The Knowledge and Abilities Catalog for Nuclear Power Plant Operators: Advanced Boiling Water Reactors (NUREG-2104, Revision 0) provides the basis for the development of content-valid licensing examinations for reactor operators (ROs) and senior reactor operators (SROs). The examinations developed using the ABWR Catalog along with the Operator Licensing Examination Standards for Power Reactors (NUREG-1021) will sample the topics listed under Title 10, Code of Federal Regulations, Part 55 (10 CFR 55).