It is the sensitivity and confidentiality of nuclear power plant decommissioning cost that prevent detailed cost information to be released to the public, which causes some limitation to analyze and reuse the costs. This limitation to access cost information means that the lessons learned from preceding cost estimating may not systematically feed back into following cost estimates. As an alternative, decommissioning cost estimation framework is indispensable to reflecting available experience and knowledge for decommission costs. This study provides the cost estimation framework including data flow and structuralization based on engineering and bottom up approach to enhance decommissioning cost estimation.