Grok —> The Russian Poseidon, a nuclear-powered, nuclear-armed torpedo, is claimed to trigger a “radioactive tsunami” devastating U.S. coasts. Experts dispute this, citing insufficient energy for a massive tsunami (e.g., 500m waves). A 2–100 megaton warhead could cause localized damage and contamination but likely only small waves (1–2m). Poseidon’s strategic role is likely psychological, with technical challenges delaying full deployment. U.S. coastal impact would be limited, not catastrophic.