Periodic Reporting for period 1 - GO-VIKING (Gathering expertise On Vibration ImpaKt In Nuclear power Generation)
Periodo di rendicontazione: 2022-06-01 al 2023-11-30
The Gathering expertise On Vibration ImpaKt In Nuclear power Generation (GO-VIKING) project takes over from the VIKING initiative that started in 2020 as an in-kind collaborative effort of European vendors, utilities, technical safety organizations, universities, and research organizations to improve the understanding and the prediction of flow-induced vibration (FIV) phenomena, relevant to nuclear power reactors. Preventive measures against FIV should be taken in the component design and during the operation of the nuclear steam supply system (NSSS) to avoid structural wear, damage or even incidental or accidental scenarios with potential radioactivity release to the environment. The overall objective of GO-VIKING is to increase the expertise and improve the tools and skills of the European nuclear stakeholders for the analysis of complex FIV phenomena in order to maintain and enhance nuclear plant safety. This will be accomplished by: -Generation of high-resolution numerical and experimental data of FIV in single and multiphase flows -Development and validation of high- and medium-resolution, as well as fast-running practical tools for the FIV analysis - Implementation of efficient methods for uncertainty propagation in the FIV results - Synthesis of best practice guidelines for FIV analysis in accordance with the needs of the stakeholders - Targeted training of graduates and young experts as well as practitioners from stakeholders in FIV related phenomena and modelling techniques The GO-VIKING project will improve the safety of contemporary reactors and the design evaluation of new concepts by making available new experimental results and improved numerical approaches for the evaluation of FIV. These will allow the nuclear operators to enhance the prediction of FIV phenomena in key NSSS components, and the vendors to improve the design of the relevant equipment, thus leading to increased reliability, availability, and safety of the European NPPs.
A large amount of research work has been performed in the first 18 months of the Go-VIKING project. An extensive literature review of the documented issues in NPPs, related to flow-induced vibrations (FIV), and the available numerical methods for FIV evaluation was performed. In February 2023, a Stakeholders’ Outreach Workshop was organised at EDF in Paris. It identified the industry needs and the regulatory expectations in terms of tools and methods for the analysis of FIV phenomena. Experimental data from five different test facilites was provided to the partners dealing with numerical analyses. New experimental data was generated, which also provided detailed information also in the fluid domain, being important for accurate validation of advanced FSI tools. The data generated was not only for vibrating structures in single, but only in two-phase flows. Further, a brand new experiment (GOKSTAD) has been drafted from scratch, which aims at providing beyond the state-of-the-art experiemntal data for code validation in the field of FIV. Multiple reduced-order models were developed and impelmented by the GO-VIKING partners to speed-up the complex FIV analyses, since the high computational time is one of the major bottlenecks of FIV analyses today. GO-VIKING parters also developed advanced uncertainty quantification methods, applicable with modern FSI models. These methods are improtant for the quantification of uncertainties in the best-estimate FIV simulations. All scheduled deliverables and milestones in this reporting period have been delivered.
The GO-VIKING experiments strive to go beyond the current state-of-the art with setups consisting of large number, of rods/tubes, high geometry details (spacer grids, springs, dimples, real life tube diameters and pitches), more realistic boundary conditions (higher Re numbers), and the use advanced instrumentation to obtain more detailed flow information. Further, high-resolution numerical data, based on either direct numerical simulation (DNS) or wall-resolved large-eddy simulation (LES) turbulence approaches is being generated to support the validation of the lower resolution FSI methods, based on Unsteady Reynolds-Averaged Navier-Stokes (URANS) or fast-running models. Such numerical data complement the experiments by providing detailed, local information on the fluid flow in 3D, that cannot be fully captured by the available measurement techniques. The impact of all this is an improved knowledge and simulation tools for the analysis of FIV phenomena that will improve the operation, safety and economics of current and future reactors through less leaking fuel rods and steam generator tubes.