PRELIMINARY STUDY ON URANIUM SILICIDE FUEL WITH 4,8 GRU/CC ON RSG-GAS FUEL ELEMENT WITH BURNABLE POISON WIRE FOR REACTIVITY REDUCTION

• Main Author: Luthfi, Wahid
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/86905
• Institution: Institut Teknologi Bandung

Fuel with high uranium density can extend the core cycle length of a nuclear reactor. The G.A. Siwabessy Multipurpose Reactor (RSG-GAS) as one of the research reactors owned by Indonesia uses silicide fuel (U3Si2-Al) with a uranium density of 2.965 grU/cc and 19.75% enriched uranium. Several studies have been conducted showing that fuel with a higher density, 4.8 grU/cc, can be used in the RSG-GAS core to extend the operating cycle. Previous studies have discussed several highdensity fuel conversion scenarios to overcome the increased reactivity of the RSGGAS core since the amount of in-core fuel element must be kept the same while maintaining the core design parameters. However, several conversion scenarios to a high density 4.8 grU/cc require the addition of control rods to suppress the excess reactivity of the RSG-GAS. This thesis focuses on determining the configuration of burnable poison in the form of a wire made of neutron-absorbing materials, namely cadmium, and hafnium on suppressing the fuel element reactivity (k-inf) at the beginning of cycle for 4.8 grU/cc fuel to approach the reactivity of 2.965 grU/cc. The k-inf calculation was performed using the SRAC2006 code system with several burnable poison wire configurations obtained from SRAC2006 recalculated using the Monte Carlo approach with the open-source program, openmc. 5 pairs of Cdwire with 0.4 mm diameter coated by 0.1 mm thick AlMg2 cladding or 7 pairs of 0.8 mm diameter Hf-wire without cladding can initially suppress the reactivity of the fuel element. The use of high-density 4.8 grU/cc fuel is projected to increase the duration of the reactor core cycle to reach 1000 MWD from only 625 MWD when using 2.965 grU/cc fuel. The moderator temperature coefficient of reactivity (MTC) and fuel temperature coefficient of reactivity (FTC) also become more negative in the high-density fuel of 4.8 grU/cc but the amount of Pu-239 produced also increases compared to the standard density of 2.965 grU/cc.