A simulator is required if the system to be studied is very costly to construct and operate, or can cause dangerous and even disastrous consequences if operated wrongly. Nuclear reactor is one of such systems that highly need to be simulated. In case of nuclear reactors there are two more reasons to do so: the readiness of the operators to manage any situation may be kept on necessary level only with regular simulator training. Since the Chernobyl accident emerged from a not properly designed and executed experiment, it is practically impossible to get authorization to make experiments on an existing nuclear plant. New ideas, new control, protection systems and new types of technological ...view middle of the document...
To build and construct the nuclear plant simulators, the main scientific issues are the neutron kinetic model and the thermo-hydraulic model which their mathematical models must be solved simultaneously. For the purpose of education and training, the IAEA established a program in nuclear reactor simulation computer programs ,  for a variety of advanced reactor types, insight and practice in their operational characteristics and their response to perturbations and accident situations.
There are recent simulators were developed to imitate different types of nuclear reactors. PCTRAN  is a desktop simulator for all types of light water nuclear reactors which is specifically designed for many different plant types, including Pressurized Water Reactor (PWR), Boiling Water Reactor (BWR), and Economic Simplified Boiling Water Reactor (ESBWR). PCTRAN's simulation scope extends to severe accidents and dose dispersion. Since its first introduction in 1985 by Micro-Simulation Technology, PCTRAN has been selected by the IAEA as the training platform for its annual Advanced Reactor Simulation workshop. Plant-specific models have been installed at nuclear power plants and institutions all over the world for practical application in training, analysis, probabilistic safety assessment, and emergency exercises.
One of the main parts of the nuclear reactor is the reactor core, which contains the fuel elements, coolant, moderator and control rods. The other part is the coolant system, which contains the primary and secondary loops, heat exchanger and pumps. The core shielding is essential for safety and all operating actions in the reactor are controlled from the control room.
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