The Department of Energy (Department) is considering a proposal known as the 2020 Vision One System (2020 Vision) that would implement a phased approach to commissioning the $12.2 billion Waste Treatment and Immobilization Plant (WTP) including making the Low-Activity Waste (LAW) facility operational approximately 15 months before commissioning the remainder of the project. Although the implementation of the phased approach offers potential benefits, early operation of the LAW facility presents significant cost, technological and permitting risks that could adversely affect the overall success of the Office of the River Protection Project's mission of retrieving and treating Hanford Site's tank waste in the WTP and closing the tank farms to protect the Columbia River. Despite identified challenges, the Department had not developed a detailed analysis of the costs, benefits and risks of the proposal even after such steps were recommended by two independent review teams. Department officials told us that they completed a high level business analysis of certain WTP costs. However, our review found that this effort did not include a cost analysis with sufficient detail to satisfy the recommendations in the external review reports. Additionally, key technology attributes needed for the proposal may not be adequately developed to support operations. In response to our findings, Department management concurred with our recommendations, and proposed and initiated corrective actions to develop a more detailed business case analysis and to gain stakeholder input on the early treatment of LAW prior to making a decision to proceed with the proposal.