Modular basket assembly for fuel assemblies

A basket assembly for receiving a plurality of fuel assemblies and configured to accommodate an irregular fuel assembly, comprising:

• a basket having a grid comprising a neutron absorbing material and defining spacing between fuel assembly compartments, the grid defining a first compartment for receiving a first fuel assembly and a second compartment for receiving a second fuel assembly, wherein the cross-sectional area of the second compartment is larger than the cross-sectional area of the first compartment, the basket assembly configured to receive in the first compartment a first fuel assembly, the first fuel assembly being a regular fuel assembly, and the basket assembly configured to receive in the second compartment the second fuel assembly, the second fuel assembly being the irregular fuel assembly that requires a relatively larger cross-sectional dimension than a cross-sectional dimension of the regular fuel assembly, wherein the irregular fuel assembly includes at least one irregular fuel rod.