The Consortium for Advanced Simulation of Light Water Reactors (CASL) brings together an exceptionally capable team that will apply existing modeling and simulation (M&S) capabilities and develop advanced capabilities to create a usable environment for predictive simulation of light water reactors (LWRs). The virtual reactor (VR) simulation capability, known as the Virtual Environment for Reactor Applications (VERA), will incorporate science-based models, state-of-the-art numerical methods, modern computational science and engineering practices, and uncertainty quantification (UQ) and validation against data from operating pressurized water reactors (PWRs). It will couple state-of-the-art fuel performance, neutronics, thermal-hydraulics (T-H), and structural models with existing tools for systems and safety analysis and will be designed for implementation on both today's leadership-class computers and the advanced architecture platforms now under development by the U.S. Department of Energy (DOE).

CASL connects fundamental research and technology development through an integrated partnership of government, academia, and industry that extends across the nuclear energy enterprise. The CASL partner institutions possess the interdisciplinary expertise necessary to apply existing M&S capabilities to real-world reactor design issues and to develop new system-focused capabilities that will provide the foundation for advances in nuclear energy technology. CASL's organization and management plan have been designed to promote collaboration and synergy among the partner institutions, taking advantage of the breadth and depth of their expertise and capitalizing on their shared focus on delivering solutions.


CASL is implementing an organization management strategy distinguished by collaboration, central leadership, and multi-disciplinary teams executing a single milestone-driven plan and integrated co-dependent projects. Major features include:


To accomplish the vision for VERA to embody predictive capability, CASL will focus on a set of challenge problems that encompass the key phenomena limiting the performance of PWRs, with the expectation that much of the capability developed will be applicable to other types of reactors. Broadly, CASL's mission is to develop and apply M&S capabilities to address three critical areas of performance for nuclear power plants (NPPs):

Work to develop VERA will be executed in six technical focus areas (FAs) selected to ensure that VERA

To deliver on its mission within the prescribed time and budget constraints CASL places priority on improved simulation of the reactor core, internals, and vessel for a PWR. The developed capability (VERA) will be tightly coupled to an existing and evolving out-of-vessel simulation capability. VERA will be applicable to other NPP types, in particular boiling water reactors (BWRs) and LWR-based small modular reactors (SMRs). During its second 5 years of operation, CASL activities will expand to include structures, systems, and components (SSC) beyond the reactor vessel and will more directly consider BWRs and small modular reactors (SMR).


The CASL 5-year vision is to develop and embody VERA with predictive capability, by coupling state-of-the-art fuel performance, neutronics, thermal hydraulics (T-H), and structural models with existing system/safety analysis tools.

To achieve this vision, CASL will accomplish the following objectives:

  1. Enable the use of leadership-class computing for engineering design and analysis to achieve reactor power uprates, life extensions, and higher fuel burn-up.
  2. Promote an enhanced scientific basis and understanding by replacing empirically based design and analysis tools with predictive capabilities.
  3. Develop a highly integrated multi-physics M&S environment for engineering analysis through increased fidelity methods [e.g., neutron transport and computational fluid dynamics (CFD) rather than diffusion theory and sub-channel methods].
  4. Incorporate uncertainty quantifications (UQ) as a basis for developing priorities and supporting application of VERA for predictive simulation.
  5. Educate today's reactor engineers in the use of advanced M&S through direct engagement in CASL activities and develop the next generation of engineers through curricula at partner universities.
  6. Engage the nuclear regulator [the Nuclear Regulatory Commission (NRC)] to obtain guidance and direction on the use and deployment of VERA to support licensing applications.

Integration of all the CASL milestones will lead to the development of a state-of-the-art pellet-to-pellet virtual reactor simulation environment, with high-resolution representation of a physical reactor on the computational platforms of today and the future, creating distinct technological innovation and paving the way for a nuclear power industrial revolution.