Characterization of the KATANA water activation loop in the JSI TRIGA reactor by reactor pulse operation using neutron detectors

¹ Jožef Stefan Institute, Reactor Physics Division, Slovenia
² Faculty of mathematics and physics, University of Ljubljana, Slovenia

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Published online: 6 November 2025

Abstract

This paper presents the characterization of the KATANA water activation facility in the TRIGA research reactor at the Jožef Stefan Institute (JSI), operating the reactor in pulse mode and using neutron detection techniques. The facility plays a crucial role in the benchmarking and validation of computational models relevant to nuclear fusion applications, particularly in the context of ITER. A dual approach was used to determine the system volume of the KATANA loop: a direct volumetric method involving a physical measurement and a novel neutron-based method using the circulation of neutron-activated water. The latter uses a ³He proportional counter to track the flow and decay of the short-lived ¹⁷N nuclides that emit neutrons with energies in the MeV range. Experimental results from both methods provided consistent volume estimates and confirmed the reliability of the neutron-based dynamic characterization technique. These results support future efforts in the development and validation of neutron and activation models for fusion-related systems.