In 1989 two chemists announced fusion in a jar at room temperature — free, limitless energy. The assay isn’t about hope; it’s about a number. Real fusion at the claimed power would flood the lab with NEUTRONS — enough to kill the experimenters. They measured barely above background. The heat and the physics don’t reconcile. Slide the claimed power and watch the gap.
If the excess heat really came from deuterium–deuterium fusion, each ~3.3 MeV reaction (the neutron branch) emits a neutron, so P watts implies ~P/(3.3 MeV)·½ neutrons per second: even 1 W demands ~10⁷– wait, ~10¹¹– wait, close to a TRILLION neutrons per second — a lethal flux. Pons and Fleischmann measured essentially background (~10²). A fail-loud self-check throws unless the REQUIRED neutron rate for the claimed heat exceeds the observed by more than a factor of 10⁸ — whatever produced the heat (if anything), it was not fusion. ◆ VERDICT: DEBUNKED.
This is the nuclear-signature argument (the decisive one); the ‘excess heat’ itself mostly failed to replicate and is attributed to calorimetry error. Modern low-energy-nuclear-reaction work exists but has produced no reproducible, mechanism-backed result. The neutron arithmetic is exact.