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6 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

A physics-based model of cladding wastage layer formation rate

In this report, lower length scale simulations to inform an engineering-scale model of fuel-cladding chemical interaction (FCCI) conducted under the auspices of the Nuclear Energy Advanced Modeling and Simulation (NEAMS) program in FY22 are described. An overall strategy for the implementation of the BISON model is described, and the past and current lower length scale work on FCCI formation is put into the context of this overall strategy. Density functional theory and kinetic Monte Carlo simulations are used to determine the diffusion coefficient of neodymium in iron. Density functional theory calculations are also used to parameterize a parabolic approximation for the dependence of free energy on composition for the intermetallic compound Fe 17 Nd 2 . A phase-field model of the Fe-Nd system was developed that includes the random solid solution body-centered cubic phase and the intermetallic Fe 17 Nd 2 . The model was used to simulate growth of the intermetallic layer in a diffusion couple and the results were compared to experiment. The model’s prediction of the parabolic growth constant is within 40 % of the experimental value. The model is also used to simulate the formation of a grain boundary attack layer that is observed in experiment. The simulations show enhanced Nd concentration along the grain boundaries, but do not clearly show formation of a Fe 17 Nd 2 layer

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

Materials Data on NdFe5 by Materials Project

NdFe5 crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Nd is bonded in a 6-coordinate geometry to eighteen Fe atoms. There are six shorter (2.97 Å) and twelve longer (3.24 Å) Nd–Fe bond lengths. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded in a 12-coordinate geometry to three equivalent Nd and six equivalent Fe atoms. All Fe–Fe bond lengths are 2.47 Å. In the second Fe site, Fe is bonded to four equivalent Nd and eight Fe atoms to form a mixture of edge, face, and corner-sharing FeNd4Fe8 cuboctahedra. All Fe–Fe bond lengths are 2.57 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NdFe2 by Materials Project

NdFe2 is Cubic Laves structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Nd is bonded in a 12-coordinate geometry to twelve equivalent Fe atoms. All Nd–Fe bond lengths are 3.09 Å. Fe is bonded to six equivalent Nd and six equivalent Fe atoms to form a mixture of edge, face, and corner-sharing FeNd6Fe6 cuboctahedra. All Fe–Fe bond lengths are 2.63 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nd3Fe29 by Materials Project

Nd3Fe29 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Nd sites. In the first Nd site, Nd is bonded in a 11-coordinate geometry to nineteen Fe atoms. There are a spread of Nd–Fe bond distances ranging from 3.05–3.32 Å. In the second Nd site, Nd is bonded in a 12-coordinate geometry to twenty Fe atoms. There are a spread of Nd–Fe bond distances ranging from 3.03–3.26 Å. There are eleven inequivalent Fe sites. In the first Fe site, Fe is bonded to two equivalent Nd and ten Fe atoms to form a mixture of edge, face, and corner-sharing FeNd2Fe10 cuboctahedra. There are a spread of Fe–Fe bond distances ranging from 2.36–2.61 Å. In the second Fe site, Fe is bonded to three equivalent Nd and nine Fe atoms to form FeNd3Fe9 cuboctahedra that share corners with twenty-two FeNd2Fe10 cuboctahedra, edges with ten FeNd3Fe9 cuboctahedra, and faces with nineteen FeNd3Fe9 cuboctahedra. There are a spread of Fe–Fe bond distances ranging from 2.43–2.66 Å. In the third Fe site, Fe is bonded to two equivalent Nd and ten Fe atoms to form a mixture of edge, face, and corner-sharing FeNd2Fe10 cuboctahedra. There are four shorter (2.45 Å) and two longer (2.63 Å) Fe–Fe bond lengths. In the fourth Fe site, Fe is bonded in a 2-coordinate geometry to one Nd and thirteen Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.41–2.89 Å. In the fifth Fe site, Fe is bonded in a 2-coordinate geometry to one Nd and thirteen Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.59–2.90 Å. In the sixth Fe site, Fe is bonded to two Nd and ten Fe atoms to form a mixture of distorted edge, face, and corner-sharing FeNd2Fe10 cuboctahedra. There are a spread of Fe–Fe bond distances ranging from 2.41–2.76 Å. In the seventh Fe site, Fe is bonded to two equivalent Nd and ten Fe atoms to form distorted FeNd2Fe10 cuboctahedra that share corners with twenty-three FeNd2Fe10 cuboctahedra, edges with four FeNd3Fe9 cuboctahedra, and faces with twenty FeNd2Fe10 cuboctahedra. There are a spread of Fe–Fe bond distances ranging from 2.47–2.54 Å. In the eighth Fe site, Fe is bonded in a 10-coordinate geometry to one Nd and thirteen Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.40–2.60 Å. In the ninth Fe site, Fe is bonded to two Nd and ten Fe atoms to form distorted FeNd2Fe10 cuboctahedra that share corners with twenty-two FeNd2Fe10 cuboctahedra, edges with seven FeNd3Fe9 cuboctahedra, and faces with seventeen FeNd2Fe10 cuboctahedra. Both Fe–Fe bond lengths are 2.43 Å. In the tenth Fe site, Fe is bonded to two Nd and ten Fe atoms to form a mixture of edge, face, and corner-sharing FeNd2Fe10 cuboctahedra. The Fe–Fe bond length is 2.48 Å. In the eleventh Fe site, Fe is bonded to three Nd and nine Fe atoms to form FeNd3Fe9 cuboctahedra that share corners with twenty-one FeNd3Fe9 cuboctahedra, edges with ten FeNd2Fe10 cuboctahedra, and faces with eighteen FeNd2Fe10 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nd2Fe17 by Materials Project

Nd2Fe17 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Nd is bonded in a 10-coordinate geometry to nineteen Fe atoms. There are a spread of Nd–Fe bond distances ranging from 3.05–3.30 Å. There are four inequivalent Fe sites. In the first Fe site, Fe is bonded to two equivalent Nd and ten Fe atoms to form a mixture of face, edge, and corner-sharing FeNd2Fe10 cuboctahedra. There are a spread of Fe–Fe bond distances ranging from 2.44–2.63 Å. In the second Fe site, Fe is bonded to two equivalent Nd and ten Fe atoms to form a mixture of distorted face, edge, and corner-sharing FeNd2Fe10 cuboctahedra. There are a spread of Fe–Fe bond distances ranging from 2.48–2.76 Å. In the third Fe site, Fe is bonded to three equivalent Nd and nine Fe atoms to form a mixture of face, edge, and corner-sharing FeNd3Fe9 cuboctahedra. There are two shorter (2.51 Å) and one longer (2.65 Å) Fe–Fe bond lengths. In the fourth Fe site, Fe is bonded in a 2-coordinate geometry to one Nd and thirteen Fe atoms. The Fe–Fe bond length is 2.42 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nd2Fe by Materials Project

Nd2Fe crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are three inequivalent Nd sites. In the first Nd site, Nd is bonded in a distorted hexagonal planar geometry to six equivalent Fe atoms. All Nd–Fe bond lengths are 3.10 Å. In the second Nd site, Nd is bonded in a linear geometry to two equivalent Fe atoms. Both Nd–Fe bond lengths are 2.66 Å. In the third Nd site, Nd is bonded in a distorted single-bond geometry to four equivalent Fe atoms. There are one shorter (2.49 Å) and three longer (3.22 Å) Nd–Fe bond lengths. Fe is bonded in a 2-coordinate geometry to eight Nd atoms.

36 MATERIALS SCIENCE↗