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Title: Which nuclear data can be validated with LLNL pulsed-sphere experiments?

Journal Article · · Annals of Nuclear Energy

It is shown here that 14-MeV D+T LLNL pulsed-sphere experiments bring complementary information into the process of validating nuclear data compared to experiments that are traditionally used for this purpose—such as critical assemblies. To be more specific, the 14-MeV D+T LLNL pulsed-sphere neutron-leakage spectra enable to validate scattering and fission nuclear data up to 15 MeV (compared to approximately up to 5 MeV when using criticality experiments) and employ to this end simple compound targets containing only few isotopes. In this work, sensitivity profiles of the spectra to nuclear data are calculated in order to understand in detail which isotopes, observables, and energy ranges of nuclear data contribute significantly to their simulation. These profiles are presented for a few selected spheres containing 16O, 12C, 56Fe, and 239Pu. It is shown that the neutron-leakage spectra of spheres containing light elements are mostly sensitive to elastic- and inelastic-scattering cross sections on discrete levels and corresponding angular distributions. Spheres of structural materials are sensitive to elastic- and inelastic-scattering cross sections, including scattering on discrete levels and the continuum, and double-differential cross sections. Actinide spheres are also strongly sensitive to the fission observables, in particular to the total-fission neutron spectrum. Thin spheres (in which neutrons experience on average less than one scatter) are mostly sensitive to data near the elastic peak, in the energy range from 12–15 MeV, while thicker ones can be sensitive to data at lower incident-neutron energies due to multiple-scattering effects. This information is brought together with simulations of 71 pulsed-sphere neutron-leakage spectra using the ENDF/B-VII.1 and ENDF/B-VIII.0 nuclear-data libraries. This analysis highlights ENDF/B-VIII.0 data that could be further investigated for potential shortcomings (6Li, 12C, 16O, 24-26Mg, 27Al, 48Ti, 56Fe, and 208Pb) or are likely reliable (1,2H, 7Li, 9Be, 14N, 235,238U, and 239Pu) as indicated by validating with LLNL pulsed-sphere experiments.

Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP); USDOE Laboratory Directed Research and Development (LDRD) Program
Grant/Contract Number:
89233218CNA000001
OSTI ID:
1804417
Alternate ID(s):
OSTI ID: 1815112
Report Number(s):
LA-UR-20-28636; TRN: US2212288
Journal Information:
Annals of Nuclear Energy, Vol. 159; ISSN 0306-4549
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

References (26)

Evaluation of the Neutron Data Standards journal February 2018
Analysis of cross sections on iron and oxygen using Cf-252 neutron source journal January 2020
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
The NJOY Nuclear Data Processing System, Version 2016 report January 2017
Benchmarking ENDF/B-VII.0 journal December 2006
CIELO Collaboration Summary Results: International Evaluations of Neutron Reactions on Uranium, Plutonium, Iron, Oxygen and Hydrogen journal February 2018
Use of shielding integral benchmark archive and database for nucleardata validation journal January 2020
IAEA CIELO Evaluation of Neutron-induced Reactions on 235 U and 238 U Targets journal February 2018
Towards a More Complete and Accurate Experimental Nuclear Reaction Data Library (EXFOR): International Collaboration Between Nuclear Reaction Data Centres (NRDC) journal June 2014
SFCOMPO-2.0: An OECD NEA database of spent nuclear fuel isotopic assays, reactor design specifications, and operating data journal December 2017
RIPL – Reference Input Parameter Library for Calculation of Nuclear Reactions and Nuclear Data Evaluations journal December 2009
Measurement of the Pu 239 ( n , f ) prompt fission neutron spectrum from 10 keV to 10 MeV induced by neutrons of energy 1–20 MeV journal September 2020
Nuclear data uncertainty propagation to integral responses using SANDY journal March 2017
Enhancing nuclear data validation analysis by using machine learning journal July 2020
ENDF/B-VII.1 Neutron Cross Section Data Testing with Critical Assembly Benchmarks and Reactor Experiments journal December 2011
Methods for Processing ENDF/B-VII with NJOY journal December 2010
ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data journal December 2011
Examples of Monte Carlo techniques applied for nuclear data uncertainty propagation journal January 2019
ENDF/B-VII.0: Next Generation Evaluated Nuclear Data Library for Nuclear Science and Technology journal December 2006
A review of the scientific contributions by Massimo Salvatores to nuclear reactor physics and engineering journal March 2021
New Monte Carlo simulations of the LLNL pulsed-sphere experiments report July 1998
Benchmark experiment with iron slab by Time-of-flight technique at CIAE journal January 2020
Calculating the Impact of Nuclear Data Changes with Crater conference January 2020
Experiment on uranium slabs of different thicknesses with D-T neutrons and validation of evaluated nuclear data journal December 2017
Prompt-fission-neutron spectra in the Pu 239 ( n , f ) reaction journal April 2020
Monte Carlo Calculation of Point-Detector Sensitivities to Material Parameters journal September 1996


Figures / Tables (19)