Alternative definitions of kinetic parameters for accelerator driven systems

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• 作者：Alberto Talamo^a ; ^{atalamo@anl.gov} ; Yousry Gohar^a ; Sandra Dulla^b ; Piero Ravetto^b
• 关键词：Accelerator driven systems ; Kinetic parameters ; Subcritical
• 刊名：Annals of Nuclear Energy
• 出版年：2012
• 期刊代码：1_03064549
• 类别：pw
• 出版时间：June, 2012
• 卷：44
• 期：Complete
• 页码：12-21
• 文件大小：1478 K

摘要

This study introduces a new formulation of kinetic parameters for accelerator driven systems and it is structured into two parts. The first part is dedicated to the classic definition of the kinetic parameters and compares different calculation methodologies. The second part considers a new definition of the kinetic parameters for subcritical assemblies, with particular emphasis on the delayed neutron fraction and the prompt neutron lifetime. This new definition takes into account neutrons from the external neutron source and (n, xn) reactions, which increase the fraction of prompt neutrons.

The developed theoretical framework has been applied by Monte Carlo and deterministic calculations to the YALINA Thermal subcritical assembly located in Belarus. This facility can be driven by californium, deuterium-deuterium (D-D), or deuterium-tritium (D-T) external neutron sources. For the D-T neutron source, (n, xn) reactions must be taken into account in order to produce accurate results because the average energy of D-T source neutrons is 14.1 MeV, a value which is much higher than the threshold energy of the (n, 2n) cross section of uranium isotopes.