Method for calculating a PCI margin associated with a loading pattern of a nuclear reactor, associated system, computer program and medium

A method for calculating a pellet-cladding interaction margin associated with a loading pattern of a nuclear reactor comprising a core in which fuel assemblies are loaded according to the loading pattern, the fuel assemblies comprising fuel rods each including nuclear fuel pellets and a cladding surrounding the pellets,

• the method being implemented by a computer and comprising the following steps:
• b) calculating a reference principal pellet-cladding interaction margin for a reference loading pattern of the fuel assemblies in the core,
• c) calculating a reference secondary pellet-cladding interaction margin for the reference loading pattern,
• d) calculating a modified secondary pellet-cladding interaction margin for a modified loading pattern of the fuel assemblies in the core,
• e) calculating a modified principal pellet-cladding interaction margin for the modified loading pattern, depending on a comparison of the modified secondary pellet-cladding interaction margin with the reference secondary pellet-cladding interaction margin;
• the method further comprising controlling, by the computer, the state of the power balance of the nuclear reactor by using the calculated principal pellet-cladding interaction margin for a considered loading pattern of the fuel assemblies in the core to avoid rupture by pellet-cladding interaction of the claddings present in the core,
• wherein when the modified secondary pellet-cladding interaction margin is greater than or equal to the reference secondary pellet-cladding interaction margin, the modified principal pellet-cladding interaction margin is equal to the reference principal pellet-cladding interaction margin, and
• when the modified secondary pellet-cladding interaction margin is less than the reference secondary pellet-cladding interaction margin, the modified principal pellet-cladding interaction margin is less than the reference principal pellet-cladding interaction margin.