Uncertainty Analysis of the TRU-Burning Thorium-Fueled RBWR Using Generalized Perturbation Theory

The RBWR-TR is a thorium-based reduced moderation BWR (RBWR) with a high transuranic (TRU) consumption rate. It is charged with LWR TRU and thorium, and it recycles all actinides an unlimited number of times while discharging only fission products and trace amounts of actinides through reprocessing losses. This design is a variant of the Hitachi RBWR-TB2, which arranges its fuel in a hexagonal lattice, axially segregates seed and blanket regions, and fits within an existing ABWR pressure vessel. The RBWR-TR eliminates the internal axial blanket, eliminates absorbers from the upper reflector, and uses thorium rather than depleted uranium as the fertile makeup fuel. This design has been previously shown to perform comparably to the RBWR-TB2 in terms of TRU consumption rate and burnup, while providing significantly larger margin against critical heat flux. This study examines the uncertainty in key neutronics parameters due to nuclear data uncertainty. As most of the fissions are induced by epithermal neutrons and since the reactor uses higher actinides as well as thorium and 233U, the cross sections have significantly more uncertainty than in typical LWRs. The sensitivity of the multiplication factor (keff) to the cross sections of many actinides is quantified using a modified version of Serpent 2.1.19 [1]. Serpent [2] is a Monte Carlo code which uses delta tracking to speed up the simulation of reactors; in this modified version, cross sections are artificially inflated to sample more collision, and collisions are rejected to preserve a “fair game.” The impact of these rejected collisions is then propagated to the multiplication factor using generalized perturbation theory [3]. Covariance matrices are retrieved for the ENDF/B-VII.1 library [4], and used to collapse the sensitivity vectors to an uncertainty on the multiplication factor. The simulation is repeated for several reactor configurations (for example, with a reduced flow rate, and with control rods inserted), and the difference in keff sensitivity is used to assess the uncertainty associated with the change (the uncertainty in the void feedback and the control rod worth). The uncertainty in the RBWR-TR is found to be dominated by the epithermal fission cross section for 233U in reference conditions, although when the spectrum hardens, the uncertainty in fast capture cross sections of 232Th becomes dominant.

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Nuclear Data Uncertainty Quantification and Propagation for Safety Analysis of Lead-Cooled Fast Reactors

Science and Technology of Nuclear Installations ◽

10.1155/2020/3961095 ◽

2020 ◽

Vol 2020 ◽

pp. 1-14

Author(s):

Ishita Trivedi ◽

Jason Hou ◽

Giacomo Grasso ◽

Kostadin Ivanov ◽

Fausto Franceschini

Keyword(s):

Cross Sections ◽

Nuclear Data ◽

Safety Analysis ◽

Data Uncertainty ◽

Monte Carlo Code ◽

Capture Cross ◽

Fast Reactors ◽

Safety Margins ◽

The Impact ◽

Capture Cross Sections

In this study, the Best Estimate Plus Uncertainty (BEPU) approach is developed for the systematic quantification and propagation of uncertainties in the modelling and simulation of lead-cooled fast reactors (LFRs) and applied to the demonstration LFR (DLFR) initially investigated by Westinghouse. The impact of nuclear data uncertainties based on ENDF/B-VII.0 covariances is quantified on lattice level using the generalized perturbation theory implemented with the Monte Carlo code Serpent and the deterministic code PERSENT of the Argonne Reactor Computational (ARC) suite. The quantities of interest are the main eigenvalue and selected reactivity coefficients such as Doppler, radial expansion, and fuel/clad/coolant density coefficients. These uncertainties are then propagated through safety analysis, carried out using the MiniSAS code, following the stochastic sampling approach in DAKOTA. An unprotected transient overpower (UTOP) scenario is considered to assess the effect of input uncertainties on safety parameters such as peak fuel and clad temperatures. It is found that in steady state, the multiplication factor shows the most sensitivity to perturbations in 235U fission, 235U ν, and 238U capture cross sections. The uncertainties of 239Pu and 238U capture cross sections become more significant as the fuel is irradiated. The covariance of various reactivity feedback coefficients is constructed by tracing back to common uncertainty contributors (i.e., nuclide-reaction pairs), including 238U inelastic, 238U capture, and 239Pu capture cross sections. It is also observed that nuclear data uncertainty propagates to uncertainty on peak clad and fuel temperatures of 28.5 K and 70.0 K, respectively. Such uncertainties do not impose per se threat to the integrity of the fuel rod; however, they sum to other sources of uncertainties in verifying the compliance of the assumed safety margins, suggesting the developed BEPU method necessary to provide one of the required insights on the impact of uncertainties on core safety characteristics.

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Pressure Effects of Foreign Gases on the 535.0 nm Fluorescence Line of Thallium

Zeitschrift für Naturforschung A ◽

10.1515/zna-1985-0803 ◽

1985 ◽

Vol 40 (8) ◽

pp. 800-809 ◽

Cited By ~ 2

Author(s):

E. Lisicki ◽

A. Bielski ◽

J. Szudy ◽

J. Wolnikowski

Keyword(s):

Cross Sections ◽

Pressure Effects ◽

Pressure Broadening ◽

Fluorescence Line ◽

Series Of Experiments ◽

The Cross ◽

The Impact

Results of a series of experiments on pressure effects caused by various foreign gases on the 535.0 nm Tl fluorescence line emitted due to the photodissociation of TlI-molecules are summarized and some aspects of the Doppler and pressure broadening of this line are discussed. The impact broadening- and shift-cross sections are determined for two sets of mean relative velocities ū of the emitter-perturber pair. An attempt is made to analyse the cross-sections for different perturbers by investigating their dependence on the quantity (α/ū)2/5, where α is the polarizability of the perturber.

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Repetitive Impact Wear Behaviors of the Tempered 25Cr3Mo2NiWV Fe-Based Steel

Coatings ◽

10.3390/coatings10020107 ◽

2020 ◽

Vol 10 (2) ◽

pp. 107

Author(s):

Cheng Zhang ◽

Pu Li ◽

Hui Dong ◽

Dongliang Jin ◽

Jinfeng Huang ◽

...

Keyword(s):

Cross Sections ◽

Wear Mechanism ◽

Optical Microscope ◽

Impact Wear ◽

Wear Properties ◽

Micro Cracks ◽

The Cross ◽

Repetitive Impact ◽

Surface Morphologies ◽

The Impact

This study aimed to reveal the impact wear behaviors of tempered 25Cr3Mo2NiWV steel. The specimens were subject to various heat treatment processes for generating different mechanical and wear properties. The impact wear tests were performed with an MLD-10 dynamic abrasive wear tester. Worn surface morphologies and micro-cracks of the cross-sections were analyzed by optical microscope and scanning electron microscope. The Vickers hardness of the sample and the impact wear mechanism were also analyzed. The steel with the best combination of hardness and toughness had the lowest wear. With the increase of wear time, the dominant wear mechanism varied from slight plastic deformation to micro-cutting and adhesive wear. Finally, micro fatigue peeling occurred. After impact wear, the cracks could initiate from the surface or the sub-surface. Micrographs of the crack in the cross-section demonstrated two different propagation modes of fatigue fractures. The results showed that the strength and toughness of steel affected the crack propagation, surface spalling, and wear failure mechanism during impact wear.

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The Method of Prediction Climatic Loads on the Building Enclosures

Materials Science Forum ◽

10.4028/www.scientific.net/msf.945.845 ◽

2019 ◽

Vol 945 ◽

pp. 845-856

Author(s):

D.Y. Zheldakov

Keyword(s):

Climate Change ◽

Cross Section ◽

Cross Sections ◽

Global Climate Change ◽

Global Climate ◽

Outer Wall ◽

Freezing And Thawing ◽

The Cross ◽

Number Of Cycles ◽

The Impact

Based on the numerical solution of the differential equation that determines one-dimensional heat transfer under unstable conditions with constant coefficients, a method was developed to calculate the temperature distribution over the cross section of the enclosing structure. Based on the developed method, a method of determining the number of cycles of freezing and thawing of moisture in the cross sections of the outer wall of the building was calculated. This method was tested in the experiment on the exterior walls of operating buildings. The results showed good convergence of the real and calculated temperature values. The calculation of the number of cycles of freezing and thawing on the cross section of the outer wall of the building according to the developed methodology and the experiment showed the same results. The method of numerical assessment was developed to show the impact of global climate change on enclosed structures. The parameter of temperature load of enclosing structures was introduce. The method uses meteorological data of outdoor air temperature over the last 50 years and the results of calculation of temperature fluctuation of the enclosed structures. The use of this method allowed to calculate the number of cycles of freezing and thawing in cross sections of the outer wall at any given time period, and, therefore, more accurately predict the durability of enclosed structures. In addition, the developed technique allows quantitative comparison of different designs of external structures on the thermal load, taking into account global climate change.

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UNCERTAINTY ANALYSIS OF SUB-EXERCISES IN UAM-SFR BENCHMARK WITH THE MCS CODE

EPJ Web of Conferences ◽

10.1051/epjconf/202124715017 ◽

2021 ◽

Vol 247 ◽

pp. 15017

Author(s):

Yunki Jo ◽

Vutheam Dos ◽

Nhan Nguyen Trong Mai ◽

Hyunsuk Lee ◽

Deokjung Lee

Keyword(s):

Monte Carlo ◽

Perturbation Theory ◽

Uncertainty Analysis ◽

Covariance Matrix ◽

Nuclear Data ◽

Monte Carlo Code ◽

Sensitivity Coefficients ◽

Classical Perturbation Theory ◽

Generalized Perturbation Theory ◽

Parameters Of Interest

Uncertainty analysis in Modelling (UAM) for Design, Operation and Safety Analysis of Sodium-cooled Fast Reactors (SFRs) has been formed by OECD/NEA to assess the effect of nuclear data uncertainties on parameters of interest in SFR analysis. In this paper, sub-exercises of a medium 1000 MWth metallic core (MET-1000) and a large 3600 MWth oxide core (MOX-3600) are tested by a Monte Carlo code MCS to perform uncertainty analysis. Classical perturbation theory and generalized perturbation theory are used to calculate sensitivity coefficients. Uncertainty is calculated by multiplying the sensitivity coefficients and relative covariance matrix from ENDF/B-VII.1 library.

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The impact of vibrational Raman scattering of air on DOAS measurements of atmospheric trace gases

Atmospheric Measurement Techniques ◽

10.5194/amt-8-3767-2015 ◽

2015 ◽

Vol 8 (9) ◽

pp. 3767-3787 ◽

Cited By ~ 19

Author(s):

J. Lampel ◽

U. Frieß ◽

U. Platt

Keyword(s):

Raman Scattering ◽

Inelastic Scattering ◽

Cross Section ◽

Cross Sections ◽

Systematic Bias ◽

Atmospheric Scattering ◽

Scattering Cross ◽

The Cross ◽

Scattering Cross Sections ◽

The Impact

Abstract. In remote sensing applications, such as differential optical absorption spectroscopy (DOAS), atmospheric scattering processes need to be considered. After inelastic scattering on N2 and O2 molecules, the scattered photons occur as additional intensity at a different wavelength, effectively leading to "filling-in" of both solar Fraunhofer lines and absorptions of atmospheric constituents, if the inelastic scattering happens after the absorption. Measured spectra in passive DOAS applications are typically corrected for rotational Raman scattering (RRS), also called Ring effect, which represents the main contribution to inelastic scattering. Inelastic scattering can also occur in liquid water, and its influence on DOAS measurements has been observed over clear ocean water. In contrast to that, vibrational Raman scattering (VRS) of N2 and O2 has often been thought to be negligible, but it also contributes. Consequences of VRS are red-shifted Fraunhofer structures in scattered light spectra and filling-in of Fraunhofer lines, additional to RRS. At 393 nm, the spectral shift is 25 and 40 nm for VRS of O2 and N2, respectively. We describe how to calculate VRS correction spectra according to the Ring spectrum. We use the VRS correction spectra in the spectral range of 420–440 nm to determine the relative magnitude of the cross-sections of VRS of O2 and N2 and RRS of air. The effect of VRS is shown for the first time in spectral evaluations of Multi-Axis DOAS data from the SOPRAN M91 campaign and the MAD-CAT MAX-DOAS intercomparison campaign. The measurements yield in agreement with calculated scattering cross-sections that the observed VRS(N2) cross-section at 393 nm amounts to 2.3 ± 0.4 % of the cross-section of RRS at 433 nm under tropospheric conditions. The contribution of VRS(O2) is also found to be in agreement with calculated scattering cross-sections. It is concluded, that this phenomenon has to be included in the spectral evaluation of weak absorbers as it reduces the measurement error significantly and can cause apparent differential optical depth of up to 3 ×10−4. Its influence on the spectral retrieval of IO, glyoxal, water vapour and NO2 in the blue wavelength range is evaluated for M91. For measurements with a large Ring signal a significant and systematic bias of NO2 dSCDs (differential slant column densities) up to (−3.8 ± 0.4) × 1014 molec cm−2 is observed if this effect is not considered. The effect is typically negligible for DOAS fits with an RMS (root mean square) larger than 4 × 10−4.

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An Investigation of Factors that Influence the Overall Magnitude of Cross-Sectional Distortions in Draw Bending

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.554-557.1394 ◽

2013 ◽

Vol 554-557 ◽

pp. 1394-1399 ◽

Cited By ~ 1

Author(s):

Torgeir Welo ◽

Fredrik Widerøe

Keyword(s):

Cross Sections ◽

Dimensional Accuracy ◽

Operational Cost ◽

Cross Sectional ◽

Material Parameters ◽

Quality Costs ◽

The Cross ◽

Draw Bending ◽

The Impact ◽

Local Distortions

European manufacturing companies are currently facing increased competition as a result of intensified globalization in the market and supply base. One strategy to meet this challenge is to develop and manufacture higher quality products at reduced cost. Metal forming is a typical manufacturing operation where improved technology can create advantages in the market place through higher value-added products. In the automotive industry, for example, improved shaping capabilities of profiles will improve product functionality, while reducing system cost due to reduction of part count and subsequent assembly operations such as welding. In addition, improved dimensional accuracy will provide benefits in terms of reduced quality costs and, sometimes, eliminating downstream processing steps such as calibration or machining. Rotary draw bending is typically used to manufacture profile-based shapes bent at tight radii with reasonable dimensional accuracy. The advantage of this process is low operational cost combined with relatively high flexibility, particularly with regard to bend angle. On the other hand, the disadvantage associated with the method is limited abilities to control local distortions of the cross section without taking special actions such as applying external stretching or complex tooling that ultimately would increase the investment and operational cost. The objective of the present paper is to identify the most important factors that influence cross-sectional distortions and quantify their impact on dimensional accuracy in draw bending, by performing a series of experiments in an industry-type draw bender. In order to accommodate different cross-sectional geometries, a flexible, modular tool concept was developed. AA6xxx aluminum alloy profile with different cross-sectional geometries (width, depth, thicknesses), single and multi-camber, were bent at different radii and bend angles, while measuring local distortions of the cross sections. The results have been presented in diagrams denoted flatness limit curves, showing the impact of various geometry (and material) parameters on local deformations of individual cross sectional members. The results show that the flange width (i.e. the free span between webs) is the main factor with regard to distortions, followed by wall thickness and bending radius and, finally, depth of the cross sections. Material parameters seem to have limited effect for the alloy tempers investigated. Attempts have been made to interpret the mechanisms associated with the development of local cross sectional distortions with the purpose of developing a practical design tool based on analytical calculations. The very first results show reasonably well agreement in the cases when local buckling of the internal compressive flange is less predominant.

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VOID COEFFICIENT SENSITIVITY ANALYSIS FOR THE TRIGA MARK II REACTOR AT L.E.N.A. (UNIPV)

EPJ Web of Conferences ◽

10.1051/epjconf/202124715005 ◽

2021 ◽

Vol 247 ◽

pp. 15005

Author(s):

D. Portinari ◽

A. Cammi ◽

S. Lorenzi ◽

M. Aufiero ◽

Y. Calzavara ◽

...

Keyword(s):

Sensitivity Analysis ◽

Cross Sections ◽

Research Reactor ◽

Multiplication Factor ◽

Delayed Neutron ◽

Reactor Physics ◽

Fission Spectrum ◽

Challenging Tasks ◽

Generalized Perturbation Theory ◽

Triga Mark Ii

Sensitivity analysis studies the effect of a change in a given parameter to a response function of the system under investigation. In reactor physics, this usually translates into the study of how cross sections and fission spectrum modifications affect the value of the multiplication factor, the delayed neutron fraction or the void coefficient for example. Generalized Perturbation Theory provides a useful tool for the assessment of adjoint weighed functions such as keff and void coefficient sensitivities. In this work, the capability of SERPENT code to perform sensitivity calculation based on GPT is used to study the TRIGA Mark II research reactor installed at L.E.N.A. of University of Pavia. A general sensitivity analysis to the most important reactor’s cross sections has been performed in order to highlight the biggest reactivity contributions. Two numerically challenging tasks related to GPT calculation have been performed thanks to the relatively quick Monte Carlo approach allowed by this reactor: investigating the linearity of the reactivity injection caused by the flooding of the central channel, and calculating the fuel void coefficient sensitivity to the coolant density.

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The Impact of PbF2-Based Glasses on Radiation Shielding and Mechanical Concepts: An Extensive Theoretical and Monte Carlo Simulation Study

10.21203/rs.3.rs-295736/v1 ◽

2021 ◽

Author(s):

A. El-Denglawey ◽

Shams A.M. Issa ◽

Yasser B. Saddeek ◽

Huseyin O. Tekin ◽

Hesham M.H. Zakaly

Keyword(s):

Monte Carlo ◽

Cross Sections ◽

Radiation Shielding ◽

Fast Neutrons ◽

Monte Carlo Code ◽

Lead Fluoride ◽

Monte Carlo Simulation Study ◽

Simulation Techniques ◽

Quenching Method ◽

The Impact

Abstract This work aimed to investigate the impact of Lead-fluoride based glasses via theoretical and simulation techniques on mechanical and radiation shielding parameters. Accordingly, a glass composition PbF2 blended with TeO2-B2O3-Bi2O3 glasses were synthesised by using melt-quenching method. Using Fluka Monte Carlo code, the radiation shielding properties have measured. Moreover. Comparatively higher density PbF80= 6.163g/cm3 with 80 mol % Bi2O3, greater µ, µm and Zeff and lower T1/2, l, tenth value layer values achieved for TeO2-B2O3-Bi2O3/PbF2 glass pointed it out as the best shield of gamma. Besides, the computed effective removal cross-sections against fast neutrons (ΣR) observed that the PbF80 sample has commensurately greater with value 5.2954 (cm-1) The results observed that the variation Bi2O3/PbF2 improves the gamma protection ability of Lead-fluoride based glasses. The longitudinal modulus-L, shear modulus-S, bulk modulus-K, and Young’s modulus-Y raised from 15.89 to 25.9 -GPa, from 8.49 to 12.09 -GPa, from 4.58 to 9.77 -GPa, and from 15.74 to 25.69 -GPa, respectively. The results indicate that the highest Bi2O3/PbF2 ratio encoded PbF80 has the best shielding and mechanical competence with measurable physical properties.

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