scholarly journals Fission yields and cross sections: correlated or not?

2021 ◽  
Vol 7 ◽  
pp. 5
Author(s):  
Dimitri Alexandre Rochman ◽  
Eric Bauge
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Previous Analysis ◽  
Fission Products ◽  
Nuclear Data ◽  
Isotopic Compositions ◽  
Different Types ◽  
Fission Yields ◽  
Integral Data ◽  
Selection Of

Cross sections and fission yields can be correlated, depending on the selection of integral experimental data. To support this statement, this work presents the use of experimental isotopic compositions (both for actinides and fission products) from a sample irradiated in a reactor, to construct correlations between various cross sections and fission yields. This study is therefore complementing previous analysis demonstrating that different types of nuclear data can be correlated, based on experimental integral data.

scholarly journals Feedback from experimental isotopic compositions of used nuclear fuels on neutron cross sections and cumulative fission yields of the JEFF-3.1.1 library by using integral data assimilation

2019 ◽  
Vol 5 ◽  
pp. 24
Author(s):  
Axel Rizzo ◽  
Claire Vaglio-Gaudard ◽  
Gilles Noguere ◽  
Romain Eschbach ◽  
Gabriele Grassi ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Cross Sections ◽  
Fission Products ◽  
Nuclear Data ◽  
Capture Cross ◽  
Nuclear Fuels ◽  
Fission Yields ◽  
Integral Data ◽  
Capture Cross Sections

Comparisons of calculated and experimental isotopic compositions of used nuclear fuels can provide valuable information on the quality of nuclear data involved in neutronic calculations. The experimental database used in the present study − containing more than a thousand isotopic ratio measurements for UOX and MOX fuels with burnup ranging from 10 GWd/t up to 85 GWd/t − allowed to investigate 45 isotopic ratios covering a large number of actinides (U, Np, Pu, Am and Cm) and fission products (Nd, Cs, Sm, Eu, Gd, Ru, Ce, Tc, Mo, Ag and Rh). The Integral Data Assimilation procedure implemented in the CONRAD code was used to provide nuclear data trends with realistic uncertainties for Pressurized Water Reactors (PWRs) applications. Results confirm the quality of the 235U, 239Pu and 241Pu neutron capture cross sections available in the JEFF-3.1.1 library; slight increases of +1.2 ± 2.4%, +0.5 ± 2.2% and +1.2 ± 4.2% are respectively suggested, these all being within the limits of the quoted uncertainties. Additional trends on the capture cross sections were also obtained for other actinides (236U, 238Pu, 240Pu, 242Pu, 241Am, 243Am, 245Cm) and fission products (103Rh, 153Eu, 154Eu) as well as for the 238U(n,2n) and 237Np(n,2n) reactions. Meaningful trends for the cumulative fission yields of 144Ce, 133Cs, 137Cs and 106Ru for the 235U(nth,f) and 239Pu(nth,f) reactions are also reported.

scholarly journals Separation of Lanthanide Isotopes from Mixed Fission Product Samples

Separations ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 104
Author(s):  
Leah M. Arrigo ◽  
Jun Jiang ◽  
Zachary S. Finch ◽  
James M. Bowen ◽  
Staci M. Herman ◽  
...  
Keyword(s):  
Fission Product ◽  
Fission Products ◽  
Nuclear Data ◽  
Product Analysis ◽  
Data Production ◽  
Thermal Irradiation ◽  
Nuclear Events ◽  
Lanthanide Separation ◽  
Enriched Uranium ◽  
Fission Yields

The measurement of radioactive fission products from nuclear events has important implications for nuclear data production, environmental monitoring, and nuclear forensics. In a previous paper, the authors reported the optimization of an intra-group lanthanide separation using LN extraction resin from Eichrom Technologies®, Inc. and a nitric acid gradient. In this work, the method was demonstrated for the separation and quantification of multiple short-lived fission product lanthanide isotopes from a fission product sample produced from the thermal irradiation of highly enriched uranium. The separations were performed in parallel in quadruplicate with reproducible results and high decontamination factors for 153Sm, 156Eu, and 161Tb. Based on the results obtained here, the fission yields for 144Ce, 153Sm, 156Eu, and 161Tb are consistent with published fission yields. This work demonstrates the effectiveness of the separations for the intended application of short-lived lanthanide fission product analysis requiring high decontamination factors.

HADRON SPIN-FLIP AMPLITUDE AND SLOPE OF DIFFERENTIAL CROSS-SECTIONS

1999 ◽  
Vol 14 (03) ◽  
pp. 223-230 ◽  
Author(s):  
O. V. SELYUGIN
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Differential Cross ◽  
Scattering Amplitude ◽  
Previous Analysis ◽  
Differential Cross Sections ◽  
Spin Flip ◽  
Flip Amplitude

A possibility to obtain restrictions of the magnitude of the elastic spin-flip hadron scattering amplitude from accurately measured experimental data on the differential cross-sections of elastic hadron–hadron scattering is shown. Appropriate estimations confirm the previous analysis of experimental data at [Formula: see text] GeV and a probable contribution of the hadron spin-flip amplitude.

scholarly journals Critical review of CIELO evaluations of n+ 235U, 238U using differential experiments

2018 ◽  
Vol 4 ◽  
pp. 27 ◽  
Author(s):  
Roberto Capote ◽  
Andrej Trkov
Keyword(s):  
Cross Sections ◽  
Critical Review ◽  
Nuclear Data ◽  
Reaction Cross ◽  
Reaction Models ◽  
Reaction Channels ◽  
Data Files ◽  
Integral Data ◽  
Evaluated Nuclear Data ◽  
Reaction Cross Sections

Key reactions have been selected to compare JEFF-3.3 (CIELO 2) and IAEA CIELO (CIELO 1) evaluated nuclear data files for neutron induced reactions on 235U and 238U targets. IAEA CIELO evaluation uses reaction models to construct the evaluation prior, but strongly relied on differential data including all reaction cross sections fitted within the IAEA Neutron Standards project. The JEFF-3.3 evaluation relied on a mix of differential and integral data with strong contribution from nuclear reaction modelling. Differences in evaluations are discussed; a better reproduction of differential data for the IAEA CIELO evaluation is shown for key reaction channels.

scholarly journals Theoretical calculation and evaluation of neutron inducedreactions on Pu isotopes

2020 ◽  
Vol 239 ◽  
pp. 03008
Author(s):  
Hairui Guo ◽  
Yinlu Han ◽  
Tao Ye ◽  
Weili Sun ◽  
Wendi Chen
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Nuclear Data ◽  
Reaction Cross ◽  
Driven Systems ◽  
Intranuclear Cascade ◽  
Pu Isotopes ◽  
Design Requirements ◽  
Accelerator Driven Systems ◽  
Reaction Cross Sections

The nuclear data on n+239,240,242,244Pu reactions for the incident energy up to 200 MeV are consistently calculated and evaluated in order to meet the design requirements of Generation-IV reactors and accelerator driven systems. The optical model, the distorted wave Born approximation theory, the Hauser-Feshbach theory, the fission model, the evaporation model, the exciton model and the intranuclear cascade model are used in the calculation, and new experimental data are taken into account. Our data are compared with experimental data and the evaluated data from JENDL-4/HE and TENDL. In addition, the variation tendency of reaction cross sections related to the target mass numbers is obtained, which is very important for the prediction of nuclear data on neutron-actinides reactions because the experimental data are lacking.

scholarly journals Completeness of neutron-, photo-induced and spontaneous fission yields data

2020 ◽  
Vol 239 ◽  
pp. 09003
Author(s):  
B. Pritychenko ◽  
O. Schwerer ◽  
J. Totans ◽  
V. Zerkin ◽  
O. Gritzay
Keyword(s):  
Nuclear Reaction ◽  
Cross Sections ◽  
Data Center ◽  
Nuclear Data ◽  
Published Data ◽  
Data Sets ◽  
Scientific Publications ◽  
Nuclear Science ◽  
And Storage ◽  
Fission Yields

Nuclear data collection, evaluation and dissemination activities have been performed worldwide for many years. They are absolutely essential for the overall progress of science and technology to create the complete collections of experimental data sets and associated publications, and store these data in publicly accessible databases. Due to many historical and technological reasons not all published data have been identified and compiled. These "missing data" manifest themselves via scientific publications, data evaluations and nuclear databases comparisons. The detailed analysis of the Nuclear Science References (NSR) and the Experimental Nuclear Reaction (EXFOR) databases shows thousands of previously missed nuclear reaction experiments and creates a roadmap for the creation of complete data records for fission cross sections, yields and covariances. The National Nuclear Data Center (NNDC) program for identification, compilation and storage of missing fission yields data sets is described, and recommendations for improving the databases completeness are given.

scholarly journals Developments in New Measurements of Fission Cross-Sections, Fragment Yields, and Prompt and Quasi-Prompt Gammas for Nuclear Data Needs

2020 ◽  
Vol 242 ◽  
pp. 01002
Author(s):  
Adam Hecht ◽  
Phoenix Baldez ◽  
Baldez Baldez
Keyword(s):  
Cross Sections ◽  
Ionization Chamber ◽  
Gamma Ray ◽  
Fission Products ◽  
Product Yield ◽  
Nuclear Data ◽  
University Of New Mexico ◽  
Alpha Emission ◽  
Time Projection ◽  
The University

The University of New Mexico Fission Spectrometer was developed to measure fission product yield, as part of the LANL SPIDER collaboration. The spectrometer operates as an E-v detector to extract product mass event-by-event, with a time of flight region followed by an ionization chamber for kinetic energy measurements. By using the ionization chamber as a singlecathode/single-anode time projection chamber, stopping power and thus Z information is extracted, for coupled A and Z measurements. New work is being performed to add gamma ray detectors in the data stream, placed near the target region for prompt gammas and near the ionization chamber for quasiprompt (>50 ns) and later gammas, correlated with individual fission products. A stand-alone parallel plate ionization chamber (PPIC) is also being developed for fission tagging gamma ray data. The PPIC will also allow discrimination between charged particle out events and (n,n’γ), and discriminate between alpha emission and fission. Using layers in the PPIC, other targets can be measured simultaneously with a calibration target, giving relative fission cross sections. Past measurements with the spectrometer were performed at LANSCE and we plan to continue measurements there. The current work is supported by the NNSA Stewardship Science Academic Alliance.

scholarly journals Validating nuclear data uncertainties obtained from a statistical analysis of experimental data with the “Physical Uncertainty Bounds” method

2020 ◽  
Vol 6 ◽  
pp. 19
Author(s):  
Denise Neudecker ◽  
Morgan Curtis White ◽  
Diane Elizabeth Vaughan ◽  
Gowri Srinivasan
Keyword(s):  
Experimental Data ◽  
Statistical Analysis ◽  
Information Content ◽  
Cross Section ◽  
Cross Sections ◽  
Nuclear Data ◽  
Current Version ◽  
Neutron Data ◽  
Data Standards ◽  
Actual Evaluation

Concerns within the nuclear data community led to substantial increases of Neutron Data Standards (NDS) uncertainties from its previous to the current version. For example, those associated with the NDS reference cross section 239Pu(n,f) increased from 0.6–1.6% to 1.3–1.7% from 0.1–20 MeV. These cross sections, among others, were adopted, e.g., by ENDF/B-VII.1 (previous NDS) and ENDF/B-VIII.0 (current NDS). There has been a strong desire to be able to validate these increases based on objective criteria given their impact on our understanding of various application uncertainties. Here, the “Physical Uncertainty Bounds” method (PUBs) by Vaughan et al. is applied to validate evaluated uncertainties obtained by a statistical analysis of experimental data. We investigate with PUBs whether ENDF/B-VII.1 or ENDF/B-VIII.0 239Pu(n,f) cross-section uncertainties are more realistic given the information content used for the actual evaluation. It is shown that the associated conservative (1.5–1.8%) and minimal realistic (1.1–1.3%) uncertainty bounds obtained by PUBs enclose ENDF/B-VIII.0 uncertainties and indicate that ENDF/B-VII.1 uncertainties are underestimated.

scholarly journals Evaluating nuclear data and their uncertainties

2018 ◽  
Vol 4 ◽  
pp. 29
Author(s):  
Patrick Talou
Keyword(s):  
Experimental Data ◽  
Uncertainty Quantification ◽  
Cross Sections ◽  
Coming Out ◽  
Nuclear Data ◽  
Covariance Matrices ◽  
Alternative Approaches ◽  
Data Libraries ◽  
Nuclear Data Libraries ◽  
Evaluated Nuclear Data

In the last decade or so, estimating uncertainties associated with nuclear data has become an almost mandatory step in any new nuclear data evaluation. The mathematics needed to infer such estimates look deceptively simple, masking the hidden complexities due to imprecise and contradictory experimental data and natural limitations of simplified physics models. Through examples of evaluated covariance matrices for the soon-to-be-released U.S. ENDF/B-VIII.0 library, e.g., cross sections, spectrum, multiplicity, this paper discusses some uncertainty quantification methodologies in use today, their strengths, their pitfalls, and alternative approaches that have proved to be highly successful in other fields. The important issue of how to interpret and use the covariance matrices coming out of the evaluated nuclear data libraries is discussed.

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.

Sign in / Sign up

Export Citation Format

Share Document