Intermediate scale applications with Trio_U
 Application to new generation nuclear reactors: study of a blocking situation in the Helium channels



The nuclear core studied corresponds to that of a HTGR (High Temperature Gas Reactor).  It is a direct cycle high temperature reactor, with a thermal neutronic spectrum and whose coolant is Helium.  This study deals with the incidental blocking of Helium channels in a nuclear fuel assembling; the goal is to show the resulting temperature rise.

Blocking of Helium channels

 Application to new generation nuclear reactors: study of the flow in the outlet plenum



In gas cooled reactors, Helium flows through the core via holes perforated into fuel blocks.  Other secondary flow contributions converge to the outlet plenum.  These flows are at different temperatures and are then mixed.  This zone est thus the location of an intense turbulent mixing between hot Helium jets coming from perforated columns (coming from fuel blocks) and a cooler main flow.

Outlet plenum of a gas cooled nuclear reactor

 Application to new generation gas cooled reactors: study of the internal flow of a turbomachine



It is very important to know the thermal-hydraulic behavior within a compressor because the latter is a major coolant device for the core and is also a major device for the energy transformation.  In particular, the exploration of the application range of the compressor towards low mass flow rates is an important issue for the design and safety studies.  Low mass flow rates correspond to situations where the compressor blades are subject to large angles of attack of the flow.

Internal flow of a turbomachine

 Study of thermal fatigue


Thermal fatigue is a phenomenon that makes material more fragile when they are submitted to cyclic temperature variations. In the case of fluid flows in pipes, such fluctuations in the solid are due to fluctuations of the fluid temperature that flows inside the pipe.  These fluctuations are due to the turbulent nature of the flow. The temperature fluctuations are more particularly important down a T-junction as illustrated on the figure.

Study of thermal fatigue by large-eddy simulation

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