As an interesting sidelight : there is no generic LWR fuel. Core-design calculations have to be run for each reload, and the assemblies have to be tailored to match the desired reactivity profile, taking into account the history of the assemblies which are not being exchanged (but may be moved around). AREVA figures suggest that this is a full-time job for a nuclear engineer for each reactor supported.
Meanwhile, each and every CANDU bundle is identical.