Environmentally-assisted fatigue of dissimilar joints in nuclear power plant pipes

Type Modeling & calculation
Industry Nuclear
Country ar Argentina
Technologies CAE

Detailed analysis of fatigue under environmentally-assisted conditions of welds over dissimilar materials in pipes of systems directly related to the safety of a heavy-water nuclear power plant. Differential thermal expansion effects over operational and incidental transients had to be considered, including the occurrence of design-basis earthquakes. Stress linearization according to ASME VIII, fatigue analysis according to ASME III and NRC/EPRI computation of water-assisted fatigue factors had to be performed. All in all 24 dissimilar joints were analyzed. Transient heat conduction and quasi-static elasticity was solved with Fino. Fatigue assessment was performed using wasora. All the input files and scripts used to obtain the final results were tracked with Git, and each of the 24 final reports contained the hash of the corresponding calculation repository for full traceability.

milonga: a free nuclear reactor core analysis code

Type Development
Industry Nuclear
Country N/A
Technologies Free Software UNIX CAE

Milonga is a free core-level neutronic code that solves the steady-state multigroup neutron transport equation using either the diffusion approximation, or the discrete ordinates method over unstructured grids (although simple structured grids can also be used) based on either a finite-volumes, or a finite-elements discretization scheme. It works on top of the wasora framework, which provides means to parse and understand a high-level plain-text input file containing algebraic expressions, data for function interpolation, differential equations and output instructions amongst other facilities. Therefore, any mathematical computation which can be done by wasora—i.e. parametric calculations, multidimensional optimization, function interpolation and integration, etc.—can be combined with the facilities that milonga provides to solve the neutron diffusion equation.