Advancing seismic risk metrics for nuclear infrastructure in low-to-moderate seismicity regions: a CAV-interval framework for Ghana

As Ghana advances towards nuclear power deployment, seismic safety requires attention despite its low-to-moderate seismicity. Conventional Seismic Probabilistic Safety Assessment (SPSA) typically combines Peak Ground Acceleration (PGA) with lognormal fragility models; however, PGA alone does not explicitly capture shaking duration, while single fragility parameter sets may conceal epistemic uncertainty. This study develops a screening-level Ghanaian SPSA framework using Cumulative Absolute Velocity (CAV) as the principal intensity measure and bounded fragility parameters for a representative emergency diesel generator (EDG). The CAV hazard domain spans 0.05–0.25 g·s, with median CAV capacity sampled over 0.20–0.28 g·s and logarithmic dispersion β over 0.30–0.45. Uncertainty is propagated exclusively through Monte Carlo simulation using 100,000 Latin Hypercube samples in MATLAB R2024a. The resulting EDG-based seismic core-damage-frequency surrogate ranges from 1.9 × 10−6 to 7.5 × 10−6 reactor−1 year−1, whereas a conventional PGA point case yields 2.8 × 10−6 reactor−1 year−1. Because the cases differ in intensity measure and uncertainty representation, the difference cannot be attributed solely to CAV. These component-level screening estimates are neither a complete plant-level SPSA nor validated site-specific risk results. The framework transparently represents duration sensitivity and bounded uncertainty while identifying regional data and component-testing requirements for validation and future regulatory application.