Carr argues that mainstream fusion—especially tokamak‑based D‑T systems like ITER and the planned DEMO plant—faces intrinsic, likely insurmountable barriers: extreme cost driven by enormous reactor size and complexity, chronically low availability due to rapid neutron‑induced component damage, and a fundamental scarcity of tritium that requires fission reactors to supply startup fuel. He contrasts this with mature, economically competitive fission, noting that fusion’s engineering challenges (breeder blankets, divertors, superconducting magnets, remote‑handling infrastructure) remain unresolved even after decades. ITER’s delays, manufacturing defects, and regulatory setbacks reinforce his view that commercial fusion is many decades away, while private‑sector alternatives either rely on unproven physics or face similar material limits. His conclusion is blunt: fusion offers no practical advantage over fission, will arrive far too late to matter for climate mitigation, and is unlikely ever to be economically relevant.
