Whisper: Sensitivity/Uncertainty-Based Computational Methods and Software for Determining Baseline Upper Subcritical Limits

Kiedrowski, Brian C.; Brown, Forrest B.; Conlin, Jeremy Lloyd; Favorite, Jeffrey A.; Kahler, Albert C.; A, Kersting,; Parsons, Donald Kent; Walker, Jessie

doi:10.13182/nse14-99

Cited by 46 publications

(14 citation statements)

References 11 publications

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“…Whisper-1.0 was developed during 2014 [1][2][3] to meet urgent needs for an upgrade to the NCS computational capabilities at LANL. In April, 2015, all components of whisper-1.0 were placed under version control (initially CVS, then migrated to git), and all subsequent development that led to whisper-1.1 was carried out under the MCNP SQA procedures.…”

Section: Change History For Whisper-11mentioning

confidence: 99%

“…Whisper is a statistical analysis package developed in 2014 to support nuclear criticality safety (NCS) validation [1][2][3]. It uses the sensitivity profile data for an application as computed by MCNP6 [4][5][6] along with covariance files [7,8] for the nuclear data to determine a baseline upper-subcritical-limit (USL) for the application.…”

Section: Introduction and Overviewmentioning

confidence: 99%

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Release Notes for Whisper-1.1

Brown¹,

Rising²,

Alwin³

2017

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Section: Change History For Whisper-11mentioning

confidence: 99%

Section: Introduction and Overviewmentioning

confidence: 99%

Release Notes for Whisper-1.1

Brown¹,

Rising²,

Alwin³

2017

Self Cite

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“…The only addition to the input files used for sensitivity calculations is the specific ''KSEN" card. The default options for the ''KSEN" card are used (especially for the ''BLOCKSIZE" option, set to 5) [10]. Sensitivity vectors are calculated for different isotopes using two cases of energy groups: 1) 15 energy groups used in our sensitivity and uncertainty analysis.…”

Section: Sensitivity and Uncertainty Approachmentioning

confidence: 99%

Sensitivity and Uncertainty Analysis on the Keff Produced by the 1H, 16O, 239Pu and 240Pu Cross Sections Uncertainties

Ahmed¹,

Boukhal²,

Bardouni³

et al. 2017

ujpa

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In criticality and stability studies of the nuclear reactor, it is important to evaluate the impact of the uncertainties of the basic nuclear data (cross sections) on the different neutron parameters. So this work is interested in the analysis of the sensitivity and uncertainties due to the nuclear data of 1 H, 16 O, 239 Pu and 240 Pu Isotopes in the ENDF/B-VII.1 cross sections processed by the latest version of NJOY code on the effective multiplication factor. Different rapid and thermal cases of the different IHECSBE benchmarks have been studied to calculate the sensitivity vectors for 1 H, 16 O, 239 Pu and 240 Pu Isotopes. These sensitivity vectors are calculated by using the adjoint-weighted perturbation method based on the Ksen card of the Monte Carlo code MCNP6.1. Thus, the uncertainties induced by nuclear data have been calculated by combining the sensitivity vectors with the covariance matrices that are generated by the ERRORJ module of NJOY2016. We found several cross sections and covariance matrices lack the adjustment: The capture and fission cross sections of the 239 Pu and their covariance matrices lack the adjustment in the thermal energies. And all of the four cross sections (elastic, inelastic, capture and fission) and their covariance matrices for the same isotope lack the adjustment in the rapid energies. For 16 O; the elastic cross section and its covariance matrix lack the adjustment in the thermal energies. The elastic and capture cross sections of the 1 H and their covariance matrices lack the adjustment especially in the thermal energies.

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“…Integral experiments are vitally important to many areas of nuclear engineering. Criticality safety engineers use the data from integral experiments to refine reactivity estimates and calculate bias in their results [1]. Nuclear data experts use integral experiments to validate the quality of nuclear data evaluations and libraries.…”

Section: Introductionmentioning

confidence: 99%

National Criticality Experiments Research Center (NCERC) - capabilities and recent measurements

et al. 2020

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The National Criticality Experiments Research Center (NCERC) located at the Device Assembly Facility (DAF) at the Nevada National Security Site (NNSS) and operated by Los Alamos National Laboratory (LANL) is home to four critical assemblies which are used to support of range of missions, including nuclear criticality safety and nuclear nonproliferation. Additionally, subcritical systems can also be assembled at NCERC. NCERC is providing critical and subcritical experiments valuable to the nuclear data community and experiments performed at NCERC are often published as benchmarks in the International Criticality Safety Benchmark Evaluation Project (ICSBEP) Handbook. This manuscript will give a broad overview of recent experiments performed at NCERC, upcoming experiments, and why integral measurements are important and useful to the nuclear data community. The four critical assemblies are GODIVA IV, FLATTOP, COMET, and PLANET. GODIVA IV is a cylindrical metal fast burst reactor, the fourth in the GODIVA series that dates back to the 1950’s. FLATTOP is an highly enriched uranium (HEU) or Pu core reflected by natural uranium. COMET and PLANET are vertical lift assemblies, where one half of the reactor can be lifted to the upper half of the reactor to create a critical system. Some recent experiments include various critical intermediate energy assemblies with lead, and subcritical measurements of plutonium reflected by copper, tungsten, and nickel. Work is also underway to make a better measurement of the critical mass of neptunium, using a neptunium sphere surrounded by nickel shells. Additionally, measurements will be performed next year with HEU shells from Rocky Flats. These HEU shells will be stacked together to make larger systems, allowing for a large range of criticality (from subcritical to delayed critical). Other upcoming measurements include an HEU critical assembly sensitive to intermediate energy neutrons.

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Whisper: Sensitivity/Uncertainty-Based Computational Methods and Software for Determining Baseline Upper Subcritical Limits

Cited by 46 publications

References 11 publications

Release Notes for Whisper-1.1

Release Notes for Whisper-1.1

Sensitivity and Uncertainty Analysis on the Keff Produced by the <sup>1</sup>H, <sup>16</sup>O, <sup>239</sup>Pu and <sup>240</sup>Pu Cross Sections Uncertainties

National Criticality Experiments Research Center (NCERC) - capabilities and recent measurements

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