東華大學圖書館 |

Language: English

Help

回圖書館首頁

手機版館藏查詢

Back

Switch To: Labeled | MARC Mode | ISBD

Synergistic Effects of High Particle...

Sinclair, Gregory Poppy.

Linked to FindBook

Google Book

Amazon

博客來

Synergistic Effects of High Particle Fluxes and Transient Heat Loading on Material Performance in a Fusion Environment.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Synergistic Effects of High Particle Fluxes and Transient Heat Loading on Material Performance in a Fusion Environment./
Author:	Sinclair, Gregory Poppy.
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 2018,
Description:	194 p.
Notes:	Source: Dissertations Abstracts International, Volume: 79-12, Section: B.
Contained By:	Dissertations Abstracts International79-12B.
Subject:	Nuclear engineering. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10790815
ISBN:	9780438017818

Synergistic Effects of High Particle Fluxes and Transient Heat Loading on Material Performance in a Fusion Environment.
Sinclair, Gregory Poppy.

Synergistic Effects of High Particle Fluxes and Transient Heat Loading on Material Performance in a Fusion Environment. - Ann Arbor : ProQuest Dissertations & Theses, 2018 - 194 p.

Source: Dissertations Abstracts International, Volume: 79-12, Section: B.

Thesis (Ph.D.)--Purdue University, 2018.

This item is not available from ProQuest Dissertations & Theses.

The work presented in this thesis focuses on the thermal and structural evolution of different materials when exposed to both high-flux ion irradiation and high intensity pulsed heat loading. Nuclear fusion devices create an intense radiation environment consisting of very energetic deuterium (D+) and helium (He+) ions. During operation, off-normal plasma events, such as edge-localized modes (ELMs), could cause intense heating of the plasma-facing component (PFC) surface, leading to melting and possible splashing into the fusion plasma. High-Z, refractory metals, such as tungsten (W), are therefore seen as favorable, due to their high melting point, high thermal conductivity, and low sputtering yield. However, potential splashing of the molten wall could contaminate the plasma and shut down the reactor. High-flux He+ wall loading could further exacerbate melting and splashing of the PFC surface, due to the growth of fiber form nanostructures, called fuzz, which possess a much lower mechanical and thermal strength than that of a pristine surface. Experiments performed throughout the dissertation attempt to qualify the effect of He+-induced surface structuring on the PFC thermal response during type-I ELMs. Elementary surface characterization revealed that He+ loading blurs clear melting and droplet emission thresholds observed on pristine surfaces during ELM-like heat loading, inducing thermal damage gradually through localized melting and conglomeration of fuzz tendrils. The reduced thermal conductivity of fuzz nanostructures led to increased levels of erosion due to fragmentation of molten material. Decreasing the imparted heat flux, at the sacrifice of higher frequencies, through ELM mitigation techniques showed the potential for an intermediate operating window that could heal fuzz nanostructures via annealing without the onset of splashing. Tests on transversally-oriented W microstructures (which will be used in ITER) revealed that radiation hardening along grain boundaries due to high-flux He+ loading may preferentially enhance brittle failure. Differences in penetration depth between experimental heat loading methods (millisecond laser vs. electron beam) affected heat deposition in and plasticity of the damaged surface. Simultaneous He+ particle loading and ELM-like heat loading inhibited fuzz formation due to repetitive shock-induced conglomeration. The addition of D+ ion irradiation appeared to further reduce evidence of early-stage fuzz formation, due to super-saturation of D in the near-surface layer. Significant structuring due to D+ particle loading may diminish the impact of ELM intensity on surface roughening and melting. Future studies need to expand upon the surface analysis presented throughout this dissertation and investigate the details of the subsurface to determine how intense thermal loading impacts gas trapping and migration. In addition, future PFC erosion research must utilize highly sensitive, in situ measurement techniques to obtain reliable information on material lifetime and performance.

ISBN: 9780438017818Subjects--Topical Terms:

595435
Nuclear engineering.

Synergistic Effects of High Particle Fluxes and Transient Heat Loading on Material Performance in a Fusion Environment.
LDR:04285nmm a2200349 4500 001 2207922
005 20190929184012.5
008 201008s2018 ||||||||||||||||| ||eng d
020 $a 9780438017818
035 $a (MiAaPQ)AAI10790815
035 $a (MiAaPQ)purdue:22472
035 $a AAI10790815
040 $a MiAaPQ $c MiAaPQ
100 1 $a Sinclair, Gregory Poppy. $3 3434921
245 1 0 $a Synergistic Effects of High Particle Fluxes and Transient Heat Loading on Material Performance in a Fusion Environment.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2018
300 $a 194 p.
500 $a Source: Dissertations Abstracts International, Volume: 79-12, Section: B.
500 $a Publisher info.: Dissertation/Thesis.
500 $a Advisor: Hassanein, Ahmed.
502 $a Thesis (Ph.D.)--Purdue University, 2018.
506 $a This item is not available from ProQuest Dissertations & Theses.
506 $a This item must not be sold to any third party vendors.
520 $a The work presented in this thesis focuses on the thermal and structural evolution of different materials when exposed to both high-flux ion irradiation and high intensity pulsed heat loading. Nuclear fusion devices create an intense radiation environment consisting of very energetic deuterium (D+) and helium (He+) ions. During operation, off-normal plasma events, such as edge-localized modes (ELMs), could cause intense heating of the plasma-facing component (PFC) surface, leading to melting and possible splashing into the fusion plasma. High-Z, refractory metals, such as tungsten (W), are therefore seen as favorable, due to their high melting point, high thermal conductivity, and low sputtering yield. However, potential splashing of the molten wall could contaminate the plasma and shut down the reactor. High-flux He+ wall loading could further exacerbate melting and splashing of the PFC surface, due to the growth of fiber form nanostructures, called fuzz, which possess a much lower mechanical and thermal strength than that of a pristine surface. Experiments performed throughout the dissertation attempt to qualify the effect of He+-induced surface structuring on the PFC thermal response during type-I ELMs. Elementary surface characterization revealed that He+ loading blurs clear melting and droplet emission thresholds observed on pristine surfaces during ELM-like heat loading, inducing thermal damage gradually through localized melting and conglomeration of fuzz tendrils. The reduced thermal conductivity of fuzz nanostructures led to increased levels of erosion due to fragmentation of molten material. Decreasing the imparted heat flux, at the sacrifice of higher frequencies, through ELM mitigation techniques showed the potential for an intermediate operating window that could heal fuzz nanostructures via annealing without the onset of splashing. Tests on transversally-oriented W microstructures (which will be used in ITER) revealed that radiation hardening along grain boundaries due to high-flux He+ loading may preferentially enhance brittle failure. Differences in penetration depth between experimental heat loading methods (millisecond laser vs. electron beam) affected heat deposition in and plasticity of the damaged surface. Simultaneous He+ particle loading and ELM-like heat loading inhibited fuzz formation due to repetitive shock-induced conglomeration. The addition of D+ ion irradiation appeared to further reduce evidence of early-stage fuzz formation, due to super-saturation of D in the near-surface layer. Significant structuring due to D+ particle loading may diminish the impact of ELM intensity on surface roughening and melting. Future studies need to expand upon the surface analysis presented throughout this dissertation and investigate the details of the subsurface to determine how intense thermal loading impacts gas trapping and migration. In addition, future PFC erosion research must utilize highly sensitive, in situ measurement techniques to obtain reliable information on material lifetime and performance.
590 $a School code: 0183.
650 4 $a Nuclear engineering. $3 595435
650 4 $a Plasma physics. $3 3175417
650 4 $a Materials science. $3 543314
690 $a 0552
690 $a 0759
690 $a 0794
710 2 $a Purdue University. $b Nuclear Engineering. $3 1282431
773 0 $t Dissertations Abstracts International $g 79-12B.
790 $a 0183
791 $a Ph.D.
792 $a 2018
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10790815