The NRC issued an environmental assessment and FONSI for an exemption request by Duke Energy Carolinas, LLC allowing Catawba Nuclear Station (York County, South Carolina) to maintain one already-loaded and to load nine additional transportable storage canisters (TSCs) in the MAGNASTOR storage system at its ISFSI beginning July 6, 2026, even though neutron absorber panels in those ten TSCs were fabricated outside the special process instructions required by CoC No. 1031, Amendment No. 15. A fabrication deficiency reported by NAC International in September 2025 showed that 3M-supplied panels failed boron-10 areal density requirements, but engineering evaluations confirmed the reactivity impact is negligible. The NRC found no significant radiological or non-radiological environmental impacts and determined a full EIS is not warranted.1234