Thermal hydraulic design of irradiation facility based on O-16 (n,p) N-16 activation in TRIGA reactor

Abstract

Water, typically used as the primary coolant in facilities such as fusion and fission reactors, could be exposed to a large amount of neutrons causing water activation. This phenomenon could cause radiation damage to electrical components and increase the dose to personnel. As there are only few sources of gamma rays with energies in the range of 6 MeV and 7 MeV, an irradiation system using activated cooling water as a source of energetic gamma rays is proposed at the Jozef Stefan Institute (JSI) TRIGA Mark II research reactor. A water activation irradiation loop design is proposed, inserted into a radial piercing port of a research reactor. In this thesis, a numerical model of the irradiation loop was developed and a CFD analysis was performed using ANSYS CFX. Pressure and velocity profiles were established and will serve as design limits and criteria reference for assembling the actual facility. Moreover, the 16N concentration inside the loop was studied. Its formation and decay inside the loop were predicted. This shall serve as reference for future experimental designs and further studies to be conducted using the proposed facility.