATANA IJS TRIGA fuzijski reaktorji true false true Elsevier Nizozemska Angleški jezik Slovenski jezik © 2026 The Authors. Neznano 2026-03-23 14:01:53 2026-03-23 14:01:53 2026-03-26 04:07:55 0000-00-00 00:00:00 2026 0 0 Nasl. z nasl. zaslona; Opis vira z dne 23. 3. 2026; str. 1-8 Vol. 227, [article no.] 115711 Jun. 2026 0000-00-00 Zaloznikova Objavljeno NiDoloceno 2025-10-06 2026-03-07 2026-03-16 539.1 1873-7196 10.1016/j.fusengdes.2026.115711 272669187 https://www.sciencedirect.com/science/article/pii/S0920379626000992?via%3Dihub 1 78e6372f-26b8-11f1-aa40-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=42340 RAZ_Lesjak_Primoz_2026.pdf RAZ_Lesjak_Primoz_2026.pdf 1 06DE50FDC3BD2085FFC163FF4B74868A 769c14a99c307ee110b29f2620a1e8f1c4e86c0748cff636e5dd2812130d29ec e0970950-26b8-11f1-aa40-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=42343 Institut Jožef Stefan 0 0 0