Use of small models in design and analysis of prestressed-concrete reactor vessels

Abstract

A series of small prestressed-concrete reactor vessel (PCRV) models was analyzed and tested to investigate the suitability of small-scale ( ≤ 1 20 ) mortar models and epoxy models for determining elastic stress distributions and cracking and failure modes of concrete vessels, and to demonstrate the relative accuracy of two- and three-dimensional elastic finite-element structural analyses of PCRV's. In addition to a small concrete vessel that served as the prototype, there were two small-scale mortar models, a prestressed epoxy model, and a simple axisymmetric epoxy model. The test results from each model were compared with those from the other models and with finite-element predictions. The prototype and the two mortar models were tested to failure with internal pressure. The prototype and one mortar model were pressurized hydraulically, but the other mortar model was tested pneumatically to examine possible differences in structural behavior. The epoxy models were tested in the elastic range only. Structural behavior of the small-scale mortar models closely duplicated that of the concrete prototype. The behavior characteristics of the two mortar models indicated that failure, whether caused by pneumatic pressure or hydraulic pressure, was gradual and not catastrophic. Both two- and three-dimensional finite-element analyses were used to analyze the models, and comparison of the predicted behavior with test results showed reasonably good agreement, even with the two-dimensional analyses, thus demonstrating the reliability of the finite-element computer analyses currently being used for evaluating PCRV's.