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Description:
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The purpose of this report is to present the results of the study and analysis of loss -of -coolant and loss -of -flow simulations performed on the Modular Helium Reactor developed by General Atomics using the thermal -hydraulics code RELAP5 -3D /ATHENA . The MHR is a high temperature gas cooled reactor . It is a prismatic core concept for New Generation Nuclear Plant (NGNP ) . Very few reactors of that kind have been designed in the past . Furthermore , the MHR is supposed to be a highly passively safe concept . So there are high needs for numerical simulations in order to confirm the design . The project is dedicated to the assessment of the passive decay heat capabilities of the reactor under abnormal transient conditions . To comply with the requirements of the NGNP , fuel and structural temperatures must be kept under design safety limits under any circumstances . During the project , the MHR has been investigated : first under steady -state conditions and then under transient settings . The project confirms that satisfying passive decay heat removal by means of natural heat transfer mechanisms (convection , conduction and radiation ) occurs . |