Development of a computer code, ONCESG, for the thermal-hydraulic design of a Once-Through Steam Generator

Development of the conceptual design of a 300 MWt integral reactor, SMART ( System-integrated Modular Advanced ReacTor), for utilization in nuclear cog eneration plants has been completed at the Korea Atomic Energy Research Ins titute (KAERI). The major primary components of the SMART such as modular h elical steam generators, main circulation pumps and a self regulating press urizer are integrated into a reactor vessel. It is a common practice to emp loy a once-through steam generator in integral reactor designs because of i ts advantages in compactness and simplicity of the flow path arrangements. In this study, a thermal hydraulic design and performance analysis computer code for a once-through steam generator using helically coiled tubes, ONCE SG, is developed. To benchmark the developed physical models and computer c ode, once-through steam generators developed by other designers are simulat ed and ONCESG calculated results are compared with the design data. The ove rall characteristics of heat transfer area, pressure and temperature distri butions calculated by ONCESG showed general agreements with the published d ata and it is demonstrated that the ONCESG code can be utilized for diverse purposes, such as, sensitivity analyses and optimum thermal design of a on ce-through steam generator.