Now in its second phase after renewed five-year funding was authorized in 2015, the Consortium for Advanced Simulation of Light water reactors, or CASL, is continuing to make progress toward its goal: developing a “virtual reactor” for the predictive simulation of LWRs to help ensure safety, improve efficiency and speed innovation.
The U-M is a founding partner of CASL, a U.S. Department of Energy Innovation Hub based at Oak Ridge National Laboratory (ORNL). In addition to U-M and ORNL, the effort includes MIT and North Carolina State University, three other national laboratories and three industry partners.
NERS Professor William Martin serves as the principal investigator of CASL at U-M and also heads CASL’s radiation transport methods focus area. Some 30 individuals across campus are involved in the consortium — about 10 faculty and 20 students and postdoctoral researchers. “It’s a large effort with contributions from faculty, staff and students from several disciplines,” Martin said.
The thrust of the CASL work at U-M centers on development of code — dubbed MPACT for Michigan Parallel Characteristics Radiation Transport — to predict neutron behavior in reactors. Other U-M efforts focus on thermal hydraulics, structural analysis and materials response to radiation.
Phase one of CASL focused on the component physics, Martin explained, while phase two is investigating coupled problems.
“Reactors are complicated beasts that couple thermal hydraulics, neutronics, chemistry and materials phenomena. Several challenge problems have existed but, because of the complexity, we haven’t had the tools to solve them. Now we’re in a position where we can make meaningful progress.”
One of those challenge areas has been the prediction of CRUD (Chalk River Unidentified Deposits) growth, or corrosive deposits on fuel pins and other reactor parts. CRUD is a serious issue since it can impact safety and power generation. NERS Professor Annalisa Manera, an expert in thermal hydraulics, has made significant headway on developing tools to predict CRUD growth. Manera was recently awarded the Director’s Award from CASL for her computational fluid dynamics simulations. Going forward, work will continue on refining models and their parameters.
Feedback on the U-M contributions to CASL has been positive, and Westinghouse will be integrating MPACT as a benchmark tool for reactor analysis, Martin said. In addition, an upcoming special issue of the Journal of Computational Physics will be devoted to CASL. The issue will contain several papers from U-M team members. And five recent U-M PhD students who worked on the CASL program have gone on to positions at ORNL.
Participation in CASL brings visibility and recognition to the NERS department and University, especially given the long-time strength of NERS in radiation transport. Being part of the consortium also offers exciting opportunities for multidisciplinary collaboration, Martin noted.
“We’re taking full advantage of the chance to collaborate with people in many disciplines — chemistry, fluid dynamics, heat transfer, materials science, structural analysis and statistics to solve some of these large, long-standing, complex challenges,” Martin said. “The most interesting problems to work on are the ones that haven’t been solved yet, and they’re the ones between the conventional disciplines.”