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  • 351.
    Hernandez Solis, Augusto
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    On the importance of the spatial dependence of gap properties in the design of modern fast reactor cores2015Conference paper (Refereed)
  • 352.
    Hernandez Solis, Augusto
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjostrand, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Alhassan, Erwin
    Helgesson, Petter
    DRAG-MOC: A tool for the study of uncertainty analysis through OpenMOC2015Conference paper (Refereed)
  • 353.
    Hernandez Solis, Augusto
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Alhassan, Erwin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Helgesson, Petter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Development Of Drag-MOC: A tool for the study of uncertainty analysis through the deterministic OpenMOC transport code2016Conference paper (Refereed)
  • 354.
    Hernandez Solis, Augusto
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Helgesson, Petter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Propagation of neutron-reaction uncertainties through multi-physics models of novel LWR's2017In: ND 2016: INTERNATIONAL CONFERENCE ON NUCLEAR DATA FOR SCIENCE AND TECHNOLOGY / [ed] Plompen, A; Hambsch, FJ; Schillebeeckx, P; Mondelaers, W; Heyse, J; Kopecky, S; Siegler, P; Oberstedt, S, Les Ulis: EDP Sciences, 2017, Vol. 146, article id 02035Conference paper (Refereed)
    Abstract [en]

    The novel design of the renewable boiling water reactor (RBWR) allows a breeding ratio greater than unity and thus, it aims at providing for a self-sustained fuel cycle. The neutron reactions that compose the different microscopic cross-sections and angular distributions are uncertain, so when they are employed in the determination of the spatial distribution of the neutron flux in a nuclear reactor, a methodology should be employed to account for these associated uncertainties. In this work, the Total Monte Carlo (TMC) method is used to propagate the different neutron-reactions (as well as angular distributions) covariances that are part of the TENDL-2014 nuclear data (ND) library. The main objective is to propagate them through coupled neutronic and thermal-hydraulic models in order to assess the uncertainty of important safety parameters related to multi-physics, such as peak cladding temperature along the axial direction of an RBWR fuel assembly. The objective of this study is to quantify the impact that ND covariances of important nuclides such as U-235, U-238, Pu-239 and the thermal scattering of hydrogen in H2O have in the deterministic safety analysis of novel nuclear reactors designs.

  • 355. Hirayama, S.
    et al.
    Watanabe, Y.
    Naitou, Y.
    Andersson, P
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Bevilacqua, Riccardo
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gustavsson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Österlund, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Simutkin, Vasily
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, The Svedberg Laboratory.
    Prokofiev, Alexander V.
    Uppsala University, The Svedberg Laboratory.
    Tesinsky, M.
    Tippawan, U.
    Light-ion Production from a Thin Silicon Target Bombarded by 175 MeV Quasi Mono-energetic Neutrons2011In: Journal of the Korean Physical Society, ISSN 0374-4884, E-ISSN 1976-8524, Vol. 59, no 2, p. 1447-1450Article in journal (Refereed)
    Abstract [en]

    Double-differential production yields of light ions (p, d, t, (3)He, and alpha) from a thin silicon target induced by 175 MeV quasi mono-energetic neutrons were measured using the MEDLEY setup at the The Svedberg Laboratory (TSL) in Uppsala in order to benchmark evaluated nuclear data and nuclear reaction models. The MEDLEY is a conventional spectrometer system which consists of eight counter telescopes. Each telescope is composed of two silicon surface barrier detectors as the Delta E detectors and a CsI(Tl) scintillator as the E detector for particle identification. The telescopes are placed at angles from 20 degrees to 160 degrees in steps of 20 degrees. The measured double-differential yields of light ions are compared with PHITS calculations using the following nuclear reaction options: the high-energy nuclear data library (JENDL/HE-2007), the quantum molecular dynamics (QMD) model, and the intra-nuclear cascade (INC) model.

  • 356.
    Hirayama, Shusuke
    et al.
    Kyushu University.
    Watanabe, Yukinobu
    Hayashi, Masateru
    Naitou, Yuuki
    Watanabe, Takehito
    Bevilacqua, Riccardo
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Blomgren, Jan
    Nilsson, Leif
    Öhrn, Angelica
    Österlund, Michael
    Prokofiev, Alexander V.
    Uppsala University, The Svedberg Laboratory.
    Simutkin, Vasily
    Tippawan, Udomrat
    Production of protons, deuterons, and tritons from carbon bombarded by 175 MeV quasi mono-energetic neutrons2011In: Progress in Nuclear Science and Technology, Vol. 1, p. 69-72Article in journal (Refereed)
    Abstract [en]

    We have measured double-differential yields of protons, deuterons, and tritons produced from carbon induced by 175 MeV quasi mono-energetic neutrons using the MEDLEY setup at the TSL neutron beam facility. The measured data are used for benchmarking of a high-energy nuclear data file, JENDL/HE-2007, and both intra-nuclear cascade (INC) model and quantum molecular dynamics (QMD) calculations.

  • 357.
    Hirayama, Shusuke
    et al.
    Kyushu University.
    Watanabe, Yukinobu
    Naitou, Yuuki
    Andersson, Pernilla
    Bevilacqua, Riccardo
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gustavsson, Cecilia
    Hjalmarsson, Anders
    Österlund, Michael
    Pomp, Stephan
    Prokofiev, Alexander
    Simutkin, Vasily
    Sjöstand, Herik
    Tesinsky, Milan
    Tippawan, Udomrat
    Light-ion production from a thin silicon target bombarded by 175 MeV quasi mono-energetic neutrons2011In: Nuclear Engineering and Technology: Proceedings of the International Conference on Nuclear Data for Science and Technology 2010 / [ed] Korean Nuclear Society, 2011Conference paper (Refereed)
  • 358. Hobirk, J.
    et al.
    Imbeaux, F.
    Crisanti, F.
    Buratti, P.
    Challis, C. D.
    Joffrin, E.
    Alper, B.
    Andrew, Y.
    Beaumont, P.
    Beurskens, M.
    Boboc, A.
    Botrugno, A.
    Brix, M.
    Calabro', G.
    Coffey, I.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ford, O.
    Frigione, D.
    Garcia, J.
    Giroud, C.
    Hawkes, N. C.
    Howell, D.
    Jenkins, I.
    Keeling, D.
    Kempenaars, M.
    Leggate, H.
    Lotte, P.
    de la Luna, E.
    Maddison, G. P.
    Mantica, P.
    Mazzotta, C.
    McDonald, D. C.
    Meigs, A.
    Nunes, I.
    Rachlew, E.
    Rimini, F.
    Schneider, M.
    Sips, A. C. C.
    Stober, J. K.
    Studholme, W.
    Tala, T.
    Tsalas, M.
    Voitsekhovitch, I.
    de Vries, P. C.
    Improved confinement in JET hybrid discharges2012In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 54, no 9, p. 095001-Article in journal (Refereed)
    Abstract [en]

    A new technique has been developed to produce plasmas with improved confinement relative to the H-98,H-y2 scaling law (ITER Physics Expert Groups on Confinement and Transport and Confinement Modelling and Database ITER Physics Basics Editors and ITER EDA 1999 Nucl. Fusion 39 2175) on the JET tokamak. In the mid-size tokamaks ASDEX upgrade and DIII-D heating during the current formation is used to produce a flat q-profile with a minimum close to 1. On JET this technique leads to q-profiles with similar minimum q but opposite to the other tokamaks not to an improved confinement state. By changing the method utilizing a faster current ramp with temporary higher current than in the flattop (current overshoot) plasmas with improved confinement (H-98,H-y2 = 1.35) and good stability (beta(N) approximate to 3) have been produced and extended to many confinement times only limited by technical constraints. The increase in H-98,H-y2-factor is stronger with more heating power as can be seen in a power scan. The q-profile development during the high power phase in JET is reproduced by current diffusion calculated by TRANSP and CRONOS. Therefore the modifications produced by the current overshoot disappear quickly from the edge but the confinement improvement lasts longer, in some cases up to the end of the heating phase.

  • 359. Holcombe, S.
    et al.
    Eitrheim, K.
    Svärd, Staffan Jacobsson
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hallstadius, L.
    Willman, C.
    Advanced fuel assembly characterization capabilities based on gamma tomography at the halden boiling water reactor2012In: Proc. Int. Conf. on Advances in Reactor Physics, 2012, p. 3478-3489Conference paper (Refereed)
    Abstract [en]

    Characterization of individual fuel rods using gamma spectroscopy is a standard part of the Post Irradiation Examinations performed on experimental fuel at the Halden Boiling Water Reactor. However, due to handling and radiological safety concerns, these measurements are presently carried out only at the end of life of the fuel, and not earlier than several days or weeks after its removal from the reactor core. In order to enhance the fuel characterization capabilities at the Halden facilities, a gamma tomography measurement system is now being constructed, capable of characterizing fuel assemblies on a rod-by-rod basis in a more timely and efficient manner. Gamma tomography for measuring nuclear fuel is based on gamma spectroscopy measurements and tomographic reconstruction techniques. The technique, previously demonstrated on irradiated commercial fuel assemblies, is capable of determining rod-by-rod information without the need to dismantle the fuel. The new gamma tomography system will be stationed close to the Halden reactor in order to limit the need for fuel transport, and it will significantly reduce the time required to perform fuel characterization measurements. Furthermore, it will allow rod-by-rod fuel characterization to occur between irradiation cycles, thus allowing for measurement of experimental fuel repeatedly during its irradiation lifetime. The development of the gamma tomography measurement system is a joint project between the Institute for Energy Technology - OECD Halden Reactor Project, Westinghouse (Sweden), and Uppsala University.

  • 360.
    Holcombe, Scott
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gamma Spectroscopy and Gamma Emission Tomography for Fuel Performance Characterization of Irradiated Nuclear Fuel Assemblies2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Gamma spectroscopy and gamma emission tomography are two non-destructive measurement techniques for assessing the performance of nuclear fuel which have been investigated in this thesis for existing and novel applications through theoretical studies and experimental demonstrations. For assessment of individual fuel rods using gamma spectroscopy, fuel assemblies are dismantled so that the fuel rods may be measured separately, which is time-consuming and may cause damage to the fuel. Gamma tomography is more seldom used, but its application on complete fuel assemblies would enable the assessment of individual fuel rods without the need to disassemble the fuel. Both techniques are based on recording gamma rays, emitted at characteristic energies from decaying radioactive products in the fuel.

    The feasibility of measuring short-lived fission gasses in the gas plenum of fuel rods with short cooling time was experimentally investigated. Based on the feasibility demonstration, a method was proposed and experimentally demonstrated for determining the fission gas release fraction of 133Xe in fuel rods with short cooling time. Additionally, a method for investigating the origin of released fission gasses based on the measured ratio of 133Xe/85Kr in the fuel rod gas plenum was demonstrated. These methods may be employed at research reactors, where fuel with short cooling time is available for measurement.

    A gamma emission tomography instrument has been designed, constructed and experimentally demonstrated on a Halden Reactor fuel assembly. Simulation studies showed that the instrument and the tomographic reconstruction methods employed may be useful for: identifying a leaking fuel rod in an assembly by its lack of fission gas content; reconstruction of the rod-wise fission product distributions in the fuel stack and plenum regions of the assembly; and determining the rod-wise fission gas release fractions.

    In the experimental demonstration, the rod-wise distributions of the fission products 137Cs and 85Kr in the fuel stack and plenum regions of the assembly were reconstructed, as well as the distributions of the activation products 60Co and 178mHf in the plenum region, revealing the plenum springs and tie rods, respectively. The reconstructed data was in the form of images, useful for qualitative assessment of the fuel.

  • 361.
    Holcombe, Scott
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Nondestructive Fission Gas Measurements by Means of Gamma Spectroscopy and Gamma Tomography2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    There is a continuous need in the nuclear industry to characterize irradiated nuclear fuel rods and assemblies, both for fuel performance and for safeguards purposes, and consequently there are various destructive and nondestructive measurement techniques available to meet this need. Gamma spectroscopy is one such nondestructive technique, which has been extensively used for a variety of fuel characterization applications. Furthermore, gamma tomography – a combination of gamma spectroscopic measurements and tomographic reconstruction – has in recent years been demonstrated as an efficient technique for characterization of irradiated nuclear fuel assemblies on a rod-by-rod basis without the need to dismantle the fuel. This thesis comprises four scientific papers in which novel applications of these two techniques have been developed and evaluated.

    The major part of this work has been performed at the Halden Boiling Water Reactor (HBWR), where a gamma tomography measurement system is currently under construction, as presented in this thesis. The methods and evaluations presented in this work are based on the conditions at the HBWR.

    Based on gamma spectroscopy, a novel nondestructive method for determining fission gas release which occurs over short irradiation sequences has been developed, comprising the measurement and analysis of short lived isotopes in individual fuel rods. The method has been demonstrated based on gamma-ray spectra recorded from an experimental fuel rod irradiated in the HBWR.

    Based on gamma tomography, a novel method for identifying failed fuel rods within a nuclear fuel assembly has also been developed. The method comprises the measurement of gamma rays emitted in the decay of selected fission gas isotopes in the gas plenum region of a fuel assembly, tomographic image reconstruction of the internal source distribution and subsequent analysis of the resulting image in order to determine if any of the fuel rods in the assembly has unexpectedly low activity, indicating that it is a leaking fuel rod. Simulation studies performed for HBWR fuel show highly promising results for gamma rays emitted in the decay of two selected fission gas isotopes.

    The methods will be further investigated at the HBWR, by performing dedicated gamma spectroscopy measurements and by using the tomographic measurement system currently under construction.

  • 362.
    Holcombe, Scott
    et al.
    OECD Halden Reactor Project.
    Andersson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gamma Emission Tomography Measurements of Fuel Assemblies at the Halden Reactor2016Conference paper (Refereed)
    Abstract [en]

    Gamma emission tomography measurements have been performed at the Halden Reactor Project using a dedicated instrument, which utilizes a high-resolution gamma-ray detector allowing for spectroscopic analysis of the measurement data. Measurements have been performed on two fuel assemblies consisting of 9 and 13 rods, respectively, in order to characterize the rod-wise radioactive source distribution (i.e. fission and activation products) within the fuel. The 9-rod fuel assembly consisted of five fuel rods at 50 MWd/kgUO2 and four fuel rods at 26 MWd/kgUO2, where all rods had cooled for approximately 22 years at the time of measurement. The rods in the 13-rod assembly all had a burnup of ~4.5 MWd/kgUO2, and cooled for approximately 1.5 years at the time of measurement.

     

    In this paper, the tomographic data was reconstructed using the Filtered Backprojection technique, where no consideration to gamma-ray attenuation in the fuel was given. Due to the varying burnup and cooling times between the assemblies, the spectroscopic data also varied between the respective sets of measurements. The high-resolution detector used in the measurements allowed for tomographic reconstruction of many gamma-ray peaks corresponding to various fission products and activation products present in the fuel and structural materials.

     

    The qualitative tomographic images presented in this paper are analyzed to determine the positions of the fuel rods and structural components in the fuel. This geometrical information will subsequently be used as input to algebraic reconstruction algorithms which are used to determine the quantitative rod-wise gamma-ray source distributions.

     

    The gamma tomography instrument in Halden was designed, constructed, and demonstrated in collaboration between the Westinghouse (Sweden), and Uppsala University. 

  • 363.
    Holcombe, Scott
    et al.
    Halden Reactor Project.
    Andersson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gamma Emission Tomography Measurements of Fuel Assemblies at the Halden ReactorManuscript (preprint) (Other academic)
  • 364.
    Holcombe, Scott
    et al.
    Inst Energy Technol, OECD Halden Reactor Project, Halden, Norway.
    Andersson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Halistadius, Lars
    Westinghouse Elect Sweden AB, Fredholmsgatan 22, S-72163 Vasteras, Sweden.
    Determination of the Rod-wise Fission Gas Release Fraction in a Complete Fuel Assembly Using Non-destructive Gamma Emission Tomography2016In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 837, p. 99-108Article in journal (Refereed)
    Abstract [en]

    A gamma tomography instrument has been developed at the Halden Boiling Water Reactor (HBWR) in cooperation between the Institute for Energy Technology, Westinghouse (Sweden) and Uppsala University. The instrument is used to record the gamma radiation field surrounding complete fuel assemblies and consists of a shielded enclosure with fixtures to accurately position the fuel and detector relative to each other. A High Purity Germanium detector is used for acquiring high-resolution spectroscopic data, allowing for analysis of multiple gamma-ray peaks. Using the data extracted from the selected peaks, tomographic reconstruction algorithms are used to reproduce the corresponding spatial gamma-ray source distributions within the fuel assembly. With this method, rod-wise data can be can be deduced without the need to dismantle the fuel.

    In this work, the tomographic device has been experimentally benchmarked for non-destructive rod-wise determination of the Fission Gas Release (FGR) fraction. Measurements were performed on the fuel-stack and gas-plenum regions of a complete fuel assembly, and quantitative tomographic reconstructions of the measurement data were performed in order to determine the rod-wise ratio of 85Kr in the gas plenum to 137Cs in the fuel stack. The rod-wise ratio of 85Kr/137Cs was, in turn, used to calculate the rod-wise FGR fraction. In connection to the tomographic measurements, the fuel rods were also measured individually using gamma scanning in order to provide an experimental benchmark for the tomographic method.

    Fuel rods from two donor driver fuel assemblies were placed into a nine-rod HBWR driver fuel assembly configuration. In order to provide a challenging measurement object and thus an appropriate benchmark for the tomographic method, five rods were taken from an assembly with a burnup of 51 MWd/kgUO2, and four rods were from an assembly with a burnup of 26 MWd/kgUO2. At the time of the measurements, the nine rods had cooled for approximately 22 years. All fuel rods had operated at high linear heat rates (around 70 kW/m), thus leading to relatively high FGR fractions. Here, the FGR fraction was determined to be ~24% in the high-burnup rods, and ~17% in the low-burnup rods. The tomography measurement results were in good agreement with the results from individual rod scanning, demonstrating the feasibility of tomography for this application. The capability of tomography to assess individual fuel rods without the need to dismantle the assembly can be particularly valuable in cases of fuels that do not allow disassembly, such as experimental HBWR fuel fitted with extensive instrumentation.

  • 365.
    Holcombe, Scott
    et al.
    OECD Halden Reactor Project.
    Andersson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hallstadius, Lars
    Westinghouse Electric Sweden AB.
    Determination of the rod-wise fission gas release fraction in a complete fuel assembly using non-destructive gamma emission tomography2016In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 837Article in journal (Refereed)
    Abstract [en]

    A gamma tomography instrument has been developed at the Halden Boiling Water Reactor (HBWR) in cooperation between the Institute for Energy Technology, Westinghouse (Sweden) and Uppsala University. The instrument is used to record the gamma radiation field surrounding complete fuel assemblies and consists of a shielded enclosure with fixtures to accurately position the fuel and detector relative to each other. A High Purity Germanium detector is used for acquiring high-resolution spectroscopic data, allowing for analysis of multiple gamma-ray peaks. Using the data extracted from the selected peaks, tomographic reconstruction algorithms are used to reproduce the corresponding spatial gamma-ray source distributions within the fuel assembly. With this method, rod-wise data can be can be deduced without the need to dismantle the fuel.

    In this work, the tomographic device has been experimentally benchmarked for non-destructive rod-wise determination of the Fission Gas Release (FGR) fraction. Measurements were performed on the fuel-stack and gas-plenum regions of a complete fuel assembly, and quantitative tomographic reconstructions of the measurement data were performed in order to determine the rod-wise ratio of 85Kr in the gas plenum to 137Cs in the fuel stack. The rod-wise ratio of 85Kr/137Cs was, in turn, used to calculate the rod-wise FGR fraction. In connection to the tomographic measurements, the fuel rods were also measured individually using gamma scanning in order to provide an experimental benchmark for the tomographic method.

    Fuel rods from two donor driver fuel assemblies were placed into a nine-rod HBWR driver fuel assembly configuration. In order to provide a challenging measurement object and thus an appropriate benchmark for the tomographic method, five rods were taken from an assembly with a burnup of 51 MWd/kgUO2, and four rods were from an assembly with a burnup of 26 MWd/kgUO2. At the time of the measurements, the nine rods had cooled for approximately 22 years. All fuel rods had operated at high linear heat rates (around 70 kW/m), thus leading to relatively high FGR fractions. Here, the FGR fraction was determined to be ~24% in the high-burnup rods, and ~17% in the low-burnup rods. The tomography measurement results were in good agreement with the results from individual rod scanning, demonstrating the feasibility of tomography for this application. The capability of tomography to assess individual fuel rods without the need to dismantle the assembly can be particularly valuable in cases of fuels that do not allow disassembly, such as experimental HBWR fuel fitted with extensive instrumentation.

  • 366.
    Holcombe, Scott
    et al.
    Halden Reactor Project.
    Andersson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hallstadius, Lars
    Non-destructive Determination of the Rod-wise Fission Gas Release Fraction Using Gamma Emission Tomography on Complete Fuel Assemblies2016Report (Other academic)
  • 367.
    Holcombe, Scott
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eitrheim, Knut
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Development of a Gamma Tomography Measurement System for Characterizing Halden Boiling Water Reactor Fuel2011Conference paper (Other academic)
  • 368.
    Holcombe, Scott
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hallstadius, Lars
    HWR-1133: LOCA Test IFA-650.14, Fission Gas Analysis Based on Nondestructive Gamma Spectroscopy Measurements of Short-lived and Long-lived Fission Products2014Report (Other academic)
  • 369.
    Holcombe, Scott
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eitrheim, Knut
    Hallstadius, Lars
    A Non-destructive Gamma-spectroscopy-based Method for Investigating the Radial Origin of Released Fission Gasses from High Burnup Fuel Pellets2013Conference paper (Other academic)
  • 370.
    Holcombe, Scott
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eitrheim, Knut
    Hallstadius, Lars
    A Nondestructive Method for Investigating the Origin of Released Fission Gasses in Nuclear Fuel Rods2013In: Proceedings of Topfuel 2013, Charlotte, North Carolina, U.S.A., 2013Conference paper (Refereed)
  • 371.
    Holcombe, Scott
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eitrheim, Knut
    Hallstadius, Lars
    Characterization of Nuclear Fuel Rods Operated at High Linear Heat Rates Using Nondestructive Gamma-ray Spectroscopy2014Conference paper (Refereed)
  • 372.
    Holcombe, Scott
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eitrheim, Knut
    Hallstadius, Lars
    Gamma Emission Tomography for Characterizing Halden Boiling Water Reactor Fuel Assemblies: Instrumentation, Simulations, and Experimental Demonstration2014Conference paper (Other academic)
  • 373.
    Holcombe, Scott
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eitrheim, Knut
    Hallstadius, Lars
    Willman, Christofer
    Advanced Fuel Assembly Characterization Capabilities Based on Gamma Tomography at the Halden Boiling Water Reactor2012Conference paper (Refereed)
  • 374.
    Holcombe, Scott
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eitrheim, Knut
    Hallstadius, Lars
    Willman, Christofer
    Feasibility of identifying leaking fuel rods using gamma tomography2013In: Annals of Nuclear Energy, ISSN 0306-4549, E-ISSN 1873-2100, Vol. 57, p. 334-340Article in journal (Refereed)
    Abstract [en]

    In cases of fuel failure in irradiated nuclear fuel assemblies, causing leakage of fission gasses from a fuel rod, there is a need for reliable non-destructive measurement methods that can determine which rod is failed. Methods currently in use include visual inspection, eddy current, and ultrasonic testing, but additional alternatives have been under consideration, including tomographic gamma measurements.

    The simulations covered in this report show that tomographic measurements could be feasible. By measuring a characteristic gamma energy from fission gasses in the gas plenum, the rod-by-rod gamma source distribution within the fuel rod plena may be reconstructed into an image or data set which could then be compared to the predicted distribution of fission gasses, e.g. from the STAV code. Rods with significantly less fission gas in the plenum may then be identified as leakers.

    Results for rods with low fission gas release may, however, in some cases be inconclusive since these rods will already have a weak contribution to the measured gamma-ray intensities and for such rods there is a risk that a further decrease in fission gas content due to a leak may not be detectable. In order to evaluate this and similar experimental issues, measurement campaigns are planned using a tomographic measurement system at the Halden Boiling Water Reactor.

  • 375.
    Holcombe, Scott
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Willman, Christofer
    Eitrheim, Knut
    Hallstadius, Lars
    Reparaz, Adolfo
    Feasibility of performing Pool-Side Fission Gas Release Measurements on Fuel Rods with Short Decay Time2011Conference paper (Refereed)
  • 376.
    Holcombe, Scott
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Svärd, Staffan Jacobsson
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eitrheim, Knut
    Hallstadius, Lars
    Willman, Christofer
    Method For Analyzing Fission Gas Release In Fuel Rods Based On Gamma-Ray Measurements Of Short-Lived Fission Products2013In: Nuclear Technology, ISSN 0029-5450, E-ISSN 1943-7471, Vol. 184, no 1, p. 96-106Article in journal (Refereed)
    Abstract [en]

    Fission gases are produced as a result of fission reactions in nuclear fuel. Most of these gases remain trapped within the fuel pellets, but some may be released to the fuel rod internal gas volume under certain conditions. This phenomenon of fission gas release is important for fuel performance since the released gases can degrade the thennal properties of the fuel rod. fill gas and contribute to increasing fuel rod internal pressure. Various destructive and nondestructive methods are available for determining the amount of fission gas release; however, the current methods are primarily useful for determining the integrated fission gas release fraction, i.e., the amount of fission gas produced in the fuel that has been released to the free rod volume over the entire lifetime of a nuclear fuel rod. In this work, a method is proposed for determining the fission gas release that occurs during short irradia-tion sequences. The proposed method is based on spectroscopic measurements of gamma rays emitted in the decay of short-lived fission gas isotopes. Determining such sequence-specific fission gas release can be of interest when evaluating the fuel behavior for selected times during irradiation, such as during power ramps. The data obtained in this type of measurement may also be useful for investigating the mechanisms behind fission gas release for fuel at high burnup. The method is demonstrated based on the analysis of experimental gamma-ray spectra previously collected using equipment not dedicated for this purpose; however, the analysis indicates the feasibility of the method. Further evaluation of the method is planned, using dedicated equipment at the Halden Boiling Water Reactor.

  • 377.
    Holcombe, Scott
    et al.
    Inst Energy Technol, OECD Halden Reactor Project, N-1751 Halden, Norway..
    Svärd, Staffan Jacobsson
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hallstadius, Lars
    Westinghouse Elect Sweden AB, S-72163 Vasteras, Sweden..
    A Novel gamma emission tomography instrument for enhanced fuel characterization capabilities within the OECD Halden Reactor Project2015In: Annals of Nuclear Energy, ISSN 0306-4549, E-ISSN 1873-2100, Vol. 85, p. 837-845Article in journal (Refereed)
    Abstract [en]

    Gamma emission tomography is a method based on gamma-ray spectroscopy and tomographic reconstruction techniques, which can be used for rod-wise characterization of nuclear fuel assemblies without dismantling the fuel. By performing a large number of measurements of the gamma-ray flux intensity around a fuel assembly using a well-collimated gamma-ray detector, the internal source distribution in the assembly may be reconstructed using tomographic algorithms. If a spectroscopic detection system is used, different gamma-ray emitting isotopes can be selected for analysis, enabling nondestructive fuel characterization with respect to a variety of fuel parameters. In this paper, we describe a novel gamma emission tomography instrument, which has been designed, constructed and tested at the Halden Boiling Water Reactor (HBWR). The device will be used to characterize fuel assemblies irradiated in the HBWR as part of ongoing nuclear fuel research conducted within the OECD Halden Reactor Project (HRP). As compared to single-rod gamma scanning, where the fuel is dismantled and the gamma radiation from each rod is measured separately, handling time associated with characterizing the fuel can be significantly reduced when using the gamma emission tomography device. Furthermore, because gamma emission tomography enables rod-wise fuel characterization without dismantling, even instrumented experimental fuel assemblies may be characterized repeatedly throughout the fuel's lifetime, with limited risk of damaging the fuel or its instrumentation. Accordingly, the capabilities of fuel characterization within the OECD HRP are expected to be strongly enhanced by the deployment of this device. Here, the gamma-tomographic method and the experimental setup are demonstrated through experimental measurements of the fuel stack and gas plenum regions of a nine-rod HBWR fuel assembly configuration, where four rods had a burnup of approximately 26 MWd/kgUO(2) and five rods had a burnup of approximately 50 MWd/kgUO(2). Tomographic images are presented, which show the applicability for assessment of fission gas contents in the gas plena and of fission products in the fuel stack. Furthermore, neutron activation products are analyzed, which give additional information on construction material properties.

  • 378.
    Holmkvist, Carolin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Kvantifiering av osäkerheter i lyftkraftsmodellen2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    With today´s power uprates in BWR reactors the bundle lift force has become aproblem. The lift force is calculated using a best estimate approach and the resultfrom the calculation should pass the existing lift force margin. Lift force margin isdefined so that the lift force may not exceed 80 % of the fuel weight. The margin issupposed to cover all the uncertainties that exist in the lift force calculations.However, no uncertainty analysis has been conducted to quantify the uncertainties.

    In this report the uncertainties in the lift force model have been quantified. Each inputparameter to the lift force model which has been assumed to have an uncertainty isassigned a probability distribution. Through the Monte Carlo method and Wilk´smethod an uncertainty propagation has been performed at different points in thereactor´s power flow map. By using these two methods, uncertainty in input datahave been translated into uncertainty in output data. This study has investigated fuelfrom different companies. From the Monte Carlo and Wilk´s method the lift force hasbeen calculated at various probabilities. By using these results, a lift force margin hasbeen calculated for each fuel type and at various probabilities.

    The results from the uncertainty propagation shows that the current lift force margincorresponds to approximately 95 % probability that lift doesn´t occur for all fueltypes. By using the uncertainty propagation, a new way of calculation the lift forcemargin has been developed.

  • 379. Hong, Q.
    et al.
    Platt, S.P.
    Prokofiev, Alexander V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Passoth, Elke
    Uppsala University, The Svedberg Laboratory.
    Detailed Geant4 simulations of the ANITA and ANITA-CUP neutron facilities2015Conference paper (Refereed)
    Abstract [en]

    Simulations of the ANITA spallation neutron source at The Svedberg Laboratory (TSL) are described. Neutron radiation calculations show close agreement with measurements at both standard and close user positions. Gamma radiation characteristics are also predicted.

  • 380.
    Hong, Sanghyun
    et al.
    Univ Tasmania, Fac Sci Engn & Technol, Private Bag 55, Hobart, Tas 7001, Australia..
    Qvist, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Brook, Barry W.
    Univ Tasmania, Fac Sci Engn & Technol, Private Bag 55, Hobart, Tas 7001, Australia..
    Economic and environmental costs of replacing nuclear fission with solar and wind energy in Sweden2018In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 112, p. 56-66Article in journal (Refereed)
    Abstract [en]

    Nuclear power is facing an uncertain future in Sweden due to political directives that are seeking to phase out this energy source over coming decades. Here we examine the environmental and economic costs of hypothetical future renewable-energy-focused cases compared with the current nuclear and hydroelectricity-centred mix in Sweden. We show that if wind and photovoltaics replace entire nuclear power while maintaining the current level of dispatchable backup capacity including hydroelectric power and peak gas power, 154 GW of wind power will be required and will generate 427.1 TWh (compared with the actual demand of 143.7 TWh) to reliably meet demand each hour of the year. As a consequence, the annual spending on electricity systems will be five times higher than the status quo. Increasing dispatchable power, increasing transmission capacities to other countries, and generating electricity from combined heat and power plants even when there is no heat demand, will together reduce the required capacities of wind and solar photovoltaic by half, but it will double the greenhouse gas emissions during the combustion process. In conclusion, our economic and greenhouse-gas emissions analyses demonstrate that replacing nuclear power with renewables will be neither economic nor environmentally friendly with regards to the climate.

  • 381.
    Huber, Alexander
    et al.
    Forschungszentrum Julich, Inst Energie & Klimaforsch Plasmaphys, Trilateral Euregio Cluster, D-52425 Julich, Germany..
    Sergienko, Gennady
    Forschungszentrum Julich, Inst Energie & Klimaforsch Plasmaphys, Trilateral Euregio Cluster, D-52425 Julich, Germany..
    Kinna, David
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Huber, Valentina
    Forschungszentrum Julich, Supercomp Ctr, D-52425 Julich, Germany..
    Milocco, Alberto
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England.;Univ Milano Bicocca, Piazza Sci 3, I-20126 Milan, Italy..
    Mercadier, Laurent
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Balboa, Itziar
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cramp, Simon
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Kiptily, Vasili
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Kruezi, Uron
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Lambertz, Horst Toni
    Forschungszentrum Julich, Inst Energie & Klimaforsch Plasmaphys, Trilateral Euregio Cluster, D-52425 Julich, Germany..
    Linsmeier, Christian
    Forschungszentrum Julich, Inst Energie & Klimaforsch Plasmaphys, Trilateral Euregio Cluster, D-52425 Julich, Germany..
    Matthews, Guy
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Popovichev, Sergey
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Mertens, Philippe
    Forschungszentrum Julich, Inst Energie & Klimaforsch Plasmaphys, Trilateral Euregio Cluster, D-52425 Julich, Germany..
    Silburn, Scott
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Zastrow, Klaus-Dieter
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Response of the imaging cameras to hard radiation during JET operation2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 669-673Article in journal (Refereed)
    Abstract [en]

    The analysis of the radiation damage of imaging systems is based on all different types-of aiialoiue/digital cameras with uncooled as well as actively cooled image sensors in the VIS/NIR/MWIR spectral ranges. The Monte Carlo N-Particle (MCNP) code has been used to determine the neutron fluence at different camera locations in JET. An explicit link between the sensor damage and the neutron fluence has been observed. Sensors show an increased dark-current and increased numbers of hot-pixels. Uncooled cameras must be replaced once per year after exposure to a neutron fluence of similar to 1.9-3.2 x 10(12)neutrons/cm(2). Such levels of fluence will be reached after approximate to 14-22 ELMy H-mode pulses during the future D-T campaign. Furthermore, dynamical noise seen as a random pattern of bright pixels was observed in the presence of hard radiation (neutrons and gammas). Failure of the digital electronics inside the cameras as well as of industrial controllers is observed beyond a neutron fluence of about similar to 4 x 10(9) neutrons/cm(2). The impact of hard radiation on the different types of electronics and possible application of cameras during future D-T campaign is discussed.

  • 382.
    Hunold, Oliver
    et al.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Chen, Yen-Ting
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Music, Denis
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Persson, Per O. A.
    Linkoping Univ, Dept Phys Chem & Biol IFM, S-58183 Linkoping, Sweden..
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Baben, Moritz
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Achenbach, Jan-Ole
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Keuter, Philipp
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Schneider, Jochen M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Correlative theoretical and experimental investigation of the formation of AIYB(14) and competing phases2016In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 119, no 8, article id 085307Article in journal (Refereed)
    Abstract [en]

    The phase formation in the boron-rich section of the Al-Y-B system has been explored by a correlative theoretical and experimental research approach. The structure of coatings deposited via high power pulsed magnetron sputtering from a compound target was studied using elastic recoil detection analysis, electron energy loss spectroscopy spectrum imaging, as well as X-ray and electron diffraction data. The formation of AlYB14 together with the (Y,Al)B-6 impurity phase, containing 1.8 at. % less B than AlYB14, was observed at a growth temperature of 800 degrees C and hence 600 degrees C below the bulk synthesis temperature. Based on quantum mechanical calculations, we infer that minute compositional variations within the film may be responsible for the formation of both icosahedrally bonded AlYB14 and cubic (Y,Al)B-6 phases. These findings are relevant for synthesis attempts of all boron rich icosahedrally bonded compounds with the space group: Imma that form ternary phases at similar compositions.

  • 383.
    Hunold, Oliver
    et al.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Keuter, Philipp
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Bliem, Pascal
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Music, Denis
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Wittmers, Friederike
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Ravensburg, Anna L.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Schneider, Jochen M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Elastic properties of amorphous T0.75Y0.75B14 (T = Sc, Ti, V, Y, Zr, Nb) and the effect of O incorporation on bonding, density and elasticity (T ' = Ti, Zr)2017In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 29, no 8, article id 085404Article in journal (Refereed)
    Abstract [en]

    We have systematically studied the effect of transition metal valence electron concentration (VEC) of amorphous T0.75Y0.75B14 (a-T0.75Y0.75B14, T = Sc, Ti, V, Y, Zr, Nb) on the elastic properties, bonding, density and electronic structure using ab initio molecular dynamics. As the transition metal VEC is increased in both periods, the bulk modulus increases linearly with molar- and mass density. This trend can be understood by a concomitant decrease in cohesive energy. T' = Ti and Zr were selected to validate the predicted data experimentally. A-Ti0.74Y0.80B14 and a-Zr0.75Y0.75B14 thin films were synthesized by high power pulsed magnetron sputtering. Chemical composition analysis revealed the presence of up to 5 at.% impurities, with O being the largest fraction. The measured Young's modulus values for a-Ti0.74Y0.80B14 (301 +/- 8 GPa) and a-Zr0.75Y0.75B14 (306 +/- 9 GPa) are more than 20% smaller than the predicted ones. The influence of O incorporation on the elastic properties for these selected systems was theoretically studied, exemplarily in a-Ti0.75Y0.75B12.75O1.25. Based on ab initio data, we suggest that a-Ti0.75Y0.75B14 exhibits a very dense B network, which is partly severed in a-Ti0.75Y0.75B12.75O1.25. Upon O incorporation, the average coordination number of B and the molar density decrease by 9% and 8%, respectively. Based on these data the more than 20% reduced Young's modulus obtained experimentally for films containing impurities compared to the calculated Young's modulus for a-Ti0.75Y0.75B14 (without incorporated oxygen) can be rationalized. The presence of oxygen impurities disrupts the strong B network causing a concomitant decrease in molar density and Young's modulus. Very good agreement between the measured and calculated Young's modulus values is obtained if the presence of impurities is considered in the calculations. The implications of these findings are that prediction efforts regarding the elastic properties of amorphous borides containing oxygen impurities on the at.% level are flawed without taking the presence of impurities into account.

  • 384.
    Huttner, Hagen B.
    et al.
    Karolinska Inst, Dept Cell & Mol Biol, Stockholm, Sweden; Univ Hosp Erlangen, Dept Neurol, Erlangen, Germany.
    Bergmann, Olaf
    Karolinska Inst, Dept Cell & Mol Biol, Stockholm, Sweden; Tech Univ Dresden, DFG Ctr Regenerat Therapies Dresden, Dresden, Germany.
    Salehpour, Mehran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    El Cheikh, Raouf
    Aix Marseille Univ, Inserm S 911, CRO2, SMARTc Pharmacokinet Unit, Marseille, France.
    Nakamura, Makoto
    Univ Hosp Hannover, Dept Neurosurg, Hannover, Germany.
    Tortora, Angelo
    Univ Hosp Hannover, Dept Neurosurg, Hannover, Germany.
    Heinke, Paula
    Tech Univ Dresden, DFG Ctr Regenerat Therapies Dresden, Dresden, Germany.
    Coras, Roland
    Univ Hosp Erlangen, Dept Neuropathol, Erlangen, Germany.
    Englund, Elisabet
    Univ Hosp Lund, Dept Pathol, Lund, Sweden.
    Eyuepoglu, Ilker Y.
    Univ Hosp Erlangen, Dept Neurosurg, Erlangen, Germany.
    Kuramatsu, Joji B.
    Univ Hosp Erlangen, Dept Neurol, Erlangen, Germany.
    Roeder, Sebastian S.
    Univ Hosp Erlangen, Dept Neurol, Erlangen, Germany.
    Kloska, Stephan P.
    Univ Hosp Erlangen, Dept Neuroradiol, Erlangen, Germany.
    Muehlen, Iris
    Univ Hosp Erlangen, Dept Neuroradiol, Erlangen, Germany.
    Doerfler, Arnd
    Univ Hosp Erlangen, Dept Neuroradiol, Erlangen, Germany.
    Schwab, Stefan
    Univ Hosp Erlangen, Dept Neurol, Erlangen, Germany.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala Univ, Dept Phys & Astron, Div Ion Phys, Uppsala, Sweden..
    Bernard, Samuel
    Univ Lyon, CNRS, UMR 5208, Inst Camille Jordan, Villeurbanne, France.
    Frisen, Jonas
    Karolinska Inst, Dept Cell & Mol Biol, Stockholm, Sweden.
    Meningioma growth dynamics assessed by radiocarbon retrospective birth dating2018In: EBioMedicine, ISSN 0360-0637, E-ISSN 2352-3964, Vol. 27, p. 176-181Article in journal (Refereed)
    Abstract [en]

    It is not known how long it takes from the initial neoplastic transformation of a cell to the detection of a tumor, which would be valuable for understanding tumor growth dynamics. Meningiomas show a broad histological, genetic and clinical spectrum, are usually benign and considered slowly growing. There is an intense debate regarding their age and growth pattern and when meningiomas should be resected. We have assessed the age and growth dynamics of 14 patients with meningiomas (WHO grade I: n = 6 with meningothelial and n = 6 with fibrous subtype, as well as n = 2 atypical WHO grade II meningiomas) by combining retrospective birth-dating of cells by analyzing incorporation of nuclear-bomb-test-derived 14C, analysis of cell proliferation, cell density, MRI imaging and mathematical modeling. We provide an integrated model of the growth dynamics of benign meningiomas. The mean age of WHO grade I meningiomas was 22.1 ± 6.5 years, whereas atypical WHO grade II meningiomas originated 1.5 ± 0.1 years prior to surgery (p < 0.01). We conclude that WHO grade I meningiomas are very slowly growing brain tumors, which are resected in average two decades after time of origination.

  • 385. Huttner, Hagen B
    et al.
    Bergmann, Olaf
    Salehpour, Mehran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Rácz, Attila
    Tatarishvili, Jemal
    Lindgren, Emma
    Csonka, Tamás
    Csiba, László
    Hortobágyi, Tibor
    Méhes, Gábor
    Englund, Elisabet
    Solnestam, Beata Werne
    Zdunek, Sofia
    Scharenberg, Christian
    Ström, Lena
    Ståhl, Patrik
    Sigurgeirsson, Benjamin
    Dahl, Andreas
    Schwab, Stefan
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Bernard, Samuel
    Kokaia, Zaal
    Lindvall, Olle
    Lundeberg, Joakim
    Frisén, Jonas
    The age and genomic integrity of neurons after cortical stroke in humans2014In: Nature Neuroscience, ISSN 1097-6256, E-ISSN 1546-1726, Vol. 17, no 6, p. 801-803Article in journal (Refereed)
    Abstract [en]

    It has been unclear whether ischemic stroke induces neurogenesis or neuronal DNA rearrangements in the human neocortex. Using immunohistochemistry; transcriptome, genome and ploidy analyses; and determination of nuclear bomb test-derived (14)C concentration in neuronal DNA, we found neither to be the case. A large proportion of cortical neurons displayed DNA fragmentation and DNA repair a short time after stroke, whereas neurons at chronic stages after stroke showed DNA integrity, demonstrating the relevance of an intact genome for survival.

  • 386.
    Hägg, Linus
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. KTH, Avdelningen för fusionsplasmafysik.
    Plasma diagnostics for particle confinement studies in magnetic fusion devices2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis investigates the performance and improves a double color interferometer setup, absolutely calibrates a line radiation Balmer H-alpha measurement setup, and uses measurements from both setups to estimate the particle confinement time of a plasma.

    The double colour interferometer at the magnetic confinement plasma device EXTRAP T2R measures the line integrated electron density of the plasma. Electron density is an important parameter in fusion plasma diagnostics but the interferometer at EXTRAP T2R have had several problems. The interferometer setup was changed as follows: A piezo phase shifter was added, the beam expander was adjusted with the help of thermal image plates, and the electronics setup was rewired to remove interferences.

    The setup for Balmer H-alpha line radiation measurements was calibrated and characterized. The particle confinement time was estimated using Abel inversion to produce radial profiles of electron density, electron temperature and H-alpha irradiance.

    The interferometer upgrades did not solve all the problems, but the electron density measurements are now reliable up to around 10 – 20 ms. Since the interferometer only has one channel the electron density profile could not be determined reliably. However, the particle confinement time was estimated for two possible electron density profiles and the results agree with previous studies.

  • 387.
    Håkansson, Ane
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Davour, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Höök, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Natural Resources and Sustainable Development.
    Lantz, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ottosson, Jan
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Economic History.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Qvist, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Svensk elförsörjning i framtiden – en fråga med globala dimensioner: En tvärvetenskaplig rapport från Uppsala universitet2014Report (Other academic)
  • 388.
    Håkansson, Ane
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ottosson, Jan
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Economic History.
    Qvist, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lantz, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    IPCC förordar kärnkraft för att minska utsläppen2014In: Svenska Dagbladet (SvD), Vol. 11 novArticle in journal (Other (popular science, discussion, etc.))
  • 389.
    Höök, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Utvärdering av beräkningskoden APROS för användning i inneslutningsanalyser2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    At Forsmark nuclear power plant the rather old-fashioned software COPTA is used in containment safety analysis. There exists a desire within the organisation to introduce a more modern software with ability to more detailed modeling and increased usability.

    The goal of this thesis was to evaluate the software APROS in containment safety analysis. APROS models describing one of the containments at Forsmark NPP have been developed. Two simulations of typical containment incidents, one of them a large pipe break, have been made where containment safety parameters such as pressure and temperature are studied. Results are analyzed and verified against results from corresponding COPTA models. The other part of the evaluation includes a listing of detected possibilities and limitations with APROS regarding containment modeling in general.

    Overall the developed APROS models show a good agreement with results from corresponding COPTA models. Observed differences can in most cases be explained by minor differences in model choices, mostly concerning flow patterns and heat transfer. APROS has many similarities with COPTA regarding the main calculation and modeling methods but APROS can in most cases be seen as the more sophisticated software with more possibilities regarding modeling complexity. The general conclusion is that APROS shows good potential to be used in containment safety analysis.

  • 390.
    Ianakiev, Kiril
    et al.
    Los Alamos National Laboratory.
    Swinhoe, Martyn
    Los Alamos National Laboratory.
    Iliev, M.L.
    Los Alamos National Laboratory.
    Tobin, Stephen
    Los Alamos National Laboratory.
    Sjöland, Anders
    Swedish Nuclear Fuel and Waste Management Company.
    Liljenfeldt, Henrik
    Swedish Nuclear Fuel and Waste Management Company.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Underwater Testing of Detectors and Electronics Hardware for Spent Fuel Measurements2015Conference paper (Other academic)
    Abstract [en]

    Underwater gamma and neutron spent fuel measurement techniques are being researched to meet thecombined needs of the international safeguards community and the Swedish Nuclear Fuel and WasteManagement Company (SKB), which is responsible for fuel encapsulation and repository operation inSweden. Both SKB and the involved regulators anticipate measuring each spent fuel assemblyindividually before encapsulation; such a measurement plan presents a real challenge for the performanceand long-term behavior of detectors and electronics hardware. The reliability and radiation hardness of theelectronics and detectors are a big challenge for users of this technology. For instance, the gammadetectors and electronics may have to operate at count rates up to few million counts per second whilemaintaining good spectral resolution to detect lines from 137Cs, 134Cs, and 152Eu. If the 10B proportionalcounters are to replace the difficult-to-transport 235U fission chambers, they must tolerate a gamma doserate of many thousand R/h (many tens of Sv/h) without gain changes due to space charge effects or long-term degradation of the gas mixture. To address these challenges, a special underwater enclosure wasdeveloped for testing these detectors and electronics in parallel with the design and deployment ofnondestructive assay options for characterization of the spent fuel. In this paper we describe the hardwareand modeling components of the testing setup.

  • 391.
    Isaksson, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Transientanalys för Forsmark block 2 och 3: Studie av hur val av driftpunkt och pumpreglering påverkar torrkokningsgränsvärdet2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The dry out criterion (MCPR) has been calculated for the most limiting H2-events for Forsmarks unit 2 and 3, at operating points that are normally not analyzed before each cycle. The operating points that normally are regarded as the ones with the lowest margin to dry out are the ones where the thermal power is the highest at agiven recirculation flow. This report shows that this is not the case for Forsmark 3. MCPR-values at partial power operating points are higher for the limiting case inside rather than on the boundary of the region of operation. It is therefore recommended that the method for determining the dry out criterion for Forsmark 3 is revised to account for this effect. It is recommended that the number of operating points studied is increased or that a conservative value is established of how large the effect of operating point can have on MCPR. This conclusion does not, however, apply to Forsmark 2 where the most limiting case has its largest MCPR-values at the boundary.

    The effect on MCPR of changing the A/B- and scram-runback ramps of the recirculation pumps for Forsmark 3 has also been calculated. The alternative rampused was found to give a decrease in the MCPR value between about 20-30 units, depending on fuel type, at partial power operation. The full power limit would not change because the most limiting case at full power is not dependent on the runback ramp of the recirculation pumps.

  • 392.
    Jablonka, Lukas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Kubart, Thomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Gustavsson, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Abedin, Ahmad
    KTH Royal Institute of Technology.
    Hellström, Per-Erik
    KTH Royal Institute of Technology.
    Östling, Mikael
    KTH Royal Institute of Technology.
    Jordan-Sweet, Jean L.
    IBM, TJ Watson Research Center.
    Lavoie, Christian
    IBM, TJ Watson Research Center.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Scalability Study of Nickel Germanides2016Conference paper (Refereed)
  • 393.
    Jablonka, Lukas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Kubart, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Abedin, Ahmad
    KTH Royal Inst Technol, Sch Informat & Commun Technol, SE-16440 Kista, Sweden..
    Hellstrom, Per-Erik
    KTH Royal Inst Technol, Sch Informat & Commun Technol, SE-16440 Kista, Sweden..
    Ostling, Mikael
    KTH Royal Inst Technol, Sch Informat & Commun Technol, SE-16440 Kista, Sweden..
    Jordan-Sweet, Jean
    IBM Corp, TJ Watson Res Ctr, Yorktown Hts, NY 10598 USA..
    Lavoie, Christian
    IBM Corp, TJ Watson Res Ctr, Yorktown Hts, NY 10598 USA..
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Formation of nickel germanides from Ni layers with thickness below 10 nm2017In: Journal of Vacuum Science & Technology B, ISSN 1071-1023, E-ISSN 1520-8567, Vol. 35, no 2, article id 020602Article in journal (Refereed)
    Abstract [en]

    The authors have studied the reaction between a Ge (100) substrate and thin layers of Ni ranging from 2 to 10 nm in thickness. The formation of metal-rich Ni5Ge3 was found to precede that of the monogermanide NiGe by means of real-time in situ x-ray diffraction during ramp-annealing and ex situ x-ray pole figure analyses for phase identification. The observed sequential growth of Ni5Ge3 and NiGe with such thin Ni layers is different from the previously reported simultaneous growth with thicker Ni layers. The phase transformation from Ni5Ge3 to NiGe was found to be nucleationcontrolled for Ni thicknesses < 5 nm, which is well supported by thermodynamic considerations. Specifically, the temperature for the NiGe formation increased with decreasing Ni (rather Ni5Ge3) thickness below 5 nm. In combination with sheet resistance measurement and microscopic surface inspection of samples annealed with a standard rapid thermal processing, the temperature range for achieving morphologically stable NiGe layers was identified for this standard annealing process. As expected, it was found to be strongly dependent on the initial Ni thickness.

  • 394.
    Jacobsen, A. S.
    et al.
    Culham Sci Ctr, EUROfus Consortium, JET, Abingdon OX14 3DB, Oxon, England.;Max Planck Inst Plasma Phys, Garching, Germany..
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Culham Sci Ctr, EUROfus Consortium, JET, Abingdon OX14 3DB, Oxon, England.
    Cazzaniga, C.
    Culham Sci Ctr, EUROfus Consortium, JET, Abingdon OX14 3DB, Oxon, England.;Sci & Technol Facil Council, Rutherford Appleton Lab, ISIS Facil, Didcot OX11 0QX, Oxon, England..
    Eriksson, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Culham Sci Ctr, EUROfus Consortium, JET, Abingdon OX14 3DB, Oxon, England.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Culham Sci Ctr, EUROfus Consortium, JET, Abingdon OX14 3DB, Oxon, England.
    Nocente, M.
    Culham Sci Ctr, EUROfus Consortium, JET, Abingdon OX14 3DB, Oxon, England.;Univ Milano Bicocca, Dipartimento Fis G Occhialini, Milan, Italy..
    Salewski, M.
    Culham Sci Ctr, EUROfus Consortium, JET, Abingdon OX14 3DB, Oxon, England.;Tech Univ Denmark, Dept Phys, Kongens Lyngby, Denmark..
    Tardini, G.
    Culham Sci Ctr, EUROfus Consortium, JET, Abingdon OX14 3DB, Oxon, England.;Max Planck Inst Plasma Phys, Garching, Germany..
    Velocity-space sensitivities of neutron emission spectrometers at the tokamaks JET and ASDEX Upgrade in deuterium plasmas2017In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 88, no 7, article id 073506Article in journal (Refereed)
    Abstract [en]

    Future fusion reactors are foreseen to be heated by the energetic alpha particles produced in fusion reactions. For this to happen, it is important that the energetic ions are sufficiently confined. In present day fusion experiments, energetic ions are primarily produced using external heating systems such as neutral beam injection and ion cyclotron resonance heating. In order to diagnose these fast ions, several different fast-ion diagnostics have been developed and implemented in the various experiments around the world. The velocity-space sensitivities of fast-ion diagnostics are given by so-called weight functions. Here instrument-specific weight functions are derived for neutron emission spectrometry detectors at the tokamaks JET and ASDEX Upgrade for the 2.45 MeV neutrons produced in deuterium-deuterium reactions in deuterium plasmas. Using these, it is possible to directly determine which part of velocity space each detector observes.

  • 395. Jacobsen, A. S.
    et al.
    Salewski, M.
    Eriksson, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Korsholm, S. B.
    Leipold, F.
    Nielsen, S. K.
    Rasmussen, J.
    Stejner, M.
    Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET2014In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 85, no 11, p. 11E103-Article in journal (Refereed)
    Abstract [en]

    The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutronemission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of ameasured time-of-flight spectrum from TOFOR.

  • 396. Jacobsen, A. S.
    et al.
    Salewski, M.
    Eriksson, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Korsholm, S. B.
    Leipold, F.
    Nielsen, S. K.
    Rasmussen, J.
    Stejner, M.
    Velocity-space sensitivity of neutron spectrometry measurements2015In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 55, no 5, article id 053013Article in journal (Refereed)
    Abstract [en]

    Neutron emission spectrometry (NES) measures the energies of neutrons produced in fusion reactions. Here we present velocity-space weight functions for NES and neutron yield measurements. Weight functions show the sensitivity as well as the accessible regions in velocity space for a given range of the neutron energy spectrum. Combined with a calculated fast-ion distribution function, they determine the part of the distribution function producing detectable neutrons in a given neutron energy range. Furthermore, we construct a forward model based on weight functions capable of rapidly calculating neutron energy spectra. This forward model can be inverted and could thereby be used to directly measure the fast-ion phase-space distribution functions, possibly in combination with other fast-ion diagnostics. The presented methods and results can be applied to neutron energy spectra measured by any kind of neutron spectrometer and to any neutron yield measurement.

  • 397. Jacobsen, A.S.
    et al.
    Salewski, M.
    Eriksson, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Korsholm, S.B.
    Leipold, F.
    Nielsen, S.K.
    Rasmussen, J.
    Stejner, M.
    Velocity-space interrogation regions of neutron spectrometers2014In: 41th EPS Conference on Plasma Physics 2014 (EPS 2014): Europhysics Conference Abstracts, 2014Conference paper (Other academic)
  • 398. Jacobsen, Asger
    et al.
    Salewski, Mirko
    Geiger, B.
    Stagner, L.
    Eriksson, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Nielsen, S. K.
    Heidbrink, W. W.
    Korsholm, S. B.
    Leipold, S.
    Rasmussen, J.
    Stejner, M.
    Weiland, M.
    Determining fast-ion velocity-space distribution functions using velocity-space tomography2015Conference paper (Other academic)
  • 399.
    Jacobsson, S
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Backlin, A
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hakansson, A
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    A tomographic method for experimental verification of the integrity of spent nuclear fuel2000In: Applied Radiation and Isotopes, ISSN 0969-8043, E-ISSN 1872-9800, Vol. 53, no 4-5, p. 681-689Article in journal (Refereed)
    Abstract [en]

    A tomographic method for verification of the integrity of spent nuclear fuel assemblies has been developed. The gamma radiation field emanating from emitted radiation from within the assembly is recorded and utilised for reconstructing the internal source

  • 400.
    Jacobsson, Staffan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson, Camilla
    Håkansson, Ane
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Bäcklin, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    A Tomographic Method for Verification of the Integrity of Spent Nuclear Fuel Assemblies - I: Simulation Studies2001In: Nuclear Technology, ISSN 0029-5450, Vol. 135, no 2, p. 131-145Article in journal (Refereed)
    Abstract [en]

    A tomographic method for experimental investigation of the integrity of used light water reactor fuel assemblies has been developed. It is based on spectroscopic measurements of the gamma radiation from fission products in fuel rods. The method utilizes beforehand information about the nominal geometry of both the measured fuel assembly and the measurement equipment. A reconstruction code of the algebraic type has been written.

    The potential of the technique has been examined in extensive simulations, assuming a gamma-ray energy of either 662 keV (137Cs) or 1274 keV (154Eu). The ability of detecting various configurations of manipulated rods, both single and in groups, has been investigated. Two main types of manipulations have been simulated.

    First, there is the removal of rods without replacement. The results indicate that all investigated configurations of removed rods in boiling water reactor (BWR) fuel can be reliably detected using 137Cs radiation. For pressurized water reactor (PWR) fuel, the same result is obtained, with the exception of the most central positions. Here, the more penetrating radiation from 154Eu may have to be used.

    Second, there is the replacement of rods with fresh fuel or fuel-like material. The results clearly indicate that all simulated cases of such manipulation can be most confidently detected. The simulations include various configurations of replaced rods in both BWR and PWR fuel, using both gamma-ray energies.

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