DE-TOP has been developed by the International Atomic Energy Agency as a tool for the thermodynamic analysis and optimization of nuclear cogeneration systems (currently with options for nuclear desalination and district heating applications). DE-TOP can be used to models the steam power cycle (Rankine cycle) of different water cooled reactors or fossil plants, and the coupling with any other non-electrical application. With an intuitive graphical user interface and flexible system configuration, the user can select different coupling arrangements between power plant and non-electric application (single steam extraction, multiple steam extraction, backpressure operation, etc.). DE-TOP executes thermodynamics energy and exergy analyses of the cogeneration system and produces detailed reports for plant performance at different cogeneration modes. The DE-TOP tool is under continuous development. Currently, DE-TOP 2.0 Beta version is available to download.