STRUCTURE SIMULATION OF PRE-STRESSED CONCRETECONTAINMENT STRUCTURES

摘要

With respect to the high priority of the integrity of containments for meeting safety requirements innuclear power plants especially in the framework of probabilistic safety analyses (PSA) of level 2, thequalification of the methods, procedures and inspections used for the assessment of integrity and leaktightness is of special importance. Within a series of large scale tests on the failure behaviour of modelcontainments a 1:4 scaled pre-stressed concrete containment model with metallic liner was investigatedat Sandia National Laboratories (Albuquerque, New Mexico). After completion of the tests theInternational Standard Problem ISP 48, supported by CSNI/IAGE, was defined to perform aninternational comparative study on the present state of analysis methods used for the assessment ofpre-stressed concrete containments concerning load-carrying capacity and leak tightness. Calculationswere performed of the so-called Limit State Test which was finished with an internal pressure of 1.29Mpa (about 3.3 times design pressure) as well as of combined pressure and temperature loading cases.Axisymmetric and 3d finite element models were developed and used by GRS first without considerationof geometric inhomogenities due to penetrations in the wall. The steel liner at the inner surface and theconcrete parts are made of continuum elements, while the rebar and tendon parts are modelled as trusselements. Nonlinear material models are used. The concrete material model includes the formation ofmicro-cracks for tensile stresses exceeding a critical value. In the paper selected results of GRSanalyses are summarized.