자료유형  

 학위논문

Control Number  

0016935186

International Standard Book Number  

9798380720021

Dewey Decimal Classification Number  

547.2

Main Entry-Personal Name  

Beausoleil II, Geoffrey.

Publication, Distribution, etc. (Imprint  

[S.l.] : North Carolina State University., 2023

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2023

Physical Description  

1 online resource(118 p.)

General Note  

Source: Dissertations Abstracts International, Volume: 85-05, Section: B.

General Note  

Advisor: Kaoumi, Djamel;Gupta, Rajeev;Koch, Karl;Horn, Tim;Roach, Allen.

Dissertation Note  

Thesis (Ph.D.)--North Carolina State University, 2023.

Restrictions on Access Note  

This item must not be sold to any third party vendors.

Summary, Etc.  

요약Previous research has shown that multi-principal element alloys (MPEAs) using refractory elements can form stable body centered cubic (BCC) structures across a large temperature region (e.g., 25 to 1000 °C). This is the same structure and space group as γ phase uranium (U), which has shown desirable behavior in previous alloy fuel research. It is thought that by using an MPEA approach to fuel alloy design it might be possible to stabilize a uranium based MPEA (U-MPEA) into a BCC phase suitable for nuclear fuel use. Additionally, refractory based MPEAs have exhibited behaviors that make them promising candidates for high temperature cladding applications. Thus, it is hypothesized that refractory MPEAs (R-MPEAs) could be used as both cladding and as an alloying framework for advanced fuel systems for Generation IV reactors.Initially, R-MPEAs were fabricated and characterized using only the refractory elements of Cr, Mo, Nb, Ti, V, and Zr by cryogenically milling high purity powders and consolidation via spark plasma sintering (SPS). These alloys were characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDS). The results showed that the alloys fabricated were predominantly a BCC system with an HCP secondary phase. The results also provided insight into the natural preference that certain elements may have towards forming single phase, solid solution systems. The refractory MPEAs were then made into diffusion couples with depleted uranium to understand chemical compatibility and interactions between the different phases and alloying elements. These were also characterized using XRD, SEM, EDS, and transmission electron microscopy (TEM) to investigate both alloy thermal stability and the interaction regions of the diffusion couples. The interactions at temperatures below the g-U transition temperature were negligible where-as the interactions above the transition was much more significant.Lastly, four MPEAs with uranium (U-MPEA) were developed using empirical predictors and Monte Carlo n-Particle (MCNP). The objective in this was to identify viable fuel alloys compared to conventional fuel forms based upon neutronic impacts of alloying elements and the bulk uranium density. These results determined that a potential alloy with the stoichiometry of M3U2 (M is three different alloying elements) could produce a viable candidate U-MPEA fuel. The elements of Mo, Nb, Ta, Ti, and V were chosen based upon these results with the four down-selected alloys of MaNbTaU2, MoNbTiU2, NbTaTiU2, and NbTaVU2. All four alloys were fabricated using arc-melting of raw elemental foils/chunks. Characterization of the fabricated alloys included XRD, SEM, EDS, TEM, and APT. The results showed a two-phase system with a g-U matrix (the phase desired for fuel performance reasons) surrounding a dendritic secondary phase exclusively made up of the refractory elements. TEM and APT analysis showed that the uranium phase was not pure uranium but rather a series of unique cocktails of refractory elements that show to stabilize the g-U phase. It thus concluded that the MPEA approach to alloy fuel development can both make a cladding material resistant to chemical interactions with fuels as well as able to produce g-phase uranium alloys.

Subject Added Entry-Topical Term  

Solid solutions.

Subject Added Entry-Topical Term  

Nuclear reactors.

Subject Added Entry-Topical Term  

Uranium.

Subject Added Entry-Topical Term  

Grain boundaries.

Subject Added Entry-Topical Term  

Solvents.

Subject Added Entry-Topical Term  

High temperature.

Subject Added Entry-Topical Term  

Maps.

Subject Added Entry-Topical Term  

Design.

Subject Added Entry-Topical Term  

Stainless steel.

Subject Added Entry-Topical Term  

Intermetallic compounds.

Subject Added Entry-Topical Term  

Research & development--R&D.

Subject Added Entry-Topical Term  

Couples.

Subject Added Entry-Topical Term  

Zirconium alloys.

Subject Added Entry-Topical Term  

Entropy.

Subject Added Entry-Topical Term  

Radiation.

Subject Added Entry-Topical Term  

High temperature physics.

Subject Added Entry-Topical Term  

Nuclear engineering.

Subject Added Entry-Topical Term  

Physics.

Subject Added Entry-Topical Term  

Thermodynamics.

Added Entry-Corporate Name  

North Carolina State University.

Host Item Entry  

Dissertations Abstracts International. 85-05B.

Host Item Entry  

Dissertation Abstract International

Electronic Location and Access  

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Control Number  

joongbu:642925