Extremely accurate sequential verification of RELAP5-3D

AbstractLarge computer programs like RELAP5-3D solve complex systems of governing, closure, and special process equations to model the underlying physics of thermal-hydraulic systems and include specialized physics for the modeling of nuclear power plants. Further, these programs incorporate other mechanisms for selecting optional code physics, input, output, data management, user interaction, and post-processing. Before being released to users, software quality assurance requires verification and validation. RELAP5-3D verification and validation are focused toward nuclear power plant applications. Verification ensures that the program is built right by checking that it meets its design specifications, comparing coding algorithms to equations, comparing calculations against analytical solutions, and the method of manufactured solutions.Sequential verification performs these comparisons initially, but thereafter only compares code calculations between consecutive code versions to demonstrate that no uninte...