A Boundary-Limited Physical Framework for Runaway Failure in Localized Confined Energy Systems

This paper presents a physics-based classification framework for understanding runaway failure in localized confined energy systems, such as batteries, pressure vessels, chemical reactors, and enclosed fuel systems. Rather than focusing on specific chemical or mechanical mechanisms, the framework identifies a necessary physical condition common to all such failures: a coupled mismatch between the rate of internal energy conversion and the boundary’s ability to dissipate mass and energy within its characteristic response time. By defining boundary limits, response times, and internal feedback escalation as independently measurable physical properties that exist prior to failure, the framework avoids circular reasoning and tautology. Runaway failure is classified as a boundary-limited phenomenon arising from transport constraints and timescale separation, providing a unifying physical perspective across otherwise unrelated engineered systems without relying on mathematical derivations or mechanism-specific models.