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Soba, A.*; Prudil, A.*; Zhang, J.*; Dethioux, A.*; Han, Z.*; Dostal, M.*; Matocha, V.*; Marelle, V.*; Lasnel-Payan, J.*; Kulacsy, K.*; et al.
Proceedings of TopFuel 2021 (Internet), 10 Pages, 2021/10
Singh, B.*; Basunia, M. S.*; Martin, M.*; McCutchan, E. A.*; Bara, I.*; Caballero-Folch, R.*; Canavan, R.*; Chakrabarti, R.*; Chekhovska, A.*; Grinder, M. M.*; et al.
Nuclear Data Sheets, 160, p.405 - 471, 2019/09
Times Cited Count:6 Percentile:68.96(Physics, Nuclear)Martin, P. G.*; Louvel, M.*; Cipiccia, S.*; Jones, C. P.*; Batey, D. J.*; Hallam, K. R.*; Yang, I. A. X.*; Satou, Yukihiko; Rau, C.*; Mosselmans, J. F. W.*; et al.
Nature Communications (Internet), 10, p.2801_1 - 2801_7, 2019/06
Times Cited Count:24 Percentile:78.39(Multidisciplinary Sciences)Synchrotron radiation (SR) analysis techniques alongside secondary ion mass spectrometry (SIMS) measurements have been made on sub-mm particulate material derived from reactor Unit 1 of the Fukushima Daiichi Nuclear Power Plant (FDNPP). Using these methods, it has been possible to investigate the distribution, state and isotopic composition of micron-scale U particulate contained within the larger Si-based ejecta material. Through combined SR micro-focused X-ray fluorescence (SR-micro-XRF) and absorption contrast SR micro-focused X-ray tomography (SR-micro-XRT), the U particulate was found to be located around the exterior circumference of the highly-porous particle. Synchrotron radiation micro-focused X-ray absorption near edge structure (SR-micro-XANES) analysis of a number of these entrapped particles revealed them to exist within the U(IV) oxidation state, as UO, and identical in structure to reactor fuel. Confirmation that this U was of nuclear origin (U-enriched) was provided through secondary ion mass spectrometry (SIMS) analysis with an isotopic enrichment ratio characteristic of a provenance from reactor Unit 1 at the FDNPP. These results provide clear evidence of the event scenario (that a degree of core fragmentation and release occurred from reactor Unit 1), with such spent fuel ejecta existing; (i) within the stable U(IV) oxidation state; and (ii) contained within a bulk Si-based particle. While this U is unlikely to represent an environmental or health hazard, such assertions would likely change, however, should break-up of the Si-containing bulk particle occur. However, more important to the long-term decommissioning of the reactors (and clean-up) on the FDNPP, is the knowledge that core integrity of reactor Unit 1 was compromised with nuclear material existing outside of the reactors primary containment.
Dostl, M.*; Rossiter, G.*; Dethioux, A.*; Zhang, J.*; Amaya, Masaki; Rozzia, D.*; Williamson, R.*; Kozlowski, T.*; Hill, I.*; Martin, J.-F.*
Proceedings of Annual Topical Meeting on Reactor Fuel Performance (TopFuel 2018) (Internet), 10 Pages, 2018/10
Kim, S. B.*; Zhang, Y.*; Won, S. M.*; Bandodkar, A. J.*; Sekine, Yurina; Xue, Y.*; Koo, J.*; Harshman, S. W.*; Martin, J. A.*; Park, J. M.*; et al.
Small, 14(12), p.1703334_1 - 1703334_11, 2018/03
Times Cited Count:86 Percentile:95.48(Chemistry, Multidisciplinary)Matthi, D.*; Ehresmann, B.*; Lohf, H.*; Khler, J.*; Zeitlin, C.*; Appel, J.*; Sato, Tatsuhiko; Slaba, T. C.*; Martin, C.*; Berger, T.*; et al.
Journal of Space Weather and Space Climate (Internet), 6, p.A13_1 - A13_17, 2016/03
Times Cited Count:60 Percentile:93.45(Astronomy & Astrophysics)The Radiation Assessment Detector (RAD) on the Mars Science Laboratory (MSL) has been measuring the radiation environment on the surface of Mars since August 6th 2012. In this work, several models such as GEANT4, PHITS, and HZETRN/OLTARIS are used to predict the radiation environment caused by galactic cosmic rays on Mars in order to compare and validate them with the experimental results. Although good agreement is found in many cases for GEANT4, PHITS and HZETRN/OLTARIS, some models still show large, sometimes order of magnitude, discrepancies in certain particle spectra. We have found that RAD data is helping make better choices of input parameters and physical models. These results help to predict dose rates for future manned missions as well as to perform shield optimization studies.
Soler, J. M.*; Landa, J.*; Havlov, V.*; Tachi, Yukio; Ebina, Takanori*; Sardini, P.*; Siitari-Kauppi, M.*; Eikenberg, J.*; Martin, A. J.*
Journal of Contaminant Hydrology, 179, p.89 - 101, 2015/08
Times Cited Count:37 Percentile:81.75(Environmental Sciences)Matrix diffusion is a key process for radionuclide retention in crystalline rocks. An in-situ diffusion experiment in granite matrix was performed at the Grimsel Test Site (Switzerland). Several tracers (HTO, Na, Cs) were circulated through a borehole and the decrease in tracer concentrations was monitored for 2.5 years. Then, the borehole section was overcored and the tracer profiles in the rock were analyzed. Transport distances in the rock were 20 cm for HTO, 10 cm for Na and 1 cm for Cs. The dataset was analyzed with diffusion-sorption models by different teams using different codes, with the goal of obtaining effective diffusivities (De) and rock capacity factors. There was a rather good agreement between the values from different teams, implied that De and capacity factors in the borehole damaged zone are larger than those in the bulk rock. However, HTO seems to display large discrepancies between measured and modeled results.
Soler, J. M.*; Landa, J.*; Havlov, V.*; Tachi, Yukio; Ebina, Takanori*; Sardini, P.*; Siitari-Kauppi, M.*; Martin, A. J.*
Materials Research Society Symposium Proceedings, Vol.1665, p.85 - 91, 2014/09
Matrix diffusion is a key process for radionuclide retention in crystalline rocks. An in-situ diffusion experiment in granite matrix was performed at the Grimsel Test Site (Switzerland). Several tracers (HTO, Na, Cs) were circulated through a borehole and the decrease in tracer concentrations was monitored for 2.5 years. Then, the borehole section was overcored and the tracer profiles in the rock were analyzed. Transport distances in the rock were 20 cm for HTO, 10 cm for Na and 1 cm for Cs. The dataset was analyzed with diffusion-sorption models by different teams using different codes, with the goal of obtaining effective diffusivities (e) and rock capacity factors. There was a rather good agreement between the values from different teams, implied that e and capacity factors in the borehole damaged zone are larger than those in the bulk rock. However, HTO seems to display large discrepancies between measured and modeled results, which have to be investigated in more detail.
Soler, J. M.*; Landa, J.*; Havlov, V.*; Tachi, Yukio; Ebina, Takanori*; Sardini, P.*; Siitari-Kauppi, M.*; Martin, A.*
Nagra NAB 12-53, 80 Pages, 2013/02
An in-situ long-term diffusion (LTD) experiment was performed at the Grimsel Test Site (Switzerland). Tracers, HTO, Na, Cs, were continuously circulated through a packed-off borehole and the tracer concentrations in the solution was monitored for 2.5 years. Subsequently, the borehole section was overcored and the tracer profiles in the rock analyzed. The drop in activity for Cs in the solution was much pronounced. Transport distances were about 20 cm for HTO, 10 cm for Na and 1 cm for Cs. The dataset was analyzed with diffusion-sorption models by different teams using different codes, with the goal of obtaining effective diffusion coefficients () and rock capacity () values. There was a rather good agreement between the values from different teams, implied that and values in the BDZ are larger than those in the bulk rock. However, HTO seems to display large discrepancies between measured and modeled results, which have to be investigated in more detail.
Walsh, M.*; Andrew, P.*; Barnsley, R.*; Bertalot, L.*; Boivin, R.*; Bora, D.*; Bouhamou, R.*; Ciattaglia, S.*; Costley, A. E.*; Counsell, G.*; et al.
Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 8 Pages, 2011/03
Reichle, R.*; Andrew, P.*; Counsell, G.*; Drevon, J.-M.*; Encheva, A.*; Janeschitz, G.*; Johnson, D. W.*; Kusama, Yoshinori; Levesy, B.*; Martin, A.*; et al.
Review of Scientific Instruments, 81(10), p.10E135_1 - 10E135_5, 2010/10
Times Cited Count:29 Percentile:75.35(Instruments & Instrumentation)Tagawa, Masahito*; Yokota, Kumiko*; Matsumoto, Koji*; Suzuki, Mineo*; Teraoka, Yuden; Kitamura, Akira*; Belin, M.*; Fontaine, J.*; Martin, J. M.*
Surface & Coatings Technology, 202(4-7), p.1003 - 1010, 2007/12
Times Cited Count:61 Percentile:89.24(Materials Science, Coatings & Films)Effects of 5 eV atomic oxygen beam on MoS and diamond-like carbon (DLC) lubrication films are evaluated relevance to space environmental effects in the low Earth orbit. X-ray photoelectron spectra indicate that the loss of S atoms and Mo oxidation at the atomic oxygen irradiated MoS is significant. Depth profiles of S and Mo indicate that the oxidation is restricted within 3 nm from the surface. This is due to the fact that Mo oxide plays as a protective layer against further oxidation. The surface oxidation affects the friction coefficient. However, due to the delamination of oxide layer, wear-life of the film is reduced in some conditions. In contrast, no sever oxidation states of C atoms are detected at DLC surface. However, the loss of DLC itself is measured by Rutherford backscattering spectroscopy. It is concluded that the protection of DLC film is mandatory for the use of DLC in the LEO space applications.
Faenov, A. Y.; Magunov, A. I.*; Pikuz, T. A.*; Skobelev, I. Y.*; Giulietti, D.*; Betti, S.*; Galimberti, M.*; Gamucci, A.*; Giulietti, A.*; Gizzi, L. A.*; et al.
JETP Letters, 86(3), p.178 - 183, 2007/08
Times Cited Count:5 Percentile:37.33(Physics, Multidisciplinary)Doyle, E. J.*; Houlberg, W. A.*; Kamada, Yutaka; Mukhovatov, V.*; Osborne, T. H.*; Polevoi, A.*; Bateman, G.*; Connor, J. W.*; Cordey, J. G.*; Fujita, Takaaki; et al.
Nuclear Fusion, 47(6), p.S18 - S127, 2007/06
no abstracts in English
McDonald, D. C.*; Cordey, J. G.*; Thomsen, K.*; Kardaun, O. J. W. F.*; Snipes, J. A.*; Greenwald, M.*; Sugiyama, L.*; Ryter, F.*; Kus, A.*; Stober, J.*; et al.
Nuclear Fusion, 47(3), p.147 - 174, 2007/03
Times Cited Count:50 Percentile:29.82(Physics, Fluids & Plasmas)This paper describes the updates to and analysis of the International Tokamak Physics Activity (ITPA) Global H-node Confinement Database version 3 (DB3) over the period 1994-2004. Global data, for the energy confinement time and its controlling parameters, have now been collected from 18 machines of different sizes and shapes: ASDEX, ASDEX Upgrade, C-Mod CoMPASS-D, DIII-D, JET, JFT-2M, JT-60U, MAST, NSTX, PBX-M, PDX, START, T-10, TCV, TdeV, TFTR and TUMAN-3M. A wide range of physics studies has been performed on DB3 with particular progress made in the separation of core and edge behavior, dimensionless parameter analyses and the comparison of the database with one-dimensional transport code. A key aim of the database has always been to provide a basis for estimating the energy confinement properties of next step machines such as ITER, and so the impact of the database and its analysis on such machines is also discussed.
Kaye, S. M.*; Valovic, M.*; Chudnovskiy, A.*; Cordey, J. G.*; McDonald, D.*; Meakins, A.*; Thomsen, K.*; Akers, R.*; Bracco, G.*; Brickley, C.*; et al.
Plasma Physics and Controlled Fusion, 48(5A), p.A429 - A438, 2006/05
Times Cited Count:15 Percentile:46.15(Physics, Fluids & Plasmas)The effects of aspect ratio and beta on confinement scaling are studied with the use of the H-mode database extended by the low aspect ratio data from NSTX and MAST. Various statistical methods are applied. Development of scalings using engineering parameters as predictor variables results in the inverse-aspect-ratio scaling with the range from 0.38 to 1.29. The transformation of these scalings to physics variables results in an unfavorouble dependence of the normalized energy confinement time on beta. There is a strong correlation between the inverse aspect ratio and beta, and this makes scalings based on physics variables imprecise.
Cordey, J. G.*; Thomsen, K.*; Chudnovskiy, A.*; Kardaun, O. J. W. F.*; Takizuka, Tomonori; Snipes, J. A.*; Greenwald, M.*; Sugiyama, L.*; Ryter, F.*; Kus, A.*; et al.
Nuclear Fusion, 45(9), p.1078 - 1084, 2005/09
Times Cited Count:51 Percentile:82.47(Physics, Fluids & Plasmas)The condition of the latest version of the ELMy H-mode database has been re-examined. It is shown that there is bias in the ordinary least squares regression for some of the variables. To address these shortcomings three different techniques are employed: (a)principal component regression, (b)an error in variables technique and (c)the selection of a better conditioned dataset with fewer variables. Scalings in terms of the dimensionless physics valiables, as well as the standard set of engineering variables, are derived. The new scalings give a very similar performance for existing scalings for ITER at the standard beta, but a much improvement performance at higher beta.
Martin, A. J.; Takahashi, M.*; Umeda, Koji; Yusa, Yasuhisa
Acta Geophysica Polonica, 51(3), p.271 - 289, 2003/00
None
Tagawa, Masahito*; Asada, Hidetoshi*; Yokota, Kumiko*; Ohara, Hisanori*; Nakahigashi, Takahiro*; Teraoka, Yuden; Martin, J. M.*; Belin, M.*
no journal, ,
Effect of space environment on a hydrogenated diamond-like carbon (DLC), which is a candidate of next generation space-approved solid lubricant, has been studied. No significant changes in friction coefficient and surface oxidation states were detected with energetic atomic oxygen fluence of 510 atoms/cm.
Yokota, Kumiko*; Asada, Hidetoshi*; Tagawa, Masahito*; Ohara, Hisanori*; Nakahigashi, Takahiro*; Yoshigoe, Akitaka; Teraoka, Yuden; Martin, J. M.*; Belin, M.*
no journal, ,
Hydrogenated diamond-like carbon (DLC) is expected as a lubricant for space uses because of its ultra low friction charactor in vacuum. Thus, DLC films were exposed to atomic oxygens which were generated by a laser detonation method simulating a low orbit space environment. The DLC surfaces were analysed and the results are reported in this talk. The hydrogenated amorphous DLC was fabricated by a RF-CVD method on Si substrates. Relative collision energy of space planes against atomic oxygens can be simulated with the space environment experimental apparatus. The DLC films exposed to atomic oxygens were analysed by an SR-PES method etc. The SR-PES was performed at the surface chemical reaction analysis station installed in the BL23SU of SPring-8. It was suggested that some volatile oxides were formed and desorbed from the DLC surface when DLC surface was irradiated by atomic oxygens with an incident energy of 4.2 eV and fluence of 510atoms/cm.