Thermal-hydraulic Safety Assessment of a Miniature Neutron Source Reactor

Abstract

The main objective of this study is to assess the thermal-hydraulic safety capability of the PLTEMP/ANL v 4.0 in analyzing Ghana Research Reactor-1 (GHARR-1), with vertical fuel rods cooled by natural convection, operating at a nominal power (30 kW) with sufficient safety margins. The neutronic analysis of the core was performed using MCNP X code, where parameters of interest were the power distributions and the power peaking factors. The thermal-hydraulic model of the Ghana Research Reactor-1 core was simulated using the PLTEMP/ANL v 4.0 code designed for steady-state axial nodal analysis. The thermal-hydraulics axial properties of all 344 fuel rod bundled together with the individual lattice positions in the reactor core have been modeled. Applying the concept of hot channel factors, ring A was determined to be the hottest region in the core containing the hottest fuel rod and coolant channel. Also, the hot spot location on each fuel rod was observed to occur on the axial node twelve (12) for all fuel rods with each fuel rod having twenty-one axial nodes. The main thermal-hydraulic safety margins of the core have been evaluated. The outcome of this work certifies that GHARR-1 can be operated at steady state without compromising on safety.

Keywords:  Thermal hydraulics, safety assessment, fuel rod, mcnp x, uranium 235, PLTEMP /ANL v 4.0 code, natural convection