Progress on Nuclear Data Covariances: AFCI-1.2 Covariance Library

Obložinský, P.; Herman, M.; Talou, P.; Kawano, Toshihiko

doi:10.2172/972322

Cited by 16 publications

(13 citation statements)

References 6 publications

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“…[94] Table 16 shows the relative uncertainties of the main integral parameters of a series of fast systems: ABR metal and oxide fuel cores, a SFR with low TRU conversion ratio, the sodium-cooled European Fast Reactor (EFR), a GFR, a LFR, and an accelerator-driven minor actinide burner (ADMAB). [95] The uncertainties were estimated using the AFCI-1.2 cross section covariance data [96]. The estimated multiplication factor uncertainties were significantly larger than the targeted prediction accuracy for Generation-IV systems [97]; it is above 1% for all systems considered and for SFR and ADMAB, it is above 2% because of the high content of minor actinides.…”

Section: Perturbation Theory and Uncertainty Analysis Codesmentioning

confidence: 99%

Fast Reactor Physics and Computational Methods

Yang¹

2012

Nuclear Engineering and Technology

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Section: Perturbation Theory and Uncertainty Analysis Codesmentioning

confidence: 99%

Fast Reactor Physics and Computational Methods

Yang¹

2012

Nuclear Engineering and Technology

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“…After review, uncertainties were increased in the threshold region following dispersion analysis (see AFCI-1.2 report [1]). We gave due consideration to users' comments on elastic and inelastic uncertainties and tended towards conservative estimates whenever possible.…”

Section: -Fe 56-fe 57-fe (#13-15)mentioning

confidence: 99%

AFCI-2.0 Neutron Cross Section Covariance Library

Herman¹,

Obložinský²,

Mattoon³

et al. 2011

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SUMMARYThe COMMARA-2.0 covariance library has been developed by BNL-LANL collaboration for Advanced Fuel Cycle Initiative applications over the period of three years, 2008-2010. It contains covariances for 110 materials relevant to fast reactor R&D. The library is to be used together with the ENDF/B-VII.0 central values of the latest official release of US files of evaluated neutron cross sections.COMMARA-2.0 library contains neutron cross section covariances for 12 light nuclei (coolants and moderators), 78 structural materials and fission products, and 20 actinides. Covariances are given in 33-energy groups, from 10−5 eV to 19.6 MeV, obtained by processing with LANL processing code NJOY using 1/E flux. In addition to these 110 files, the library contains 20 files with nu-bar covariances, 3 files with covariances of prompt fission neutron spectra (238,239,240-Pu), and 2 files with mu-bar covariances (23-Na, 56-Fe).Over the period of three years several working versions of the library have been released and tested by ANL and INL reactor analysts. Useful feedback has been collected allowing gradual improvements of the library. In addition, QA system was developed to check basic properties and features of the whole library, allowing visual inspection of uncertainty and correlations plots, inspection of uncertainties of integral quantities with independent databases, and dispersion of cross sections between major evaluated libraries.The COMMARA-2.0 beta version of the library was released to ANL and INL reactor analysts in October 2010. The final version, described in the present report, was released in March 2011. COMMARA-2.0 Covariance Library iv

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“…We note that 55 Mn is almost pure scatterer, meaning that Γ n >> Γ γ , hence ∆Γ γ = δΓ γ /Γ γ defines the average capture cross section uncertainty ∆σ γ . A comparison is made with the uncertainties given in AFCI-1.2 library [14]. This library is produced in 33-energy group representation, mostly with groups of the same lethargy 0.5, starting in reverse order with group 1 (19.6 MeV -10 MeV), down through group 22 (454 eV -304 eV) to group 33 (10…”

Section: Covariancesmentioning

confidence: 99%

Formalism for neutron cross section covariances in the resonance region using kernel approximation

Obložinský¹,

Cho²

2010

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We describe analytical formalism for estimating neutron radiative capture and elastic scattering cross section covariances in the resolved resonance region. We use capture and scattering kernels as the starting point and show how to get average cross sections in broader energy bins, derive analytical expressions for cross section sensitivities, and deduce cross section covariances from the resonance parameter uncertainties in the recently published Atlas of Neutron Resonances. The formalism elucidates the role of resonance parameter correlations which become important if several strong resonances are located in one energy group. Importance of potential scattering uncertainty as well as correlation between potential scattering and resonance scattering is also examined. Practical application of the formalism is illustrated on 55 Mn(n,γ) and 55 Mn(n,el).

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Progress on Nuclear Data Covariances: AFCI-1.2 Covariance Library

Cited by 16 publications

References 6 publications

Fast Reactor Physics and Computational Methods

Fast Reactor Physics and Computational Methods

AFCI-2.0 Neutron Cross Section Covariance Library

Formalism for neutron cross section covariances in the resonance region using kernel approximation

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