Abstract: The electric heater of the concentrated boron circuit in nuclear power plants is a critical equipment to ensure the safety function of reactor core emergency cooling. Fault tree analysis (FTA) is applied to verify and analyze the root causes of specific failure cases. Detailed operation methods and risk mitigation measures are provided for replacement work. Technical improvement plans and management strategies are proposed to address potential hazards in design and manufacturing. This study aims to assist maintenance personnel in handling such issues and effectively enhance system reliability.