The aim of the present paper is to study the behaviour of a rectangular reinforced concrete pool or tank on detonation of an internal explosive. The first part of the paper studies the propagation of shock waves in order to assess the behaviour of pool or tank walls when subjected to a rapid pressure change versus time increase. The second part of the paper studies the use of MOI (wave propagation computer code) and CASTEM (mechanical finite element computer code) software to assess structural dynamic response and damage. The MOI code is a simplified assessment method based on empirical laws of wave propagation in water. This specific software based on the method of images was developed and validated by comparison with 3D calculations. First, the impacts of parameters such as the size of the pool or tank, the type and amount of explosive, the vertical and horizontal position of the explosive charge and the free surface were researched. Then, for a given geometry of the pool and a quantity of explosive, the position of the explosive charge for maximum pool wall load was researched. Pool wall dynamic response and associated damage were assessed. The wall behaviour was taken into account (fundamental concrete laws, steel bar and cladding shell elastoplastic behaviour). The damage corresponds to the evaluation of the material ductility which enables the assessment of the pool behaviour versus explosive charge (position, mass and type) to be assessed.