This workshop was designed to meet the needs of those currently involved in or are planning a nuclear programme involving research and/or power fission reactors. The workshop had a broad scope including not only fission reactor core calculations, but also safety, fuel management, waste disposal reactor licensing. The lectures and computer exercises covered almost all aspects of the operation of fission reactors.This workshop introduced participants to the methods currently used in fission reactor calculations and to some computer codes in which these methods are used.