Isomer Energy Architecture: Triggered De-excitation of High-K Nuclear Isomers as a Conceptual Energy Store

Isomer Energy Architecture: Triggered De-excitation of High-K Nuclear Isomers as a Conceptual Energy Store C. J Tully Independent Researcher, Engineer Australia https://orcid.org/0009-0007-5661-7332 [email protected] 29th October 2026 Abstract This work examines whether nuclear-scale energy can be stored in a long-lived metastable nuclear isomer and released on demand without a neutron chain reaction. The candidate material is hafnium-178m2 (excitation energy 2.446 MeV, half-life approximately 31 years, spin-parity 16+). One gram of the pure isomer stores approximately 1.32 GJ, or about 28,800 times the energy density of gasoline and roughly 62 times lower than uranium-235 fission. DE excitation produces gamma rays and conversion electrons, not neutrons; a fission-like chain reaction is therefore impossible. The isomer is itself radioactive, and its production may generate radioactive byproducts, so claims of zero radioactive waste are not accurate. Triggered de-excitation of 178m2Hf remains experimentally contested and has not been independently demonstrated at a usable cross section. The architecture described here is a theoretical research program, not a demonstrated reactor. Unsupported claims of 99.1% conversion efficiency, failure probabilities below 10^−93, non-radiative magnetic self-quenching, and absolute safety are removed. Keywords: nuclear isomer; 178m2Hf; triggered de-excitation; energy storage; no chain reaction.