EXECUTIVE SUMMARY Under the Reactor Product Line (RPL) of DOE/NE's Nuclear Energy Advanced Modeling and Simulation (NEAMS) program, an SFR System Analysis Module is being developed at Argonne National Laboratory for whole-plant safety analysis. This tool will simulate tightly coupled physical phenomena-including nuclear fission, heat transfer, fluid dynamics, and thermal-mechanical response-in SFR structures, systems, and components. It is based on the MOOSE (Multi-physics Object-Oriented Simulation Environment) framework, which relies upon open-source libraries such as libMesh and PETSc for mesh generation, finite element analysis, and numerical solutions. This development is a coordinated effort along with the development of RELAP-7, which is an advanced safety analysis tool for light-water reactors developed at Idaho National Laboratory. The SFR Module is aimed to model and simulate the SFR systems with much higher fidelity and with well-defined and validated prediction capabilities. It will provide fast-running, modest-fidelity, whole-plant transient analyses capability, which is essential for fast turnaround design scoping and engineering analyses. The SFR System Module is being built based on RELAP-7 and the MOOSE framework. It leverages the common features between LWRs and SFRs (e.g., single-phase flow in a pipe and steam-system modeling for the balance of plant). The existing RELAP-7 physics models and component library are directly available for use in the SFR System Module. On the other hand, the SFR Module effort assists with RELAP-7 development by providing code verification and contributing general physics models and components applicable to all reactor types. Although the MOOSE and RELAP-7 based SFR system analysis module is a relative new effort (less than two years), significant accomplishments have been achieved. A 1-D FEM flow model using a pressure-based formulation with numerical stabilization schemes has been developed for use in incompressible sodium flows. A set of SFR-specific physics models and component has also been developed. The SFR primary system simulation capabilities of the SFR Module have been demonstrated by simulating the early stage of the Protected Loss-Of-Flow (PLOF) accident in the Advanced Burner Test Reactor (ABTR). Both the steady-state and PLOF transient simulation results are compared with the SAS4A/SASSYS-1 simulation results. It is confirmed that major physics phenomena in the primary coolant loop during the transient can be captured by the SFR Module. The SFR Module also emphasizes providing multi-scale multi-physics modeling capabilities by integrating with other higher-fidelity advanced simulation tools. This investigation is important to the integration between the MOOSE-based system code and the high-fidelity and medium-fidelity advanced simulation capabilities developed under the NEAMS RPL. The multi-scale coupling capability has been demonstrated in the coupled SFR Module and STAR-CCM+ code simulation of the ABTR PLOF transient. The importance of the multi-re...