Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 21

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Primary radiation damage; A Review of current understanding and models

Nordlund, K.*; Zinkle, S. J.*; Sand, A. E.*; Granberg, F.*; Averback, R. S.*; Stoller, R. E.*; Suzudo, Tomoaki; Malerba, L.*; Banhart, F.*; Weber, W. J.*; et al.

Journal of Nuclear Materials, 512, p.450 - 479, 2018/12

 Times Cited Count:271 Percentile:99.52(Materials Science, Multidisciplinary)

Scientific understanding of any kind of radiation effects starts from the primary damage. We consider the extensive experimental and computer simulation studies that have been performed over the past several decades on what the nature of the primary damage is. We review both the production of crystallographic or topological defects in materials as well as radiation mixing, i.e. the process where atoms in perfect crystallographic positions exchange positions with other ones in non-defective positions. We also consider the recent effort to provide alternatives to the current international standard for quantifying this energetic particle damage, the Norgett-Robinson-Torrens displacements per atom (NRT-dpa) model for metals. We present in detail new complementary displacement production estimators ("athermal recombination corrected dpa": arc-dpa) and atomic mixing ("replacements per atom": rpa) functions that extend the NRT-dpa, and discuss their advantages and limitations.

Journal Articles

Improving atomic displacement and replacement calculations with physically realistic damage models

Nordlund, K.*; Zinkle, S. J.*; Sand, A. E.*; Granberg, F.*; Averback, R. S.*; Stoller, R.*; Suzudo, Tomoaki; Malerba, L.*; Banhart, F.*; Weber, W. J.*; et al.

Nature Communications (Internet), 9, p.1084_1 - 1084_8, 2018/03

 Times Cited Count:198 Percentile:98.86(Multidisciplinary Sciences)

Atomic collision processes are fundamental to numerous advanced materials technologies such as electron microscopy, semiconductor processing and nuclear power generation. Experimental and computer simulation studies over the past several decades provide the physical basis for understanding the atomic-scale processes occurring during primary displacement events. The current international standard for quantifying this particle damage, the Norgett-Robinson-Torrens displacements per atom (NRT-dpa) model, has nowadays several well-known limitations. In particular, the number of radiation defects produced in energetic cascades in metals is only $$sim$$1/3 the NRT-dpa prediction, while the number of atoms involved in atomic mixing is about a factor of 30 larger than the dpa value. Here we propose two new complementary displacement production estimators.

Journal Articles

Effect of helium on irradiation creep behavior of B-doped F82H irradiated in HFIR

Ando, Masami; Nozawa, Takashi; Hirose, Takanori; Tanigawa, Hiroyasu; Wakai, Eiichi; Stoller, R. E.*; Myers, J.*

Fusion Science and Technology, 68(3), p.648 - 651, 2015/10

 Times Cited Count:3 Percentile:26.04(Nuclear Science & Technology)

Pressurized tubes of F82H and B-doped F82H irradiated at 573 and 673 K up to $$sim$$6dpa have been measured by a laser profilometer. The irradiation creep strain in F82H irradiated at 573 and 673 K was almost linearly dependent on the effective stress level for stresses below 260 MPa and 170 MPa, respectively. The creep strain of $$^{10}$$BN-F82H was similar to that of F82H IEA at each effective stress level except 294 MPa at 573 K irradiation. For 673 K irradiation, the creep strain of some $$^{10}$$BN-F82H tubes was larger than that of F82H tubes. It is suggested that a swelling caused in each $$^{10}$$BN-F82H because small helium babbles might be produced by a reaction of $$^{10}$$B(n, $$alpha$$) $$^{7}$$Li.

Journal Articles

Primary radiation damage in materials

Nordlund, K.*; Sand, A. E.*; Granberg, F.*; Zinkle, S. J.*; Stoller, R.*; Averback, R. S.*; Suzudo, Tomoaki; Malerba, L.*; Banhart, F.*; Weber, W. J.*; et al.

NEA/NSC/DOC(2015)9 (Internet), 86 Pages, 2015/00

Within this report, we review the current understanding of primary radiation damage from neutrons, ions and electrons with emphasis on the range of validity of the dpa concept in all main classes of materials, and in particular discuss known shortcomings. We recognise that the current NRT-dpa standard is fully valid in the sense of a scaled radiation exposure measure, as it is essentially proportional to the radiation energy deposited per volume. As such, it is highly recommended to be used in reporting neutron damage results to enable comparison between different nuclear reactor environments and ion irradiations. However, in the sense of a measure of damage production the NRT-dpa value has several well-known problems. We discuss this matter and propose an improved dpa definition.

Journal Articles

Physical properties of F82H for fusion blanket design

Hirose, Takanori; Nozawa, Takashi; Stoller, R. E.*; Hamaguchi, Dai; Sakasegawa, Hideo; Tanigawa, Hisashi; Tanigawa, Hiroyasu; Enoeda, Mikio; Kato, Yutai*; Snead, L. L.*

Fusion Engineering and Design, 89(7-8), p.1595 - 1599, 2014/10

 Times Cited Count:41 Percentile:96.55(Nuclear Science & Technology)

The material properties, focusing on the properties used for design analysis were re-assessed and newly investigated for various heats including F82H-IEA. Moreover, irradiation effects on those properties were studied in this work. As for thermal properties, thermal conductivity that has significant impacts on the thermo-hydraulic properties of the blanket was investigated on several heats of F82H including F82H-IEA. According to the measurements, the thermal conductivity falls in the range 28.3$$pm$$1.1 W/m/K at 293 K. Although this is comparable with that of the other ferritic/martensitic steels, it is 20% lower than the published value for F82H-IEA. The re-assessment on the published value revealed that the thermal diffusivity was over-estimated. As for irradiation effects on the physical properties, electric resistivity was measured after irradiation up to 6 dpa at 573 K and 673 K. The reduction of resistivity in F82H and its welds were 3% and 6%, respectively.

Journal Articles

Irradiation response in weldment and HIP joint of reduced activation ferritic/martensitic steel, F82H

Hirose, Takanori; Sokolov, M. A.*; Ando, Masami; Tanigawa, Hiroyasu; Shiba, Kiyoyuki; Stoller, R. E.*; Odette, G. R.*

Journal of Nuclear Materials, 442(1-3), p.S557 - S561, 2013/11

 Times Cited Count:9 Percentile:57.76(Materials Science, Multidisciplinary)

Journal Articles

Annealing simulation of cascade damage in $$alpha$$-Fe; Damage energy and temperature dependence analyses

Suzudo, Tomoaki; Golubov, S. I.*; Stoller, R. E.*; Yamaguchi, Masatake; Tsuru, Tomohito; Kaburaki, Hideo

Journal of Nuclear Materials, 423(1-3), p.40 - 46, 2012/01

 Times Cited Count:8 Percentile:52.71(Materials Science, Multidisciplinary)

In this paper, kinetic Monte Carlo method was applied to investigate the long time evolution of cascade damage prepared by molecular dynamics simulations in $$alpha$$-Fe up to recoil energy of more than 200 keV. We conducted thorough investigation on how the surviving defects vary with cascade damage energy and annealing temperature. The results can be used for input parameters of rate equations to simulate microstructural evolution under irradiation. The study also suggested that neighboring sub-cascades evolves almost independently during annealing, and that the temperature dependence of the annealing results can be explained by the temperature dependence of vacancy-migration and vacancy-dissociation probabilities.

Journal Articles

Irradiation hardening in F82H irradiated at 573 K in the HFIR

Hirose, Takanori; Okubo, Nariaki; Tanigawa, Hiroyasu; Ando, Masami; Sokolov, M. A.*; Stoller, R. E.*; Odette, G. R.*

Journal of Nuclear Materials, 417(1-3), p.108 - 111, 2011/10

 Times Cited Count:16 Percentile:78.97(Materials Science, Multidisciplinary)

This paper summarizes recent results of the irradiation experiments focused on F82H and its modified steels irradiated at 573 K. The materials used in this research were F82H-IEA and its modified steels. Post irradiation mechanical tests revealed that irradiation hardening of F82H is saturated by 9 dpa and the as-irradiated proof stress is less than 1 GPa. The deterioration of total elongation was also saturated by 9 dpa. Irradiation response of F82H-mod3, which is stable to temperature instability during material production and HIP treatment, was very similar to that of F82H-IEA, and negative impacts of extra tantalum was not observed. Therefore it can be an attractive option for the structural materials for blanket components manufactured by HIP.

Journal Articles

Heat treatment effect on fracture toughness of F82H irradiated at HFIR

Okubo, Nariaki; Sokolov, M. A.*; Tanigawa, Hiroyasu; Hirose, Takanori; Jitsukawa, Shiro; Sawai, Tomotsugu; Odette, G. R.*; Stoller, R. E.*

Journal of Nuclear Materials, 417(1-3), p.112 - 114, 2011/10

 Times Cited Count:10 Percentile:61.04(Materials Science, Multidisciplinary)

Irradiation hardening and fracture toughness of reduced-activation ferritic/martensitic steel F82H after irradiation were investigated with a focus on changing the fracture toughness transition temperature as a result of several heat treatments. The specimens were standard F82H-IEA (IEA), F82H-IEA with several heat treatments (Mod1 series) and a higher tantalum containing (0.1%) heat of F82H (Mod3). The specimens were irradiated up to 18 dpa at 300 $$^{circ}$$C in High Flux Isotope Reactor under a collaborative research program between JAEA/US-DOE. The results of hardness tests showed that irradiation hardening of IEA was comparable with that of Mod3. However, the fracture toughness transition temperature of Mod3 was lower than that of IEA. The transition temperature of Mod1 was also lower than that of the IEA heat. These results suggest that tightening of specifications on the heat treatment condition and modification of the minor alloying elements seem to be effective to reduce the fracture toughness transition temperature after irradiation.

Journal Articles

Status and key issues of reduced activation ferritic/martensitic steels as the structural material for a DEMO blanket

Tanigawa, Hiroyasu; Shiba, Kiyoyuki; M$"o$slang, A.*; Stoller, R. E.*; Lindau, R.*; Sokolov, M. A.*; Odette, G. R.*; Kurtz, R. J.*; Jitsukawa, Shiro

Journal of Nuclear Materials, 417(1-3), p.9 - 15, 2011/10

 Times Cited Count:127 Percentile:99.57(Materials Science, Multidisciplinary)

ITER construction was started, and R&D toward DEMO shifted to more practical stage. On this stage, the candidate material for DEMO blanket have to be the one which have sound engineering bases to be ready for engineering designing activity for DEMO reactor in 10 years. Reduced activation ferritic/martensitic (RAFM) steels, such as F82H (Fe-8Cr-2W-0.2V-0.04Ta) or EUROFER97 (Fe-9Cr-1W-0.2V- 0.12Ta), is the only material which currently have enough potential to meet this requirement, and selected as the target material in the R&D on materials engineering for DEMO blanket under the International Fusion Energy Research Centre (IFERC) project in the Broader Approach (BA) activities between EU and Japan. In this paper, current status of RAFM R&D is overviewed especially on fabrication technology, inspection/testing technology, and material database. Overview on irradiation effect study is also provided.

Journal Articles

Irradiation temperature determination of HFIR target capsules using dilatometric analysis of silicon carbide monitors

Hirose, Takanori; Okubo, Nariaki; Tanigawa, Hiroyasu; Kato, Yutai*; Clark, A. M.*; McDuffee, J. L.*; Heatherly, D. W.*; Stoller, R. E.*

DOE/ER-0313/49, p.94 - 99, 2010/12

Journal Articles

Kinetic Monte Carlo annealing simulation of cascade damage in $$alpha$$-Fe

Suzudo, Tomoaki; Golubov, S.*; Stoller, R.*; Yamaguchi, Masatake; Tsuru, Tomohito; Kaburaki, Hideo

Proceedings of Joint International Conference of 7th Supercomputing in Nuclear Application and 3rd Monte Carlo (SNA + MC 2010) (USB Flash Drive), 6 Pages, 2010/10

Molecular dynamics is a useful tool to analyze cascade damage in structural materials of nuclear devices, but the time scale accessible to molecular dynamics is 100 ps. Kinetic Monte Carlo annealing simulation of cascade damage is useful for analyzing the longer time development of cascade damage. We conducted a series of such annealing simulations in $$alpha$$-Fe. The surviving displacement ratio to the NRT displacements before annealing is 0.3 in the case of primary knock-on atom's energy more than 10 keV, but it decreased by 30 % through the annealing at 300 K because of recombination of vacancies and self-interstitial atoms, and the recombination ratio increased as the annealing temperature increased. These results are meaningful when applied to the simulation of accumulation of cascades using rate theory. This work is useful for R&D of nuclear materials.

Journal Articles

Assembly of the US-Japan MFE-RB-15J experiment for irradiation in the HFIR

Hirose, Takanori; Ando, Masami; Tanigawa, Hiroyasu; Okubo, Nariaki; McDuffee, J. L.*; Heatherly, D. W.*; Sitterson, R. G.*; Stoller, R. E.*; Yamamoto, Takuya*

Fusion Materials Semiannual Progress Report (DOE/ER-0313/46) (Internet), p.72 - 78, 2009/06

This work is being carried out under Annex I of the collaboration on Fusion Materials between the U.S. DOE and the Japan Atomic Energy Agency. The MFE-RB-15J capsule is a part of the Phase-V experiments with the goal of elucidating the effects of helium in fusion structural candidate engineering alloys, and verifying the irradiation response of alloy F82H and its joint for ITER-TBM (Test Blanket Module) application. The target dose of this capsule is 6 dpa at the peak and it will introduce 300 appm of transmutation helium in F82H with additional boron-10. Assembly of the MFE-RB-15J capsule was completed on April, 2008. Irradiation began for MFE-RB-15J with cycle 415, starting June 3, 2008. The MFE-RB-15J experiment was installed in location RB-1A with europium thermal neutron shield. A detailed specimen loading list for the capsule is provided in this report.

Journal Articles

Effect of two-steps heat treatments on irradiation hardening in F82H irradiated at 573 K

Ando, Masami; Tanigawa, Hiroyasu; Wakai, Eiichi; Stoller, R. E.*

Journal of Nuclear Materials, 386-388, p.315 - 318, 2009/04

 Times Cited Count:18 Percentile:74.84(Materials Science, Multidisciplinary)

Radiation hardening and embrittlement due to neutron irradiation around 573 K are the important issues on RAF/M steels. It is expected that the improvement of radiation hardening might be one of effective ways to control the mechanical properties after irradiation. The purposes of this study are to find the condition of heat treatment for minimum of radiation hardening in F82H steel using Neutron/Ion-irradiation and to examine a correlation between tensile property and micro-hardness before/after irradiation. Neutron irradiation was performed in HFIR up to 9 dpa. Ion-irradiation at $$sim$$573 K was carried out at the TIARA facility of JAEA. For the results of tensile test and hardness test of F82H and F82H heat treatment variants neutron-irradiated at 573 K, all specimens caused radiation hardening. The radiation hardening ($$Delta$$H) obtained by hardness test is almost same level, however radiation hardening ($$Delta$$YS) of F82H heat treatment variants is smaller than that of F82H.

Journal Articles

Technical issues of reduced activation ferritic/martensitic steels for fabrication of ITER test blanket modules

Tanigawa, Hiroyasu; Hirose, Takanori; Shiba, Kiyoyuki; Kasada, Ryuta*; Wakai, Eiichi; Serizawa, Hisashi*; Kawahito, Yosuke*; Jitsukawa, Shiro; Kimura, Akihiko*; Kono, Yutaka*; et al.

Fusion Engineering and Design, 83(10-12), p.1471 - 1476, 2008/12

 Times Cited Count:78 Percentile:97.75(Nuclear Science & Technology)

Reduced activation ferritic/martensitic steels (RAFMs) are recognized as the primary candidate structural materials for fusion blanket systems. F82H, which were developed and studied in Japan, was designed with an emphasis on high temperature properties and weldability. The database on F82H properties is currently the most extensive available among the existing RAFMs. The objective of this paper is to review the R&D status of F82H and to identify the key technical issues for the fabrication of an ITER Test Blanket Module (TBM) suggested by recent achievements in Japan.

Journal Articles

Irradiation creep behavior of reduced activation ferritic/martensitic steel irradiated in HFIR

Ando, Masami; Tanigawa, Hiroyasu; Shiba, Kiyoyuki; Jitsukawa, Shiro; Kono, Yutaka*; Koyama, Akira*; Li, M.*; Stoller, R. E.*

Nihon Kinzoku Gakkai-Shi, 71(7), p.559 - 562, 2007/07

 Times Cited Count:0 Percentile:0.01(Metallurgy & Metallurgical Engineering)

no abstracts in English

Oral presentation

Correlation between tensile property and micro-hardness with its micro-deformation zone in irradiated Ferritic/Martensitic steels

Ando, Masami; Tanigawa, Hiroyasu; Wakai, Eiichi; Stoller, R.*

no journal, , 

The correlation between tensile property and micro-hardness with its micro-deformation zone in neutron/ion irradiated Ferritic/Martensitic steels was examined. The materials were F82H IEA heat and heat treatment variants. The neutron irradiation was performed in HFIR up to 9 dpa at 573 K. The ion-beam irradiation experiment was also carried out at the TIARA facility. Hardness and tensile test were performed at irradiated specimens. Irradiation hardening occurred by neutron/ion irradiation at $$sim$$573 K about F82H IEA and F82H heat treatment variants. The lowest hardness is an over-tempered F82H specimen before/after irradiation. For result of tensile tests, the increase of yield stress in an over-tempered F82H is less than that of F82H IEA. These results are similar to the tensile properties of TIG weldment irradiated at 573 K. This shows that a condition of heat treatment for smaller radiation hardening in F82H steel was obtained in this experiment.

Oral presentation

Effect of heat treatment on radiation hardening in F82H

Ando, Masami; Tanigawa, Hiroyasu; Wakai, Eiichi; Jitsukawa, Shiro; Koyama, Akira*; Stoller, R.*

no journal, , 

no abstracts in English

Oral presentation

Effect of tempering condition on radiation hardening of F82H steel irradiated in HFIR

Ando, Masami; Tanigawa, Hiroyasu; Wakai, Eiichi; Hirose, Takanori; Stoller, R.*

no journal, , 

no abstracts in English

Oral presentation

Microstructure evolution in pressurized creep tube specimens of neutron-irradiated ferritic/martensitic steels

Ando, Masami; Tanigawa, Hiroyasu; Li, M.*; Nakata, Toshiya; Stoller, R.*; Kono, Yutaka*

no journal, , 

Irradiation creep of RAF/M steels has been recognized as one of the most important properties for engineering data due to the ITER test blanket structural design. The objective of this work is to examine an irradiation creep mechanism by using a microstructural observation in pressurized tubes of irradiated F82H and JLF-1. Irradiation was performed in the HFIR up to 5 dpa at 573 and 773 K. A small piece was cut from the center of each irradiated tube after diametral measurement. The microstructural examination with FIBed samples and replica films was carried out using a TEM. The creep strain for all steels at 573 and 773 K shows linear dependence on the applied hoop stress up to $$sim$$250 MPa and $$sim$$100 MPa, respectively. As results of extraction replica samples irradiated at 573 K, finer spherical precipitations were observed in highest hoop stress level. The detailed discussion will be presented along with the results of microstructure observation for irradiated specimens.

Oral presentation

Cascade damage annealing analyses using kinetic Monte Carlo method

Suzudo, Tomoaki; Yamaguchi, Masatake; Tsuru, Tomohito; Hamaguchi, Dai; Golubov, S.*; Stoller, R.*

no journal, , 

Cascade displacements in structural nuclear materials cannot be observed by experimental methods, and molecular dynamics (MD) is the only tool to investigate such a phenomenon. Nevertheless, time length MD can follow is 100 ps, and MD is not available for the long-term analysis of radiation damage. Thus the application of kinetic Monte Carlo method to annealing simulations starting from the results given by cascade damage MD simulations is of importance. Recently the understanding of the migration of self-interstitial atom cluster were newly established, and we reevaluated the annealing behavior using the new theory. The results indicated that the radiation damage in Fe is overestimated in the past study. This work is useful for the R&D of nuclear materials.

21 (Records 1-20 displayed on this page)