UK-Norway Initiative: Research into Information Barriers to allow warhead attribute verification without release of sensitive or proliferative information.

The UK-Norway Initiative is an ongoing collaboration between a Nuclear Weapon State (NWS) and a Non-Nuclear Weapon State (NNWS) which seeks to investigate technical and procedural challenges associated with a possible future nuclear disarmament verification regime. This has been a process of building trust and cooperation in an area which presents significant technical and political challenges to both parties. In a future verification regime for nuclear warhead dismantlement, Inspecting parties are likely to request measurements on warhead and warhead components, to ensure that the items presented are consistent with the declarations made by the Host party. Such measurements are likely to be based on radiation signatures, and would be used to confirm physical attributes of the fissile material present within the system. Almost any measurement of this type, which would be of use for inspection purposes, would be likely to contain sensitive or proliferative information. It will therefore be essential for such measurements to be performed behind an Information Barrier which, while protecting the sensitive information, will reveal a pass/fail to an agreed attribute threshold. It will be crucial that the Information Barrier design process builds in mechanisms whereby both parties can have high confidence in the validity and veracity of any result obtained. This paper highlights the outputs from the ongoing technical cooperation between the UK and Norway on Information Barriers. This includes results from the jointly designed prototype Information Barrier system, and the process by which confidence in such a system could be built between two parties.