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Materials Data on PuZr by Materials Project

PuZr is alpha La-derived structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are three inequivalent Pu sites. In the first Pu site, Pu is bonded to six equivalent Pu and six equivalent Zr atoms to form PuPu6Zr6 cuboctahedra that share corners with twelve PuPu6Zr6 cuboctahedra, edges with twelve PuPu6Zr6 cuboctahedra, edges with twelve equivalent ZrPu6Zr6 cuboctahedra, faces with six equivalent PuPu6Zr6 cuboctahedra, and faces with twelve equivalent ZrPu6Zr6 cuboctahedra. All Pu–Pu bond lengths are 3.28 Å. All Pu–Zr bond lengths are 3.24 Å. In the second Pu site, Pu is bonded to six equivalent Pu and six Zr atoms to form PuPu6Zr6 cuboctahedra that share corners with five equivalent ZrPu6Zr10 cuboctahedra, corners with twelve PuPu6Zr6 cuboctahedra, edges with ten ZrPu6Zr6 cuboctahedra, edges with twelve PuPu6Zr6 cuboctahedra, faces with six equivalent PuPu6Zr6 cuboctahedra, and faces with fifteen ZrPu6Zr6 cuboctahedra. All Pu–Pu bond lengths are 3.28 Å. All Pu–Zr bond lengths are 3.24 Å. In the third Pu site, Pu is bonded to six equivalent Pu and six Zr atoms to form PuPu6Zr6 cuboctahedra that share corners with five equivalent ZrPu6Zr10 cuboctahedra, corners with twelve PuPu6Zr6 cuboctahedra, edges with ten ZrPu6Zr6 cuboctahedra, edges with twelve PuPu6Zr6 cuboctahedra, faces with six equivalent PuPu6Zr6 cuboctahedra, and faces with fifteen ZrPu6Zr6 cuboctahedra. All Pu–Pu bond lengths are 3.28 Å. All Pu–Zr bond lengths are 3.24 Å. There are two inequivalent Zr sites. In the first Zr site, Zr is bonded to six Pu and six equivalent Zr atoms to form ZrPu6Zr6 cuboctahedra that share corners with twelve ZrPu6Zr6 cuboctahedra, edges with twelve PuPu6Zr6 cuboctahedra, edges with twelve ZrPu6Zr6 cuboctahedra, faces with six equivalent ZrPu6Zr6 cuboctahedra, and faces with twelve PuPu6Zr6 cuboctahedra. All Zr–Zr bond lengths are 3.28 Å. In the second Zr site, Zr is bonded to six Pu and ten equivalent Zr atoms to form ZrPu6Zr10 cuboctahedra that share corners with ten PuPu6Zr6 cuboctahedra, corners with twelve ZrPu6Zr6 cuboctahedra, edges with eight PuPu6Zr6 cuboctahedra, edges with sixteen ZrPu6Zr6 cuboctahedra, faces with sixteen equivalent ZrPu6Zr10 cuboctahedra, and faces with eighteen PuPu6Zr6 cuboctahedra. There are a spread of Zr–Zr bond distances ranging from 3.28–6.55 Å.

36 MATERIALS SCIENCE↗

Experimental and Modeling Review of the Plutonium-Zirconium (Pu-Zr) System: Lost in Translation and Over Time?

This article presents a review of the phase equilibria of the Pu-Zr system and discusses the contradictory reports on the experimental phase diagram and misinterpretations that have led to confusion over time. In addition, a review of the few Pu-Zr CALPHAD (CALculation of PHAse Diagrams) assessments is presented with emphasis on the heat of formation of the bcc phase, highlighting a disagreement between CALPHAD and ab initio calculations. Based on the information gathered in this study, a critical re-assessment of the Pu-Zr system involving the ζ (Pu 28 Zr), θ (Pu 4 Zr), kinetically hindered κ (PuZr 2 ), and once observed ι phases is called for.

36 MATERIALS SCIENCE↗