Development of Transient Analysis Capability of PROTEUS-MOC for Micro-reactor Applications
Albert Hsieh, University, My
2022
Micro-reactors are gaining increasing interest from the industry, and various micro-reactors are being developed. These micro-reactors typically have a complex core configuration, and thus neutronics analysis are usually performed with Monte Carlo codes. However, the application of Monte Carlo method to transient analysis is not practical yet. Motivated by the need for accurate and efficient deterministic tool which supports irregular geometry problems, transient analysis capabilities and
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... ate acceleration schemes have been developed and implemented into the PROTEUS-MOC code of Argonne National Laboratory (ANL), which has an arbitrary geometry modeling capability through unstructured finite element meshes. To improve the computational performance of PROTEUS-MOC prototype for practical reactor problem applications, coarse mesh finite difference (CMFD) acceleration methods were developed and implemented in PROTEUS-MOC to speed up both the steady state and transient calculations. The original GMRES iteration method for solving the within-group transport equations was replaced with a nonlinear fixed-point iteration method. The conditionally stable CMFD acceleration method was replaced with the two-level partial current CMFD formulation (pCMFD), which is unconditionally stable and more efficient. More importantly, an unstructured CMFD method (uCMFD) was developed for the application to irregular complex geometry problems. Verification tests with the C5G7 benchmark, a TREAT experiment, and the EMPIRE micro-reactor design showed that the two-level CMFD results in a speed-up of ~20 times and the uCMFD yields a speed-up of more than 10 times. Three new pin-resolved transient solvers were developed into PROTEUS-MOC. Using the direct time integration method, a new transient fixed-source problem (TFSP) solver was developed without relying on the isotropic approximation of the angular flux time derivative. A moving axial mesh scheme was implemented to model the control rod movement without the control rod cusping problem [...]
doi:10.7302/4634
fatcat:253pdp3g4bganmhhnag2vz4lfu