Methods for simulating the flow of a fluid in a vessel of a nuclear reactor and for calculating the mechanical deformation of assemblies of a nuclear reactor core, and associated computer program products

A method for simulating the flow of a fluid inside a vessel of a nuclear reactor, the nuclear reactor comprising the vessel and a core positioned inside the vessel, the core including nuclear fuel assemblies, each assembly extending in an axial direction and including nuclear fuel rods and at least one grid for maintaining the rods, each assembly being spaced apart from another assembly by a clearance between the grids in a transverse direction perpendicular to the axial direction, the fluid being able to flow inside the core,

• the method comprising, implementing by a computer including a processor and a memory associated with the processor, the following steps:
• i) determining head loss coefficients in the core by determining a transverse head loss coefficient in the assemblies as a function of a transverse Reynolds number in the transverse direction, and determining an axial head loss coefficient in the clearance as a function of the dimension of the clearance in the transverse direction;
• ii) computing the pressure of the fluid and component(s) of a speed of the fluid in the core, using the following equation:
• ∇P=−K×V
• where ∇ is the order one spatial derivation nabla operator,
• P is the component of the pressure of the fluid,
• K is a matrix including the head loss coefficients determined during step i), and
• V is a vector including the component(s) of the speed of the fluid;
• and
• generating a simulation of the flow of the fluid inside the core such that the fluid is simulated to flow inside the core in accordance with values of the pressure of the fluid and the component(s) of the speed computed in step ii).