Knowledge acquisition and knowledge base verification are important activities in developing knowledge-based systems such as alarm processing systems in nuclear power plants (NPPs). In this work, we developed an integrated tool, for knowledge acquisition and verification of NPP alarm processing systems, by using a G2 tool. The tool integrates the documents analysis method and extended colored Petri net (ECPN) matrix analysis method with backward simulation for knowledge acquisition and knowledge verification, respectively. This tool enables knowledge engineers to perform their tasks from knowledge acquisition to knowledge verification effectively and consistently. (C) 2001 Published by Elsevier Science Ltd.