Behaviour of prestressed concrete containment structures

The most significant finds from a study to assess the response of prestressed concrete secondary containment structures for nuclear reactors under the influence of high internal overpressures are presented. A method of analysis is described for determining the strains and deflections including effects of inelastic behaviour at various points in the structure resulting from increasing internal pressures. Experimentally derived relationships between the strains and crack spacing, crack width and leakage rate are given. These procedures were applied to the Gentilly-2 containment building to obtain the following results: (1) The first through-the-wall cracks would occur in the dome at 48 psi or 2.3 times the proof test pressure. (2) At this pressure leakage would begin and would increase exponentially as the pressure increases such that at 93% of the predicted failure load the calculated leakage rate would be approximately equal to the volume of the containment each second. (3) Assuming the pressurizing medium could be supplied sufficiently rapidly, failure would occur due to rupture of the horizontal tendons at approximately 77 psi. (author)