F. RASTK-F

Download Intro_RASTK-F (to be updated)

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Introduction

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

Neutronics

– 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