For example, the UK strategy for Magnox decommissioning involves deferring decommissioning of the reactor core for about 100 years because in this time a key radionuclide, cobalt-60, will decay to insignificant levels. This enables much greater man-access to the reactor, meaning reduced risks and reduced costs. Drivers for the complex decommissioning challenges associated with legacy waste facilities such as those at Sellafield are similarly simple – although also very complex in their derivation and execution – in that timely hazard reduction needs to be achieved in a manner that is robust to irresolvable uncertainties and identified risks.

Quintessa can help to highlight such driving factors around which detailed plans can be built. We do this through structured assessment of strategic options (e.g. BAT studies), backed up with technical knowledge of the decommissioning process. As part of this where decisions are subject to significant uncertainty, we have applied the Evidence Support Logic (ESL) approach to help understand and present the impacts of uncertainty, and to present the case for action given the issues that require management. The periodic review of decommissioning strategies using such approaches is important in ensuring that they remain valid against evolving technologies, regulatory requirements, and funding profiles.