Periodic Reporting for period 2 - GO-VIKING (Gathering expertise On Vibration ImpaKt In Nuclear power Generation)
Reporting period: 2023-12-01 to 2025-05-31
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 second reporting period of the GO-VIKING project (December 2023 – May 2025). The design of the new GOKSTAD experimental facility was finalized. GOKSTAD was commissioned and put in operation, delivering first experimental results for a tube bundle exposed to a cross-flow. Experimental single- and two-phase flow data from the Cantilever Rod (single- and two-phase flow), TREFLE, TITAN, AMOVI and GOKSTAD facilities was provided to the partners dealing with numerical analyses. Part of this data provided detailed information in the fluid domain, being important for accurate validation of advanced FSI tools that are being developed within the project. Multiple reduced-order models, based on the fluid or solid domain, were developed and implemented by the GO-VIKING partners to speed-up the complex FIV analyses. The high computational time is one of the major bottlenecks of FIV analyses today. Some of these new methods were already validated on the experimental data mentioned above. The GO-VIKING partners also developed advanced uncertainty quantification methods, which are applicable with modern FSI models. Some of these were already tested on reactor relevant examples and are currently being validated. These methods are important for the quantification of uncertainties in the best-estimate FIV simulations.
The GO-VIKING experiments went 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 was generated to support the validation of the lower resolution FSI methods, based on Unsteady Reynolds-Averaged Navier-Stokes (URANS) turbulence approach 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.