FULL CORE MODELLING OPTIMIZATION OF PB-BI COOLED CANDLE REACTOR FOR STARTUP AND EQUILIBRIUM STATE USING PARALLEL COMPUTATION MCNP6 CODE

• Main Author: Afifah, Maryam
• Format: Dissertations
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/87087
• Institution: Institut Teknologi Bandung

The CANDLE Reactor (Constant Axial Shape of Neutron Flux, Nuclide Densities, and Power Profile during the Life of Energy Production) is a Generation IV reactor with a unique fuel-burning pattern resembling a candle that burns from the top down or vice versa. This reactor can operate using natural uranium during the equilibrium state. At startup, the fuel composition is assumed to be based on the spent fuel from an APWR reactor. The objective of this research is to determine the initial fuel composition at startup to ensure the reactor remains critical until it reaches the equilibrium state, analyze various neutronic characteristics, and evaluate the effects of thermal power variation and core size on neutronic calculations. The reactor design was then optimized to achieve a lower excess reactivity compared to the initial design. Neutronic calculations were conducted using the Monte Carlo method with MCNP6, referencing the Evaluated Nuclear Data File (ENDF/B-VII.1). Preliminary results show that for core designs with thermal power variations from 400 MWth to 800 MWth, criticality can be maintained for 80 years of burnup . Burning wave velocity can be calculated from the shifting of power peak position for several thermal power core designs. After optimization, a minimum of 4 assembly layers with around 240 fuel pins per assembly was achieved. The optimized design resulted in reactivity below 2%.