Applying a Template of Expected Uncertainties to Updating 239Pu(n,f) Cross-section Covariances in the Neutron Data Standards Database

Neudecker, Denise; Smith, Donald L.; Tovesson, Fredrik; Capote, Roberto; White, Morgan Curtis; Bowden, Nathaniel S.; Snyder, Lucas; Carlson, Allan D.; Casperson, Robert J.; Pronyaev, Vladimir; Sangiorgio, Samuele; Schmitt, Kyle Thomas; Seilhan, Brandon; Walsh, Nicolas; Younes, Walid

doi:10.1016/j.nds.2019.12.005

Title: Applying a Template of Expected Uncertainties to Updating ²³⁹Pu(n,f) Cross-section Covariances in the Neutron Data Standards Database

Abstract

Templates of uncertainties expected in specific measurement types were recently developed. One aim of these templates is to help evaluators in identifying (1) missing or suspiciously low uncertainties and (2) missing correlations between uncertainties of the same and different experiments, when estimating covariances for experimental data employed in their evaluations. These templates also provide realistic estimates of standard deviations and correlations for a particular uncertainty source and measurement type that can be used by evaluators in situations where they are not supplied by the experimenters. This information allows for a more comprehensive uncertainty analysis across all measurements considered in an evaluation and, thus, more realistic evaluated covariances. Here, in this work, we extend a template that is applicable to uncertainties expected in neutron-induced fission, (n,f), cross-section measurements. It is applied to improving covariances of ²³⁹Pu(n,f) cross-section measurements in the database underlying the Neutron Data Standards evaluations. This particular example was chosen since this evaluation is primarily based on experimental information. Also, some uncertainties of individual ²³⁹Pu(n,f) cross-section experiments in this database were suspected to be underestimated. The evaluated uncertainties obtained after updating the covariances in the database by means of the template indeed do increase compared to their original values.more »« less

Authors:

^[1]; Smith, Donald L. ^[2];

^[3]; Capote, Roberto ^[4];

^[1]; Bowden, Nathaniel S. ^[5]; Snyder, Lucas ^[5]; Carlson, Allan D. ^[6]; Casperson, Robert J. ^[7]; Pronyaev, Vladimir ^[8]; Sangiorgio, Samuele ^[5];

^[1]; Seilhan, Brandon ^[5]; Walsh, Nicolas ^[5]; Younes, Walid ^[5]

Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Argonne National Lab. (ANL), Argonne, IL (United States)
Los Alamos National Lab. (LANL), Los Alamos, NM (United States); National Nuclear Security Agency, Washington, DC (United States)
International Atomic Energy Agency, Vienna (Austria)
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States)
Lawrence Livermore National Laboratory, Livermore, CA 94551-0808, USA
State Corporation Rosatom, Moscow (Russia). PI Atomstandart; International Atomic Energy Agency, Vienna (Austria)

Publication Date:: 2020-01-27

Research Org.:: Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Sponsoring Org.:: USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:: 1601400

Alternate Identifier(s):: OSTI ID: 1605061

Report Number(s):: LA-UR-19-23127; LLNL-JRNL-783165
Journal ID: ISSN 0090-3752; TRN: US2103637

Grant/Contract Number:: 89233218CNA000001; AC52-07NA27344

Resource Type:: Accepted Manuscript

Journal Name:: Nuclear Data Sheets

Additional Journal Information:: Journal Volume: 163; Journal Issue: C; Journal ID: ISSN 0090-3752

Publisher:: Elsevier

Country of Publication:: United States

Language:: English

Subject:: 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 239Pu Neutron-induced fission cross-section; Neutron Data Standard; Uncertainty Quantification

Citation Formats


                    Neudecker, Denise, Smith, Donald L., Tovesson, Fredrik, Capote, Roberto, White, Morgan Curtis, Bowden, Nathaniel S., Snyder, Lucas, Carlson, Allan D., Casperson, Robert J., Pronyaev, Vladimir, Sangiorgio, Samuele, Schmitt, Kyle Thomas, Seilhan, Brandon, Walsh, Nicolas, and Younes, Walid. Applying a Template of Expected Uncertainties to Updating 239Pu(n,f) Cross-section Covariances in the Neutron Data Standards Database.  United States: N. p., 2020. 
Web.  doi:10.1016/j.nds.2019.12.005.

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                    Neudecker, Denise, Smith, Donald L., Tovesson, Fredrik, Capote, Roberto, White, Morgan Curtis, Bowden, Nathaniel S., Snyder, Lucas, Carlson, Allan D., Casperson, Robert J., Pronyaev, Vladimir, Sangiorgio, Samuele, Schmitt, Kyle Thomas, Seilhan, Brandon, Walsh, Nicolas, & Younes, Walid. Applying a Template of Expected Uncertainties to Updating 239Pu(n,f) Cross-section Covariances in the Neutron Data Standards Database.  United States.  https://doi.org/10.1016/j.nds.2019.12.005

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                    Neudecker, Denise, Smith, Donald L., Tovesson, Fredrik, Capote, Roberto, White, Morgan Curtis, Bowden, Nathaniel S., Snyder, Lucas, Carlson, Allan D., Casperson, Robert J., Pronyaev, Vladimir, Sangiorgio, Samuele, Schmitt, Kyle Thomas, Seilhan, Brandon, Walsh, Nicolas, and Younes, Walid. Mon .  
"Applying a Template of Expected Uncertainties to Updating 239Pu(n,f) Cross-section Covariances in the Neutron Data Standards Database".  United States.  https://doi.org/10.1016/j.nds.2019.12.005.  https://www.osti.gov/servlets/purl/1601400.

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@article{osti_1601400,

  title        = {Applying a Template of Expected Uncertainties to Updating 239Pu(n,f) Cross-section Covariances in the Neutron Data Standards Database},

  author       = {Neudecker, Denise and Smith, Donald L. and Tovesson, Fredrik and Capote, Roberto and White, Morgan Curtis and Bowden, Nathaniel S. and Snyder, Lucas and Carlson, Allan D. and Casperson, Robert J. and Pronyaev, Vladimir and Sangiorgio, Samuele and Schmitt, Kyle Thomas and Seilhan, Brandon and Walsh, Nicolas and Younes, Walid},

  abstractNote = {Templates of uncertainties expected in specific measurement types were recently developed. One aim of these templates is to help evaluators in identifying (1) missing or suspiciously low uncertainties and (2) missing correlations between uncertainties of the same and different experiments, when estimating covariances for experimental data employed in their evaluations. These templates also provide realistic estimates of standard deviations and correlations for a particular uncertainty source and measurement type that can be used by evaluators in situations where they are not supplied by the experimenters. This information allows for a more comprehensive uncertainty analysis across all measurements considered in an evaluation and, thus, more realistic evaluated covariances. Here, in this work, we extend a template that is applicable to uncertainties expected in neutron-induced fission, (n,f), cross-section measurements. It is applied to improving covariances of 239Pu(n,f) cross-section measurements in the database underlying the Neutron Data Standards evaluations. This particular example was chosen since this evaluation is primarily based on experimental information. Also, some uncertainties of individual 239Pu(n,f) cross-section experiments in this database were suspected to be underestimated. The evaluated uncertainties obtained after updating the covariances in the database by means of the template indeed do increase compared to their original values. Even more importantly, the evaluated mean values change noticeably. These modified cross sections impact application calculations significantly, as is demonstrated by employing them in simulations of the effective neutron multiplication factor for a few selected critical assemblies. However, this updated evaluated 239Pu(n,f) cross section should not be interpreted as the final one that should replace values of the current Neutron Data Standards project. Evaluations for the Neutron Data Standards of the 239Pu(n,f) cross section must be linked to many other observables included in the associated database, most notably to cross sections for 235U(n,f), but also to those for 10B(n,α), 6Li(n,t), 238U(n,f), and 238U(n,γ), because of included measurements of the 239Pu(n,f) cross section that appear as ratios to these reactions. Some of these other reactions are correlated to further observables in the database. Hence, updating uncertainties of data sets of any of these observables can potentially impact the 239Pu(n,f) cross section. Uncertainties for all measurements of these linked physical observables have to be updated before a comprehensive evaluation of the 239Pu(n,f) cross section and its corresponding uncertainties can be provided.},

  doi          = {10.1016/j.nds.2019.12.005},

  journal      = {Nuclear Data Sheets},

  number       = C,

  volume       = 163,

  place        = {United States},

  year         = {2020},

  month        = {1}

}

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Title: Applying a Template of Expected Uncertainties to Updating 239Pu(n,f) Cross-section Covariances in the Neutron Data Standards Database

Abstract

Citation Formats

A new approach to measuring fission cross-section ratios journal, May 1982

Absolute measurements of 235U and 239Pu fission cross-sections with photoneutron sources journal, January 1978

Fission-Fragment Scattering journal, June 1966

A Measurement of the Fission Cross Sections of 239 Pu and 233 U Relative to 235 U journal, June 1970

Measurement of the Ratios of Capture and Fission Neutron Cross Sections of 235 U, 238 U, and 239 Pu at 130 to 1400 keV journal, June 1970

Simultaneous Measurement of the Neutron Fission and Absorption Cross Sections of Plutonium-239 Over the Energy Region 0.02 eV to 30 keV journal, July 1971

A Monte Carlo computer program for the transport of energetic ions in amorphous targets journal, August 1980

Further Radiochemical Studies of Fission of the U 2 3 6 * Compound Nucleus journal, October 1962

Fission Fragment Backscattering Corrections to Absolute Fission Counting Rate Measurements journal, June 1980

International Evaluation of Neutron Cross Section Standards journal, December 2009

The uncertainty of counting at a defined solid angle journal, May 2015

The fission cross sections of 233U, 234U, 235U, 236U, 237Np 239Pu, 240Pu and 241Pu for 24 keV neutrons journal, June 1965

A time projection chamber for high accuracy and precision fission cross-section measurements journal, September 2014

Fragment Anisotropies in Neutron-, Deuteron-, and Alpha-Particle-Induced Fission journal, February 1965

Uncertainty-driven nuclear data evaluation including thermal (n, α ) applied to 59 Ni journal, November 2017

Subthreshold Fission Cross Section of 237 Np journal, May 2008

Srim-2003 journal, June 2004

The Fission Cross Sections of 233 U, 235 U, 238 U and 239 Pu for Neutrons in the Energy Range 0.030 MeV to 3.0 MeV journal, August 1957

Unrecognized Sources of Uncertainties (USU) in Experimental Nuclear Data journal, January 2020

Data Covariances from R-Matrix Analyses of Light Nuclei journal, January 2015

Absolute Neutron Fission Cross Sections of 235 U, 238 U, and 239 Pu at 13.9 and 14.6 MeV journal, November 1978

Fission Cross-Section Ratio Measurements of 239 Pu and 233 U to 235 U from 0.24 to 24 keV journal, March 1970

Evaluation of the Neutron Data Standards journal, February 2018

ENDF/B-VIII.0: The 8 th Major Release of the Nuclear Reaction Data Library with CIELO-project Cross Sections, New Standards and Thermal Scattering Data journal, February 2018

Directional fast neutron detection using a time projection chamber journal, December 2010

Towards a More Complete and Accurate Experimental Nuclear Reaction Data Library (EXFOR): International Collaboration Between Nuclear Reaction Data Centres (NRDC) journal, June 2014

Neutron-Induced Fission of 233 U, 238 U, 232 Th, 239 Pu, 237 Np, nat Pb and 209 Bi Relative to 235 U in the Energy Range 1-200 MeV journal, August 2002

Determination of Resonance Parameters and their Covariances from Neutron Induced Reaction Cross Section Data journal, December 2012

The Fission Cross Sections of Plutonium-239 and Plutonium-242 Relative to Uranium-235 from 0.1 to 10 MeV journal, December 1978

Performance of a MICROMEGAS-based TPC in a high-energy neutron beam journal, February 2018

High Resolution Measurements of Neutron-Induced Fission Cross Sections for 233 U, 235 U, 239 Pu and 241 Pu Below 30 keV journal, June 1973

The fission cross sections of 233U, 234U, 236U, 238U, 237Np, 239Pu, 240Pu and 241Pu relative to that of 235U for neutrons in the energy range 1–14 MeV journal, August 1967

Measurement of the 239Pu(n,f) cross section from thermal up to 30 keV neutron energy journal, January 1980

Assaying of targets for nuclear measurements with a gridded ionization chamber journal, June 1985

The effect of fragment anisotropy on fission-chamber efficiency journal, July 1974

Experimental and theoretical investigation of the backscattering of fission fragments journal, November 1979

ENDF/B-VII.1 Neutron Cross Section Data Testing with Critical Assembly Benchmarks and Reactor Experiments journal, December 2011

Measurement of the Fission Cross Sections of Uranium-233 and Plutonium-239 Relative to Uranium-235 from 1 keV to 30 MeV journal, May 1978

DeCE: the ENDF-6 data interface and nuclear data evaluation assist code journal, July 2019

Measurement of the Neutron Capture and Fission Cross Sections of 239 Pu and 235 U, 0.02 eV to 200 keV, the Neutron Capture Cross Sections of 197 Au, 10 to 50 keV, and Neutron Fission Cross Sections of 233 U, 5 to 20 journal, February 1976

Subthreshold Fission Cross Section of 240 Pu and the Fission Cross Sections of 235 U and 239 Pu journal, December 1984

Methods for primary standardization of activity journal, August 2007

High-Resolution Fission Cross-Section Measurements of 235 U and 239 Pu journal, August 1992

Measurement of the ratio of the239Pu and235U fission cross sections for 0.024-7.4-MeV neutrons journal, October 1977

Geant4—a simulation toolkit journal, July 2003

Measurements of the Neutron Fission and Absorption Cross Sections of 239 Pu Over the Energy Region 0.02 eV to 30 keV journal, May 1970

Measurement of the normalized U 238 ( n , f ) / U 235 ( n , f ) cross section ratio from threshold to 30 MeV with the NIFFTE fission Time Projection Chamber journal, March 2018

Neutron Fission Cross Sections of 239 Pu and 240 Pu Relative to 235 U journal, July 1983

On the impact of the fissile coating on the fission chamber signal journal, July 2012

Validating nuclear data uncertainties obtained from a statistical analysis of experimental data with the “Physical Uncertainty Bounds” method journal, January 2020

Title: Applying a Template of Expected Uncertainties to Updating ²³⁹Pu(n,f) Cross-section Covariances in the Neutron Data Standards Database

A new approach to measuring fission cross-section ratios
journal, May 1982

Absolute measurements of 235U and 239Pu fission cross-sections with photoneutron sources
journal, January 1978

Fission-Fragment Scattering
journal, June 1966

A Measurement of the Fission Cross Sections of ²³⁹ Pu and ²³³ U Relative to ²³⁵ U
journal, June 1970

Measurement of the Ratios of Capture and Fission Neutron Cross Sections of ²³⁵ U, ²³⁸ U, and ²³⁹ Pu at 130 to 1400 keV
journal, June 1970

Simultaneous Measurement of the Neutron Fission and Absorption Cross Sections of Plutonium-239 Over the Energy Region 0.02 eV to 30 keV
journal, July 1971

A Monte Carlo computer program for the transport of energetic ions in amorphous targets
journal, August 1980

Further Radiochemical Studies of Fission of the $U^{236 *}$ Compound Nucleus
journal, October 1962

Fission Fragment Backscattering Corrections to Absolute Fission Counting Rate Measurements
journal, June 1980

International Evaluation of Neutron Cross Section Standards
journal, December 2009

The uncertainty of counting at a defined solid angle
journal, May 2015

The fission cross sections of 233U, 234U, 235U, 236U, 237Np 239Pu, 240Pu and 241Pu for 24 keV neutrons
journal, June 1965

A time projection chamber for high accuracy and precision fission cross-section measurements
journal, September 2014

Fragment Anisotropies in Neutron-, Deuteron-, and Alpha-Particle-Induced Fission
journal, February 1965

Uncertainty-driven nuclear data evaluation including thermal (n, α ) applied to 59 Ni
journal, November 2017

Subthreshold Fission Cross Section of ²³⁷ Np
journal, May 2008

Srim-2003
journal, June 2004

The Fission Cross Sections of ²³³ U, ²³⁵ U, ²³⁸ U and ²³⁹ Pu for Neutrons in the Energy Range 0.030 MeV to 3.0 MeV
journal, August 1957

Unrecognized Sources of Uncertainties (USU) in Experimental Nuclear Data
journal, January 2020

Data Covariances from R-Matrix Analyses of Light Nuclei
journal, January 2015

Absolute Neutron Fission Cross Sections of ²³⁵ U, ²³⁸ U, and ²³⁹ Pu at 13.9 and 14.6 MeV
journal, November 1978

Fission Cross-Section Ratio Measurements of ²³⁹ Pu and ²³³ U to ²³⁵ U from 0.24 to 24 keV
journal, March 1970

Evaluation of the Neutron Data Standards
journal, February 2018

ENDF/B-VIII.0: The 8 th Major Release of the Nuclear Reaction Data Library with CIELO-project Cross Sections, New Standards and Thermal Scattering Data
journal, February 2018

Directional fast neutron detection using a time projection chamber
journal, December 2010

Towards a More Complete and Accurate Experimental Nuclear Reaction Data Library (EXFOR): International Collaboration Between Nuclear Reaction Data Centres (NRDC)
journal, June 2014

Neutron-Induced Fission of ²³³ U, ²³⁸ U, ²³² Th, ²³⁹ Pu, ²³⁷ Np, ^nat Pb and ²⁰⁹ Bi Relative to ²³⁵ U in the Energy Range 1-200 MeV
journal, August 2002

Determination of Resonance Parameters and their Covariances from Neutron Induced Reaction Cross Section Data
journal, December 2012

The Fission Cross Sections of Plutonium-239 and Plutonium-242 Relative to Uranium-235 from 0.1 to 10 MeV
journal, December 1978

Performance of a MICROMEGAS-based TPC in a high-energy neutron beam
journal, February 2018

High Resolution Measurements of Neutron-Induced Fission Cross Sections for ²³³ U, ²³⁵ U, ²³⁹ Pu and ²⁴¹ Pu Below 30 keV
journal, June 1973

The fission cross sections of 233U, 234U, 236U, 238U, 237Np, 239Pu, 240Pu and 241Pu relative to that of 235U for neutrons in the energy range 1–14 MeV
journal, August 1967

Measurement of the 239Pu(n,f) cross section from thermal up to 30 keV neutron energy
journal, January 1980

Assaying of targets for nuclear measurements with a gridded ionization chamber
journal, June 1985

The effect of fragment anisotropy on fission-chamber efficiency
journal, July 1974

Experimental and theoretical investigation of the backscattering of fission fragments
journal, November 1979

ENDF/B-VII.1 Neutron Cross Section Data Testing with Critical Assembly Benchmarks and Reactor Experiments
journal, December 2011

Measurement of the Fission Cross Sections of Uranium-233 and Plutonium-239 Relative to Uranium-235 from 1 keV to 30 MeV
journal, May 1978

DeCE: the ENDF-6 data interface and nuclear data evaluation assist code
journal, July 2019

Measurement of the Neutron Capture and Fission Cross Sections of ²³⁹ Pu and ²³⁵ U, 0.02 eV to 200 keV, the Neutron Capture Cross Sections of ¹⁹⁷ Au, 10 to 50 keV, and Neutron Fission Cross Sections of ²³³ U, 5 to 20
journal, February 1976

Subthreshold Fission Cross Section of ²⁴⁰ Pu and the Fission Cross Sections of ²³⁵ U and ²³⁹ Pu
journal, December 1984

Methods for primary standardization of activity
journal, August 2007

High-Resolution Fission Cross-Section Measurements of ²³⁵ U and ²³⁹ Pu
journal, August 1992

Measurement of the ratio of the239Pu and235U fission cross sections for 0.024-7.4-MeV neutrons
journal, October 1977

Geant4—a simulation toolkit
journal, July 2003

Measurements of the Neutron Fission and Absorption Cross Sections of ²³⁹ Pu Over the Energy Region 0.02 eV to 30 keV
journal, May 1970

Measurement of the normalized ${}^{238}U (n, f) / {}^{235}U (n, f)$ cross section ratio from threshold to 30 MeV with the NIFFTE fission Time Projection Chamber
journal, March 2018

Neutron Fission Cross Sections of ²³⁹ Pu and ²⁴⁰ Pu Relative to ²³⁵ U
journal, July 1983

On the impact of the fissile coating on the fission chamber signal
journal, July 2012

Validating nuclear data uncertainties obtained from a statistical analysis of experimental data with the “Physical Uncertainty Bounds” method
journal, January 2020