Work

Simulation of water activation in the KATANA activation loop of the TRIGA reactor

Year: 2026

Type: article

Abstract: Water is widely used as a coolant in both fission and fusion nuclear reactors. However, when exposed to neutrons, it becomesactivated and can turn into a significant radiation source especially in fusion reactors operating with deuterium-tritium plasma. Thiseffect influences reactor design and requires accurate modeling to ensure safe and reliable operation. During the development of theITER fusion reactor, methods and codes were created to simulate the process of water activation and its flow through the coolingsystem. 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 Jozef Stefan Institute withthe 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 integratesfluid dynamics with neutron and gamma-ray transport simulations. The analysis focuses on activation calculations based on thelatest loop design. Additionally, we examine how uncertainties in some of the main input parameters, i.e. flow rate and the totalvolume of the loop components, influence the overall uncertainty in the determined activity of water.

Source: Fusion Engineering and Design

DOI: 10.1016/j.fusengdes.2026.115711

Authors: Primož Lesjak, Aljaž Čufar, Domen Kotnik, Julijan Peric, Marco De Pietri, Luka Snoj

Institutions: University of Ljubljana, Jožef Stefan Institute, Massachusetts Institute of Technology

Language: English

Topic: Nuclear reactor physics and engineering

Subfield: Aerospace Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Clean water and sanitation

Open Access status: hybrid

Estimated APC paid: $2,810