A Generalized Geometric Shape Function for Evaluation of SIF Values of Thin-Walled Axially-Cracked Fuel Pin Specimens

For integrity assessment of fuel pin of nuclear reactor, the solutions for fracture mechanics parameters such as stress intensity factor (SIF), η and γ functions etc. are necessary with postulated flaws. These geometries do not conform to that of ASTM standard and hence, above parameters are usually not available. In an earlier work, the authors have developed the SIF solutions for fuel pins of Indian Boiling Water Reactors using finite element analysis and analytical methods. However, these functions are not applicable for such fuel pins of different diameters. In this work, a diameter and thickness dependent geometric function has been suggested for evaluation of SIF. Experiments have been carried out on different types of specimen geometries with various initial crack lengths and the results have been compared with those of FE analysis. Later, the crack growth information during the testing of the Pin-Loading-Tension (PLT) specimens have been obtained through the use of a load-normalization technique, which is used subsequently in evaluation of J-R curves of the fuel pin specimens.