A dimensioning study on electric vehicle batteries as components of a post nuclear detonation radiological environment

Understanding the neutron activation of modern urban materials following a nuclear detonation is important for effective emergency rescue and response planning, yet neutron-activation data for contemporary infrastructure remain limited. This study presents a dimensioning assessment of neutron-induced activation in electric vehicle (EV) battery systems, an increasingly common high-mass, high-metal component of modern cities. Using detailed Monte Carlo simulations, supported by controlled activation experiments with a thermalized neutron field, the activation products and resulting dose rates for three major battery chemistries (NMC-811, NCA, and LFP) arranged in a representative battery pack, were evaluated. Results show that EV batteries can generate substantial short-lived gamma activity immediately after neutron exposure, dominated by ²⁸Al, ⁶⁴Cu and ⁵⁶Mn for nickel- and cobalt-bearing chemistries, while long-term activity is driven primarily by ⁶⁰Co (NMC/NCA) and ³²P (LFP). Dose rate estimations indicate that elevated fields may be present during the first hours post-detonation but decrease by several orders of magnitude within 24 h. Comparisons with activation of urban road materials reveal that ²⁴Na generated in asphalt and sand substrates can equal or exceed battery-derived dose contributions. Overall, EV batteries constitute a relevant but transient localized radiological hazard in the immediate aftermath of a nuclear detonation, with significance highly dependent on battery chemistry and the timing of response operations. These findings support improved modelling of post-detonation environments and help contextualize EV batteries within broader urban activation scenarios.