The response of a typical steel‐lined reinforced concrete nuclear reactor containment to postulated internal hydrogen detonations is investigated by axisymmetric nonlinear dynamic finite element analyses. Internal wall pressure histories used as input to the analysis are first generated by numerical solution of the hydrogen detonation problem with a technique that reproduces the sharp discontinuity at the shock front. In place variability of the mechanical properties of reinforcing bars and of the strengths of mechanical splices is included in the containment model through effective stress‐strain laws of the elements modeling the reinforcement. Dynamic analyses performed for atmospheric initial pressure show that the response is more sensitive to the point of initiation than to the strength of the detonation. Due to the vulnerability of the containment to postulated detonations, it is important to prevent formation of a detonable mixture in the containment atmosphere.