Initial Demonstration of New Griffin Technologies for Simulating the Running-In Phase of Pebble Bed Reactors

Technical Report · Mon Jun 17 04:00:00 EDT 2024

DOI:https://doi.org/10.2172/2402990· OSTI ID:2402990

Hanophy, Joshua Thomas ^[1]; Park, Hansol ^[2]; Labouré, Vincent M. ^[1]; Jung, Yeon Sang ^[2]; Schunert, Sebastian ^[1]; Wang, Yaqi ^[1]; Ortensi, Javier ^[1]

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1. Idaho National Laboratory (INL), Idaho Falls, ID (United States)
2. Argonne National Laboratory (ANL), Argonne, IL (United States)

Griffin is a reactor multiphysics modeling application based on MOOSE (Multiphysics Object-Oriented Simulation Environment) and specifically targeting transient modeling of advanced reactors. Griffin has been used recently to model pebble-bed reactors for the Nuclear Regulatory Commission (NRC) Office of Nuclear Regulatory Research and the Advanced Reactor Technology program. This modeling work has focused thus far on the direct calculation of equilibrium cores. This report documents an initial demonstration of a new running-in simulation capability. The new running-in capability is verified using the existing direct equilibrium core calculation capability. A simplified pebble-bed reactor model is then used to demonstrate the running-in simulation capability. This demonstration shows that Griffin is able to simulate years of operation during the running-in phase efficiently with each depletion step taking only several seconds. Two new technologies are also presented in this report which have been developed in Griffin that will be essential for improved accuracy both of the direct equilibrium core computation and the new running-in simulation capability. The first technology is an online cross section generation capability specifically targeted for pebble-bed reactors. This will improve the accuracy of the depletion calculation as the cross sections are generated at the exact core status. This also avoids the difficult step of pre-generating a separate standalone multigroup cross section set. Secondly, a newly implemented discretization for discontinuous finite element method (DFEM) SN transport in cylindrical (RZ) coordinates, which can be solved efficiently using the existing SN sweep solver, is discussed and some results are shown demonstrating the usefulness of the additional accuracy transport provides over a diffusion approximation.

• Research Organization: Idaho National Laboratory (INL), Idaho Falls, ID (United States); Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE)
• DOE Contract Number: AC07-05ID14517; AC02-06CH11357
• OSTI ID: 2402990
• Report Number(s): INL/RPT--23-74913-Rev000
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
Pebble Bed Reactor
burning-in
running-in