The global energy demand is increasing by 2-3% every year due to boosted strong global economic growth. The challenge of satisfying energy demands goes with the increase in carbon emissions, and efforts to combat climate change are still far from satisfactory. The low carbon, secure and economic ways of energy production such as nuclear fission reactors are still under investigation. The main challenge for energy production from nuclear power lies in the improvement of current technologies to achieve economic competitiveness with safety, sustainability, and demonstration of safe disposal of radioactive waste. This doctoral studentship will provide significant impact from its outcomes to pilot and demonstrate the economic, social, and environmental viability of low carbon development pathways of energy production. The research project will establish a foundation for the use of nanotechnology in nuclear structure materials to meet the exceptionally high durability and structural integrity demands of the irradiated environment. The stability of nanoparticles in the nuclear-irradiated environment will be used to underpin the safe life of the structure materials and develop a proactive risk mitigation framework preventing unexpected failures in the nuclear reactor life cycle to assist regulatory, compliance and safety standards for translation of nanotechnology in the nuclear energy production supply chain. The cladding and tubing of nuclear reactor components are expected to resist against synergetic interaction of irradiation and thermal ageing. The low cycle fatigue (LCF) during start-up/ shutdown of reactors and creep-fatigue interaction are the damage and failure mechanisms in the life cycle of the material. However, the interaction of irradiation with thermal loads age hardens the material. The ductility reduction of the material also affects the ultimate plastic strain posing a significant threat of sudden unexpected failures in the start-up and shutdown process of nuclear reactors which causes plastic strain in the LCF regime. The ODS steels provide high resistance against irradiation, creep, and swelling without considerable degradation of their material properties hence can be extremely useful in cladding, tubing, and the blanket of high-temperature Gen-IV nuclear reactors. The Body-Centered Cubic (BCC) crystalline ODS steels with added nano-size yttrium oxides trap the radiation-induced point defects and helium bubbles without substitution transformation of crystal structures. The resistance against creep and creep-fatigue interaction has been the subject of interest for the qualification of the materials for nuclear reactor applications. However, the life cycle of materials with nanoparticles cannot be characterised with conventional macro and microscale deformation test methods. The nanoparticles in the life cycle of material transform to new complex oxides and sometimes are released from agglomerates; both conditions in nuclear reactor applications are ill characterised. The loading on the material with a considerable percentage of nanoclusters promotes the stress concentration with the bulk material leading to premature failure of the material at thermomechanical stresses well below the design stresses. Our understanding of ODS steels material behaviour has reached to a level where the deformation in creep and creep-fatigue interaction is well understood. The current nanomaterials regulations do not consider the functionality, implementation, transformation, ageing, and accidental release consequences of nanoparticles in the process liquor. There is very little knowledge about the secure low activation, maintenance, hazardous nature, and safe disposal of material with transformed nanoscale particles in irradiated service life. The designs for low-risk unexpected failures of materials with nanoparticles