Nowadays the Project Management is increasingly adapted into almost all the fields in business management processes among leading companies both in Korea and overseas. However its actual practices are rare to be found. Among the Project Life Cycle, this report covers the real cases of the PMBOK knowledge areas in NPP Architect Engineering. The areas of the Construction, Start-up and Operation will be exception of the cases. By way of analyzing the KEPCO ENC's Processes/Procedures/Systems and the ones in PMBOK Guide, this report will show the contents in the PMBOK Guide is rather practical than theoretical. Meanwhile, implications whether the conclusions of this report might be applied to other industries such as general construction, non-nuclear plants, etc. should be left behind to follow-up studies.