Numerical Analysis of Scaled Containment Model

Abstract

Bhabha Atomic Research Centre (BARC), Trombay has organized an International Round Robin Analysis program to carry out the ultimate load capacity assessment of BARC Con- tainment (BARCOM) test model. The test model located in BARC facilities Tarapur is a 1:4 scale representation of 540 MWe Pressurized Heavy Water Reactor (PHWR) pre- stressed concrete inner containment. The model construction activities along with the embedded sensor installation continued from November 2006 to December 2008. More than 800 embedded sensors have been installed during the construction phases in different concrete pours and additional around 300 surface type sensors are installed.The model has been tested pneumatically during the Low Pressure Tests (LPTs) followed by Proof Test (PT) and Integrated Leakage Rate Test (ILRT) during commissioning, which was followed by the Over Pressure Test (OPT) up to the functional failure of the test model. Finally the Ultimate Load Capacity Test (ULCT) will be completed. For the pre-test predictions and post-test ultimate load capacity evaluation of BARCOM test model, thirteen participants from research, academic, industrial and technical or- ganization from all over the globe have participated. Total sixty-nine specified sensor locations (SSLs) out of around 1100 sensors were identified for the pre-test predictions by the participants. With this International Round Robin exercise, it has been possible to predict the ultimate load capacity of the BARCOM test model and understand the overall global and local failure modes. In the present study, numerical modeling of BARCOM test model has been carried out with due consideration of geometrical and material properties. The numerical results at the Specified Sensor Locations (SSLs) of BARCOM model are extracted using finite element based software in order to compare them with the experimentally obtained results. Numerical analysis helps in benchmarking different computer codes and the constitutive models to derive ultimate load capacity of concrete containment. Further, with the evalu- ation of the test data, the margin against the design pressure of the PHWR containment structures will be established with greater confidence. Thus, the PHWR containment structure performance evaluation for extremely low probable beyond the design basis ac- cidents can be made for the public acceptance of Indian nuclear power plants. The response of the containment model in the form of strains, displacements, etc. have been studied in depth at various locations. It was observed that around the free field area of BARCOM model, the numerical results are in good agreement with the experimental results. However, the response near the discontinuities like the openings, local thickenings around the openings, at junctions of BARCOM model the results are deviating a little.