GEN-IV and SMR systems should be designed for operational lifetimes exceeding 60 years, under high temperatures and in corrosive environments, where conventional qualification based on long uniaxial creep and corrosion campaigns becomes a major bottleneck. LEXPOPLAN develops an accelerated qualification path by validating Small Punch Creep (SPC) testing as a reliable, minimally invasive method to assess the long-term structural integrity of 316L(N) austenitic stainless steel. The task benchmarks SPC against conventional uniaxial creep in both air and liquid lead, and demonstrates SPC capability for structural health monitoring by testing creep-damaged material extracted from uniaxial specimens with known histories. LEXPOPLAN establishes protocols to quantify and model combined creep-corrosion damage using pre-corroded and in-situ tested specimens in liquid Pb, including corrosion-rate estimation, cross-section loss assessment and true-stress corrections. Results will be consolidated into predictive creep and creep-corrosion models. All datasets will be structured in FAIR, ECCC-compatible formats, feeding a dedicated database and enabling a code of practice and recommendations supporting standardisation and nuclear design rules.