A web portal for nuclear reactor domain has been developed and is christened as Knowledge Management for Nuclear Reactor (KMNuR). This article reports about the development of the portal for fast breeder test reactor (FBTR). The methodology adopted for the development of the portal is described. Formats like RDF (Resource Description Framework), OWL (Web Ontology Language), Graphs, UML (Unified Modeling Language) were used to represent nuclear reactor knowledge. The ontology for the portal is created using Protégé. Central data processing system of the FBTR is taken as an example for giving the details of the functionality of KMNuR portal and its knowledge representation.