Open Access

ARTICLE

BEDOK: An In-House Numerical Reactor Simulator Effort in Singapore

Yan Ren Than, Sicong Xiao^*
Singapore Nuclear Research and Safety Institute, National University of Singapore, 16 Prince George’s Park, Singapore
* Corresponding Author: Sicong Xiao. Email:
(This article belongs to the Special Issue: Neutronic and Thermal-Hydraulic Analysis of Advanced Nuclear Reactors)

Energy Engineering https://doi.org/10.32604/ee.2026.082487

Received 17 March 2026; Accepted 27 April 2026; Published online 03 June 2026

Abstract

This paper presents the development and capabilities of the Broad-scope Environment for Dual-phase advanced reactor Operation simulation Kit (BEDOK), an in-house nuclear reactor simulator code created in Singapore to enhance regional expertise in the complex field of numerical simulation techniques and its applications. Designed with an emphasis on both flexibility and precision, BEDOK currently supports steady-state problems in light water reactors (LWRs), with the intention of further development of simulation capabilities, which may cover advanced small modular reactors (SMRs) that are of interest in the local region. The code features a modular architecture, allowing easy integration of thermal-hydraulic models, neutron kinetics, and fuel behaviour algorithms in future development. BEDOK is currently demonstrated with the semi-analytical nodal method for neutron kinetics as well as a four-equation drift-flux model for thermal-hydraulics. Validation against IAEA and NEACRP LWR core benchmark problems confirms the accuracy and robustness of the steady-state core neutronics driver, as well as the thermal-hydraulic feedback module, which is itself verified against OECD sub-channel bundle tests. BEDOK also demonstrates the accommodation of acceleration and stability techniques for non-linear solvers, for which the choice is also intended to be modular, given the wide variety of techniques in existing literature. Some novel insights regarding the convergence to the highly non-linear drift flux equations are also presented.

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Keywords

Numerical simulator; drift-flux; nodal methods; multiphysics

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