Newcleo is designing and building the next generation of nuclear lead-cooled fast reactors (LFRs) fueled with MOX. A fast-spectrum Small Modular Reactor of 30 MWe will be commissioned in 2030 (the Demonstrator) and a First-Of-Kind 200 MWe a few years later. To this end, newcleo develops an incremental strategy, starting first with the consolidation of mature and promising technologies with its own R&D laboratories and collaborations with major institutes and companies. This step aims to demonstrate the applicability of chosen technologies to a full mock-up of the reactor (the Precursor) available in 2026 for experiments. Inclusion of ISI&R (In Service Inspection and Repair) at the earliest stages of designs is a necessity to achieve a sufficient level of maturity and confidence in the technologies, and to increase safety, availability, and preservation of investments of experimental devices and reactors during their whole life.