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

Abstract.The 237 Np neutron-induced fission cross section has been recently measured in a large energy range (from eV to GeV) at the n_TOF facility at CERN. When compared to previous measurement the n_TOF fission cross section appears to be higher by 5-7% beyond the fission threshold. To check the relevance of n_TOF data, we apply a criticality experiment performed at Los Alamos with a 6 kg sphere of 237 Np, surrounded by enriched uranium 235 U so as to approach criticality with fast neutrons. The multiplication factor k e f f of the calculation is in better agreement with the experiment (the deviation of 750 pcm is reduced to 250 pcm) when we replace the ENDF/B-VII.0 evaluation of the 237 Np fission cross section by the n_TOF data. We also explore the hypothesis of deficiencies of the inelastic cross section in 235 U which has been invoked by some authors to explain the deviation of 750 pcm. With compare to inelastic large distortion calculation, it is incompatible with existing measurements. Also we show that the ν of 237 Np can hardly be incriminated because of the high accuracy of the existing data. Fission rate ratios or averaged fission cross sections measured in several fast neutron fields seem to give contradictory results on the validation of the 237 Np cross section but at least one of the benchmark experiments, where the active deposits have been well calibrated for the number of atoms, favors the n_TOF data set. These outcomes support the hypothesis of a higher fission cross section of 237 Np.

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“…< σ > U235 ENDF/B-VII.0 and ENDF/B-VII.1 [5] libraries have been tested with different fission rate experiments [7].…”

Section: Epj Web Of Conferencesmentioning

confidence: 99%

Criticality experiments and benchmarks for cross section evaluation: the neptunium case

Leong

Tassan‐Got

Audouin

et al. 2013

EPJ Web of Conferences

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“…As it is shown in Table I at cero neutron energy, E n =0, and in the case of the n TOF data the evolution of the URR parameters with E n is the one described in [39]. The ratio between the results obtained in [19,20]. Indeed, the changes in the ENDF/B-VII.1 evaluation with respect to ENDF/B-VII.0 were motivated by the results of this integral experiment [14].…”

Section: Analysis At Higher Energiesmentioning

confidence: 87%

“…The references [19] and [20] provide calculated to experimental ratios (C/E) of the mentioned effective capture cross section, σ cap , each of them calculated with a different neutron data library. We did not have enough information to calculate these C/E values, but with the shape of the neutron flux we could calculate ratios between σ cap values obtained from different libraries, i.e., we could calculate ratios between different C/E values.…”

Section: Analysis At Higher Energiesmentioning

confidence: 99%

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Measurement and analysis of theAm243neutron capture cross section at the n_TOF facility at CERN

Mendoza¹,

Cano‐Ott²,

Guerrero³

et al. 2014

Phys. Rev. C

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Background: The design of new nuclear reactors and transmutation devices requires to reduce the present neutron cross section uncertainties of minor actinides.Purpose: Reduce the 243 Am(n,γ) cross section uncertainty. Method:The 243 Am(n,γ) cross section has been measured at the n TOF facility at CERN with a BaF 2 Total Absorption Calorimeter, in the energy range between 0.7 eV and 2.5 keV.Results: The 243 Am(n,γ) cross section has been successfully measured in the mentioned energy range. The resolved resonance region has been extended from 250 eV up to 400 eV. In the unresolved resonance region our results are compatible with one of the two incompatible capture data sets available below 2.5 keV. The data available in EXFOR and in the literature has been used to perform a simple analysis above 2.5 keV. Conclusions:The results of this measurement contribute to reduce the 243 Am(n,γ) cross section uncertainty and suggest that this cross section is underestimated up to 25% in the neutron energy range between 50 eV and a few keV in the present evaluated data libraries. PACS numbers: 25.40.Lw,28.20.Np,27.90.+b 4

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“…Perhitungan sel target batu topaz dan LEU dilakukan dengan paket program WIMSD5B dengan data nuklir ENDF/B-VII.1 [17] dalam 4 kelompok tenaga neutron. Perhitungan teras dilakukan dengan paket program metode difusi neutron 2-dimensi (2-D), Batan-2DIFF, dalam model geometri X-Y.…”

Section: Pendahuluanunclassified

ANALISIS OPTIMASI TARGET U-235 PENGKAYAAN RENDAH (LEU) UNTUK MENDUKUNG PRODUKSI 99Mo DAN TARGET BATU TOPAZ DI REAKTOR RSG-GAS

Sutrisno

Ratnawati

Susanti

2018

gnd

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

Cited by 55 publications

References 13 publications

Criticality experiments and benchmarks for cross section evaluation: the neptunium case

Criticality experiments and benchmarks for cross section evaluation: the neptunium case

Measurement and analysis of theAm243neutron capture cross section at the n_TOF facility at CERN

ANALISIS OPTIMASI TARGET U-235 PENGKAYAAN RENDAH (LEU) UNTUK MENDUKUNG PRODUKSI 99Mo DAN TARGET BATU TOPAZ DI REAKTOR RSG-GAS

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