Design of a new Small Modular Nuclear Reactor using TVS-2M Fuel Assemblies and Fuel Depletion analysis during the fresh-core cycle length

Abstract

In this paper, a new fresh Small Modular Nuclear Reactor core with changes on the Fuel Assembly-type, fuel enrichment, and gadolinium (Gd) concentration of the Fuel Assemblies (FAs) is designed and proposed to improve and enhance the NuScale nuclear reactor as a typical PWR-Small Modular Reactor. An algorithm is additionally presented to redesign the core consisting of square lattice FAs into a core including hexagonal FAs. This algorithm is implemented based on the utilization of MCNP code which classifies the design criteria considering simplified modeling and complicated modeling with high computational cost. The algorithm is helpful for a designer to manage the computational cost of modeling during the design process.Core design Basis Limits including Neutronic and Thermal-hydraulics (TH) analysis, are performed and verified for the first cycle of the presented new Small Modular Nuclear Reactor as a Hexagonal NuScale (HNu). Via ANSYS-FLUENT& MCNP codes, TH and Neutronic analysis have been coupled. Also, the burnup calculations for the presented core have been done to analyze the core first cycle length. The excess reactivity and power peaking factor have been assessed during the first-cycle length. Average core fuel depletion has been taken into account, and masses of produced fission fragments and build-up of plutonium isotopes and the remaining mass of uranium isotopes (and Gd) have been computed at the end of the cycle (EOC).The presented new core (HNu) has the benefits of both the TVS-2M FA and NuScale. Compared to the NuScale, HNu has several advantages and superiority, such as increasing MDNBR, decreasing the maximum temperature of fuel and clad, more fuel burn-up, longer working cycle length, and decreasing the maximum power peaking factor.