Monte Carlo modeling and analyses of YALINA- booster subcritical assembly Part II : pulsed neutron source.

Talamo, A. ; Gohar, M. Y. A. ; Rabiti, C. ; Nuclear Engineering Division

关键词: BELARUS;    BENCHMARKS;    COMPUTER CODES;    DELAYED NEUTRONS;    FISSION;    IAEA;    KINETICS;    NEUTRON SOURCES;    NEUTRON TRANSPORT;    NEUTRONS;    REACTION KINETICS;    SIMULATION;   

DOI  :  10.2172/946033
RP-ID  :  ANL-08/33
PID  :  OSTI ID: 946033
Others  :  TRN: US0901261

学科分类：物理（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

One of the most reliable experimental methods for measuring the kinetic parameters of a subcritical assembly is the Sjoestrand method applied to the reaction rate generated from a pulsed neutron source. This study developed a new analytical methodology for characterizing the kinetic parameters of a subcritical assembly using the Sjoestrand method, which allows comparing the analytical and experimental time dependent reaction rates and the reactivity measurements. In this methodology, the reaction rate, detector response, is calculated due to a single neutron pulse using MCNP/MCNPX computer code or any other neutron transport code that explicitly simulates the fission delayed neutrons. The calculation simulates a single neutron pulse over a long time period until the delayed neutron contribution to the reaction is vanished. The obtained reaction rate is superimposed to itself, with respect to the time, to simulate the repeated pulse operation until the asymptotic level of the reaction rate, set by the delayed neutrons, is achieved. The superimposition of the pulse to itself was calculated by a simple C computer program. A parallel version of the C program is used due to the large amount of data being processed, e.g. by the Message Passing Interface (MPI). The new calculation methodology has shown an excellent agreement with the experimental results available from the YALINA-Booster facility of Belarus. The facility has been driven by a Deuterium-Deuterium or Deuterium-Tritium pulsed neutron source and the (n,p) reaction rate has been experimentally measured by a {sup 3}He detector. The MCNP calculation has utilized the weight window and delayed neutron biasing variance reduction techniques since the detector volume is small compared to the assembly volume. Finally, this methodology was used to calculate the IAEA benchmark of the YALINA-Booster experiment.