A novel model was proposed for U-Tube Steam Generators in Pressurized Water Reactors to be utilized in dynamics and control studies. The steam generator was divided into 14 nodes and investigated by applying mass and energy conservation equations in differential form. A system of nonlinear differential equations was obtained. This equation system was numerically simulated using the Julia programming language through a fourth order Runge–Kutta method. Accurate values for thermodynamic properties were taken from the Coolprop library, eliminating the need to take constant values or linear interpolations. A three-element proportional and integral control was applied as the control system in the model. Changes in feedwater flow rate, steam outlet flow rate, primary inlet flow rate, feedwater inlet temperature and primary inlet temperature were investigated, and the response of the steam generator was simulated using the developed model. It was observed that the proposed model gives results for U-Tube Steam Generators comparable to those in the literature and that it can be used in dynamic model and control simulations.

In this study, the chemical exergy of low profile industrial lignite has been studied through a case study at the 1440 MW Afşin-Elbistan B lignite-fired power plant. Chemical exergy methods in the literature were applied to design lignite to investigate results on the exergy efficiency of the power plant for different power rates. The ASTM standard and well known methods have been compared by equating higher heating value (HHV) to chemical exergy. The HHV and chemical exergy of the design lignite were investigated with a previous study to locate the fuel for the plant among the tertiary coals in Turkey. These approaches predicted exergy efficiencies ranging between −2.08% and 4.29% from the average value of the mentioned methods, which showed that there existed an array of exergy efficiencies. The HHV, dry and ash-free chemical exergy and as-received chemical exergy values of Afşin-Elbistan lignite had a very low profile among the tertiary coals in Turkey.