Reference Manual for Endf Thermal Neutron Scattering Data.

Koppel, J.U.; Houston, D.H.

doi:10.2172/4075168

Cited by 28 publications

(22 citation statements)

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“…Because such studies must be done for each isotope over the entire energy range, cross sections are evaluated by numerous parties throughout the world. In order to provide continuity and ease of technology transfer, the ENDF (Evaluated Nuclear Data File) format was created by H. Honeck at Brookhaven National Laboratory in the middle 1960's (Koppel and Houston, 1978). The ENDF is divided into two parts: ENDF/A, which primarily includes data from private industry and laboratories as it becomes available; ENDF/B, which is comprised of data that is complete for all reactions of interest (Duderstadt and Hamilton, 1976).…”

Section: Background and History Of Cross Section Generationmentioning

confidence: 99%

“…The majority of the necessary input for the LEAPR code is available in the General Atomics (GA) thermal scattering data (Koppel and Houston, 1978), which contains input parameters for the older counterpart to LEAPR, GASKET (Koppel, et al, 1967). The overall frequency spectrum weights for each portion are listed in Table 5-1. There are two discrete oscillators, whose energies are 0.205 eV and 0.48 eV, with corresponding weights 0.166667 and 0.333333, respectively.…”

Section: Hydrogen In Water For the Leapr Codementioning

confidence: 99%

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Reactivity Feedback Mechanisms in Aqueous Fissile Solutions

Kornreich

1993

Nuclear Science and Engineering

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This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer.The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction.In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. My primary contact for the cross section generation portion of this project was Robert MacFarlane. His tireless aid through countless phone conversations is appreciated more than he may ever know, and the experience gained through his efforts is invaluable. Having just brushed the surface of an area to which he has dedicated a career has given me an appreciation for the complexity of cross section generation, and has stirred great curiosity and interest.Two groups at Los Alamos National Laboratory have also aided in this project. The Advanced Nuclear Technology Group provided an ideal workplace for my summer Practicum, and much of the concepts developed here began last summer. I would also like to thank Tom MacLaughlin and Doug O'Dell from Criticality Safety for the use of their marvelous CRAY.As an aside, Forrest Brinkley has shown such an interest in helping me with TWODANT whenever there was a question that he had to be mentioned. He truly enjoys helping others, and he does this to a degree which could never expected.The writing of this thesis could not have been accomplished without the unending support of my family. Many sacrifices were made during the exponential portion of the project so that the computer could be available for my use.

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Section: Background and History Of Cross Section Generationmentioning

confidence: 99%

Section: Hydrogen In Water For the Leapr Codementioning

confidence: 99%

Reactivity Feedback Mechanisms in Aqueous Fissile Solutions

Kornreich

1993

Nuclear Science and Engineering

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“…The new evaluations for light and heavy water are based on the CAB Model, which is an improvement over two older water thermal scattering evaluations: the General Atomics Model [4] and the IKE Model [5].…”

Section: Modelsmentioning

confidence: 99%

New evaluation of thermal neutron scattering libraries for light and heavy water

et al. 2017

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Abstract. In order to improve the design and safety of thermal nuclear reactors and for verification of criticality safety conditions on systems with significant amount of fissile materials and water, it is necessary to perform high-precision neutron transport calculations and estimate uncertainties of the results. These calculations are based on neutron interaction data distributed in evaluated nuclear data libraries. To improve the evaluations of thermal scattering sub-libraries, we developed a set of thermal neutron scattering cross sections (scattering kernels) for hydrogen bound in light water, and deuterium and oxygen bound in heavy water, in the ENDF-6 format from room temperature up to the critical temperatures of molecular liquids. The new evaluations were generated and processable with NJOY99 and also with NJOY-2012 with minor modifications (updates), and with the new version of NJOY-2016. The new TSL libraries are based on molecular dynamics simulations with GROMACS and recent experimental data, and result in an improvement of the calculation of single neutron scattering quantities. In this work, we discuss the importance of taking into account self-diffusion in liquids to accurately describe the neutron scattering at low neutron energies (quasielastic peak problem). To improve modeling of heavy water, it is important to take into account temperaturedependent static structure factors and apply Sköld approximation to the coherent inelastic components of the scattering matrix. The usage of the new set of scattering matrices and cross-sections improves the calculation of thermal critical systems moderated and/or reflected with light/heavy water obtained from the International Criticality Safety Benchmark Evaluation Project (ICSBEP) handbook. For example, the use of the new thermal scattering library for heavy water, combined with the ROSFOND-2010 evaluation of the cross sections for deuterium, results in an improvement of the C/E ratio in 48 out of 65 international benchmark cases calculated with the Monte Carlo code MCNP5, in comparison with the existing library based on the ENDF/B-VII.0 evaluation.

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“…All reactions given in a particular cross-section evaluation are accounted for. The thermal neutrons can be described by both the free gas and the S(,) models (Copley, 1988); in the present work we used the latter with the thermal cross section found by Koppel & Houston (1978). Only the samples of the ®rst set (small holes in 1 and 2 mm Cd plates) were considered, and the scattered intensities were calculated by considering the proper neutron wavelength and a wavelength spread, Á!/!, of 10%.…”

Section: Mcnpmentioning

confidence: 99%

Sample geometry effects on incoherent small-angle scattering of light water

et al. 2000

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Light water is frequently used as a standard for calibrating small-angle neutron scattering (SANS) data. The intensities collected for 1 and 2 mm of light water in standard quartz cells may differ by up to about 50% due to the presence of multiple and inelastic scattering [Rennie & Heenan (1993).Proceedings of ISSI Meeting, Dubna,pp. 254–260, Report E3-93-65; Teixeira (1992).Structure and Dynamics of Strongly Interacting Colloids and Supramolecular Aggregates in Solution, edited by S. H. Chen, pp. 625–658. Dordrecht: Kluwer Academic Publishers]. Multiple scattering increases with the thickness of the sample. The use of only elastically scattered neutrons may lead to an absolute intensity of the SANS data of about a factor of 2 higher than that obtained by taking into account all of the neutrons on the detector [Ghosh & Rennie (1990).Inst. Phys. Conf. Ser.107, 233–244]. However, it is shown here that the scattering intensities collected with different ratios of sample-to-beam dimension do present large differences as a function of sample thickness. In particular, ratios smaller and larger than unity are considered and the results are discussed and compared with Monte Carlo simulations.

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Reference Manual for Endf Thermal Neutron Scattering Data.

Cited by 28 publications

References 0 publications

Reactivity Feedback Mechanisms in Aqueous Fissile Solutions

Reactivity Feedback Mechanisms in Aqueous Fissile Solutions

New evaluation of thermal neutron scattering libraries for light and heavy water

Sample geometry effects on incoherent small-angle scattering of light water

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