May-June 2019 NPJ

NuclearPlantJournal.com 29 Nuclear Plant Journal, May-June 2019 (Continued on page 30) CASL By Dave Kropaczek, Kevin Clarno, Mehdi Asgari, Oak Ridge National Laboratory and Zach McDaniel, Westinghoue Electric Company. Dave Kropaczek Dave Kropaczek is the Director of the Consortium for Advanced Simulation of Light Water Reactors (CASL) at Oak Ridge National Labo- ratory, a position he assumed in August 2018. In this role he is responsible for over- all planning, coordi- nation, and execution of CASL scope includ- ing scientific research and technology deliv- erables. Dave has over 30 years of experience in the field of nuclear energy with a focus on computational methods and software development in the fields of nuclear fuel cycle optimization, reactor physics and thermal-hydraulics for both pressurized and boiling water reactors. His most recent position was the Duke Energy Distinguished Professor in Nuclear Engineering at North Carolina State University where he also served as CASL Chief Scientist. Previous experience includes positions in both R&D and leadership within Westinghouse, General Electric, and Studsvik Scandpower (as President and Chief Executive Officer). Dave has a B.S. in Engineering Science from New Jersey Institute of Technology and Master and Ph.D. degrees from North Carolina State University. The Consortium for Advanced Sim- ulation of Light Water Reactors (CASL) was founded in 2010 as a Department of Energy (DOE) Energy Innovation Hub with the vision to provide a comprehen- sive and fully integrated modeling and simulation capability that is deployed and applied throughout the nuclear en- ergy industry. CASL has focused on solving a set of challenge problems for the nuclear fleet that focus on reactor op- erational efficiency, safety, and economic performance with the objective of seam- lessly bridging the aps between basic esearch, engineer- ng development, and ommercialization. To achieve this goal, CASL consists of arge, highly integrat- d and collaborative reative teams from DOE government lab- ratories, academia, nd industry work- ng to solve priority echnology challeng- s. CASL’s strategy f closely coupling higher-fidelity tools with integrated sci- ence-based methods represents a technol- ogy step change for today’s nuclear en- ergy industry. Within the Virtual Environ- ment for Reactor Applications (VERA), CASL-developed and applied models and methods are capable of accelerating advances in the development and deploy- ment of advanced nuclear technologies. CASL’s integrated, coupled technology is guided by methods that help to identify and reduce the uncertainties to provide an improved prediction of the reactor’s behavior. 1. What is the progress in predicting the lifetime of key structural components in the plant to ensure extending plant lifetimes of existing reactors? VERA provides high resolution, high fidelity simulation of multi-physics phenomena for nuclear reactors that includes the effects of radiation transport and component damage, two-phase flow thermal-hydraulics, system chemistry, and fuel performance. Simulations include the capability to not only model the detailed core behavior but also the accumulated radiation dose on structural components both within and outside the reactor core.An example is the calculation of fluence for the reactor vessel which is considered a limiting reactor component for plant lifetime. VERA is being used to analyze the accumulated vessel fluence over an entire reactor operating history which is shown to be highly sensitive to the cycle specific core design (especially as impacts the fuel rod power on the core periphery). VERA capabilities are applicable to all reactor components beyond the reactor vessel where radiation induced component damage can reduce plant lifetime. Reducing the uncertainty in such calculations through best estimate analyses afforded by VERA will contribute to extending plant lifetimes for existing reactors. 2. Your project is very much in line with the “Nuclear Promise” launched by NEI, which emphasizes reducing the cost and increasing the efficiency of plants. The following questions are related to optimizing plant efficiency. a. What tools will be utilized to predict unanticipated plant outages to increase power generation? Several of the CASL challenge problems have focused on reducing risks related to reactor operation. For example, the grid-to-rod-fretting (GTRF) challenge problem has focused on advancing the understanding and the modeling of phenomena related to flow induced vibration that can lead to fuel failures. Similarly, the pellet-clad-interaction (PCI) challenge problem has focused on the fuel mechanical performance behavior during operational power maneuvers as are common during reactor startup and load follow operation. The crud challenge problem has focused on the modeling of the reactor behavior for the prediction of crud induced power shift (CIPS) and crud induced localized corrosion (CILC), phenomena that has led to power de- rates as well as fuel failures. Figure 1 g r i c l e c o a i t e o Practical Applications of CASL