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U doppler reactivity effect in FCA cores simulating light-water-moderated MOX fuel latticesAndo, Masaki; Fukushima, Masahiro; Okajima, Shigeaki; Kawasaki, Kenji*
Journal of Nuclear Science and Technology, 44(4), p.537 - 547, 2007/04
Times Cited Count：2 Percentile：18.72(Nuclear Science & Technology)U Doppler reactivity effect was measured using the FCA facility for the purpose of obtaining the data of the U Doppler reactivity effect in light-water-moderated MOX fuel and evaluating the prediction accuracy of current analysis code systems and nuclear data library. The experimental data of the Doppler reactivity effect from room temperature up to 800
C were obtained using various cylindrical natural-uranium samples in the mockup cores for MOX-fueled LWR with different neutron energy spectra and in a uranium fueled core. The analyses were performed using current standard analysis code systems for fast and thermal reactors with JENDL-3.3 data library. Both the analyses yielded calculated/experimental (C/E) ratios of 0.96 to 1.06 for the MOX cores, which showed a good agreement with the experiment within the experimental error and were similar to those in the uranium core.
U Doppler effect measured in FCA LWR simulating cores; Analysis with JENDL-3.3 library and SRAC system (Joint research)Kawasaki, Kenji*; Ando, Masaki; Okajima, Shigeaki; Fukushima, Masahiro; Nakano, Makoto*; Matsumoto, Hideki*
JAEA-Research 2006-008, 40 Pages, 2006/03
JAEA-Research-2006-008.pdf:3.6MB
Analysis was performed to evaluate prediction accuracy of a neutronics code system for thermal reactor; the SRAC system with the use of the latest nuclear data library JENDL-3.3 for the U Doppler effect measured in the uranium fueled (FCA-XXI-1D2) and MOX fueled (XXII-1 series) cores. The results of the analysis with the diffusion theory showed overestimation by up to +11%. In relatively soft neutron spectra, however, the calculated values agreed with the experimental ones within the experimental errors.
U doppler effect in the soft neutron spectra using FCA (Joint research)Ando, Masaki; Kawasaki, Kenji*; Okajima, Shigeaki; Fukushima, Masahiro; Matsuura, Yutaka*; Kaneko, Yuji*
JAERI-Research 2005-026, 39 Pages, 2005/09
JAERI-Research-2005-026.pdf:4.37MB
U Doppler effect measurements in moderated neutron spectra (uranium fuel and MOX simulated fuel) were carried out using FCA for the purpose of contributing to the improvement in prediction accuracy for Doppler coefficient in LWR. In the mockup cores for MOX fuel, the measurements were performed in different neutron spectra, where the voidage of moderator material was varied systematically. The experimental data were obtained using cylindrical uranium samples with different outer diameter up to 800C. Analyses were performed using a standard code system designed to analyze fast reactor mock-up experiments at FCA with the use of the JENDL-3.2 library. The results of the analyses showed that the calculation accuracy did not depend on the types of the core fuel or the Doppler samples. The calculated values agreed with the experimental ones within the experimental error. Any dependency of the prediction accuracy on the neutron spectra was not observed in the MOX simulated fuel cores.
Okumura, Keisuke; Kawasaki, Kenji*; Mori, Takamasa
JAERI-Research 2005-018, 64 Pages, 2005/08
JAERI-Research-2005-018.pdf:3.26MB
In the KRITZ-2 critical experiments, criticality and pin power distributions were measured at room temperature and high temperature (about 245 degree C) for three different cores loading slightly enriched UO
or MOX fuels. For nuclear data testing, benchmark analysis was carried out with a continuous-energy Monte Carlo code MVP and its four nuclear data libraries based on JENDL-3.2, JENDL-3.3, JEF-2.2 and ENDF/B-VI.8. As a result, fairly good agreements with the experimental data were obtained with any libraries for the pin power distributions. However, the JENDL-3.3 and ENDF/B-VI.8 give under-prediction of criticality and too negative isothermal temperature coefficients for slightly enriched UO cores, while the older nuclear data JENDL-3.2 and JEF-2.2 give rather good agreements with the experimental data. From the detailed study with an infinite unit cell model, it was found that the differences among the libraries are mainly due to the different fission cross section of U-235 in the energy rage below 1.0 eV.
Ando, Masaki; Nakano, Yoshihiro; Okajima, Shigeaki; Kawasaki, Kenji
JAERI-Research 2003-029, 72 Pages, 2003/12
JAERI-Research-2003-029.pdf:3.41MB
The objectives of this study is to clarify calculation accuracy for the Doppler effect of the resonance materials; erbium (Er), tungsten (W) and thorium (ThO). Doppler effect measurements were carried out in a fast neutron spectrum (XX-2 core) and in an intermediate neutron spectrum (XXI-1D2 core) by the sample-heated and reactivity worth measurement method up to 800C using FCA. The experiment was analyzed with the standard analysis method for fast reactor cores at FCA with the use of the JENDL-3.2. The SRAC system was also used to investigate the calculation accuracy of the system and to compare it with that of the FCA standard analysis method. The standard analysis method underestimated for the XX-2 core and agreed the experiments within the experimental errors for the XXI-1D2 core. The analysis with the SRAC system gave smaller values by 3%
10% for the Er sample and bigger values by 2%5% for the W sample than the standard analysis method.
Ando, Masaki; Nakano, Yoshihiro; Okajima, Shigeaki; Kawasaki, Kenji
Journal of Nuclear Materials, 319, p.126 - 130, 2003/06
Times Cited Count：0 Percentile：0.01(Materials Science, Multidisciplinary)Doppler effect experiments on resonance materials for ROX fuels were carried out to examine the calculation accuracy in the intermediate neutron spectrum using Fast Critical Assembly (FCA) at Japan Atomic Energy Research Institute. This study is the second phase of a series of the Doppler effect experiments on the resonance materials, which is following the measurements in the fast neutron spectrum. The Doppler effect was measured as the sample reactivity change between the heated and unheated samples. The cylindrical samples of the resonance materials such as erbium (Er), tungsten (W) and thorium (ThO) were used. The sample was heated up to 800C at the center of the FCA core. The Doppler effect measurements were analyzed using the SRAC 95 code system with the use of JENDL 3.2. The calculated values agreed with the experiment within the experimental error for the W and ThO samples, while the calculation overestimated the experiment for the Er sample about 10 %.
