Multi-physics core analysis and verification of NuScale reactor with coupling PARCS/RELAP

The attractiveness of small modular reactors (SMR) lies in high safety, simplicity of design, reduced siting costs, etc. The NuScale is considered one of the unique SMR reactors due to design advantages such as the immersion of the containment vessel in the reactor pool, natural circulation cooling mechanism, integrated loop, and flexibility of its safety functions for up to 72 h after severe accidents. Investigating the neutronic and thermal-hydraulic parameters of a reactor is one of the concerns of nuclear-reactor designers because such parameters play an essential role in the design process and safety assessment. Therefore, in the present study, the internal coupling capability of the PARCS and RELAP codes has been used to analyze the multi-physics parameters of the core and loop of the NuScale reactor. The DRAGON5 code was used to perform lattice calculations and prepare the PMAXS library for PARCS. The code-by-code verification of lattice and core calculations was carried out by the MCNP code. Multiplication factor, power distribution, fuel and moderator feedback coefficients, and other thermal -hydraulic parameters were calculated under a steady-state condition. Burnup calculations have also been performed to investigate the fuel cycle parameters. The results show an acceptable accuracy in comparison with the NuScale reported data.