Fission Product Yields of 233U, 235U, 238U and 239Pu in Fields of Thermal Neutrons, Fission Neutrons and 14.7-MeV Neutrons

Laurec, J.; Ádám, A.; Bruyne, Thierry de.; Bauge, E.; Granier, T.; Aupiais, Jean; Bersillon, O.; Petit, G. Le; Authier, Nicolas; Casoli, P.

doi:10.1016/j.nds.2010.11.004

Cited by 52 publications

(34 citation statements)

References 26 publications

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“…The GEF prediction is close to the symmetric data of Glendenin et al [194] but higher than the data from Chapman et al [201]. This is in line with an analysis reported in [193], where comparisons were made with the Ford experimental data [198] which are consis- [194,198,199] tent with the Glendenin data, according to which the Chapman data seem to systematically underestimate the symmetric part.…”

Section: Andsupporting

confidence: 89%

General Description of Fission Observables: GEF Model Code

Schmidt

Jurado

Amouroux

et al. 2016

Nuclear Data Sheets

444

421

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The GEF ("GEneral description of Fission observables") model code is documented. It describes the observables for spontaneous fission, neutron-induced fission and, more generally, for fission of a compound nucleus from any other entrance channel, with given excitation energy and angular momentum. The GEF model is applicable for a wide range of isotopes from Z = 80 to Z = 112 and beyond, up to excitation energies of about 100 MeV. The results of the GEF model are compared with fission barriers, fission probabilities, fission-fragment mass-and nuclide distributions, isomeric ratios, total kinetic energies, and prompt-neutron and prompt-gamma yields and energy spectra from neutron-induced and spontaneous fission. Derived properties of delayed neutrons and decay heat are also considered.The GEF model is based on a general approach to nuclear fission that explains a great part of the complex appearance of fission observables on the basis of fundamental laws of physics and general properties of microscopic systems and mathematical objects. The topographic theorem is used to estimate the fission-barrier heights from theoretical macroscopic saddle-point and ground-state masses and experimental ground-state masses. Motivated by the theoretically predicted early localisation of nucleonic wave functions in a necked-in shape, the properties of the relevant fragment shells are extracted. These are used to determine the depths and the widths of the fission valleys corresponding to the different fission channels and to describe the fission-fragment distributions and deformations at scission by a statistical approach. A modified composite nuclear-level-density formula is proposed. It respects some features in the superfluid regime that are in accordance with new experimental findings and with theoretical expectations. These are a constant-temperature behaviour that is consistent with a considerably increased heat capacity and an increased pairing condensation energy that is consistent with the collective enhancement of the level density. The exchange of excitation energy and nucleons between the nascent fragments on the way from saddle to scission is estimated according to statistical mechanics. As a result, excitation energy and unpaired nucleons are predominantly transferred to the heavy fragment in the superfluid regime. This description reproduces some rather peculiar observed features of the prompt-neutron multiplicities and of the even-odd effect in fission-fragment Z distributions. For completeness, some conventional descriptions are used for calculating pre-equilibrium emission, fission probabilities and statistical emission of neutrons and gamma radiation from the excited fragments. Preference is given to simple models that can also be applied to exotic nuclei compared to more sophisticated models that need precise empirical input of nuclear properties, e.g. spectroscopic information.The approach reveals a high degree of regularity and provides a considerable insight into the physics of the fission process. Fission obs...

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Section: Andsupporting

confidence: 89%

General Description of Fission Observables: GEF Model Code

Schmidt

Jurado

Amouroux

et al. 2016

Nuclear Data Sheets

444

421

View full text Add to dashboard Cite

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“…The results of these experiments, analyzed and published recently for the first time [6,7], have been compared with evaluated data and are in good agreement for reactions on uranium 233 and uranium 235. Nevertheless the experimental results seem to underestimate some evaluations, especially for reactions on plutonium 239.…”

Section: Nuclear Data Evaluationmentioning

confidence: 65%

Characterization of the CALIBAN Critical Assembly Neutron Spectra using Several Adjustment Methods Based on Activation Foils Measurement

Casoli

Grégoire

Rousseau

et al. 2016

EPJ Web of Conferences

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Abstract. CALIBAN is a metallic critical assembly managed by the Criticality, Neutron Science and Measurement Department located on the French CEA Center of Valduc. The reactor is extensively used for benchmark experiments dedicated to the evaluation of nuclear data, for electronic hardening or to study the effect of the neutrons on various materials. Therefore CALIBAN irradiation characteristics and especially its central cavity neutron spectrum have to be very accurately evaluated. In order to strengthen our knowledge of this spectrum, several adjustment methods based on activation foils measurements are being studied for a few years in the laboratory. Firstly two codes included in the UMG package have been tested and compared: MAXED and GRAVEL. More recently, the CALIBAN cavity spectrum has been studied using CALMAR, a new adjustment tool currently under development at the CEA Center of Cadarache. The article will discuss and compare the results and the quality of spectrum rebuilding obtained with the UMG codes and with the CALMAR software, from a set of activation measurements carried out in the CALIBAN irradiation cavity.

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“…TUNL possesses a 10 MV FN Tandem Van de Graaff accelerator, capable of accelerating beams of both protons, deuterons and other light ions. Quasi-monoenergetic neutrons are produced at TUNL via the 7 Li(p,n) 7 Be, 3 H(p,n) 3 He, 2 H(d,n) 3 He and 3 H(d,n) 4 He reactions. The measurements were performed in what is termed the Neutron Time-of-Flight (NTOF) room at TUNL.…”

Section: Methodsmentioning

confidence: 99%

“…A primary motivation for the present work is to address issues raised [1][2][3][4] regarding possible energy dependencies of certain fission product yields. The paper by Chadwick et al [1] presented compelling evidence for a positive energy dependence for the fission product yield of 147 Nd from neutron induced fission of 239 Pu in the low-energy region between 0.2 and 2 MeV incident neutron energy as measured using critical assemblies and fast reactors.…”

Section: Introductionmentioning

confidence: 99%

Energy dependence of fission product yields from ²³⁵U, ²³⁸U, and ²³⁹Pu with monoenergetic neutrons between thermal and 14.8 MeV

et al. 2017

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Abstract. Under a joint collaboration between TUNL-LANL-LLNL, a set of absolute fission product yield measurements has been performed. The energy dependence of a number of cumulative fission product yields (FPY) have been measured using quasi-monoenergetic neutron beams for three actinide targets, 235 U, 238 U and 239 Pu, between 0.5 and 14.8 MeV. The FPYs were measured by a combination of fission counting using specially designed dual-fission chambers and γ -ray counting. Each dual-fission chamber is a back-to-back ionization chamber encasing an activation target in the center with thin deposits of the same target isotope in each chamber. This method allows for the direct measurement of the total number of fissions in the activation target with no reference to the fission cross-section, thus reducing uncertainties. γ -ray counting of the activation target was performed on well-shielded HPGe detectors over a period of two months post irradiation to properly identify fission products. Reported are absolute cumulative fission product yields for incident neutron energies of 0.5, 1.37, 2.4, 3.6, 4.6, 5.5, 7.5, 8.9 and 14.8 MeV. Preliminary results from thermal irradiations at the MIT research reactor will also be presented and compared to present data and evaluations.

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Fission Product Yields of 233U, 235U, 238U and 239Pu in Fields of Thermal Neutrons, Fission Neutrons and 14.7-MeV Neutrons

Cited by 52 publications

References 26 publications

General Description of Fission Observables: GEF Model Code

General Description of Fission Observables: GEF Model Code

Characterization of the CALIBAN Critical Assembly Neutron Spectra using Several Adjustment Methods Based on Activation Foils Measurement

Energy dependence of fission product yields from ²³⁵U, ²³⁸U, and ²³⁹Pu with monoenergetic neutrons between thermal and 14.8 MeV

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Fission Product Yields of 233U, 235U, 238U and 239Pu in Fields of Thermal Neutrons, Fission Neutrons and 14.7-MeV Neutrons

Cited by 52 publications

References 26 publications

General Description of Fission Observables: GEF Model Code

General Description of Fission Observables: GEF Model Code

Characterization of the CALIBAN Critical Assembly Neutron Spectra using Several Adjustment Methods Based on Activation Foils Measurement

Energy dependence of fission product yields from 235U, 238U, and 239Pu with monoenergetic neutrons between thermal and 14.8 MeV

Contact Info

Product

Resources

About

Energy dependence of fission product yields from ²³⁵U, ²³⁸U, and ²³⁹Pu with monoenergetic neutrons between thermal and 14.8 MeV