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Neutronic Characterization of the PSBR Irradiation Positions using a Burnup Coupled MCNP Simulation with MURE



Dagistan NMN Sahin, Kenan Unlu, Kostadin Ivanov


Penn State Breazeale Reactor (PSBR) is a Training, Research, Isotopes, General Atomics (TRIGA) Mark III type, 1 MW nuclear research reactor. PSBR has been operational at the Pennsylvania State University Radiation Science and Engineering Center since 1965. Research and educational requirements mainly direct the PSBR operating schedule. With such operating schedules, one particular area of concern, specifically in regards to nuclear analytical applications, is perhaps the time-dependent changes in neutronic characteristics at neutron irradiation positions. Continuous variations in the reactor operations may cause drastic fluctuations in neutronic characteristics, such as the location of maximum neutron flux, the thermal to epithermal neutron flux ratio (f), the measure of the nonideal epithermal neutron flux distribution (¿), spectral index ( r ¿(T_n/T_o ) ) and neutron temperature ( T_n ) within these irradiation positions. This study shows analysis of such neutronic variations and their dependence on various core conditions of use of a detailed burnup coupled neutronic simulation. Such information is beneficial for nuclear analytical sciences as well as nuclear fuel management perspective. Monte Carlo Utility for Reactor Evolutions (MURE) and MCNP5 codes are used to develop the burnup coupled neutronic simulation of the PSBR reactor. The simulation results were verified by reactor core neutronic characterization measurements, including core excess reactivity, control rod worth, fission-product buildup and temperature dependent reactivity loss, integral control rod worth curves and individual fuel element worth. Within the PSBR irradiation positions, T_n and ¿ were found to be reasonably stable in time, while f and r ¿(T_n/T_o ) were found to be relatively responsive to changes in the core.
Nuclear Technology


burnup coupled neutronic analysis, neutron activation analysis, neutron flux characterization


, D. , Unlu, K. and Ivanov, K. (2016), Neutronic Characterization of the PSBR Irradiation Positions using a Burnup Coupled MCNP Simulation with MURE, Nuclear Technology, [online], (Accessed April 23, 2024)
Created June 1, 2016, Updated February 19, 2017