scholarly journals Uncertainty quantification works relevant to fission yields and decay data

2018 ◽  
Vol 4 ◽  
pp. 43
Author(s):  
Go Chiba ◽  
Shunsuke Nihira
Keyword(s):  
Perturbation Theory ◽  
Uncertainty Quantification ◽  
Nuclear Data ◽  
Code System ◽  
Reactor Physics ◽  
Delayed Neutrons ◽  
Decay Data ◽  
Decay Heat ◽  
Numerical Tools ◽  
Fission Yields

In the present paper, firstly, we review our previous works on uncertainty quantification (UQ) of reactor physics parameters. This consists of (1) development of numerical tools based on the depletion perturbation theory (DPT), (2) linearity of reactor physics parameters to nuclear data, (3) UQ of decay heat and its reduction, and (4) correlation between decay heat and β-delayed neutrons emission. Secondly, we show results of extensive calculations about UQ on decay heat with several different numerical conditions by the DPT-based capability of a reactor physics code system CBZ.

scholarly journals BURNUP SENSITIVITY CALCULATIONS WITH CBZ FOR LIGHT WATER REACTOR ASSEMBLY PROBLEMS

2021 ◽  
Vol 247 ◽  
pp. 15013
Author(s):  
Go Chiba
Keyword(s):  
Perturbation Theory ◽  
Nuclear Fuel ◽  
Nuclear Data ◽  
Light Water Reactor ◽  
Code System ◽  
Reactor Physics ◽  
Light Water ◽  
Water Reactor ◽  
Fuel Assemblies ◽  
Reactor Assembly

Sensitivities of k∞ and nuclides number densities during nuclear fuel burnup with respect to nuclear data are calculated with a reactor physics code system CBZ. Sensitivity calculations are carried out with the depletion perturbation theory applicable to nuclear fuel assemblies including burnable absorbers. Numerical results are presented both for BWR and PWR assemblies, and those demonstrate usefulness and effectiveness of burnup sensitivity calculation capabilities for LWR fuel assemblies.

scholarly journals NUCLEAR DATA UNCERTAINTY QUANTIFICATION FOR THE DECAY HEAT OF PWR MOX FUELS USING DATA ASSIMILATION OF ELEMENTARY FISSION BURSTS

2021 ◽  
Vol 247 ◽  
pp. 10002
Author(s):  
V. Vallet ◽  
J. Huyghe ◽  
C. Vaglio-Gaudard ◽  
D. Lecarpentier ◽  
C. Reynard-Carette
Keyword(s):  
Data Assimilation ◽  
Uncertainty Quantification ◽  
Uncertainty Propagation ◽  
Fission Products ◽  
Nuclear Data ◽  
Data Uncertainty ◽  
Decay Heat ◽  
Using Data ◽  
The Impact ◽  
Fission Yields

Currently there is no integral experimental data for code validation regarding the decay heat of MOX fuels, excepted fission burst experiments (for fission products contributions at short cooling times) or post-irradiated experiments on nuclide inventories (restricted number of nuclide of interest for decay heat). The uncertainty quantification mainly relies on uncertainty propagation of nuclear data covariances. In the recent years, the transposition method, based on the data assimilation theory, was used in order to transpose the experiment-to-calculation discrepancies at a given set of parameters (cooling time, fuel burnup) to another set of parameters. As an example, this method was used on the CLAB experiments and the experiment-to-calculation discrepancies at 13 years were transposed to an UOX fuel between 5 and 27 years and for burnups from 10 to 50 GWd/t. The purpose of this paper is to study to what extent the transposition method could be used for MOX fuels. In particular, the Dickens fission burst experiment of 239Pu was considered for MOX fuels at short cooling times (< 1h30) and low burnup (< 10 GWd/t). The impact of fission yields (FY) correlations was also discussed. As a conclusion, the efficiency of the transposition process is limited by the experimental uncertainties larger than nuclear data uncertainties, and by the fact that fission burst experiments would only be representative to the FY contribution of the decay heat uncertainty of an irradiated reactor fuel. Nevertheless, this method strengthens the decay heat uncertainties at very short cooling times, previously based only on nuclear data covariance propagation through computation.

scholarly journals ANSWERS® TOOLS FOR UNCERTAINTY QUANTIFICATION AND VALIDATION

2021 ◽  
Vol 247 ◽  
pp. 15015
Author(s):  
Paul N Smith ◽  
Dave Hanlon ◽  
Geoff Dobson ◽  
Richard Hiles ◽  
Tim Fry ◽  
...  
Keyword(s):  
Uncertainty Quantification ◽  
Sampling Method ◽  
Similarity Index ◽  
Nuclear Data ◽  
Covariance Matrices ◽  
Reactor Physics ◽  
Development Environment ◽  
Post Process ◽  
Manufacturing Tolerances ◽  
Validation Experiments

ANSWERS® is developing a set of uncertainty quantification (UQ) tools for use with its major physics codes: WIMS/PANTHER (reactor physics), MONK (criticality and reactor physics) and MCBEND (shielding and dosimetry). The Visual Workshop integrated development environment allows the user to construct and edit code inputs, launch calculations, post-process results and produce graphs, and recently uncertainty quantification and optimisation tools have been added. Prior uncertainties due to uncertainties in nuclear data or manufacturing tolerances can be estimated using the sampling method or using the sensitivity options in the physics codes combined with appropriate covariance matrices. To aid the user in the choice of appropriate validation experiments, the MONK categorisation scheme and/or a similarity index can be used. An interactive viewer has been developed which allows the user to search through, and browse details of, over 2,000 MONK validation experiments that have been analysed from the ICSBEP and IRPhE validation sets. A Bayesian updating approach is used to assimilate the measured data with the calculated results. It is shown how this process can be used to reduce bias in calculated results and reduce the calculated uncertainty on those results. This process is illustrated by application to a PWR fuel assembly.

scholarly journals Status of fission fragment observables measured with the LOHENGRIN spectrometer

2019 ◽  
Vol 211 ◽  
pp. 04004 ◽  
Author(s):  
S. Julien-Laferrière ◽  
L. Thombansen ◽  
G. Kessedjian ◽  
A. Chebboubi ◽  
O. Serot ◽  
...  
Keyword(s):  
Fission Fragment ◽  
Isomeric Ratio ◽  
Nuclear Data ◽  
Nuclear Fission ◽  
Experimental Program ◽  
Spent Fuel ◽  
Reactor Physics ◽  
Model Calculations ◽  
Common Effort ◽  
Fission Yields

Nuclear fission yields are key parameters to evaluate reactor physics observables, such as fuel inventory, decay heat, spent fuel radiotoxicity, criticality but also for understanding the fission process. Despite a significant effort allocated to measure fission yields during the last decades, the recent evaluated libraries still need improvements in particular in the description of the uncertainties with the associated correlations. Additional kinds of measurements provide complementary information in order to test the models used in the nuclear data evaluation. Moreover, some discrepancies between these libraries must be explained. A common effort by the CEA, the LPSC and the ILL aims at tackling these issues by providing precise measurement of isotopic and isobaric fission yields with the related variance-covariance matrices. Nevertheless, the experimental program represents itself a large range of observables requested by the evaluations: isotopic yields, nuclear charge polarization, odd-even effect, isomeric ratio and their dependency with fission fragment kinetic energy as a probe of the nuclear de-excitation path in the (E*, Jπ) representation. Measurements for thermal neutron induced fission of 241Pu have been carried out at the Institut Laue Langevin using the LOHENGRIN mass spectrometer. Experimental program, observables reachable, results and comparison to model calculations are shown.

scholarly journals Integral data assimilation of the MERCI-1 experiment for the nuclear data associated with the PWR decay heat computation

2019 ◽  
Vol 211 ◽  
pp. 07004
Author(s):  
J. Huyghe ◽  
C. De Saint-Jean ◽  
D. Lecarpentier ◽  
C. Reynard-Carette ◽  
C. Vaglio-Gaudard ◽  
...  
Keyword(s):  
Reactor Core ◽  
Nuclear Data ◽  
Nuclear Decay ◽  
Crucial Issue ◽  
Decay Heat ◽  
Uncertainty Calculation ◽  
Experimental Values ◽  
The Impact ◽  
Fission Yields ◽  
Integral Data

Nuclear decay heat is a crucial issue for PWR in-core safety after reactor shutdown and back-end cycle. It is a dimensioning parameter for safety injection systems (SIS) to avoid a dewatering of the reactor core. The decay heat uncertainty needs to be controlled over the largest range of applications. The assimilation of the MERCI-1 experiment was studied to provide feedbacks on nuclear data. This experiment consisted in the measurement of the decay heat of a PWR UOX fuel sample irradiated in the OSIRIS reactor, for cooling times between 45 minutes and 42 days. More specifically, the consideration of several experimental values of MERCI-1 at different cooling times was tested. This raised issues about correlations to consider between different measurements. Besides, the impact of considering correlations between independent fission yields in covariance matrices on the decay heat uncertainty calculation and on the feedbacks on nuclear data is discussed.

scholarly journals Summation Calculations for Reactor Antineutrino Spectra, Decay Heat and Delayed Neutron Fractions Involving New TAGS Data and Evaluated Databases

2019 ◽  
Vol 211 ◽  
pp. 01001
Author(s):  
M. Estienne ◽  
M. Fallot ◽  
L. Giot ◽  
V. Guadilla-Gomez ◽  
L. Le Meur ◽  
...  
Keyword(s):  
Fission Product ◽  
Neutron Emission ◽  
Fission Products ◽  
Nuclear Data ◽  
Delayed Neutron ◽  
Data Bases ◽  
Decay Data ◽  
Decay Heat ◽  
Reactor Antineutrino ◽  
Decay Properties

Three observables of interest for present and future reactors depend on the β decay properties of the fission products: antineutrinos from reactors, the reactor decay heat and delayed neutron emission. In these proceedings, we present new results from summation calculations of the first two quantities quoted above, performed with evolved independent yields coupled with fission product decay data, from various nuclear data bases or models. New TAGS results from the latest experiment of the TAGS collaboration at the JYFL facility of Jyväskylä will be displayed as well as their impact on the antineutrino spectra and the decay heat associated to fission pulses of the main actinides.

Nuclear data-induced uncertainty quantification of prompt neutron decay constant based on perturbation theory for ADS experiments at KUCA

2019 ◽  
Vol 57 (2) ◽  
pp. 196-204 ◽  
Author(s):  
Tomohiro Endo ◽  
Kenichi Watanabe ◽  
Go Chiba ◽  
Masao Yamanaka ◽  
Willem Frederik Geert van Rooijen ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Uncertainty Quantification ◽  
Decay Constant ◽  
Nuclear Data ◽  
Prompt Neutron ◽  
Neutron Decay

scholarly journals Perturbation-Theory-Based Sensitivity and Uncertainty Analysis with CASMO-4

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Maria Pusa
Keyword(s):  
Perturbation Theory ◽  
Uncertainty Analysis ◽  
Adjoint System ◽  
Nuclear Data ◽  
Theoretical Background ◽  
Reactor Physics ◽  
Deterministic Transport ◽  
Practical Guidelines ◽  
Rate Ratios ◽  
Sensitivity And Uncertainty Analysis

The topic of this paper is the development of sensitivity and uncertainty analysis capability to the reactor physics code CASMO-4 in the context of the UAM (Uncertainty Analysis in Best-Estimate Modelling for Design, Operation, and Safety Analysis of LWRs) benchmark. The sensitivity analysis implementation is based on generalized perturbation theory, which enables computing the sensitivity profiles of reaction rate ratios efficiently by solving one generalized adjoint system for each response. Both the theoretical background and the practical guidelines for modifying a deterministic transport code to compute the generalized adjoint solutions and sensitivity coefficients are reviewed. The implementation to CASMO-4 is described in detail. The developed uncertainty analysis methodology is deterministic, meaning that the uncertainties are computed based on the sensitivity profiles and covariance matrices for the uncertain nuclear data parameters. The main conclusions related to the approach used for creating a covariance library compatible with the cross-section libraries of CASMO-4 are presented. Numerical results are given for a lattice physics test problem representing a BWR, and the results are compared to the TSUNAMI-2D sequence in SCALE 6.1.

scholarly journals Recent advances in beta decay measurements

2018 ◽  
Vol 4 ◽  
pp. 24
Author(s):  
Magali Estienne ◽  
Muriel Fallot ◽  
Lydie Giot ◽  
Loïc Le Meur ◽  
Amanda Porta
Keyword(s):  
Neutron Emission ◽  
Uncertainty Propagation ◽  
Fission Products ◽  
Nuclear Data ◽  
Summation Method ◽  
Experimental Simulation ◽  
Decay Data ◽  
Decay Heat ◽  
Systematic Effects ◽  
Working Groups

Three observables of interest for present and future reactors depend on the β decay data of the fission products: the reactor decay heat, antineutrinos from reactors and delayed neutron emission. Concerning the decay heat, significant discrepancies still exist between summation calculations in − their two main ingredients: the decay data and the fission yields − performed using the most recent evaluated databases available. It has been recently shown that the associated uncertainties are dominated by the ones on the decay data. But the results subtantially differ taking into account or not the correlations between the fission products. So far the uncertainty propagation does not include as well systematic effects on nuclear data such as the Pandemonium effect which impacts a large number of nuclei contributing to the decay heat. The list of nuclei deserving new TAGS measurements has been updated recently in the frame of IAEA working groups. The issues listed above impact in the same way the predicted energy spectra of the antineutrinos from reactors computed with the summation method, the interest of which has been recently reinforced by the Daya Bay latest publication. Nuclear data should definitely contribute to refine and better control these calculations. Lastly, a lot of nuclear data related to delayed neutrons are missing in nuclear databases. Despite the progresses already done these last years with new measurements now requiring to be included in evaluated databases, the experimental efforts which still need to be done are significant. These different issues will be addressed here before to comment on recent experimental results and on their impacts on the quoted observables. Some perspectives will also be presented. Solving the issues listed above will require to bring together experimental, simulation, evaluation and theoretical activities.

scholarly journals NUCLEAR DATA V&V ANALYSIS FOR FUSION APPLICATIONS: INTEGRAL BENCHMARKS AND DECAY DATA

2021 ◽  
Vol 247 ◽  
pp. 10015
Author(s):  
Olga Vilkhivskaya ◽  
Mark Gilbert
Keyword(s):  
Nuclear Data ◽  
High Energy ◽  
Operational Environment ◽  
Operational Parameters ◽  
Plasma Parameters ◽  
Decay Data ◽  
Decay Heat ◽  
High Energy Neutron ◽  
Nuclear Data Library ◽  
Energy Neutron

A reliable estimation of the operational parameters is one of the primary concerns in the design of magnetic fusion devices such as ITER and DEMO. Methods of diagnostics and control over the critical plasma parameters determining its stability and efficiency rely on the high-energy neutron field monitoring. Extreme operational environment, such as high-energy neutron flux, electromagnetic radiation, and high temperatures might reduce the performance of the detector systems. Therefore, research and development activities in detector prototyping are carried out to address this problem. To predict the performance of the detector materials, simulations using the latest releases of the nuclear data libraries as input for the inventory codes are carried out. This paper describes the latest validation and verification (V&V) benchmark exercise for FISPACT-II & TENDL-2017 based on the fusion decay heat measurements performed at the Japanese FNS facility for the materials in the diagnostic components for the radiation measurements. The breakdown of decay-heat contributions from individual radionuclides have been employed to interpret the simulated results, benchmark the data against the experimental measurements, and revise the neutron-induced reactions cross-section and decay data for the associated radionuclides for the upcoming release of the TENDL-2019 nuclear data library.

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