Sustained Excess-Heat Production in Gas-Phase LENR Experiments Using Engineered Nanoscale Materials

Reports in the low-energy nuclear reaction (LENR) literature describe observations of nuclear signatures and net energy production from hydrogen-fueled experiments. However, progress has been delayed by the lack of reproducible experimental pathways. In this review, we identify an emerging pathway involving low-energy input, gas-phase systems, and nanomaterials. Specifically, we review reports of (a) excess-heat production in which the output thermal power exceeds the total system input electrical power, (b) excess thermal power and time-integrated excess energy, (c) repeatability by originating research groups and reproducibility by independent laboratories, and (d) specific energy and energy density values that exceed known chemical energy-density limits under the reported normalization. Furthermore, we identify a shift in the last decade away from Pd–D2 electrolytic systems and toward more successful Ni–H2 gas-phase systems employing engineered nanoscale materials. We also discuss known unresolved technological challenges. LENR experiments are distinct from beam, accelerator, and other ion-driven fusion experiments as well as magnetic- and inertial-confinement fusion systems, which use moderate- to high-energy inputs to induce nuclear fusion reactions. The non-LENR approaches produce the expected fusion products. In contrast, LENR experiments involve materials-mediated condensed-matter processes initiated by much lower external input energies. LENRs produce nuclear reaction products, but they are not consistent with the product pairs, energies, and branching ratios expected from deuterium-deuterium (D-D) nuclear fusion. Among all these approaches, only LENR experiments have demonstrated system-level net power output. A further distinction is that all of those fusion experiments, when producing measurable thermal output, also produce commensurate levels of penetrating ionizing radiation; LENR experiments do not.