Evaluation of the operational and financial resilience of the nuclear sector during a global pandemic

• Pandemic financial flexibility varied among nuclear regulators and waste operators. • Regulators show weaker surplus-based resilience (<0) compared to operators (0–4.44). • Regulators also show tighter budget control than waste operators (0.27 < BUR < 0.95). • Operators’ resilience rising by 55%, outpacing regulators (−94%) in post-pandemic. • More research on the operational and financial resilience of the sector is warranted. Existing studies provide limited insight into financial resilience in nuclear governance by overlooking the combined roles of institutional structure and operational efficiency. This study develops a phase-based financial resilience framework integrating surplus per output efficiency, balance-sheet structure, revenue efficiency, and budget utilization, and applies it to two nuclear regulators (ONR, CNSC) and two waste management operators (SÚRAO, ENRESA) over a 7-year study period with pre-pandemic, COVID-19, and post-pandemic phases. Regulators follow a workforce-driven oversight model with limited surplus capacity (FSE −0.57 to + 0.12 million USD·TWh −1 ). In contrast, waste management operators emphasize long-term repository stewardship and exhibit stronger surplus performance, particularly ENRESA (peak FSE + 4.99), indicating greater shock-absorption capacity and sustained management resilience. Regulators also show tight budget control, with BUR clustering near unity, while waste management operators consistently operate below unity (0.27–0.95), reflecting deliberate budget underspending to preserve funds for long-term goals. The phase-based pandemic analysis reveals that waste management operators (surplus and revenue efficiency rising up to + 55%) consistently outperform regulators (surplus and revenue efficiency decreases upto −155%). Stewardship-oriented and balance-sheet-based funding models enable operators to absorb shocks and recover more quickly than workforce and fee-dependent regulatory models. These findings reveal uneven financial robustness across nuclear governance and centrality to nuclear energy security. This insight provides a practical basis for aligning funding design with institutional mandates to strengthen resilience under future systemic shocks.