Yang Liu receives DOE grant to establish databases to improve nuclear reactor safety , design
A new lab , to be built on Virginia Tech ’ s Blacksburg campus , will help nuclear engineers develop and test a database for computational fluid dynamics ( CFD ) codes . The codes are used to model and simulate two-phase flow , which will help engineers design safer and more efficient nuclear reactors .
Yang Liu , assistant professor of nuclear engineering in the College of Engineering ' s Department of Mechanical Engineering , recently received an $ 800,000 grant from the Nuclear Energy University Programs , overseen by the Department of Energy .
Two-phase flow modeling is one of the most challenging issues in simulating nuclear reactors . The grant will help establish three high-quality , high-resolution databases to develop advanced models and validate the NEK-2P code , a multiphase CFD code developed at Argonne National Laboratory .
“ There are reactor thermal-hydraulics codes that exist from the 1960s and 1970s ,” said Liu , principle investigator on the project , “ but the uncertainties of these codes are generally very large . This project will help us create a database for the advancement of more accurate CFD codes , such as NEK-2P .”
The codes and models created as part of the project will be used for safety analysis , power uprate and life extension of existing reactors , and potential new reactor designs .
The new lab will include a test rig of a 3x3 heated rod bundle section to generate vapor bubbles – in line with the type produced in nuclear rod bundles . The instrumentation system will include particle image velocimetry , planar laser-induced fluorescence , high-speed imaging , X-ray densitometry , and multisensor conductivity probes . In the Virginia Tech and Ohio State University labs , researchers will conduct high-fidelity optical measurements using existing air-water flow loops , followed by tests in the new rod bundle facility .
“ Our bundle will consist of nine rods contained in pressurized water and heated to produce vapor bubbles ,” Liu said . “ By measuring both the gas and the liquid , we will be able to characterize the process and create accurate , advanced models of the flow , and we ’ ll look at the void distribution in the bundle ’ s geometry , which is important for the fission reaction rate in nuclear reactors .”
Liu uses automobiles as an example of the importance of modeling data . “ Thirty years ago , if you punched your car , you ’ d stand a chance of breaking your hand ,” he said . “ Today , if you punch your car , you stand a better chance of breaking your car . But despite that , today ’ s cars are much safer than the thicker , heavier models of the past . The same holds true for how buildings and aircraft are designed . By improving the predictive accuracy of our models through code validation and verification , our simulations become more robust and useful . We can build facilities that are safer , more reliable , and more efficient .”
Liu will collaborate on the project with Ohio State University , Argonne National Laboratory , and Westinghouse Electric Company to develop a comprehensive two-phase flow database for the validation of NEK-2P .
The new lab is expected to be completed in the spring of 2018 .