The Need for Precise and Well-documented Experimental Data on Prompt Fission Neutron Spectra from Neutron-induced Fission of 239Pu

Neudecker, Denise; Taddeucci, T.N.; Haight, R. C.; Lee, Hye Young; White, Morgan Curtis; Rising, Michael Evan

doi:10.1016/j.nds.2015.12.005

Cited by 35 publications

(28 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The covariances of experimental data [8][9][10][11][12][13][14][15][16] were estimated in detail using information provided in Refs. [17,18]. The Los Alamos model [20] combined with the Hauser-Feshbach [21] and the exciton models [22] were used to model prompt fission, pre-fission compound nucleus and pre-equilibrium neutron emissions.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Evaluation of the ²³⁵U prompt fission neutron spectrum including a detailed analysis of experimental data and improved model information

et al. 2017

View full text Add to dashboard Cite

Abstract. We present an evaluation of the 235 U prompt fission neutron spectrum (PFNS) induced by thermal to 20-MeV neutrons. Experimental data and associated covariances were analyzed in detail. The incident energy dependence of the PFNS was modeled with an extended Los Alamos model combined with the HauserFeshbach and the exciton models. These models describe prompt fission, pre-fission compound nucleus and pre-equilibrium neutron emissions. The evaluated PFNS agree well with the experimental data included in this evaluation, preliminary data of the LANL and LLNL Chi-Nu measurement and recent evaluations by Capote et al. and Rising et al. However, they are softer than the ENDF/B-VII.1 (VII.1) and JENDL-4.0 PFNS for incident neutron energies up to 2 MeV. Simulated effective multiplication factors k eff of the Godiva and Flattop-25 critical assemblies are further from the measured k eff if the current data are used within VII.1 compared to using only VII.1 data. However, if this work is used with ENDF/B-VIII.0β2 data, simulated values of k eff agree well with the measured ones.

show abstract

Section: Discussionmentioning

confidence: 99%

“…Additional uncertainties were included in Cov N based on MCNP studies [17,18] of the experiments highlighted in Fig. 1.…”

Section: Input For Evaluationmentioning

confidence: 99%

Evaluation of the ²³⁵U prompt fission neutron spectrum including a detailed analysis of experimental data and improved model information

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Recently experiments have concentrated on the correlation in angle and energy of prompt fission neutrons, and its dependence on mass splits. Prompt fission neutron spectra are being addressed to try to resolve discrepancies in literature results as summarized in [14,15]. Past measurements, originally analyzed without neutron scattering corrections, are now being reanalyzed with advanced Monte Carlo codes [16].…”

Section: Neutrons Emitted Promptly In Fission Nu-bar Neutron Multipmentioning

confidence: 99%

Overview of Nuclear Fission — Present Experiments

Haight¹

2017

Fission and Properties of Neutron-Rich Nuclei

View full text Add to dashboard Cite

After nearly 80 years of research on nuclear fission, we still do not fully understand the fission process. A combination of new requirements for accurate fission nuclear data, the ability to calculate sophisticated models of fission, and the development of new experimental techniques has re-energized the field. This paper concentrates on recent developments in the experimental realm and what the new results can contribute to the database for applications and to improving the underlying physical models. This overview is intended to be an introduction to fission presentations at this meeting.

show abstract

“…As far as the applications are concerned, it has been recently shown that accurate predictions of nuclear criticality using neutron transport codes crucially depend on the underlying nuclear data, especially the prompt fission neutron spectrum [1]. While the accuracy of evaluated neutron multiplicities, ν , has improved in recent years for some nuclei, the experimental database of prompt fission neutron spectra consists of a limited number of datasets, far less precise than those on the other key fission observables and often discrepant [2,3].…”

Section: Introductionmentioning

confidence: 99%

Prompt-fission-neutron spectra in the Pu239(n,f) reaction

et al. 2020

View full text Add to dashboard Cite

Prompt fission neutron spectra from 239 Pu (n, f ) were measured with respect to 252 Cf spontaneous fission for incident neutron energies from 0.7 to 700 MeV at the Weapons Neutron Research facility (WNR) of the Los Alamos Neutron Science Center. A newly designed high-efficiency fission chamber was coupled to the highly segmented Chi-Nu neutron liquid scintillator array to detect neutrons emitted in fission events. The double time-of-flight technique was used to deduce the incident-neutron energies from the spallation target and the outgoing-neutron energies from the fission chamber. Prompt fission neutron spectra (PFNS) were measured with respect to 252 Cf spontaneous fission down to 200 keV and up to about 12 MeV for all the incident neutron energies with typical total uncertainties well below 2% up to about 7 MeV outgoing-neutron energy. The general trend of PFNS is well reproduced by JEFF3.3 and ENDF/B-VIII.0 evaluations, although a better agreement is found with JEFF3.3 . Discrepancies were observed for the low-energy part of the spectra, especially around the opening of the 2 nd -, 3 rd -and 4 th -chance fission. Neutron average kinetic energies as a function of incident-neutron energy are obtained experimentally with reported total uncertainties below 0.5%.The measured values agree with the most recent data. The trend is fairly well reproduced by the JEFF3.3 evaluation, although it fails to reproduce the experimental values within their uncertainties.

show abstract

The Need for Precise and Well-documented Experimental Data on Prompt Fission Neutron Spectra from Neutron-induced Fission of 239Pu

Cited by 35 publications

References 42 publications

Evaluation of the ²³⁵U prompt fission neutron spectrum including a detailed analysis of experimental data and improved model information

Evaluation of the ²³⁵U prompt fission neutron spectrum including a detailed analysis of experimental data and improved model information

Overview of Nuclear Fission — Present Experiments

Prompt-fission-neutron spectra in the Pu239(n,f) reaction

Contact Info

Product

Resources

About

The Need for Precise and Well-documented Experimental Data on Prompt Fission Neutron Spectra from Neutron-induced Fission of 239Pu

Cited by 35 publications

References 42 publications

Evaluation of the 235U prompt fission neutron spectrum including a detailed analysis of experimental data and improved model information

Evaluation of the 235U prompt fission neutron spectrum including a detailed analysis of experimental data and improved model information

Overview of Nuclear Fission — Present Experiments

Prompt-fission-neutron spectra in the Pu239(n,f) reaction

Contact Info

Product

Resources

About

Evaluation of the ²³⁵U prompt fission neutron spectrum including a detailed analysis of experimental data and improved model information

Evaluation of the ²³⁵U prompt fission neutron spectrum including a detailed analysis of experimental data and improved model information