Estimation of fracture behavior of thin walled nuclear reactor fuel pins using Pin-Loading-Tension (PLT) test

For integrity assessment of fuel pins of nuclear reactors using fracture mechanics technique, the solutions for fracture mechanics parameters such as stress intensity factor (SIF), η and γ functions, J–R curve are necessary. These parameters are different for different pin geometries with various types of postulated flaws. These geometries do not conform to that of ASTM standard and hence, the above-mentioned parameters are usually not available. In this work, the authors have devised a pin-loaded tension (PLT) setup to determine the geometric functions for evaluation of stress intensity factors from experimental data using two different analytical methods. A 3D finite element (FE) analysis of the whole PLT setup has been carried out to evaluate the stress intensity factors and hence to validate the analytical solutions. FE analysis is carried out for various pin geometries (with different diameter and thickness values) to evaluate the limit loads and these solutions have been used to evaluate the η and γ functions which are essential for evaluation of the J-integral. Later, a load normalization technique has been used to estimate the J–R curves of a typical fuel pin geometry using the above η and γ functions. The results have been compared with available solutions from the literature.