Juliana Pacheco Duarte, an assistant professor in nuclear engineering within Virginia Tech’s department of mechanical engineering, is the primary investigator on an award of $499,517 from the U.S. Nuclear Regulatory Commission to study instabilities in boiling water reactors. Other collaborators on the project include Virginia Tech Associate Professor Yang Liu, University of Illinois Urbana-Champaign Associate Professor Tomasz Kozlowski, and University of Wisconsin-Madison Professor Michael Corradini.

The proposal is to use data collected in Germany’s Karlstein Thermal Hydraulic Test Facility to show how natural circulation test results might apply to boiling water reactor instabilities under anticipated transient without scram (ATWS). The analysis will include the development of a non-dimensional analysis and criteria for two-phase flow instability, including the failure to rewet events that can be applicable to future system analysis under similar operating conditions.

The team proposes to investigate the Maximum Extended Load Line Limit Analysis Plus (MELLLA+) conditions that could lead to dryout and rewet cycles and possible damage to the fuel rods. Research will include coupled thermal-hydraulics and neutronic simulations and the investigation on the transition boiling heat transfer regime.

The grant will also support Ph.D. student Paul Hurley to expand his work on boiling heat transfer phenomena.