John Turner to provide...
CAAR/Denovo (Contact ??)
OAK RIDGE — Scientists at the Nuclear Science and Technology Division of the U.S. Department of Energy's Oak Ridge National Laboratory (ORNL) are merging decades of nuclear energy and safety expertise with high-performance computing to effectively address a range of nuclear energy- and security-related challenges.
John Wagner, technical integration manager for nuclear modeling within ORNL's Nuclear Science and Technology Division (NSTD), says one of the goals of his organization is to integrate existing nuclear energy and nuclear national security modeling and simulation capabilities and associated expertise with high-performance computing to solve problems that were previously "unthinkable or impractical in terms of the computing power required to address them."
In the area of nuclear energy, the Nuclear Modeling staff specializes in developing and applying computational methods and software for simulating radiation in order to support the design and safety of nuclear facilities, improve reactor core designs and nuclear fuel performance — and ensure the safety of nuclear materials, such as spent nuclear fuel.
The Nuclear Modeling staff is internationally known for developing and maintaining SCALE, a comprehensive nuclear analysis software package originally developed for the Nuclear Regulatory Commission with signature capabilities in the criticality safety, reactor physics and radiation shielding areas.
In recent years, ORNL has placed an emphasis on transforming its current capabilities through high-performance computing, as well as the development of new and novel computational methods.
"Traditionally, reactor models for radiation dose assessments have considered just the reactor core … or a small part of the core," Wagner stated in an ORNL release. "However, we're now simulating entire nuclear facilities, such as a nuclear power reactor facility with its auxiliary buildings and the ITER fusion reactor, with much greater accuracy than any other organization that we're aware of."
More accurate models enable nuclear plants to be designed with more accurate safety margins and shielding requirements, which helps to improve safety and reduce costs.
The technology that makes this sort of leading-edge simulation possible is a combination of ORNL's Jaguar, "the world's fastest supercomputer"; advanced transport methods; and a next-generation software package called Denovo.
"At first, we tried adapting older software to the task, but we abandoned that idea pretty quickly," says NSTD scientist and Denovo creator Tom Evans. As a result of that decision, Evans started from scratch to develop new software that is far more efficient at creating computer models on state-of-the-art supercomputers.
Evans observes that, in some ways, Denovo is a synthesis of the last decade of research in the field, according to the ORNL release.
"Software for modeling radiation transport has been around for a long time," he explains, "but it hadn't been adapted to build on developments that have revolutionized computational science.
"There's no special transformational technology in this software," Evans added, "but it's designed specifically to take advantage of the massive computational and memory capabilities of the world's fastest computers."
Denovo, which appropriately enough means "from new" or "from scratch," was recently awarded eight million processor hours on the Jaguar supercomputer by the DOE Office of Science's Innovative and Novel Computational Impact on Theory and Experiment (INCITE) program to develop a uniquely detailed simulation of the power distribution inside a nuclear reactor core. This simulation will be used to help to design the next generation of reactors by expediting experiments that can take years to conduct and to help to ensure that reactor designs are as efficient as possible.
Wagner notes that Denovo provides a fundamental capability for radiation transport modeling that continues to be expanded and applied to numerous ORNL projects. However, he is also quick to point out that these computer simulations won't completely eliminate the need for experimental or measurement data to confirm or "validate" the software. Instead, the new generation of nuclear modeling will increase confidence in the results using a more limited set of physical data.
"We want to develop a predictive capability that has increased accuracy, reliability and flexibility," he says, "that can be used to improve our knowledge and understanding and increase our confidence in the decisions we make about design, safety, and performance of nuclear facilities.
"That's the goal."
CAAR/NRDF (Contact Bobby Philip)
The objective of the CAAR NRDF project is to demonstrate how a fairly complex adaptive mesh refinement (AMR) application employing state of the art solution methods might perform on the hybrid multicore-GPU Titan system. NRDF is a non-equilibrium radiation diffusion code with applications in the areas of inertial confinement, and astrophysics. NRDF solves a time dependent coupled system of nonlinear equations for radiation energy and material temperature using a diffusion approximation. NRDF uses (1) AMR to reduce the computational and memory requirements, combined with (2) implicit time integration for stable long term time integration on the dynamical time scale of the problem, (3) Jacobian free Newton Krylov (JFNK) methods to solve the resulting nonlinear systems of equations accurately at each timestep, and (4) optimal multilevel preconditioners to efficiently solve the linear systems at each Newton step. These techniques have all been highlighted as essential in the move to solving increasingly complex problems of interest to DOE and it is extremely important to understand how these algorithms and techniques will perform on next generation systems. Particular application areas that could benefit by the application of these techniques include energy applications (energy storage, combustion, nuclear reactors, fusion), astrophysics, environmental applications, and climate.
CASL (Contact John Turner)
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.
Nuclear Energy Advanced Modeling and Simulation (NEAMS) (Contact John Turner)
In April of 2010, the DOE Office of Nuclear Energy (NE) published a roadmap for nuclear energy research and development (R&D) activities. NE R&D efforts are aimed at accomplishing four objectives that will help to ensure that nuclear energy remains a key contributor in meeting the United States’ energy needs:(1) develop technologies and other solutions that can improve the reliability, sustain the safety, and extend the life of current reactors; (2) develop improvements in the affordability of new reactors to enable nuclear energy to help meet the Administration's energy security and climate change goals; (3) develop sustainable nuclear fuel cycles; and (4) understand and minimize risks of nuclear proliferation and terrorism.
Modeling and simulation are crosscutting tools important to the entire NE R&D portfolio. NEAMS was established to develop and advance these crosscutting tools in a coordinated and efficient manner. NEAMS will examine and address the challenges to applying advanced modeling and simulation to meet NE R&D needs. Benefits of a consolidated modeling and simulation effort include: a focused mission with clearly established milestones; a dedicated effort to understand stakeholder requirements; a coordinated approach to meeting these requirements; and streamlined programmatic interfaces.
NEAMS Program Elements
The NEAMS Program works to support the full range of NE R&D aimed at enabling the expanded use of nuclear energy for clean, safe and affordable power in the United States. To address this broad range, NEAMS has been organized as shown in the figure below: