|"A Challenge to Multivariate Statistical Analysis: Spent Nuclear Fuel" Philip Edmondson, Tyler Gerczak, Chad Parish, Kurt Terrani, Microscopy & Microanalysis Vol. 22 2016 Link|
|"A combined APT and SANS investigation of a' phase precipitation in neutron-irradiated model FeCrAl alloys" Philip Edmondson, Kevin Field, Kumar Sridharan, Kurt Terrani, Samuel A. Briggs, Kenneth Littrell, Yukinori Yamamoto, Richard Howard, Charles Daily, Acta Materialia Vol. 129 2017 217-228 Link|
|"An Atom Probe Tomography Study of the Through Wall Attenuation Effect on Cu-rich Precipitate Formation in a Reactor Pressure Vessel Steel" Philip Edmondson, Caleb Massey, Mikhail Sokolov, Thomas Rosseel, Journal of Nuclear Materials Vol. 543 2021 Link|
|"Applications of Combined Transmission Kikuchi Diffraction and STEM-SDD X-Ray Analysis in Irradiated Materials" Chad Parish, Kun Wang, Philip Edmondson, David Hoelzer, Microscopy and Microanalysis Vol. 24 2018 736-737 Link|
"Characterisation of the spatial variability of material properties of Gilsocarbon and NBG-18 using random fields"
Jose Arregui-Mena, Philip Edmondson, Lee Margetts, DV Griffiths, William Windes, Mark Carroll, Paul Mummery,
Journal of Nuclear Materials
Graphite is a candidate material for Generation IV concepts and is used as a moderator in Advanced Gascooled Reactors (AGR) in the UK. Spatial material variability is present within billets causing different material property values between different components. Variations in material properties and irradiation effects can produce stress concentrations and diverse mechanical responses in a nuclear reactor graphite core. In order to characterise the material variability, geostatistical techniques called variography and random field theory were adapted for studying the density and Young's modulus of a billet of Gilsocarbon and NBG-18 graphite grades. Variography is a technique for estimating the distance over which material property values have significant spatial correlation, known as the scale of fluctuation or spatial correlation length. The paper uses random field theory to create models that mimic the original spatial and statistical distributions of the original data set. This study found different values of correlation length for density and Young's modulus around the edges of a Gilsocarbon billet, while in the case of NBG-18, similar correlation lengths where found across the billet. Examples of several random fields are given to reproduce the spatial patterns and values found in the original data.
|"Combining Transmission Kikuchi Diffraction and Scanning Transmission Electron Microscopy for Irradiated Materials Studies" Philip Edmondson, Chad Parish, Kurt Terrani, Kun Wang, Xunxiang Hu, Rachel Seibert, Yutai Katoh, Microscopy & Microanalysis Vol. 23 2017 2218-2219 Link|
|"Complementary Techniques for Quantification of a' Phase Precipitation in Neutron-Irradiated Fe-Cr-Al Model Alloys" Samuel A. Briggs, Philip Edmondson, Kevin Field, Kumar Sridharan, Yukinori Yamamoto, Kenneth Littrell, Charles Daily, Microscopy & Microanalysis Vol. 22 2016 1470-1471 Link|
|"Corrigendum to “Atom probe tomography characterization of neutron irradiated surveillance samples from the R.E. Ginna reactor pressure vessel”" Philip Edmondson, Journal of Nuclear Materials Vol. 489 2017 236-237 Link|
|"Dependencies of a' embrittlement in neutron-irradiated model Fe-Cr-Al alloys" Samuel A. Briggs, Philip Edmondson, Kevin Field, Kumar Sridharan, ANS Transactions Vol. 114 2016 1046-1047 Link|
"Development of mesopores in superfine grain graphite neutronirradiated at high fluence"
Cristian Contescu, Jose Arregui-Mena, Philip Edmondson,
Microstructural changes induced by neutron irradiation of superfine grain graphite G347A (Tokai Carbon, Japan) were examined by nitrogen adsorption at 77 K and by three microscopy techniques (SEM, TEM and FIB-SEM tomography). The specimens were irradiated at doses of up to 30 dpa, covering stages before and after the turnaround fluence at three temperatures (300, 450, 750 C) of their irradiation envelope. The initial graphite densification at low fluences did not produce any detectable effect in the pore size range (<350 nm) measured by gas adsorption. However, graphite irradiated at high fluences, after turnaround, showed severe structural changes. At all three temperatures and high irradiation fluences, gas adsorption revealed significant increase of the volume of narrow mesopores (<5e20 nm) and up to five times increase of BET surface area, both in linear relationship with the relative volume expansion. Analysis of microscopy images showed multiplication of fine macropores (>50 nm) at high irradiation fluences and more structural changes on multiple scales, from nanometers to microns. This work demonstrates the unique ability of gas adsorption techniques to analyze open pores with sizes between sub-nanometer and sub-micron in bulk nuclear graphite, with supporting microscopy results.
"Development of mesopores in superfine grain graphite neutron-irradiated at high fluence"
Cristian Contescu, Jose Arregui-Mena, Anne Campbell, Philip Edmondson,
Microstructural changes induced by neutron irradiation of superfine grain graphite G347A (Tokai Carbon, Japan) were examined by nitrogen adsorption at 77 K and by three microscopy techniques (SEM, TEM and FIB-SEM tomography). The specimens were irradiated at doses of up to 30 dpa, covering stages before and after the turnaround fluence at three temperatures (300, 450, 750 °C) of their irradiation envelope. The initial graphite densification at low fluences did not produce any detectable effect in the pore size range (<350 nm) measured by gas adsorption. However, graphite irradiated at high fluences, after turnaround, showed severe structural changes. At all three temperatures and high irradiation fluences, gas adsorption revealed significant increase of the volume of narrow mesopores (<5–20 nm) and up to five times increase of BET surface area, both in linear relationship with the relative volume expansion. Analysis of microscopy images showed multiplication of fine macropores (>50 nm) at high irradiation fluences and more structural changes on multiple scales, from nanometers to microns. This work demonstrates the unique ability of gas adsorption techniques to analyze open pores with sizes between sub-nanometer and sub-micron in bulk nuclear graphite, with supporting microscopy results.
"Dislocation loop evolution during in-situ ion irradiation of model FeCrAl alloys"
Philip Edmondson, Kevin Field, Jack Haley, Steve Roberts, Kumar Sridharan, Samuel A. Briggs, Sergio Lozano-Perez,
Model FeCrAl alloys of Fe-10%Cr-5%Al, Fe-12%Cr-4.5%Al, Fe-15%Cr-4%Al, and Fe-18%Cr-3%Al (in wt %) were irradiated with 1 MeV Kr++ ions in-situ with transmission electron microscopy to a dose of 2.5 displacements per atom (dpa) at 320 °C. In all cases, the microstructural damage consisted of dislocation loops with ½<111> and <100> Burgers vectors. The proportion of ½<111> dislocation loops varied from ~50% in the Fe-10%Cr-5%Al model alloy and the Fe-18Cr%-3%Al model alloy to a peak of ~80% in the model Fe-15%Cr-4.5%Al alloy. The dislocation loop volume density increased with dose for all alloys and showed signs of approaching an upper limit. The total loop populations at 2.5 dpa had a slight (and possibly insignificant) decline as the chromium content was increased from 10 to 15 wt %, but the Fe-18%Cr-3%Al alloy had a dislocation loop population ~50% smaller than the other model alloys. The largest dislocation loops in each alloy had image sizes of close to 20 nm in the micrographs, and the median diameters for all alloys ranged from 6 to 8 nm. Nature analysis by the inside-outside method indicated most dislocation loops were interstitial type.
|"Energetic particle irradiation study of TiN coatings: are these films appropriate for accident tolerant fuels?" Philip Edmondson, Journal of Nuclear Materials Vol. 512 2018 239-245 Link|
|"Influence of mechanical alloying and extrusion conditions on the microstructure and tensile properties of Low-Cr ODS FeCrAl alloys" Caleb Massey, Sebastien Dryepondt, Philip Edmondson, Kurt Terrani, Steven Zinkle, Journal of Nuclear Materials Vol. 512 2018 227-238 Link|
"Irradiation-enhanced a' precipitation in model FeCrAl alloys"
Philip Edmondson, Kevin Field, Kumar Sridharan, Samuel A. Briggs, Yukinori Yamamoto, Richard Howard, Kurt Terrani,
Model FeCrAl alloys with varying compositions (Fe(10–18)Cr(10–6)Al at.%) have been neutron irradiated at ~ 320 to damage levels of ~ 7 displacements per atom (dpa) to investigate the compositional influence on the formation of irradiation-induced Cr-rich a' precipitates using atom probe tomography. In all alloys, significant number densities of these precipitates were observed. Cluster compositions were investigated and it was found that the average cluster Cr content ranged between 51.1 and 62.5 at.% dependent on initial compositions. This is significantly lower than the Cr-content of a' in binary FeCr alloys. Significant partitioning of the Al from the a' precipitates was also observed.
|"Nitrogen adsorption data,FIB-SEM tomography and TEM micrographs of neutron-irradiated superfine graingraphite" Jose Arregui-Mena, Cristian Contescu, Philip Edmondson, Data in brief Vol. 21 2018 2643-2650|
|"Phase instabilities in austenitic steels during particle bombardment at high and low dose rates" Samara Levine, C. Pareige, Philip Edmondson, Gary Was, Steven Zinkle, Arunodaya Bhattacharya, Materials & Design Vol. 217 2022 Link|
|"Phase stability of single phase Al0.12CrNiFeCo high entropy alloy upon irradiation" Boopathy Kombaiah, Philip Edmondson, Yanliang Zhang, Materials & Design Vol. 160 2018 1208-1216 Link|
|"Post irradiation examination of nanoprecipitate stability and α′ precipitation in an oxide dispersion strengthened Fe-12Cr-5Al alloy" Caleb Massey, Philip Edmondson, Kevin Field, David Hoelzer, Kurt Terrani, Steven Zinkle, Scripta Materialia Vol. 162 2018 94-98 Link|
|"Probing the Damage Recovery Mechanism in Irradiated Stainless Steels Using In-Situ Microcantilever Bending Test" Keyou Mao, Hao Wang, Haozheng Qu, Kayla Yano, Philip Edmondson, Cheng Sun, Janelle Wharry, Frontiers in Materials Vol. 2022 Link|
"Restructuring in high burnup UO2 studied using modern electron microscopy"
Tyler Gerczak, Chad Parish, Philip Edmondson, Kurt Terrani,
Journal of Nuclear Materials
Modern electron microscopy techniques were used to conduct a thorough study of an irradiated urania fuel pellet microstructure to attempt at an understanding of high burnup structure formation in this material. The fuel was irradiated at low power to high burnups in a light water reactor, proving ideal for this purpose. Examination of grain size and orientation with strict spatial selectivity across the fuel pellet radius allowed for capturing the progression of the restructuring process, from its onset to full completion. Based on this information, the polygonization mechanism was shown to be responsible for restructuring, involving formation of low-angle grain boundaries with their initiation occurring at the original high-angle grain boundaries of the as-fabricated pellet and at the gas bubble-matrix interfaces. The low-angle character of boundaries between the subdivided grains disappeared in the fully developed high burnup structure, likely due to creep deformation in the pellet.
"Thermodynamic and kinetic modeling of Mn-Ni-Si precipitates in low-Cu reactor pressure vessel steels"
Nathan Almirall, Philip Edmondson, G. Robert Odette, Peter Wells, Huibin Ke, Leland Barnard, Dane Morgan,
Formation of large volume fractions of Mn-Ni-Si precipitates (MNSPs) causes excess irradiation embrittlement of reactor pressure vessel (RPV) steels at high, extended-life fluences. Thus, a new and unique, semi-empirical cluster dynamics model was developed to study the evolution of MNSPs in low-Cu RPV steels. The model is based on CALPHAD thermodynamics and radiation enhanced diffusion kinetics. The thermodynamics dictates the compositional and temperature dependence of the free energy reductions that drive precipitation. The model treats both homogeneous and heterogeneous nucleation, where the latter occurs on cascade damage, like dislocation loops. The model has only four adjustable parameters that were fit to an atom probe tomography (APT) database. The model predictions are in semi-quantitative agreement with systematic Mn, Ni and Si composition variations in alloys characterized by APT, including a sensitivity to local tip-to-tip variations even in the same steel. The model predicts that heterogeneous nucleation plays a critical role in MNSP formation in lower alloy Ni contents. Single variable assessments of compositional effects show that Ni plays a dominant role, while even small variations in irradiation temperature can have a large effect on the MNSP evolution. Within typical RPV steel ranges, Mn and Si have smaller effects. The delayed but then rapid growth of MNSPs to large volume fractions at high fluence is well predicted by the model. For purposes of illustration, the effect of MNSPs on transition temperature shifts are presented based on well-established microstructure-property and property-property models.
"Using complimentary microscopy methods to examine Ni-Mn-Si-precipitates in highly-irradiated reactor pressure vessel steels"
Philip Edmondson, Chad Parish,
Nano-scale Ni-Mn-Si-rich precipitates formed in a reactor pressure vessel steel under high neutron fluence have been characterized using highly complimentary atom probe tomography (APT) and scanning transmission electron microscopy with energy dispersive spectroscopy (STEM-EDS) combined with STEM-EDS modeling. Using these techniques in a synergistic manner to overcome the well-known trajectory aberrations in APT data, the average upper limit Fe concentration within the precipitates was found to be ~6 at.%. Using this knowledge, accurate compositions of the precipitates was determined and it was found that the spread of precipitate compositions was large, but mostly centered around the G2-and G-phases. The use of STEM-EDS also allowed for larger areas to be examined, and segregation of minor solutes was observed to occur on grain boundaries, along with Ni-Mn-Si-rich precipitates that were smaller in size than those in the matrix. Solute segregation at the grain boundaries is proposed to occur through a radiation induced segregation or radiation enhanced diffusion mechanism due to the presence of a denuded zone about the grain boundary. It is also proposed that the reduced precipitate size at the grain boundaries is due to the structure of the grain boundary. The lack of Ni-Mn-Si precipitates observed in larger Mo-rich precipitates is also discussed, and the absence of the minor solutes required to form the Ni-Mn-Si precipitates results in the lack of nucleation. This is in contrast to cementite phases in which Ni-Mn-Si precipitates have been observed to have formed. It was also determined through this work that the exclusion of all the Fe ions during atom probe analysis is a reasonable approximation.
"Viewpoint: Nanoscale chemistry and crystallography are both the obstacle and pathway to advanced radiation-tolerant materials"
Philip Edmondson, Chad Parish, Kun Wang,
New candidate materials for GenIV or fusion nuclear energy systems, e.g., nanostructured ferritic alloys, are distinguished from older-generation nuclear materials by much smaller feature sizes and complex local nanochemistry and crystallography. Established and perspective nuclear materials, e.g. reactor pressure vessel steels or plasma-facing tungsten, also form small nanoscale structures under in-reactor service. Here, we discuss recent advances in materials characterization – high-efficiency X-ray mapping combined with datamining; transmission Kikuchi diffraction; and atom probe tomography – that make it possible to quantitatively characterize these nanoscale structures in unprecedented detail, which enables advances in understanding and modelling of radiation service and degradation.
|"Complementary techniques for quantification of a' phase precipitation in neutron-irradiated Fe-Cr-Al model alloys" Philip Edmondson, Kevin Field, Kumar Sridharan, Microscopy & Microanalysis 2016 July 24-28, (2016) Link|
|"Dependencies of a' Embrittlement in Neutron-Irradiated Model Fe-Cr-Al Alloys" Philip Edmondson, Kevin Field, Kumar Sridharan, 2016 ANS Annual Meeting June 12-16, (2016) Link|
|"Hydride Microstructure at the Metal-Oxide Interface of a Zircaloy-4 Fuel Clad from the H. B. Robinson Nuclear Reactor" Mahmut Cinbiz, Philip Edmondson, Kurt Terrani, American Nuclear Society June 11-15, (2017) Link|
|"Hydride Microstructure at the Metal-Oxide Interface of a Zircaloy-4 Fuel Clad from the H.B. Robinson Nuclear Reactor" Mahmut Cinbiz, Philip Edmondson, Kurt Terrani, 2017 ANS Annual Meeting June 11-15, (2017)|
|"Microstructural characterization of nuclear graphite: from microscale to nanoscale" Jose Arregui-Mena, Cristian Contescu, Philip Edmondson, ORPA Research Symposium August 8-8, (2018)|
|"Neutron irradiation effects on the microstructure of nuclear graphite" Jose Arregui-Mena, Benjamin Maerz, Cristian Contescu, Anne Campbell, Philip Edmondson, Yutai Katoh, NuMat 2018 October 14-18, (2018)|
|"Radiation Effects in Binary Carbides" Karl Whittle, Philip Edmondson, MRS 2018 November 25-30, (2018)|
|"Radiation Effects in Binary Carbides" Karl Whittle, Philip Edmondson, MS&T 2018 October 14-18, (2018)|
|U.S. DOE Nuclear Science User Facilities Awards 35 Rapid Turnaround Experiment Research Proposals - Awards total approximately $1.3 million These projects will continue to advance the understanding of irradiation effects in nuclear fuels and materials in support of the mission of the DOE Office of Nuclear Energy. Wednesday, September 20, 2017 - Calls and Awards|
|DOE Awards 33 Rapid Turnaround Experiment Research Proposals - Projects total approximately $1.2 million These projects will continue to advance the understanding of irradiation effects in nuclear fuels and materials in support of the mission of the DOE Office of Nuclear Energy. Monday, June 18, 2018 - Calls and Awards|
|RTE 1st Call Awards Announced - Projects total approximately $1.4 million These projects will continue to advance the understanding of irradiation effects in nuclear fuels and materials in support of the mission of the DOE-NE. Friday, February 8, 2019 - Calls and Awards|
|DOE Awards 37 RTE Proposals - Awarded projects total nearly $1.4M in access awards Tuesday, July 14, 2020 - News Release, Calls and Awards|
This NSUF Profile is 50
Top 5% of all NSUF-supported publication authors
Presented an NSUF-supported publication
Submitted 3+ RTE Proposals to NSUF
Top 5% of all RTE Proposals awarded
Top 5% of all RTE Proposal collaborations
Reviewed an RTE Proposal
Atom probe tomography evaluation of irradiated and annealed RPV surveillance specimens from the R. E. Ginna reactor - FY 2015 RTE 2nd Call, #565
In situ amorphization studies of forsterite, diopside and quartz under ion irradiation - FY 2017 RTE 3rd Call, #1090
Micro-structural and -chemical Investigations of the Short-Term Annealing of Irradiation-Induced Late Blooming Phase Precipitates in a High-Ni Reactor Pressure Vessel Steel Weld - FY 2017 RTE 1st Call, #782
TEM Characterization of Highly Irradiated Stainless Steel - FY 2019 RTE 1st Call, #1695
Understanding the effect of neutron attenuation on Cu-rich precipitate formation in reactor pressure vessel steels using STEM-EDS - FY 2020 RTE 2nd Call, #4189
Understanding the local atomic structure in variable composition, irradiated perovskites - FY 2018 RTE 3rd Call, #1584
3D Microstructural Assessment of Irradiated and Control U-10Zr Fuels - FY 2018 RTE 3rd Call, #1590
BET and TEM characterization of nuclear graphite irradiated at temperatures below 230°C - FY 2019 RTE 2nd Call, #1773
EBSD characterization of neutron irradiated mineral concrete aggregates - FY 2019 RTE 1st Call, #1693
Effects of Welding on Radiation-Enhanced Precipitation in FeCrAl Alloys - FY 2018 RTE 2nd Call, #1441
Hydride Microstructure at the Metal-Oxide Interface of Zircaloy-4 from H.B. Robinson Nuclear Reactor - FY 2017 RTE 1st Call, #840
Hydrogen Analysis and Oxide Characterization of Reactor Irradiated Zr-Nb Alloy - FY 2017 RTE 2nd Call, #955
In situ TEM Study of the Ion Irradiation Damage on Hydrides in a Zirconium Alloy for Nuclear Fuel Cladding - FY 2017 RTE 2nd Call, #974
In Situ Transmission Electron Microscopy Study of Radiation Damage Effects on the d-Hydride Microstructure in Irradiated Zircaloy-4 - FY 2017 RTE 3rd Call, #1099
In-situ irradiation study of carbides/nitrides/carbo-nitrides in additively manufactured ferritic-martensitic steels. - FY 2019 RTE 1st Call, #1694
Interfacial Effects, Damage and Recovery in Binary Carbides - FY 2018 RTE 1st Call, #1277
Investigation of the effects of neutron irradiation on minerals of concrete aggregates - FY 2020 RTE 2nd Call, #4206
Investigation of the irradiation induced porosity in concrete aggregates with x-ray computed tomography and helium pycnometry - FY 2019 RTE 3rd Call, #2904
Mechanical property and microstructural characterization of irradiated stainless steel via in situ SEM-EBSD mechanical testing. - FY 2019 RTE 1st Call, #1698
Microstructural characterization of neutron irradiated C-C composites - FY 2023 RTE 1st Call, #4600
Micro-structural investigation of the pore structure of uncrept and crept irradiated PCEA graphite specimens with SEM and FIB tomography - FY 2018 RTE 3rd Call, #1596
Nano-precipitate Response to Neutron Irradiation in Model ODS FeCrAl Alloy 125YF - FY 2017 RTE 2nd Call, #961
Nano-precipitate Stability and a'-Precipitation in ODS and Wrought FeCrAl Alloys - FY 2019 RTE 2nd Call, #1747
Parametric study of factors affecting precipitation in model FeCrAl alloys - FY 2016 RTE 3rd Call, #687
Study of nanocluster stability in neutron- and ion-irradiated ODS FeCrAl alloys - FY 2017 RTE 2nd Call, #954
TEM investigation of irradiation, irradiation creep and thermal annealing effects in nuclear graphite - FY 2018 RTE 2nd Call, #1495