Prompt Fission Neutron Spectra of Actinides

Capote, R.; Chen, Y.-J.; Hambsch, F.‐J.; Корнилов, Н. В.; Lestone, J. P.; Litaize, O.; Morillon, B.; Neudecker, Denise; Oberstedt, S.; Ohsawa, Takaaki; Otuka, Naohiko; Pronyaev, V.G.; Saxena, A.; Sérot, O.; Shcherbakov, O. A.; Shu, Nengchuan; Smith, D.L.; Talou, P.; Trkov, A.; Tudora, Anabella; Vogt, R.; Vorobyev, A. S.

doi:10.1016/j.nds.2015.12.002

Cited by 137 publications

(131 citation statements)

References 205 publications

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“…The 235 U resolved resonance evaluation recently released within the ENDF/B-VIII.0β 2 nuclear data library [3] was developed on the basis of newly evaluated thermal neutron constants [1], as well as on new PFNS [2]. In the thermal energy range, this work relies on the values of the fission and capture cross sections reported in Table 2, along with the values of the evaluated cross sections reconstructed for T = 0 K. Figure 1.ν(E) relative toν(E th ) calculated at thermal energy (0.0253 eV) for n+ 235 U reactions.…”

Section: Cross Section and Benchmark Resultsmentioning

confidence: 99%

“…Moreover, a new evaluation of the PFNS [2] in the same energy range has determined a lower value of the average neutron energy than that reported in the existing evaluated nuclear data libraries. Simulations on a number of thermal-solution benchmarks has shown that the combined use of the new TNCs and a softer prompt fission neutron spectrum at thermal energy yields k eff values that are larger than measurements by a margin that increases as the above-thermal-leakage fraction (ATLF) increases.…”

Section: Introductionmentioning

confidence: 87%

“…Though the current analysis on the resonance parameters was limited to 100 eV, the entire evaluation extends to neutron incident energies up to 2.25 keV, and the s-wave resonances have spin and parity, 3 − and 4 − , as displayed in Table 1. To achieve the integral fission value suggested by recently measured fission TOF data [2], emphasis on producing the current resonance evaluation was devoted not only to the sub thermal and thermal regions by including thermal constants based on microscopic data, but also to neutron incident energies between 7.8-11 eV. Moreover, the newly evaluated neutron multiplicities included fluctuations (Sect.…”

Section: Introductionmentioning

confidence: 99%

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n+²³⁵U resonance parameters and neutron multiplicities in the energy region below 100 eV

et al. 2017

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Abstract. In August 2016, following the recent effort within the Collaborative International Evaluated Library Organization (CIELO) pilot project to improve the neutron cross sections of 235 U, Oak Ridge National Laboratory (ORNL) collaborated with the International Atomic Energy Agency (IAEA) to release a resonance parameter evaluation. This evaluation restores the performance of the evaluated cross sections for the thermaland above-thermal-solution benchmarks on the basis of newly evaluated thermal neutron constants (TNCs) and thermal prompt fission neutron spectra (PFNS). Performed with support from the US Nuclear Criticality Safety Program (NCSP) in an effort to provide the highest fidelity general purpose nuclear database for nuclear criticality applications, the resonance parameter evaluation was submitted as an ENDF-compatible file to be part of the next release of the ENDF/B-VIII.0 nuclear data library. The resonance parameter evaluation methodology used the Reich-Moore approximation of the R-matrix formalism implemented in the code SAMMY to fit the available time-of-flight (TOF) measured data for the thermal induced cross section of n+ 235 U up to 100 eV. While maintaining reasonably good agreement with the experimental data, the validation analysis focused on restoring the benchmark performance for 235 U solutions by combining changes to the resonance parameters and to the prompt resonanceν below 100 eV.

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Section: Cross Section and Benchmark Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

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n+²³⁵U resonance parameters and neutron multiplicities in the energy region below 100 eV

et al. 2017

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“…The prompt emission from nuclei of secondary chains was already included in the extended Los Alamos model (LAM) described in Refs. [1,2]. In the case of n+ 238 U at En up to 80 MeV, the extended LAM calculation of Ref.…”

Section: Features Of the Modelingmentioning

confidence: 99%

“…The Point-by-Point (PbP) model of prompt emission (described in Ref. [1] and references therein) is used for the first time for multi-chance fission.…”

Section: Introductionmentioning

confidence: 99%

Point-by-point model calculation of the prompt neutron multiplicity distribution ν(A) in the incident neutron energy range of multi-chance fission

Tudora

Hambsch²,

Tobosaru

2017

EPJ Web Conf.

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Abstract. Prompt neutron multiplicity distributions ν(A) are required for prompt emission correction of double energy (2E) measurements of fission fragments to determine pre-neutron fragment properties. The lack of experimental ν(A) data especially at incident neutron energies (En) where the multi-chance fission occurs impose the use of ν(A) predicted by models. The Point-by-Point model of prompt emission is able to provide the individual ν(A) of the compound nuclei of the main and secondary nucleus chains undergoing fission at a given En. The total ν(A) is obtained by averaging these individual ν(A) over the probabilities of fission chances (expressed as total and partial fission cross-section ratios). An indirect validation of the total ν(A) results is proposed. At high En, above 70 MeV, the PbP results of individual ν(A) of the first few nuclei of the main and secondary nucleus chains exhibit an almost linear increase. This shape is explained by the damping of shell effects entering the super-fluid expression of the level density parameters. They tend to approach the asymptotic values for most of the fragments. This fact leads to a smooth and almost linear increase of fragment excitation energy with the mass number that is reflected in a smooth and almost linear behaviour of ν(A).

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A Grand Tour of Nuclear Fission Physics

Younes

2020

Compound-Nuclear Reactions

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Prompt Fission Neutron Spectra of Actinides

Cited by 137 publications

References 205 publications

n+²³⁵U resonance parameters and neutron multiplicities in the energy region below 100 eV

n+²³⁵U resonance parameters and neutron multiplicities in the energy region below 100 eV

Point-by-point model calculation of the prompt neutron multiplicity distribution ν(A) in the incident neutron energy range of multi-chance fission

A Grand Tour of Nuclear Fission Physics

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Prompt Fission Neutron Spectra of Actinides

Cited by 137 publications

References 205 publications

n+235U resonance parameters and neutron multiplicities in the energy region below 100 eV

n+235U resonance parameters and neutron multiplicities in the energy region below 100 eV

Point-by-point model calculation of the prompt neutron multiplicity distribution ν(A) in the incident neutron energy range of multi-chance fission

A Grand Tour of Nuclear Fission Physics

Contact Info

Product

Resources

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n+²³⁵U resonance parameters and neutron multiplicities in the energy region below 100 eV

n+²³⁵U resonance parameters and neutron multiplicities in the energy region below 100 eV