Enhancing hydraulic stability in once-through steam generators of small nuclear power plants: A novel approach using throttling baffles and feed pipes

Given the increasing global interest in small nuclear power plants (SNPPs), the proposed research aims to investigate the design of once-through steam generators (OTSGs) used in SNPPs, with a particular focus on ensuring hydraulic stability in the heat exchange tubes. The study will examine the theoretical issues of ensuring stability and propose a new approach that includes the installation of throttling baffles and feed pipes to achieve hydraulic stability in OTSGs. The research will use a 45 MW capacity OTSG as an example, based on the design of the ship nuclear power plant KLT-40S, whose heat exchange surface (HES) is a set of coaxial cylindrical coils, similar to 60% of SNPPs with pressurized water reactors (PWRs). The rest of the SGs have either straight or Ushaped vertical heat exchange tubes (HET). The study will also explore the results of calculating the additional hydraulic resistance in front of the heat exchange tubes and propose a new method for clarifying the existing inequality used to ensure stability. Ultimately, the goal of this research is to provide a novel design for OTSGs based on throttling baffles and feed pipes to ensure hydraulic stability in SNPPs and provide new insights and methods for research in this field