FAILURE PRESSURE EVALUATION OF THE CONTAINMENT BUILDING OF A LARGE DRY NUCLEAR-POWER-PLANT

The evaluation of the failure pressure of the containment building of a large dry PWR-W three loops nuclear power plant, based on computer n umerical simulation, is described in this paper. The proposed method c onsiders fully three-dimensional finite element models in order to tak e into account the effect of the most significant structural character istics (presence of three buttresses, penetrations, additional reinfor cement around the penetrations, etc.), the lack of symmetry of the for ces generated by the prestressing system, as well as the nonlinear beh aviour of the materials and the sensitivity of the results to uncertai nties associated with several parameters. The computational model is c ompletely described, including the constitutive equations for the conc rete, the reinforcing steel and prestressing tendons, the spatial disc retization-isoparametric elements including the reinforcement are used . The structural models and the analyses performed for their calibrati on are also described. The influence on the failure pressure of incorp orating the foundation slab in the structural model, and the influence of the thermal effects, are discussed. One of the conclusions of the numerical study is that the failure process can be appropriately simul ated by means of a structural model which does not include either the foundation slab or the thermal effects. Finally, results of a probabil istic simulation of the failure pressure are given. (C) 1998 Elsevier Science S.A. All rights reserved.