Admissibility of Long-Timescale Helium Recycling in High-Energy Galactic Environments

The cosmic hydrogen–helium abundance ratio is commonly treated as a fixed outcome of primordial nucleosynthesis, with subsequent astrophysical processing assumed to play a minor role. In this work, we investigate whether long-timescale, non-stellar astrophysical environments can support partial recycling of helium into lighter baryonic constituents without violating physical self-consistency. Using a global dynamical simulation framework, we explore open, high-energy galactic systems incorporating cosmic-ray interactions, supernova shock processing, relativistic jet fragmentation, and transient unstable isotope pathways, while explicitly avoiding enforced primordial abundance constraints. An ensemble-based admissibility approach is employed to identify dynamically stable, long-lived solutions. We identify persistent regimes in which helium fragmentation, baryon redistribution, and reassembly relax into stable equilibria, maintaining causal structure, chemical coherence, and thermodynamic stability. These results demonstrate that secondary helium recycling is not forbidden by fundamental physical principles and may operate as an admissible process beyond primordial epochs. This work does not replace standard nucleosynthesis models, but establishes a theoretical foundation for investigating non-stellar baryonic recycling as a complementary mechanism in specific high-energy astrophysical environments.