Designing cost-effective and accurate nuclear decommissioning strategies has been an on-going challenge in UK and worldwide. This PhD project aims to develop waste management technologies and techniques for the recovery, accurate in-situ characterisation and treatment of nuclear wastes. Current strategies for decontaminating reactor storage ponds include uptake of Strontium and Caesium using ion exchange reactions creating a high volume of low-level waste, which is both expensive and problematic for long term storage. The proposed research would use bio-derived products (biochar, biopolymers, macro-algae etc.) which have much higher uptake capacity to concentrate metals and radionuclides via the formation of strong and stable chemical complexes. In particular, carbon products synthesized using hydrothermal carbonisation and pyrolysis would be selectively engineered for enhanced uptake of Strontium and Caesium resulting in much lower volume of intermediate level waste. These bio-derived products will be processed by secondary thermochemical treatment to further immobilise and concentrate the radionuclides. State-of-the-art synchrotron based x-ray absorption spectroscopy, imaging, and scattering techniques will be used to ascertain the fate and speciation of radionuclides at each step of the process. Overall, the project aims to accomplish stable species of highly compacted nuclear waste for cost-effective long terms storage.