A numerical stress based approach for predicting failure in NBG-18 nuclear graphite components with verification problems

This paper presents a methodology that can be used for calculating the probability of failure of graphite core components in a nuclear core design, such as that of the Pebble Bed Modular Reactor. The proposed methodology is shown to calculate the failure of multiple geometries using the parameters obtained from tensile specimen test data. Experimental testing of various geometries is undertaken to verify the results. The analysis of the experimental results and a discussion on the accuracy of the failure prediction methodology are presented. The analysis is done at 50% probability of failure as well as lower probabilities of failure.