A Roadmap to Testable Lattice-Assisted Nuclear Reactions: Interface-Dependent Screening in Metal Hydride Heterostructures

Five independent research programmes in condensed-matter nuclear science have reported results that are usually discussed separately: electron-screening measurements in deuterated metals (Raiola et al.), multilayer permeation/transmutation studies (Iwamura et al.), lattice-confinement fusion experiments in deuterated metals (NASA Glenn), critical loading/conditioning thresholds (McKubre and collaborators), and collective-surface neutron models (Widom–Larsen). This preprint proposes a single experimental programme that connects those lines of work and tests one specific hypothesis. The core hypothesis is experimentally simple and falsifiable: in metal-hydride systems, the effective electron screening relevant to low-energy nuclear reactions increases with the number of metal–insulator interfaces in the host structure. If this is correct, interface count becomes an engineering control parameter that can be measured and optimised directly. The paper develops:- a quantitative screening-scaling hypothesis (with explicit caveats and control samples),- a multilayer Pd/CaO target architecture (7 samples including volume and anisotropy controls),- a Raiola-style deuterium-beam measurement protocol to extract Ue(Neff),- predefined success / weak-signal / null-result criteria,- and a New Zealand implementation pathway using existing ion-beam and thin-film facilities (GNS Science, Victoria University of Wellington, ANSTO). A geometric/topological framework (Skyrmion / S³ / 24-cell programme) is included as theoretical motivation and as a source of additional quantitative predictions. These are presented as testable predictions rather than established results, including:- a screening-energy ceiling estimate (~841 eV, consistent with measured 70–900 eV range),- a per-interface screening increment (~140 eV, vs measured ~176 eV),- a loading-threshold estimate near D/Pd ≈ 0.93 (vs empirical > 0.9),- an even-deuteron capture selection rule from 2T group theory,- and phonon/anisotropy predictions for follow-up experiments. This is not presented as a claim that LENR is solved. It is a proposal for a decisive, relatively low-cost experiment (NZD 235–390K over 12 months) that can confirm or reject a specific interface-scaling mechanism on a practical timescale. A clear null result would still be scientifically valuable because it would rule out one of the most direct engineering interpretations of the prior screening and multilayer literature. v3.2 — Updated with quantitative predictions from the Geometric Framework v8.0. Two companion papers are under journal peer review (Foundations of Physics, Physics Letters A); three are published as preprints on Zenodo. The framework yields 14 quantities from zero adjustable parameters across particle physics, cosmology, and condensed matter nuclear science. Four rounds of adversarial review (three ChatGPT, one Claude). 15/15 numerical verification checks passed.