https://aest.aut.ac.ir/ Advances in Energy Sciences and Technologies en daily 1 Wed, 01 Apr 2026 00:00:00 +0330 Wed, 01 Apr 2026 00:00:00 +0330 https://aest.aut.ac.ir/article_6034.html Geothermal energy is a clean and renewable source of energy with low impact on the environment and the ability to provide a continuous source of energy for electricity generation. In the current study, a detailed thermodynamic model of the geothermal power plant is developed, modelled and analyzed using the energy and exergy analysis methods in order to identify the major sources of irreversibility, efficiency reduction, and performance limitation within the geothermal power plant components. To improve the efficiency and performance of the geothermal power plant, a multi-objective optimization strategy using metaheuristic, classical, and reinforcement learning algorithms is implemented to maximize the net power and exergy efficiency, and the investment and operation costs are minimized. The results are useful for the optimal design and development of efficient and cost-effective geothermal power plants using the capabilities of the optimization algorithms to obtain an effective compromise between the thermodynamic and cost-based performance parameters. https://aest.aut.ac.ir/article_6035.html Crack formation in plasma-facing materials (PFMs) under extreme transient heat loads poses a critical challenge for tokamak operation. This study investigates crack initiation and propagation in tungsten PFMs subjected to high transient heat fluxes using finite element simulations based on the Johnson–Cook constitutive model. Simulations were conducted for heat loads of 100 MJ/m² and 60 MJ/m² to capture the effects of both load amplitude and exposure time. At 100 MJ/m², cracks initiated at 0.15 s from the sample edges and propagated symmetrically toward the center, eventually leading to surface delamination. For 60 MJ/m², crack initiation was delayed to 0.5 s, with slower propagation and less extensive damage, demonstrating the strong dependence of crack evolution on both thermal load and duration. The analysis revealed that Mode I (opening mode) cracking predominates, driven by load gradients between surface and subsurface elements. These results provide quantitative insight into the thresholds for structural instability in tungsten PFMs and highlight the critical role of transient thermal stresses in predicting material performance under tokamak conditions. The findings offer valuable guidance for the design, selection, and engineering of PFMs in future fusion reactors.