Media Contact: Katie Elyce Jones
Oak Ridge National Laboratory

Westinghouse–CASL team wins major computing award for reactor core simulations on Titan


A team representing Westinghouse Electric Company and the Consortium for Advanced Simulation of Light Water Reactors (CASL), a Department of Energy (DOE) Innovation Hub led by Oak Ridge National Laboratory (ORNL), has received an International Data Corporation HPC Innovation Excellence Award for applied simulation on Titan, the nation’s most powerful supercomputer, which is managed by the Oak Ridge Leadership Computing Facility at ORNL. The award recognizes achievements made by industry users of high-performance computing technologies and was presented to awardees on June 24 at the International Supercomputing Conference in Leipzig, Germany.

The team, led by Fausto Franceschini of Westinghouse and Andrew Godfrey of ORNL, performed core physics simulations of the Westinghouse AP1000 pressurized water reactor (PWR) core using CASL’s Virtual Environment for Reactor Application (VERA). Westinghouse is deploying the AP1000 worldwide with eight plants currently under construction in China and the United States.

The simulations, performed on Titan’s Cray XK7 system, produced 3D, high-fidelity power distributions representing conditions expected to occur during the AP1000 core startup and used up to 240,000 computational units in parallel. One of the neutron transport components of VERA, the Exnihilo code suite developed at ORNL, was used for the simulations. The code includes deterministic transport solvers such as Denovo, which can take advantage of Titan’s NVIDIA graphics processing unit accelerators, as well as a new stochastic transport module known as Shift.

The results included as many as one trillion particle histories per simulation to reduce statistical errors and provide insights that improve understanding of core conditions, helping to ensure safe startup of the AP1000 PWR core.

“This is exciting because it is a real demonstration of DOE technology making its way into the hands of industry users,” said Tom Evans, deputy lead for CASL Radiation Transport Methods and team lead for CASL Exnihilo/Denovo/Shift development. “This isn’t a hypothetical problem we’re simulating. This is a real case that needed to be solved.”

In addition to Franceschini, Godfrey, and Evans, the team included Bob Oelrich of Westinghouse; the ORNL Exnihilo development team: Cihangir Celik, Greg Davidson, Steven Hamilton, Seth Johnson, and Tara Pandya; and John Turner and Jess Gehin of ORNL.

Westinghouse, a group company of Toshiba Corporation is a pioneer in nuclear energy and a leading supplier of nuclear plant products and technologies to utilities throughout the world. In 1957 the company supplied the world’s first PWR in Shippingport, Pennsylvania. Today, Westinghouse technology is the basis for approximately one-half of the world’s operating nuclear plants, including more than 50 percent of those in Europe.

CASL’s core partners are a strategic alliance of leaders in nuclear science and engineering from government, industry, and academia. For more information, visit

UT-Battelle LLC manages ORNL for DOE’s Office of Science. As the single largest supporter of basic research in the physical sciences in the United States, the Office of Science is working to address some of the most pressing challenges of our time.


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