Download Intro_RASTK-F (to be updated)

The Recommended Publication for Citing

  1. Tuan Quoc Tran, Alexey Cherezov, Xianan Du, Deokjung Lee*, “Verification of A Two-Step Code System MCS/RAST-F to Fast Reactor Core Analysis”, Nucl. Eng. Tech., (2021)
  2. Tung Dong Cao Nguyen, Hyunsuk Lee, Deokjung Lee*, “Use of Monte Carlo Code MCS for Multigroup Cross Section Generation for Fast Reactor Analysis”, Nucl. Eng. Tech., 53(9): 2788-2802, (2021)
  3. Tuan Quoc Tran, Siarhei Dzianisau, Tung Dong Cao Nguyen, Deokjung Lee*, “Verification of a depletion solver in RAST-K for Fast Reactor Analysis”, KNS Winter Meeting, Korea (online), Dec 16-18 (2020)
  4. Jaerim Jang, Alexey Chezerov, Yunki Jo, Tuan Quoc Tran, Siarhei Dzianisau, Woonghee Lee, Jinsu Park, Deokjung Lee*, “Verification of RAST-K hexagonal transient solver with OCED/NEA benchmark problem of KALININ-3 NPP”, KNS Winter Meeting, Korea (online), Dec 16-18 (2020)
  5. Jaerim Jang, Tuan Quoc Tran, Siarhei Dzianisau, Woonghee Lee,  Deokjung Lee*, “Verification of RAST-K hexagonal analysis module with SNR and VVER-440 benchmarks”, KNS Winter Meeting, Korea (online), Dec 16-18 (2020)


The RASTK-F code is under further development at the Ulsan National Institute of Science and Technology (UNIST) for the hexagonal-z geometry including the extension of two-group rectangular solver to multi-group hexagonal solver and the update of thermal-physical properties of fast reactor core materials in the internal thermal-hydraulic solver. The triangle-based polynomial expansion nodal (TPEN) method is implemented in the code to solve the multi-group neutron diffusion equation in the 3D hexagonal-z geometry. The change of nuclide concentrations during burnup steps are determined by solving Bateman equation. At present,  Chebyshev Rational Approximation Method (CRAM) is implemented in nodal diffusion code RAST-K and is adopted for fast reactor with hexagonal lattice (RASTK-HEX). Acceleration of the RASTK-F depletion solver by GPU is also under interrogation. The required 24 energy group cross section set for RASTK-HEX can be generated using our in-house Monte Carlo code MCS.

Physics Model


– Triangle-based Polynomial Expansion Nodal method (TPEN)

– CMFD acceleration

XS model

– Multi-group group constants from STREAM2D

– Micro XS for micro depletion

TH feedback

– 1D radial heat conduction

Fuel cycle analysis

– Micro-depletion for 28 actinides and 193 fission products

– CRAM depletion solver

– Sparse Gauss-Seidel Solver

– Predictor/corrector

– Triangle depletion

Engineering Features

– Multi-cycle calculation (shuffling, rotation)

– Restart calculation

The RASTK-F is verified by MCS with an in-house design of a SMLFR