Woodruff School of Mechanical Engineering

NRE 8011/8012 and MP 6011/6012 Seminar

Nuclear & Radiological Engineering and Medical Physics Programs


Thermal-Hydraulic Stability Analyses and Methodologies in BWRs


Dr. Juswald Vedovi


GE-Hitachi Nuclear Energy


Thursday, September 23, 2010 at 11:00:00 AM


Boggs Building, Room 3-47


Dr. Farzad Rahnema


There are several relevant problems of interest in the nuclear technology of the Light Water Reactors (LWRs) in the safety analysis field that require complex 3-Dimensional (3-D) Neutron Kinetics (N-K)/Thermal-Hydraulics (T-H) coupled models to be evaluated. Some of these problems are related to ongoing issues in the nuclear physics and engineering fields. Some other phenomena have surfaced recently due to today’s longer cycle exposures for plant fuel reloads, more extreme fuel designs, new reactor designs and new more limiting operating domains. One of the most relevant phenomena in Boiling Water Reactors (BWRs) technology is the Thermal-Hydraulic Stability. There are several examples in the past of inadvertent power oscillations in BWRs. When such instability occurs the core can normally be expected to oscillate in one of two different modes or, sometimes, with overlapping of the two modes. The fundamental mode is the in-phase, or global, mode where all fuel bundles oscillate together in phase; the other is the first harmonic mode, or out-of-phase, or regional, mode, where one half of the core oscillates out of phase against the other half. Both of these modes have been observed in operating BWRs. This seminar will discuss the T-H stability methodologies used in the industry for the safety analysis of BWRs.


Dr. Vedovi is currently the Thermal-Hydraulic Stability Analysis Technical Leader for the GE-Hitachi Global Nuclear Fuels facility in Wilmington, NC. He received his M.S. in Nuclear Engineering from Penn State University in 2005 and his Ph.D. (2008) in Nuclear Engineering from University of Pisa, Italy. He joined General Electric Hitachi (GEH) Company in 2005 in the Nuclear Analysis Center Of Excellence group. His main job functions at GEH are related to methodologies development and the thermal-hydraulics stability analyses for BWR, ABWR, and ESBWR. His main areas of expertise are related to the Safety Analysis and to the coupling methodologies between thermal-hydraulics and 3-Dimensional neutron kinetics for application to Light Water Reactors technology.


Refreshments will be served.