This is complete summation of the assessment of the risks and alternatives for a long-standing practice at the Sellafield site — storage of high level radioactive waste (HLW) as a liquid. The Sellafield HLW tanks represent one of the world’s most dangerous concentrations of long-lived radioactive material. Although IRSS’s work has focused on risks and alternatives for HLW management, the work has necessarily addressed some related issues. IRSS has examined the economics of nuclear fuel reprocessing at Sellafield, the UK approach to assessing nuclear activities and alternative options, and the effectiveness of the UK Nuclear Installations Inspectorate (NII). A repeated theme in this report is the need for open, comprehensive assessments of issues facing the UK nuclear industry. Though a detailed, comprehensive assessment of risks and alternatives would require a considerably larger budget and much better access to information, this interim assessment is unique and provides important lessons for policy making.