EFEK DENSITAS BAHAN BAKAR TERHADAP PARAMETER KOEFISIEN REAKTIVITAS TERAS RRI

Abstract

The multipurpose of research reactor utilization make many countries build the new reserach reactor. Trend of this reactor for this moment is multipurpose reactor type with a compact core to get high neutron flux at the low or medium level of power. The research reactor in Indonesia right now is already 25 year old. Therefor, it is needed to design a new research reactor as a alternative called it innovative research reactor (IRR) and then as an exchanger for old research reactor. The aim of this research is to complete RRI core design data as a requirement for design lisince. Calculation done is to get the RRI core reactivity coefficients with 5 x5 core configuration and 20 MW of power, has more than 40 days cycle of lenght. The RRI core reactivity coefficient calculation is done for new U-9Mo-Al fuel with variation of densities. The calculation is done by using WIMSD-5B and BATAN-FUEL computer codes. The result of calculation for conceptual design showed that the equilibrium RRI core with 5x5 configuration, 450 g, 550 g and 700 g of fuel loadings have negative reactivity coefficients of fuel temperature, moderator temperature, void fraction and density of moderator but the values of the reactivities are very variative. This results has met the safety criteria for RRI core conceptual design.