Abstract: A plant evaluation system is configured to calculate performance of a plant while receiving setting of operating conditions of the plant and devices installed in the plant and simulating a secular change occurring in the plant during an evaluation target period included in the operating conditions. At least one of the devices is added, a selection of a component improving performance of a certain device is received, and an improvement of the performance of the device by the component is expected and the performance of the plant is calculated.

Abstract: Heat-receiving pipes of a heat receiver have portions having high heat flux on at the side near an opening in a length direction and extending to positions outside of a casing in a radial direction. Expanded sections having an expanded pitch circle diameter constituted by the plurality of heat-receiving pipes are formed, and a heat input quantity per unit area of the heat-receiving pipe is decreased in the portions near the opening.