A wide range of unirradiated and irradiated uranium and plutonium mix­tures of fast reactor fuels has been left over from the research programme. These require a high level of security for the site and their storage arrange­ments. The NDA reviewed the credible options for this fuel which included stakeholder consultation. The top two options were continued storage at Dounreay or transfer to Sellafield. The former would require rebuilding of stores over a 100-year period and continuing high level security arrange­ments. The latter would allow use of common facilities and security at Sellafield but would entail transfers through many communities. The deci­sion to transfer the exotic fuels to Sellafield as the preferred option was made in February 2013 (NDA, 2013).