EARTH SCIENCES AND HUMAN CONSTRUCTIONS
Print ISSN: 2944-9154, E-ISSN: 2944-9006 An Open Access International Journal of Earth Sciences and Human Constructions
Volume 5, 2025
Enhancing Structural Safety of Reactor Pressure Vessels through Probabilistic Fracture Mechanics Modeling
Authors: , , ,
Abstract: This study presents the development and application of a Probabilistic Fracture Mechanics (PFM) code to assess the failure probability of nuclear reactor pressure vessels (RPVs) with pre-existing cracks. RPVs, made of low alloy steel and subjected to various aging mechanisms such as fatigue and stress corrosion cracking, are especially vulnerable in the beltline region where nuclear fission occurs. A Python-based PFM code was developed to evaluate failure risk considering a single initial crack, whose size follows a log-normal distribution. The final (critical) crack size is calculated using applied design stresses and plane strain fracture toughness (KIC), which is modeled based on Nil Ductility Temperature (NDT) and neutron fluence, using IAEA and ASME recommendations. Stress input- membrane, bending, thermal, and seismic- are determined analytically using ANSYS simulation tools and Bangladesh National Building Code (BNBC) seismic guidelines. Failure probabilities are evaluated for both vertical and horizontal crack orientations, and results are benchmarked against PRAISE-JNES code outputs. The study finds that vertical cracks pose a higher failure risk, and that increased temperature and pressure significantly raise failure probability. The proposed PFM framework offers a reliable and compliant tool for probabilistic safety assessment of RPVs.
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Pages: 62-69
DOI: 10.37394/232024.2025.5.7