In order to systematically perform the decommissioning for nuclear power plant, it is several necessary to establish an inventory of relevant waste based on aspects such as classification, transportation, disposal, and cost estimation. This inventory can be developed by referencing various internal data regarding mechanical, instrumentation and electrical, and civil structures of the nuclear power plant, coupled with on-site inspections and interviews with plant personnel. Through this process, an inventory of decommissioning waste including weight, dimensions, and radiation levels can be complied. Subsequently, based on the inventory findings, dismantling plans for various areas of the nuclear power plant can be formulated, facilitating the smooth progress of decommissioning-related operations.