scholarly journals Study on the Impact of Thermal Agitation on Doppler Coefficient in Epithermal Range for Gd-Bearing Fuel

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Satoshi Takeda ◽  
Satoshi Ino ◽  
Kazuhiro Wada ◽  
Michitaka Ono ◽  
Takanori Kitada
Keyword(s):  
Cross Section ◽  
Capture Cross Section ◽  
Sensitivity Coefficient ◽  
Capture Cross ◽  
Multiplication Factor ◽  
Fuel System ◽  
Thermal Agitation ◽  
Similar Tendency ◽  
The Difference ◽  
The Impact

The impact of thermal agitation on Doppler coefficient for Gd-bearing fuel was analyzed. It was found through the analysis that the impact increases when a small amount of Gd2O3is added to pure UO2fuel although the impact decreases for a large amount of Gd2O3. This tendency was discussed with the usage of simplified expression for the difference of Doppler coefficient. The simplified expression was used to consider the tendency, and it was revealed that the tendency mainly comes from the rapid decrement of multiplication factor and the relatively slow decrement of the magnitude of sensitivity coefficient of U-238 capture cross section at low Gd2O3concentration. Similar tendency which shows a maximum impact on Doppler coefficient at interior concentration is expected for other UO2fuel with a slight content of strong absorber. This indicates that Doppler coefficient of UO2fuel system with low content of strong absorber should be analyzed carefully by considering thermal agitation in epithermal range.

scholarly journals Application of the EGPT methodology in the analysis of small-sample reactivity worth experiments

2018 ◽  
Vol 4 ◽  
pp. 44 ◽  
Author(s):  
Pierre Leconte ◽  
Jean Tommasi ◽  
Alain Santamarina ◽  
Patrick Blaise ◽  
Paul Ros
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Capture Cross Section ◽  
Reference Sample ◽  
Small Sample ◽  
Capture Cross ◽  
Theoretical Formulation ◽  
Sensitivity Coefficients ◽  
Spectrum Experiment ◽  
The Impact

In the current paper, we investigate the application of the Equivalent Generalized Perturbation Theory (EGPT) to derive trends and associated covariances on the neutron capture cross section of one major fission product for both light water reactors and sodium-cooled fast reactors which is Rhodium-103. To do so, we have considered the ERMINE-V/ZONA1 & ZONA3 fast spectrum experiment and the MAESTRO thermal-spectrum experiment, where samples of these materials were oscillated in the MINERVE facility. In the paper, the theoretical formulation of EPGT is described and its derivation in the special case of the close loop oscillation technique where the reactivity worth is determined thanks to a power control system. A numerical benchmark is presented to assess the relevance of sensitivity coefficients provided by EGPT against direct perturbations where the microscopic cross sections are manually changed before calculating the adjoint and forward flux. The breakdown between direct and indirect contributions in the sensitivity analysis of the sample reactivity worth is presented and discussed, with the impact of using a calibration reference sample to normalize the measured reactivity worth. Finally, the assimilation of integral trends is done with the CONRAD code, using C/E comparisons between TRIPOLI4/JEFF3.2 calculations and experimental results and the sensitivity coefficients provided by the EGPT. Preliminary results of this study are showing that the JEFF3.2 evaluation of 103Rh gives satisfactory agreements in both thermal and fast spectrum experiments and that the combination of them can lead to a significant uncertainty reduction on the capture cross section, from ±5% to ±3% in the resolved resonance range (1 eV–10 keV) and from ±8% to ±5% in the unresolved resonance range (10 keV–1 MeV).

scholarly journals CRITICAL EXPERIMENT OF THORIUM LOADED THERMAL CORES AT KUCA (1) A NEW CRITICAL EXPERIMENT OF THORIUM LOADED CORE WITH HARDER NEUTRON SPECTRUM IN KUCA

2021 ◽  
Vol 247 ◽  
pp. 09013
Author(s):  
Tadafumi Sano ◽  
Jun-ichi Hori ◽  
Jeaong Lee ◽  
Yoshiyuki Takahashi ◽  
Kazuki Takahashi ◽  
...  
Keyword(s):  
Cross Section ◽  
Neutron Spectrum ◽  
Cross Sections ◽  
Capture Cross Section ◽  
The Other ◽  
Capture Cross ◽  
Delayed Neutron ◽  
Integral Evaluation ◽  
Critical Experiment ◽  
The Difference

In order to perform integral evaluation of 232Th capture cross section, a series of critical experiments for thorium-loaded and solid-moderated cores in KUCA had been carried out. In these experimental cores, H/235U nuclide ratio ranged about from 150 to 315, and 232Th/235U nuclide ratio ranged about from 13 to 19. In this study, a new critical experiment with Th loaded core in KUCA, which had about 70 of the H/235U ratio and 12.7 of 232Th/235U ratio, was carried out. As results, the excess reactivity was 0.086 ± 0.003 (% dk/k) and the keff was 1.0009 ± 0.0003, where the effective delayed neutron fraction was 7.656E-3. The keff was also calculated by MVP3.0 with different nuclear libraries. The respective calculations with JENDL-4.0, JENDL-3.3 and ENDF/B-VII.0 lead to 1.0056 ± 0.0086 (%), 1.0048 ± 0.0085 (%) and 1.0056 ± 0.0086 (%).On the other hand, the further MVP3.0 calculations, where only the 232Th cross sections were taken from JENDL-4.0, JENDL-3.3 or ENDF/B-VII.0 but all other nuclides were done from JENDL-4.0, were carried out to examine an impact of the difference of 232Th cross section among these nuclear libraries to the keff. The keff calculated with respective 232Th cross sections from JENDL-3.3 and ENDF/B-VII.0 was 1.0038 ± 0.0086 (%) and 1.0040 ± 0.0086 (%).

scholarly journals Neutron capture cross section of 185Re leading to ground and isomer states of 186Re in the keV-neutron energy region

2018 ◽  
Vol 178 ◽  
pp. 03005
Author(s):  
T. Katabuchi ◽  
K. Takebe ◽  
S. Umezawa ◽  
R. Fujioka ◽  
T. Saito ◽  
...  
Keyword(s):  
Cross Section ◽  
Neutron Capture ◽  
Energy Region ◽  
Capture Cross Section ◽  
Production Cross ◽  
Pulse Height ◽  
Capture Cross ◽  
Neutron Capture Cross Section ◽  
Section Data ◽  
The Difference

The neutron capture cross section of 185Re was measured in the astrophysically important energy region. Measurements were made using a neutron beam from a 7Li(p,n)7Be neutron source with energies ranging from 3 to 90 keV. Two different experimental techniques, time-of-flight (TOF) and activation methods, were employed. In the TOF experiments, the total neutron capture cross section of 185Re was determined by the pulse-height weighting technique. In the activation method, the partial capture cross section leading to the ground state of 186Re was measured by detecting decay γ-rays from neutron activated samples. The present cross section values were compared with evaluated cross section data and previous measurements. The difference between the TOF and activation results was smaller than experimental uncertainties. This suggests that the production cross section of isomer states of 186Re is very small.

scholarly journals Extracting bulk defect parameters in silicon wafers using machine learning models

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Yoann Buratti ◽  
Quoc Thong Le Gia ◽  
Josef Dick ◽  
Yan Zhu ◽  
Ziv Hameiri
Keyword(s):  
Machine Learning ◽  
Energy Level ◽  
Cross Section ◽  
Capture Cross Section ◽  
Complex Data ◽  
Capture Cross ◽  
Cross Section Ratio ◽  
Defect Energy ◽  
Section Ratio ◽  
The Impact

Abstract The performance of high-efficiency silicon solar cells is limited by the presence of bulk defects. Identification of these defects has the potential to improve cell performance and reliability. The impact of bulk defects on minority carrier lifetime is commonly measured using temperature- and injection-dependent lifetime spectroscopy and the defect parameters, such as its energy level and capture cross-section ratio, are usually extracted by fitting the Shockley-Read-Hall equation. We propose an alternative extraction approach by using machine learning trained on more than a million simulated lifetime curves, achieving coefficient of determinations between the true and predicted values of the defect parameters above 99%. In particular, random forest regressors, show that defect energy levels can be predicted with a high precision of ±0.02 eV, 87% of the time. The traditional approach of fitting to the Shockley-Read-Hall equation usually yields two sets of defect parameters, one in each half bandgap. The machine learning model is trained to predict the half bandgap location of the energy level, and successfully overcome the traditional approach’s limitation. The proposed approach is validated using experimental measurements, where the machine learning predicts defect energy level and capture cross-section ratio within the uncertainty range of the traditional fitting method. The successful application of machine learning in the context of bulk defect parameter extraction paves the way to more complex data-driven physical models which have the potential to overcome the limitation of traditional approaches and can be applied to other materials such as perovskite and thin film.

scholarly journals Impact of Thorium Capture Cross Section Uncertainty on the Thorium Utilized ADS Reactivity Calculation

2014 ◽  
Vol 2014 ◽  
pp. 1-4
Author(s):  
Thanh Mai Vu ◽  
Takanori Kitada
Keyword(s):  
Cross Section ◽  
Capture Cross Section ◽  
Design Calculation ◽  
Capture Cross ◽  
Fast System ◽  
Driven System ◽  
Accelerator Driven System ◽  
Cross Section Uncertainty ◽  
The Impact ◽  
Fast Neutron Spectrum

Recently, the researches on fast neutron spectrum system utilized thorium fuel are widely conducted. However, the recent thorium cross section libraries are limited compared to uranium cross section libraries. The impact of thorium cross section uncertainty on thorium fuel utilized accelerator driven system (ADS) reactivity calculation is estimated in this study. The uncertainty of thekeffcaused by232Th capture cross section of JENDL-4.0 is about 1.3%. The uncertainty of JENDL-4.0 is needed to be enhanced to provide more reliable results on reactivity calculation for the fast system. The impact of uncertainty of  232Th capture cross section of ENDF/B-VII is small (0.1%). Therefore, it will cause no significant impact of the thorium cross section library on the thorium utilized ADS design calculation.

scholarly journals Evaluation of neutron capture cross section on 205Pb with photonuclear data

2018 ◽  
Vol 178 ◽  
pp. 06004
Author(s):  
Nobuyuki Iwamoto ◽  
Toshiyuki Shizuma
Keyword(s):  
Cross Section ◽  
Neutron Capture ◽  
Capture Cross Section ◽  
Capture Cross ◽  
Neutron Capture Cross Section ◽  
Stellar Nucleosynthesis ◽  
Continuous Use ◽  
The Impact ◽  
Calculation Code ◽  
Existing Data

The neutron capture cross section of long-lived radioactive 205Pb is derived by using the nuclear reaction calculation code CCONE, based on photonuclear data. The present result is smaller than that of TENDL-2015 by a factor of 4. The derived Maxwellian averaged capture cross section (MACS) is the smallest compared to the existing data. The produced amount of 205Pb is explored with a simulated neutron flux in the Pb-Bi eutectic (LBE) target. The continuous use of the system in 25 years creates 205Pb with about 6 kg at maximum in the LBE (including natural Pb of 103 kg). The impact of the derived MACS on the stellar nucleosynthesis is investigated. It is found that the abundance of Tl is slightly enhanced due to the increase in the remaining abundance of 205Pb.

Measurements of the neutron capture cross section of 243Am around 23.5 keV

2021 ◽  
pp. 1-6
Author(s):  
Yu Kodama ◽  
Tatsuya Katabuchi ◽  
Gerard Rovira ◽  
Atsushi Kimura ◽  
Shoji Nakamura ◽  
...  
Keyword(s):  
Cross Section ◽  
Neutron Capture ◽  
Capture Cross Section ◽  
Capture Cross ◽  
Neutron Capture Cross Section

THERMAL NEUTRON CAPTURE CROSS-SECTION OF Na23 AND Mn55

1953 ◽  
Vol 31 (3) ◽  
pp. 204-206 ◽  
Author(s):  
Rosalie M. Bartholomew ◽  
R. C. Hawkings ◽  
W. F. Merritt ◽  
L. Yaffe
Keyword(s):  
Thermal Neutron ◽  
Cross Section ◽  
Cross Sections ◽  
Neutron Capture ◽  
Half Life ◽  
Capture Cross Section ◽  
Thermal Neutron Capture ◽  
Capture Cross ◽  
Neutron Capture Cross Section ◽  
Capture Cross Sections

The thermal neutron capture cross sections of Na23 and Mn55 have been determined using the activation method. The values are 0.53 ± 0.03 and 12.7 ± 0.3 barns respectively with respect to σAul97 = 93 barns. These agree well with recent pile oscillator results. The half-life for Mn56 is found to be 2.576 ± 0.002 hr.

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