Woodruff School of Mechanical Engineering

NRE 8011/8012 and MP 6011/6012 Seminar

Nuclear & Radiological Engineering and Medical Physics Programs


Analysis/Benchmarking of Higher Harmonic Modes of the Neutron Flux for Application to BWR Stability


Dr. John Zino


Global Nuclear Fuel-Americas (GNF)


Thursday, February 18, 2010 at 11:00:00 AM


Boggs Building, Room 3-47 (3rd FL)


Bojan Petrovic


The phenomena of BWR power-flow induced density wave stability oscillations have been observed to occur after a perturbation to core flow is experienced where the core power level has not yet started to decrease as rapidly as the core flow in an off-rated plant condition. Changes in inlet core flow induce changes in the channel moderator density that in turn cause changes in the channel neutron flux distribution that are capable of exciting either the axial, radial or azimuthal harmonic components of the neutron flux distribution to such a degree that they are able to overcome the reactivity separation from the fundamental mode and become the dominant mode in the channel for a period of time. This spatial reactivity feedback can lead to either core-wide or region-wide stability oscillations in a BWR. Because of the need to be able to predict both the reactivity separation between higher-harmonic modes of the neutron flux and the fundamental mode, as well as information regarding the relative shape and magnitude of the oscillation contours, benchmarking of 3-D nodal simulator predictions of higher harmonic modes of the neutron flux in a BWR is necessary. This seminar will discuss benchmarking of 3-D nodal simulator results to both observed stability plant test data as well as to a direct, closed-form, analytical solution of the neutron diffusion equation for a simplified, cylindrical homogeneous reactor model.


Dr. Zino is currently the Nuclear Safety & Radiation Protection Manager for the GE-Hitachi Global Nuclear Fuels facility in Wilmington, NC. He received his BSNE from N.C. State University in 1986 and MS (1994) and Ph.D. (1999) in Nuclear & Radiological Engineering from Georgia Tech. He spent ten years working as a reactor physics and criticality safety engineer for Westinghouse at the Savannah River Site before joining GE in 1999. Over the past ten years at GE he has held principal engineering positions in the both the fuels engineering nuclear methods group and the transient thermal hydraulics analysis group.


Refreshments will be served.