Preliminary design and analysis of a sodium-cooled, graphite-moderated TRISO-matrix reactor (SGTR) using OpenMC modeling

Date

2025

Authors

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Abstract

A pin cell of a sodium-cooled, graphite-moderated, thermal TRISO reactor (SGTR) is simulated and analyzed in OpenMC, an open-source Monte Carlo modeling program. The thermal properties, depletion characteristics, and power production capacity for a single pin are detailed and studied in this report, with extrapolation to a reactor comprised of 700 fuel rods. The assembled reactor core is designed to produce 100 MWth, maintains a positive reactivity through the 60th month of operation, and operates at a burnup of 79.5 (GW_d)/(MTU ) during this period. The fuel pin is simulated using a homogenous fuel material mix to approximate varying size TRISO beads embedded in a zirconium matrix at a packing fraction of 0.55. The fuel pin measures 400 cm in length with a radius of 3.6 cm, surrounded by a coolant channel of width 1.314 cm and a 20 cm pitch of graphite moderator between hexagonally arranged pins, and thin layers of stainless-steel cladding line the coolant channel. The reactor design requires 100 fuel pins arrayed among each of its 7 hexagonal subassemblies, such that each pin generates 142.9 kW at operational power. The SGTR reactor yields a core power density of 57.32 MW/m^3 with an initial heavy metal loading of 2263.8 kg Uranium.

Description

Keywords

Small Modular Reactor (SMR), Tri-structural Isotropic (TRISO) Fuel, Graphite Moderator, Sodium Coolant, OpenMC

Graduation Month

August

Degree

Master of Science

Department

Department of Mechanical and Nuclear Engineering

Major Professor

Jeremy A. Roberts

Date

Type

Report

Citation