Evaluation of Neutron Reactions on Iron Isotopes for CIELO and ENDF/B-VIII.0

Herman, M.; Trkov, A.; Capote, R.; Nobre, G. P. A.; Brown, David; Arcilla, R.; Danon, Y.; Plompen, A.; Mughabghab, S.F.; Jing, Q.; Zhigang, Ge; Tingjin, Liu; Lu, Haijiao; Ruan, Xichao; Leal, L.C.; Carlson, B. V.; Kawano, Toshihiko; Sin, M.; Simakov, S.P.; Guber, K. H.

doi:10.1016/j.nds.2018.02.004

Cited by 55 publications

(46 citation statements)

References 132 publications

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“…We initially compare the performance of both LD models when applied to 56 Fe by observing their impact on 56 Fe(n,p), which is a well-measured dosimetry reaction [19,20]. In the incident-energy region where (n,p) is prominent, it is the only relevant open channel apart from elastic and inelastic channels, which are much bigger to be significantly impacted by details of (n,p) and by fine changes in LD [25]. The (n, 2n) channel only opens above ∼ 11.5 MeV.…”

Section: Impact Of Ld Models In Cross Sectionsmentioning

confidence: 99%

“…Example of double-differential spectra for different neutron incident energies and at different scattering angles for the different LD approaches. The green curves are the results from using the LD from the GC model with its parameters fitted according to the ENDF/B-VIII.0 iron evaluation [25]; the solid-red curves are the results from using the HFB model and fitting 56 Mn HFB LD parameters to optimize agreement with (n, p) data; the dashed-blue curve is the same as the solid-red one but also with HFB LD for 56 Fe re-scaled to better agree with calculated neutron double-differential spectra. Data retrieved from EXFOR [32,33].…”

Section: A Relation Between Spectra and Ldmentioning

confidence: 99%

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Constraining level densities through quantitative correlations with cross-section data

et al. 2020

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The adopted level densities (LD) for the nuclei produced through different reaction mechanisms significantly impact the accurate calculation of cross sections for the different reaction channels. Many common LD models make simplified assumptions regarding the overall behavior of the total LD and the intrinsic spin and parity distributions of the excited states. However, very few experimental constraints are taken into account in these models: LD at neutron separation energy coming from average spacings of s-and p-wave resonances (D0 and D1, respectively) whenever they have been previously measured, and the sometimes subjective extrapolation of discrete levels. These, however, constrain the LD only in very specific regions of excitation energy, and for specific spins and parities. This work aims to establish additional experimental constraints on LD through quantitative correlations between cross sections and LD. This allows for fitting and the determination of detailed structures in LD. For this we use the microscopic Hartree-Fock-Bogoliubov (HFB) LD as a starting point as the HFB LD provide a more realistic spin and parity distributions than phenomenological models such as Gilbert-Cameron (GC). We then associate variations predicted by the HFB model with the structure observed in double-differential cross sections at low outgoing neutron energy, region that is dominated by the LD input. We also use (n, p) on 56 Fe, as an example case where angle-integrated cross sections are extremely sensitive to LD. For comparison purposes we also perform calculations with the GC model. With this approach we are able to perform fits of the LD based on actual experimental data, constraining the model and ensuring its consistency. This approach can be particularly useful in extrapolating the LD to nuclei for which high-excited discrete levels and/or values of D0 or D1 are unknown. It also predicts inelastic gamma (n, n γ) cross sections that in some cases can differ significantly from more standard phenomenological LD models such as GC.arXiv:1909.09660v1 [nucl-th]

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Section: Impact Of Ld Models In Cross Sectionsmentioning

confidence: 99%

Section: A Relation Between Spectra and Ldmentioning

confidence: 99%

Constraining level densities through quantitative correlations with cross-section data

et al. 2020

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“…It is not clear how to make the same substitution that is done in Eqs. (38) or (39) for the SPRT method.…”

Section: Comparison Of Transmission Coefficientsmentioning

confidence: 99%

“…where W MS ab ( T ) = W ab ( Γ) denotes the usual WFC, using the replacement in equation (39). Either modification possibly has dramatic implications.…”

Section: Comparison Of Transmission Coefficientsmentioning

confidence: 99%

“…7), but is difficult to reproduce with traditional Hauser-Feshbach calculations. It would be interesting to investigate the impact of superradiance in the CIELO Fe evaluation [39], however these cross sections are tightly constrained by other experimental data and would require a whole new evaluation. In any event, a measurement of 90 Zr(n, n γ) between 2 and 4 MeV would be very helpful by providing experimental evidence (or lack of) of superradiance.…”

Section: Application To 90 Zrmentioning

confidence: 99%

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Impact of alternative transmission coefficient parametrizations on Hauser-Feshbach theory

2018

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We investigate different formulations of the transmission coefficient Tc, including the form implied by Moldauer's "sum rule for resonance reactions" [P. A. Moldauer, Phys. Rev. Lett. 19, 1047], the SPRT method [G. Noguere, et al. EPJ Web Conf. 146, 02036 (2017)] and the Moldauer-Simonius form [M. Simonius, Phys. Lett. 52B, 279 (1974); P.A. Moldauer, Phys. Rev. 157, 907 (1967)]. Within these different formulations, we compute the neutron transmission coefficients in the resolved and unresolved resonance regions, allowing a direct comparison with the transmission coefficients computed using an optical model potential. For nuclei for which there are no measured resonances, these approaches allow one to predict the average neutron resonance parameters directly from the optical model and level densities. Some of the approaches are valid in both the strong and weak coupling limits (i.e., any value of the average width and mean level spacing). Finally, both the Moldauer-Simonius and Moldauer's Sum Rule forms approaches suggest that superradiance, that is, the quantum chaotic enhancement of certain channels, may be a common phenomena in nuclear collisions. Our results suggest why superradiance has been previously overlooked. We apply our approach to neutron reactions on the closed shell 90 Zr nucleus and the mid-shell 197 Au nucleus. arXiv:1807.05156v1 [nucl-th]

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Study on the fusion reactor performance with different materials and nuclear waste actinides

Şahi̇n

Sahiner

et al. 2020

Int J Energy Res

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Summary In this study, both pure fusion blanket and fusion‐fission (hybrid) reactor blanket performance were investigated and discussed separately in two phases. In the first phase, a Monte Carlo radiation damage analysis has been performed for stainless steel (SS304, SS316, and oxide dispersion strengthened (ODS)), molybdenum, vanadium, and tungsten as the first wall (FW) materials, in combination with selected tritium breeders. The main technical parameters for fusion reactors, such as tritium breeding ratio, fusion energy multiplication factor (M), displacement per atom (DPA), and gas production (He, H) have been evaluated. All numerical calculations have been carried out in spherical geometry with MCNP6 code package using continuous energy cross‐sections from the ENDF/B‐VIII.0 library, except DPA calculations. Instead of the ENDF/B‐VIII.0 library, the 30‐group CLAW‐IV library was employed for DPA calculations. Structural material selection for the FW respect to radiation damage limits and reactor performance for energy production and tritium has been concluded. Conventional thermal reactors, such as light water reactors andCanada Deuterium Uranium (CANDU) reactors are producing substantial quantities of transuranic elements, which represent serious nuisance and permanent hazard potential. On the other hand, they become fissionable material under high energetic fusion neutron irradiation and multiply the fusion energy. In the second phase, the investigations are extended to the incineration of minor actinides (MA) in the fusion‐fission (hybrid) mode. The transmutation history of MA nuclear waste is included. MA are added into the first zone of the coolant in TRi‐structural ISOtropic particle TRISO particles with a volume fraction of 6%. The transformation scenario for all MA by SS 304 steel FW is practically the same as with the ODS FW.

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Evaluation of Neutron Reactions on Iron Isotopes for CIELO and ENDF/B-VIII.0

Cited by 55 publications

References 132 publications

Constraining level densities through quantitative correlations with cross-section data

Constraining level densities through quantitative correlations with cross-section data

Impact of alternative transmission coefficient parametrizations on Hauser-Feshbach theory

Study on the fusion reactor performance with different materials and nuclear waste actinides

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