The Reactor Physics Laboratory & Computational Analysis Laboratory (RPL) at KINGS (KEPCO International Nuclear Graduate School) is dedicated to cutting-edge research in nuclear reactor physics, computational methods, and advanced core design. Located in Ulsan, Korea — the heart of Korea's nuclear energy industry — RPL bridges rigorous academic research with real-world nuclear engineering applications.
Our work spans the full spectrum of reactor physics computation: from first-principles Monte Carlo neutron transport to industry-grade whole-core diffusion solvers, and from traditional PWR core design to innovative Small Modular Reactor (SMR) concepts. We develop, validate, and deploy in-house simulation tools used to support next-generation nuclear energy systems.
With a strong international team of graduate researchers and deep ties to KEPCO Nuclear Fuel, RPL is uniquely positioned at the intersection of academia and industry.
Associate Professor & Head, Department of Nuclear Power Plant Engineering, KINGS
Prof. Joo-il Yoon is an Associate Professor and the Head of the Department of Nuclear Power Plant Engineering at KINGS. He earned his B.S., M.S., and Ph.D. degrees in Nuclear Engineering from Seoul National University — one of Asia's premier research institutions — completing his doctoral degree in 2021. His academic training is complemented by over a decade of applied industry experience at KEPCO Nuclear Fuel (KNF) from 2008 to 2023, where he contributed to the development of next-generation nuclear design codes and reactor core analysis tools.
Prof. Yoon's research program is defined by a commitment to high-fidelity computational methods for reactor physics, with particular emphasis on Monte Carlo neutron transport, deterministic transport solvers, and AI-enhanced simulation techniques. He leads the development of in-house codes including MONTEX (MONTEcarlo code for neutroniX), SPHINCS(SPH-based Pin-Homogenized Innovative Neutronics Core Simulator) and CROMA (Characteristics-based Reactor Operation and Multigroup Analysis).
Seoul National University, 2021
Seoul National University, 2009
Seoul National University, 2007
Associate Professor & Head, Nuclear Power Plant Eng. Dept., KINGS
Assistant Professor & Head, Nuclear Power Plant Eng. Dept., KINGS
Manager, Nuclear Fuel Design Department, KEPCO NF
Principal Nuclear Engineer, KEPCO NF
Nuclear Engineer, KEPCO NF
Name: Jae-seung Song
Position: Research Prof.
Email: smartjssong@naver.com
Research Topic:
- Pressurized Water Reactor Core Design & Analysis
- Develpment of DeCART2D/METIS Code System for SBF SMR Core Design
- Korea Atomic Energy Research Institute, Pricipal Researcher, April 1985 ~ April 2026
- Chosun University, Deprt. of Nuclear Engineering, Concurrent Prefessor, March 2002 ~ February 2007
- B.Sc. in Nuclear Engineering,
Seoul National University
- M.Sc. Nuclear Engineering, Korea Advanced Institute of Science and Technology
- Ph.D. Nuclear Engineering, Korea Advanced Institute of Science and Technology
- PWR Core Design and Analysis using LEU+ Fuel
- Boron Free PWR Core Design and Analysis PWR
- Load Follow and Flexible OperationV
- Removal of large piping (No LB-LOCA)
- Canned motor RCP
- Spiral steam generator
- Top-mounted ICI
- In-Vessel CEDM (No REA Acc.)
- 520 MWth (17x17, 2.4m, 69 FAs)
- Soluble boron-free operation design
- Daily Flexible operation
- 24-month long cycle operation
- Strong Burnable Absorbers
- High Fidelity Nuclear Design Code System
HIGA is a novel strong burnable absorber developed for soluble boron-free SMR operation, combining Gd₂O₃-Al₂O₃ ceramic pellets with a HANA-6 cladding tube to achieve highly intensive neutron absorption with excellent structural integrity.
- Gd₂O₃-Al₂O₃ (10~20 mol.% Gd₂O₃)
- HANA-6 Cladding, Active height: 2.4m
- Al₂O₃ cutback sections: 10~50 cm
- Diameter: ∅9.5 / ∅8.35 / ∅8.18 mm
HIGA Rod Design — HANA-6™ Cladding Tube with Gd₂O₃-Al₂O₃ neutron absorber pellet
- Developing high-fidelity neutronics code for reducing 1% of box and peaking factor uncertainties in commercial nuclear design
- Box Calculation Uncertainty: Fq,box = 4.78%, Fr,box = 3.66%, Fxy,box = 4.33% → target: 3~4%
- Control rod inserted operations, flexible operations without soluble boron → Highly and locally heterogeneous flux distribution
- Too much poison burnable absorbers for controlling excess reactivity → Highly and locally heterogeneous depletion effect
- ~20,000 neutronics calculations for nuclear design of one cycle
- Less than a minute per calculation to complete in a week (2400 minutes)
- Conventional CPU multi-core cluster systems as target hardware platform
Implementing diffusion-based 2D/1D decoupling method with parallelization for pin-by-pin neutronics calculation
Developing CMFD acceleration scheme for spatial homogenization and energy group condensation
Determining pin-by-pin equivalence factor and appropriate coarse energy group (GET vs SPH Method)
Establishing two-step calculation procedure for pin-by-pin nuclear design
Developing pin-by-pin transient calculation by modifying node-wise transient calculation scheme
Evaluating pin-by-pin code system with benchmark problems
- Development of high-fidelity neutronics code for Sodium-cooled Fast Reactor (SFR) core analysis
- Hexagonal fuel assembly geometry with pin-by-pin power distribution
- Core pin power distribution visualization and error analysis
- Coupling of CFD solver (CUPID) with neutronics codes via preCICE framework
- FEM-based fuel performance analysis
- SPHINCS and Monte Carlo code integration
- Radiation heat transfer and thermal-hydraulics coupling
- Numerical methods for Molten Salt Fast Reactor (MSFR) core analysis
- Griffin/Pronghorn code system application
- Fuel salt, reflector, shield, pump, and heat exchanger modeling
Advancing the frontiers of computational reactor physics, multi-physics and SMR/PWR and GEN-IV Reactor core design at KEPCO International Nuclear Graduate School, Ulsan, Korea.