Neutron measurements at the KATANA water-activation loop using the neutron activation methodWłodarczyk, Jakub Piotr (Avtor) Bieńkowska, Barbara (Avtor) Łaszyńska, Ewa (Avtor) Govekar, Domen (Avtor) Kotnik, Domen (Avtor) Lengar, Igor (Avtor) Peric, Julijan (Avtor) Radulović, Vladimir (Avtor) Snoj, Luka (Avtor) Villari, Rosaria (Avtor) fusion reactorswater-activation loopAs the primary coolant, water is used in most of today's fission reactors and is also a promising coolant for future fusion reactors. During operation, in-vessel components will be cooled by water that is exposed to high-energy (E ∼ 14 MeV) neutrons produced in D-T fusion reactions. The water activates and produces radioactive nuclides that emit gamma rays and neutrons (neutron energy range 0.4-1.7 MeV). Predicting the dose-rate field due to activated water is a complex task that requires coupling computational fluid dynamics (CFD), radiation-transport and activation calculations.To study these phenomena and perform validation experiments, a water-activation loop named KATANA was commissioned at the Jožef Stefan Institute (JSI) TRIGA Mark II reactor.This paper examines the newly established KATANA water-activation loop and evaluates the feasibility of using the neutron activation method for neutron measurements at the facility. The studies show that this method can be successfully applied to detect and quantify neutrons originating from 17 N decay. Furthermore, the measurements demonstrate that this technique is capable of characterising the neutron emission rate at the KATANA activation snail. Finally, the paper proposes a method for estimating the neutron fluence at sample positions within the KATANA activation snail.The results encourage further use of the neutron activation method to investigate neutrons emitted by activated water. Future experiments could determine the neutron fluence-rate profile, thereby validating fluidactivation codes for ITER, DEMO and other fusion devices. This would also contribute to reducing the uncertainty of the 17 O(n, p) 17 N reaction cross section.IOP Publishing20262026-03-10 09:41:20Neznano28099UDK: 539.1ISSN pri članku: 1361-6587DOI: 10.1088/1361-6587/ae464fCOBISS_ID: 269721859Združeno kraljestvosl© 2026 The Author(s).