scholarly journals Impact of FIFRELIN input parameters on fission observables

2018 ◽  
Vol 193 ◽  
pp. 01003
Author(s):  
Abdelaziz Chebboubi ◽  
Olivier Litaize ◽  
Olivier Serot
Keyword(s):  
Nuclear Reactor ◽  
Neutron Emission ◽  
Level Density ◽  
Strength Function ◽  
Nuclear Data ◽  
Neutron Multiplicity ◽  
Monte Carlo Code ◽  
Nuclear Level Density ◽  
Fission Fragments ◽  
The Impact

Evaluated nuclear data are essential for nuclear reactor studies. In order to significantly improve the precision of nuclear data, more and more fundamental fission models are used in the evaluation processing. Therefore, tests of fission models become a central issue. In this framework, FIFRELIN (FIssion Fragments Evaporation Leading to an Investigation of Nuclear data) is a Monte Carlo code developed in order to modelize fission fragments de-excitation through the emission of neutrons, γ and conversion e-. To be performed, a FIFRELIN calculation relies on several models such as gamma strength function and nuclear level density and of more empirical hypothesis such as total excitation energy repartition or angular momentum given by the fission reaction. Moreover, pre-emission mass yield and kinetic energy distribution per mass are necessary to process the simulation. A set of five free parameters are chosen to reproduce a target observable. Often this observable corresponds to the mean neutron multiplicity for heavy and light fragment. In this work, the impact of the set of parameters on different output observables (neutron emission probability, neutron multiplicity as function of the fission fragment mass) is investigated.

scholarly journals Influence of spin on fission fragments anisotropy

2005 ◽  
Vol 20 (1) ◽  
pp. 45-49
Author(s):  
Omid Ghodsi ◽  
Aziz Behkami ◽  
Farhad Rahimi
Keyword(s):  
Experimental Data ◽  
Level Density ◽  
Couple Channel ◽  
Spin Effect ◽  
Nuclear Level Density ◽  
Nuclear Level ◽  
Fission Fragments ◽  
Fragment Angular Distribution ◽  
Induced Fission ◽  
Channel Spin

An analysis of selected fission fragment angular distribution when at least one of the spins of the projectile or target is appreciable in induced fission was made by using the statistical scission model. The results of this model predicate that the spins of the projectile or target are affected on the nuclear level density of the compound nucleus. The experimental data was analyzed by means of the couple channel spin effect formalism. This formalism suggests that the projectile spin is more effective on angular anisotropies within the limits of energy near the fusion barrier.

scholarly journals Effects of different nuclear evaluation data on the RMC keff calculation

2020 ◽  
Vol 239 ◽  
pp. 19005
Author(s):  
Zhang Wenxin ◽  
Qiang shenglong ◽  
Yin qiang ◽  
Cui Xiantao
Keyword(s):  
Cross Section ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Reactor ◽  
Neutron Cross Section ◽  
Nuclear Data ◽  
Section Data ◽  
Calculation Results ◽  
The Impact ◽  
Physical Calculation

Neutron cross section data is the basis of nuclear reactor physical calculation and has a decisive influence on the accuracy of calculation results. AFA3Gassemble is widely used in nuclear power plants. CENACE is an ACE format multiple-temperature continuous energy cross section library that developed by China Nuclear Data Centre. In this paper, we calculated the AFA3G assemble by RMC.We respectively used ENDF6.8/, ENDF/7 and CENACE data for calculation. The impact of nuclear data on RMC calculation is studied by comparing the results of different nuclear data.

scholarly journals Fission fragments observables measured at the LOHENGRIN spectrometer

2020 ◽  
Vol 239 ◽  
pp. 05017
Author(s):  
S. Julien-Laferrière ◽  
L. Thombansen ◽  
G. Kessedjian ◽  
A. Chebboubi ◽  
O. Serot ◽  
...  
Keyword(s):  
Neutron Emission ◽  
Evaluation Process ◽  
Nuclear Data ◽  
Nuclear Fission ◽  
Experimental Program ◽  
Spent Fuel ◽  
Ionic Charge ◽  
Fission Fragments ◽  
Common Effort ◽  
Fission Yields

Nuclear fission yields are key data for reactor studies, such as spent fuel inventory or decay heat, and for understanding fission process. Despite a significant effort allocated to measure fission yields during the last decades, the recent evaluated libraries still need improvements in particular in the reduction of the uncertainties. Moreover, some discrepancies between these libraries must be explained. Additional measurements provide complementary information and estimations of experimental correlations, and new kinds of measurements enable to test the models used during the nuclear data evaluation process. A common effort by the CEA, the LPSC and the ILL aims at tackling these issues by providing precise measurements of isotopic and isobaric fission yields with the related variance-covariance matrices. Additionally, the experimental program involves a large range of observables requested by the evaluations, such as kinetic energy dependency of isotopic yields and odd-even effect in order to test the sharing of total excitation energy and the spin generation mechanism. Another example is the complete range of isotopic distribution per mass that allows the determination of the charge polarization, which has to be consistent for complementary masses (pre-neutron emission). For instance, this information is the key observable for the evaluation of isotopic yields. Finally, ionic charge distributions are indirect measurements of nanosecond isomeric ratios as a probe of the nuclear de-excitation path in the (E*, J, π) representation. Measurements for thermal neutron induced fission of 241 Pu have been carried out at the ILL in Grenoble, using the LOHENGRIN mass spectrometer. Methods, results and comparison to models calculations will be presented corresponding to a status on fission fragments observables reachable with this facility.

scholarly journals Impact of nuclear data evaluations on data assimilation for an LFR

2020 ◽  
Vol 239 ◽  
pp. 13007
Author(s):  
Pablo Romojaro ◽  
Francisco Álvarez-Velarde
Keyword(s):  
Data Assimilation ◽  
Fast Reactor ◽  
Nuclear Reactor ◽  
Critical Mass ◽  
Nuclear Data ◽  
Operational Experience ◽  
Operation Conditions ◽  
Nuclear Data Library ◽  
Safety Parameters ◽  
The Impact

The Lead-cooled Fast Reactor is one of the three technologies selected by the Sustainable Nuclear Energy Technology Platform that can meet future European energy needs. The main drawbacks for the industrial deployment of LFR are the lack of operational experience and the impact of uncertainties. In nuclear reactor design the uncertainties mainly come from material properties, fabrication tolerances, operation conditions, simulation tools and nuclear data. The uncertainty in nuclear data is one of the most important sources of uncertainty in reactor physics simulations. Furthermore, it is known that the uncertainties in reactor criti-cality safety parameters are severely dependent on the nuclear data library used to estimate them. However, the impact of using different evaluations while performing data assimilation to constraint the uncertainties in the criticality parameters has not been properly assessed yet. In this work, a data assimilation for the main isotopes contributing to the uncertainty in keff of the ALFRED lead-cooled fast reactor has been performed with the SUMMON system using JEFF-3.3, ENDF/B-VIII.0 and JENDL-4.0u2 state-of-the-art nuclear data libraries, together with critical mass experiments from the International Criticality Safety Benchmark Evaluation Project that are representative of ALFRED, in order to assess the impact of using different evaluations for data assimilation.

scholarly journals Gamma-widths, lifetimes and fluctuations in the nuclear quasi-continuum

2018 ◽  
Vol 178 ◽  
pp. 06001
Author(s):  
M. Guttormsen ◽  
A. C. Larsen ◽  
J. E. Midtbø ◽  
L. Crespo Campo ◽  
A. Görgen ◽  
...  
Keyword(s):  
Excited States ◽  
Level Density ◽  
Strength Function ◽  
Reaction Rates ◽  
Theoretical Description ◽  
Nuclear Level Density ◽  
Capture Process ◽  
Structure And Dynamics ◽  
Continuum Region ◽  
First Time

Statistical γ-decay from highly excited states is determined by the nuclear level density (NLD) and the γ-ray strength function (γSF). These average quantities have been measured for several nuclei using the Oslo method. For the first time, we exploit the NLD and γSF to evaluate the γ-width in the energy region below the neutron binding energy, often called the quasi-continuum region. The lifetimes of states in the quasi-continuum are important benchmarks for a theoretical description of nuclear structure and dynamics at high temperature. The lifetimes may also have impact on reaction rates for the rapid neutron-capture process, now demonstrated to take place in neutron star mergers.

Mass-split dependence of pre-scission neutron multiplicity by four-dimensional Langevin dynamics in 16,18O, 40Ar and 64Ni-induced fusion–fission reactions

2019 ◽  
Vol 28 (09) ◽  
pp. 1950077
Author(s):  
D. Naderi ◽  
S. A. Alavi ◽  
V. Dehghani
Keyword(s):  
Asymmetry Parameter ◽  
Reasonable Agreement ◽  
Neutron Emission ◽  
Level Density ◽  
Neutron Multiplicity ◽  
Density Parameter ◽  
Fission Reactions ◽  
Orientation Degree ◽  
Langevin Model ◽  
Neck Thickness

By using the multidimensional Langevin model, including elongation, neck thickness, asymmetry parameter and orientation degree of freedom, the fission dynamics of some [Formula: see text]O-, [Formula: see text]Ar- and [Formula: see text]Ni-induced fusion–fission reactions were investigated. We calculated mean pre-scission neutron kinetic energy, pre-scission neutron multiplicity and fission time. Mass-split dependence of pre-scission neutron multiplicity and sensitivity of multiplicity on different value of the level density parameter for fission and neutron emission of highly excited compound nuclei were studied. One can conclude reasonable agreement between theory and tentative results for different reactions.

scholarly journals Nuclear level density andγ-ray strength function of43Sc

2012 ◽  
Vol 85 (6) ◽  
Author(s):  
A. Bürger ◽  
A. C. Larsen ◽  
S. Hilaire ◽  
M. Guttormsen ◽  
S. Harissopulos ◽  
...  
Keyword(s):  
Level Density ◽  
Strength Function ◽  
Nuclear Level Density ◽  
Nuclear Level
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