Thermo-economic analysis of balance of plant for energy conversion system in Korean DEMO fusion power plant

Abstract

As carbon neutrality becomes a global priority, nuclear fusion power plants, such as K-DEMO, are considered promising candidates for clean and sustainable energy generation. In order to realize the nuclear fusion power plants, the design of Balance of Plant (BoP) for energy conversion system is essential. However, comprehensive studies on the BoP for energy conversion of K-DEMO are still lacking. This study proposes a preliminary design of K-DEMO BoP for energy coversion, consisting of the Primary Heat Transfer System (PHTS) and Power Conversion System (PCS), and evaluates the effectiveness of the divertor as a heat source through thermal performance and economic analysis. The system was modeled using EBSILON software, and the Rankine cycle, adopted in PCS, was validated by comparing simulation results with real operational data. Results indicate that utilizing the divertor as a heat source increases power generation but reduces thermal efficiency due to its placement within the cycle. An economic analysis was conducted for three cases: with the divertor, without the divertor and no additional heat from the blanket, and without the divertor but with additional heat from the blanket. The analysis indicates that, under current design constraints, blanket offers more favorable thermodynamic and economic outcomes. These findings suggest that while divertor as a heat source remains a necessary consideration for future system integration, development efforts at this stage may benefit from prioritizing the optimization of blanket heat utilization. The proposed BoP design provides a foundation for further system-level research and potential integration of advanced technologies.