Evolution of TRIGA Research Reactor: A Critical Review of Design, Safety, Utilization and Modernization

The Training Research Isotopes General Atomics (TRIGA) has probably been the most widely used research-reactor platform for education, neutron activation analysis, isotope production, reactor-physics experiments and operator training. There, its unparalleled and continual relevance is a function of uranium-zirconium hydride (U-ZrH) fuel and its prompt negative temperature coefficient which offers a robust inherent feedback mechanism to resist reactivity and thermal excursions. This review critically analyzes the past developments, design principles, reactor-physics fundamentals, comparative advantages, global distribution and use, modernization challenges and future directions of TRIGA reactors. The paper is focused specifically on quantitative performance indicators including conventional neutron flux ranges, steady-state power classes, pulse characteristics and safety-relevant fuel properties. To clarify this uniqueness and the limitations on TRIGA reactors, the review compares it with a few other reactor types including material testing reactors, heavy-water moderated research reactors and conventional pool-type systems. TRIGA reactors are still attractive owing to their accessibility, pulsing capability, passive safety behaviour and educational utility, but they depend on reliable LEU fuel supply, ageing-management programmes, digital instrumentation upgrades and regulatory compliance as well as user level for longevity.