Woodruff School of Mechanical Engineering

Faculty Candidate Seminar


Burnup-Thermal Hydraulic Coupling methods for Monte Carlo codes


Dr. Dan Kotlyar


Department of Engineering, University of Cambridge, UK


Thursday, November 19, 2015 at 11:00:00 AM


Boggs Building, Room 3-47


Dr. Bojan Petrovic


Modeling advanced reactor designs, such as high conversion (HC) LWRs, represents a significant challenge to the conventional reactor analysis methods. For example, HC concepts typically rely on a heterogeneous core configuration, where fissile zones are interspersed with fertile blanket zones in order to achieve HC ratio. Monte Carlo (MC) method is perceived as an ideal alternative to accurately model such advanced reactor systems due to the capability of simulating complex core geometries. The advances in computer technology are gradually changing the reactor analysis modeling environment. As a result, MC neutron transport codes are increasingly used as a standard calculation tool in reactor calculations. It is even becoming practical to couple MC neutron transport calculations with depletion and thermal hydraulic (TH) feedbacks to extend the range of applications even further. Many MC-burnup coupling schemes have been developed. This seminar will present coupling methods used in various MC based reactor analysis systems. In particular, the effect of different burnup-TH coupling schemes on the numerical stability and accuracy of coupled MC calculations will be presented. This work demonstrates that even for relatively short time steps, some methods can be numerically unstable. Namely, the spatial distribution of neutronic and thermal hydraulic parameters, such as nuclide densities and temperatures, exhibit oscillatory behavior. To address the numerical stability issue, new approaches are proposed. These methods solve the depletion and TH problems simultaneously and use variable relaxation factor to achieve convergence. These methods are numerically stable and accurate even for relatively large time steps and require less computation time than the existing methods.


Dr. Dan Kotlyar is a Research Associate in the Engineering Design Centre at the University of Cambridge, UK. He received his B.Sc. in Engineering in 2008 and PhD in Nuclear Engineering in 2013 from Ben-Gurion University, Israel. In 2014, he was elected a Research Fellow at Jesus College, where he contributes to undergraduate teaching and other educational activities. At the University of Cambridge, his research is focused on the design of inherently safe light water reactors, more specifically, on the investigation of thorium-based fuel cycles for efficient plutonium incineration.His research interests include development of numerical methods and algorithms for coupled Monte Carlo, fuel depletion and thermal hydraulic codes. In particular, he specializes in applying these methods to the analysis of advanced reactor systems. The area of additional interest is the application of optimisation methods to maximize the performance of various nuclear systems.


Refreshments will be served.