[en] In the final stage of decommissioning nuclear facilities, building structures are demolished to be green field conditions if dismantling is chosen as a decommissioning strategy. Since building structures are generally made from massive reinforced concrete materials, it is not a rational way to treat all concrete materials arising from its demolition as radioactive waste. Segregation of radioactive parts from building structures and measurement of radioactivity are therefore indispensable before demolishing building structures. The procedure of decontamination and measurement of radioactivity were studied for demolition of building structures in consideration of treating waste as non-radioactive materials, on the basis of the concept published by Nuclear Safety Commission. This procedure was then implemented in the Japan Power Demonstration Reactor dismantling demonstration project. The data obtained in the project relating to decontamination and measurement of radioactivity showed that the procedure was reasonable, and that the experiences will be useful for future decommissioning of nuclear power plants in Japan. This report describes the procedure studied on the segregation of non-radioactive waste related to decommissioning nuclear facilities, and the results of its implementation in the Japan Power Demonstration Reactor dismantling demonstration project. (author)