EFFECT OF THORIUM FUEL ADDITION IN THE CONFIGURATION OF PUSPATI TRIGA REACTOR

Abstract

A neutronic configuration analysis of thorium fuel has been conducted to PUSPATI TRIGA Reactor (RTP) that are using uranium zirconium hydride (U-ZrH1.6) as fuel. Sixty nine core configurations have been simulated in this project, with each core has different investigated parameters. The project use the design of core RTP, which is core #1 as the reference. It has a similar dimension, criticality (484 PCM difference), and flux distribution with the original core of RTP. There are three main core variations, namely core-01, core-02, and core-03 that are modelled and simulated. Core-01 has additional numbers of thorium fuel rods. Core-02 has extra rods of thorium fuel in ring F with subtraction of uranium fuel rods in the core. Lastly, core-03 has an arrangement of thorium fuel rods in a seed-blanket unit. All three main configurations have ten variations with each of them has different numbers of fuel rods. These variations are labelled from ‘A’ until ‘J’. This work also investigates other configurations such as the checker box design, ring by ring design, and diamond shape design. Other important variables are also studied, such as power, mass, and types of thorium fuels. All these configurations are simulated using MCNPX to determine its criticality, flux distribution, burnup rate, and uranium-233 buildup. Results show that core-Ct has the highest production of uranium-233 with 334.9 gram, and core-Bt has the longest lifecycle, which is 399 days. Thermal fluxes recorded from all simulated configurations are almost similar to the actual RTP core’s flux, ranging from 4.28  1012 to 1.36  1013 n/cm2s. Overall, the seed-blanket configuration offers the most favourable characteristics, especially criticality, that can be beneficial for PUSPATI TRIGA Reactor (RTP).