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  • 1. Baron-Wiechec, A.
    et al.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, F.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, N.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eriksson, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, C.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, The Svedberg Laboratory.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. 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.
    Skiba, M.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    Thermal desorption spectrometry of beryllium plasma facing tiles exposed in the JET tokamak2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 133, p. 135-141Article in journal (Refereed)
    Abstract [en]

    The phenomena of retention and de-trapping of deuterium (D) and tritium (T) in plasma facing components (PFC) and supporting structures must be understood in order to limit or control total T inventory in larger future fusion devices such as ITER, DEMO and commercial machines. The goal of this paper is to present details of the thermal desorption spectrometry (TDS) system applied in total fuel retention assessment of PFC at the Joint European Torus (JET). Examples of TDS results from beryllium (Be) wall tile samples exposed to JET plasma in PFC configuration mirroring the planned ITER PFC is shown for the first time. The method for quantifying D by comparison of results from a sample of known D content was confirmed acceptable. The D inventory calculations obtained from Ion Beam Analysis (IBA) and TDS agree well within an error associated with the extrapolation from very few data points to a large surface area.

  • 2.
    Batistoni, P.
    et al.
    ENEA, Dipartimento Fus & Sicurezza Nucl, Via E Fermi 45, I-00044 Frascati, Roma, Italy..
    Campling, D.
    CCFE, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Croft, D.
    CCFE, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Giegerich, T.
    Karlsruhe Inst Technol, POB 3640, D-76021 Karlsruhe, Germany..
    Huddleston, T.
    CCFE, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Lefebvre, X.
    CCFE, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Lengar, I.
    Jozef Stefan Inst, Reactor Phys Dept, Jamova 39, SI-1000 Ljubljana, Slovenia..
    Lilley, S.
    CCFE, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Peacock, A.
    Culham Sci Ctr, JET Exploitat Unit, Abingdon OX14 3DB, Oxon, England..
    Pillon, M.
    ENEA, Dipartimento Fus & Sicurezza Nucl, Via E Fermi 45, I-00044 Frascati, Roma, Italy..
    Popovichev, S.
    CCFE, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Reynolds, S.
    CCFE, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Vila, R.
    CIEMAT, Lab Nacl Fus, Madrid, Spain..
    Villari, R.
    ENEA, Dipartimento Fus & Sicurezza Nucl, Via E Fermi 45, I-00044 Frascati, Roma, Italy..
    Bekris, N.
    EUROfus Consortium, Culham Sci Ctr, ITER Phys Dept, Abingdon OX14 3DB, Oxon, England..
    Technological exploitation of Deuterium-Tritium operations at JET in support of ITER design, operation and safety2016In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 109, p. 278-285Article in journal (Refereed)
    Abstract [en]

    Within the framework of the EUROfusion programme, a work-package of technology projects (WPJET3) is being carried out in conjunction with the planned Deuterium-Tritium experiment on JET (DTE2) with the objective of maximising the scientific and technological return of DT operations at JET in support of ITER. This paper presents the progress since the start of the project in 2014 in the preparatory experiments, analyses and studies in the areas of neutronics, neutron induced activation and damage in ITER materials, nuclear safety, tritium retention, permeation and outgassing, and waste production in preparation of DTE2.

  • 3.
    Biel, W.
    et al.
    Forschungszentrum Julich, Inst Energie & Klimaforschurg, Julich, Germany;Univ Ghent, Dept Appl Phys, Ghent, Belgium.
    Albanese, R.
    Univ Napoli Federico II, Consorzio CREATE, Naples, Italy.
    Ambrosino, R.
    Univ Napoli Parthenope, Consorzio CREATE, Naples, Italy.
    Ariola, M.
    Univ Napoli Parthenope, Consorzio CREATE, Naples, Italy.
    Berkel, M. , V
    Bolshakova, I
    Magnet Sensor Lab, Lvov, Ukraine.
    Brunner, K. J.
    Max Planck Inst Plasma Phys, Greifswald, Germany.
    Cavazzana, R.
    Univ Padua, Ist Nazl Fis Nucl, ENEA, Consorzio RFX,CNR, Padua, Italy.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dinklage, A.
    Max Planck Inst Plasma Phys, Greifswald, Germany.
    Duran, I
    Czech Acad Sci, Inst Plasma Phys, Prague, Czech Republic.
    Dux, R.
    Max Planck Inst Plasma Phys, Garching, Germany.
    Eade, T.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England.
    Entler, S.
    Czech Acad Sci, Inst Plasma Phys, Prague, Czech Republic.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Fable, E.
    Max Planck Inst Plasma Phys, Garching, Germany.
    Farina, D.
    CNR, IFP, Milan, Italy.
    Figini, L.
    CNR, IFP, Milan, Italy.
    Finotti, C.
    Univ Padua, Ist Nazl Fis Nucl, ENEA, Consorzio RFX,CNR, Padua, Italy.
    Franke, Th
    Max Planck Inst Plasma Phys, Garching, Germany;EUROfus Power Plant Phys & Technol PPPT Dept, Garching, Germany.
    Giacomelli, L.
    CNR, IFP, Milan, Italy.
    Giannone, L.
    Max Planck Inst Plasma Phys, Garching, Germany.
    Gonzalez, W.
    Forschungszentrum Julich, Inst Energie & Klimaforschurg, Julich, Germany.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hron, M.
    Czech Acad Sci, Inst Plasma Phys, Prague, Czech Republic.
    Janky, F.
    Max Planck Inst Plasma Phys, Garching, Germany.
    Kallenbach, A.
    Max Planck Inst Plasma Phys, Garching, Germany.
    Kogoj, J.
    Cosylab, Ljubljana, Slovenia.
    Koenig, R.
    Max Planck Inst Plasma Phys, Greifswald, Germany.
    Kudlacek, O.
    Max Planck Inst Plasma Phys, Garching, Germany.
    Luis, R.
    Univ Lisbon, Inst Plasmas & Fusao Nucl, IST, Lisbon, Portugal.
    Malaquias, A.
    Univ Lisbon, Inst Plasmas & Fusao Nucl, IST, Lisbon, Portugal.
    Marchuk, O.
    Forschungszentrum Julich, Inst Energie & Klimaforschurg, Julich, Germany.
    Marchiori, G.
    Univ Padua, Ist Nazl Fis Nucl, ENEA, Consorzio RFX,CNR, Padua, Italy.
    Mattei, M.
    Univ Campania Luigi Vanvitelli, Consorzio CREATE, Caserta, Italy.
    Maviglia, F.
    Univ Napoli Federico II, Consorzio CREATE, Naples, Italy;EUROfus Power Plant Phys & Technol PPPT Dept, Garching, Germany.
    De Masi, G.
    Univ Padua, Ist Nazl Fis Nucl, ENEA, Consorzio RFX,CNR, Padua, Italy.
    Mazon, D.
    CEA, IRFM, F-13108 St Paul Les Durance, France.
    Meister, H.
    Max Planck Inst Plasma Phys, Garching, Germany.
    Meyer, K.
    Cosylab, Ljubljana, Slovenia.
    Micheletti, D.
    CNR, IFP, Milan, Italy.
    Nowak, S.
    CNR, IFP, Milan, Italy.
    Piron, Ch
    Univ Padua, Ist Nazl Fis Nucl, ENEA, Consorzio RFX,CNR, Padua, Italy.
    Pironti, A.
    Univ Napoli Federico II, Consorzio CREATE, Naples, Italy.
    Rispoli, N.
    CNR, IFP, Milan, Italy.
    Rohde, V
    Max Planck Inst Plasma Phys, Garching, Germany.
    Sergienko, G.
    Forschungszentrum Julich, Inst Energie & Klimaforschurg, Julich, Germany.
    El Shawish, S.
    Jozef Stefan Inst, Ljubljana, Slovenia.
    Siccinio, M.
    Max Planck Inst Plasma Phys, Garching, Germany;EUROfus Power Plant Phys & Technol PPPT Dept, Garching, Germany.
    Silva, A.
    Univ Lisbon, Inst Plasmas & Fusao Nucl, IST, Lisbon, Portugal.
    da Silva, F.
    Univ Lisbon, Inst Plasmas & Fusao Nucl, IST, Lisbon, Portugal.
    Sozzi, C.
    CNR, IFP, Milan, Italy.
    Tardocchi, M.
    CNR, IFP, Milan, Italy.
    Tokar, M.
    Forschungszentrum Julich, Inst Energie & Klimaforschurg, Julich, Germany.
    Treutterer, W.
    Max Planck Inst Plasma Phys, Garching, Germany.
    Zohm, H.
    Max Planck Inst Plasma Phys, Garching, Germany.
    Diagnostics for plasma control -: From ITER to DEMO2019In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 146, no A, p. 465-472Article in journal (Refereed)
    Abstract [en]

    The plasma diagnostic and control (D&C) system for a future tokamak demonstration fusion reactor (DEMO) will have to provide reliable operation near technical and physics limits, while its front-end components will be subject to strong adverse effects within the nuclear and high temperature plasma environment. The ongoing developments for the ITER D&C system represent an important starting point for progressing towards DEMO. Requirements for detailed exploration of physics are however pushing the ITER diagnostic design towards using sophisticated methods and aiming for large spatial coverage and high signal intensities, so that many front-end components have to be mounted in forward positions. In many cases this results in a rapid aging of diagnostic components, so that additional measures like protection shutters, plasma based mirror cleaning or modular approaches for frequent maintenance and exchange are being developed. Under the even stronger fluences of plasma particles, neutron/gamma and radiation loads on DEMO, durable and reliable signals for plasma control can only be obtained by selecting diagnostic methods with regard to their robustness, and retracting vulnerable front-end components into protected locations. Based on this approach, an initial DEMO D&C concept is presented, which covers all major control issues by signals to be derived from at least two different diagnostic methods (risk mitigation).

  • 4.
    Binda, Federico
    et al.
    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.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Calculation of the profile-dependent neutron backscatter matrix for the JET neutron camera system2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 865-868Article in journal (Refereed)
    Abstract [en]

    We investigated the dependence of the backscatter component of the neutron spectrum on the emissivity profile. We did so for the JET neutron camera system, by calculating a profile-dependent backscatter matrix for each of the 19 camera channels using a MCNP model of the JET tokamak. We found that, when using a low minimum energy for the summation of the counts in the neutron pulse height spectrum, the backscatter contribution can depend significantly on the emissivity profile. The maximum variation in the backscatter level was 24% (8.0% when compared to the total emission). This effect needs to be considered when a correction for the backscatter contribution is applied to the measured profile.

  • 5.
    Calabro, G.
    et al.
    Department of Economics, Engineering, Society and Business Organization (DEIm), University of Tuscia, Largo dell’Università snc, Viterbo, Italy.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, Nataliia
    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.
    Eriksson, Jacob
    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.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    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.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    Natl Ctr Nucl Res, Otwock, Poland.
    Divertor currents optimization procedure for JET-ILW high flux expansion experiments2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 129, p. 115-119Article in journal (Refereed)
    Abstract [en]

    This paper deals with a divertor coil currents optimized procedure to design High Flux Expansion (HFE) configurations in the JET tokamak aimed to study the effects of flux expansion variation on the radiation fraction and radiated power re-distribution. A number of benefits of HFE configuration have been experimentally demonstrated on TCV, EAST, NSTX and DIII-D tokamaks and are under investigation for next generation devices, as DEMO and DTT. The procedure proposed here exploits the linearized relation between the plasma-wall gaps and the Poloidal Field (PF) coil currents. Once the linearized model is provided by means of CREATE-NL code, the divertor coils currents are calculated using a constrained quadratic programming optimization procedure, in order to achieve HFE configuration. Flux expanded configurations have been experimentally realized both in ohmic and heated plasma with and without nitrogen seeding. Preliminary results on the effects of the flux expansion variation on total power radiation increase will be also briefly discussed.

  • 6.
    Cecconello, Marco
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Marocco, D.
    ENEA, CR Frascati, Via E Fermi 45, I-00044 Rome, Italy..
    Moro, F.
    ENEA, CR Frascati, Via E Fermi 45, I-00044 Rome, Italy..
    Esposito, B.
    ENEA, CR Frascati, Via E Fermi 45, I-00044 Rome, Italy..
    Neural network implementation for ITER neutron emissivity profile recognition2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 637-640Article in journal (Refereed)
    Abstract [en]

    The ITER Radial Neutron Camera (RNC) is a neutron diagnostic intended for the measurement of the neutron emissivity radial profile and the estimate of the total fusion power. This paper presents a proof of-principle method based on neural networks to estimate the neutron emissivity profile in different ITER scenarios and for different RNC architectures. The design, optimization and training of the implemented neural network is presented together with a decision algorithm to select, among the multiple trained neural networks, which one provides the inverted neutron emissivity profile closest to the input one. Examples are given for a selection of ITER scenarios and RNC architectures. The results from this study indicate that neural networks for the neutron emissivity recognition in ITER can achieve an accuracy and precision within the spatial and temporal requirements set by ITER for such a diagnostic.

  • 7.
    Cecconello, Marco
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Miklaszewski, R.
    Inst Plasma Phys & Laser Microfus, Hery St 23, PL-01497 Warsaw, Poland.
    Marocco, D.
    ENEA, CR Frascati, Via E Fermi 45, I-00044 Rome, Italy.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Moro, F.
    ENEA, CR Frascati, Via E Fermi 45, I-00044 Rome, Italy.
    Esposito, B.
    ENEA, CR Frascati, Via E Fermi 45, I-00044 Rome, Italy.
    Podda, S.
    ENEA, CR Frascati, Via E Fermi 45, I-00044 Rome, Italy.
    Bienkowska, B.
    Inst Plasma Phys & Laser Microfus, Hery St 23, PL-01497 Warsaw, Poland.
    Szydlowski, A.
    Inst Plasma Phys & Laser Microfus, Hery St 23, PL-01497 Warsaw, Poland.
    Strategy and guidelines for the calibration of the ITER Radial Neutron Camera2019In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 146, p. 2049-2052Article in journal (Refereed)
    Abstract [en]

    A calibration procedure is proposed for ITER Radial Neutron Camera that relies on embedded sources, reference ITER pulses and cross-calibration with ITER fission chambers and activation system coupled to Monte Carlo simulations of radiation transport. The proposed procedure would allow to measure the neutron emissivity profile and of the fusion power with 10 % accuracy and precision, a time resolution of 10 ms and a spatial resolution of a/10 for ITER entire life-time.

  • 8. Coad, J. P.
    et al.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, Nataliia
    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.
    Eriksson, Jacob
    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.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    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.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    Material migration and fuel retention studies during the JET carbon divertor campaigns2019In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 138, p. 78-108Article in journal (Refereed)
    Abstract [en]

    The first divertor was installed in the JET machine between 1992 and 1994 and was operated with carbon tiles and then beryllium tiles in 1994-5. Post-mortem studies after these first experiments demonstrated that most of the impurities deposited in the divertor originate in the main chamber, and that asymmetric deposition patterns generally favouring the inner divertor region result from drift in the scrape-off layer. A new monolithic divertor structure was installed in 1996 which produced heavy deposition at shadowed areas in the inner divertor corner, which is where the majority of the tritium was trapped by co-deposition during the deuterium-tritium experiment in 1997. Different divertor geometries have been tested since such as the Gas-Box and High-Delta divertors; a principle objective has been to predict plasma behaviour, transport and tritium retention in ITER. Transport modelling experiments were carried out at the end of four campaigns by puffing C-13-labelled methane, and a range of diagnostics such as quartz-microbalance and rotating collectors have been installed to add time resolution to the post-mortem analyses. The study of material migration after D-D and D-T campaigns clearly revealed important consequences of fuel retention in the presence of carbon walls. They gave a strong impulse to make a fundamental change of wall materials. In 2010 the carbon divertor and wall tiles were removed and replaced with tiles with Be or W surfaces for the ITER-Like Wall Project.

  • 9. Coiling, Bethany
    et al.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, Nataliia
    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.
    Eriksson, Jacob
    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.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    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.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    Testing of tritium breeder blanket activation foil spectrometer during JET operations2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 136, p. 258-264Article in journal (Refereed)
    Abstract [en]

    Accurate measurement of the nuclear environment within a test tritium breeding-blanket module of a fusion reactor is crucial to determine tritium production rates which are relevant to self-sufficiency of tritium fuel supply, tritium accountancy and also to the evaluation of localised power levels produced in blankets. This requires evaluation of the time-dependent spectral neutron flux within the test tritium breeding-blanket module under harsh radiation and temperature environments. The application of an activation foil-based spectrometer system to determine neutron flux density using a pneumatic transfer system in ITER has been studied, deployed and tested on the Joint European Torus (JET) machine in a recent deuterium - deuterium campaign for a selection of high purity activation foils. Deployment of the spectrometer system has provided important functional and practical testing of the detector measurement system, associated hardware and post processing techniques for the analysis of large data sets produced through the use of list mode data collection. The testing is invaluable for the optimisation of systems for future planned testing in tritium - tritium and deuterium - tritium conditions. Analysis of the time and energy spectra collected to date and the status of the development of methods for post processing are presented in this paper.

  • 10.
    Cruz, N.
    et al.
    Univ Lisbon, Inst Super Tecn, Inst Plasmas & Fusao Nucl, P-1049001 Lisbon, Portugal..
    Pereira, R. C.
    Univ Lisbon, Inst Super Tecn, Inst Plasmas & Fusao Nucl, P-1049001 Lisbon, Portugal..
    Santos, B.
    Univ Lisbon, Inst Super Tecn, Inst Plasmas & Fusao Nucl, P-1049001 Lisbon, Portugal..
    Fernandes, A.
    Univ Lisbon, Inst Super Tecn, Inst Plasmas & Fusao Nucl, P-1049001 Lisbon, Portugal..
    Sousa, J.
    Univ Lisbon, Inst Super Tecn, Inst Plasmas & Fusao Nucl, P-1049001 Lisbon, Portugal..
    Marocco, D.
    ENEA, CR Frascati, Dipartimento FSN, Via E Fermi,45 Frascati, I-00044 Rome, Italy..
    Riva, M.
    ENEA, CR Frascati, Dipartimento FSN, Via E Fermi,45 Frascati, I-00044 Rome, Italy..
    Centioli, C.
    ENEA, CR Frascati, Dipartimento FSN, Via E Fermi,45 Frascati, I-00044 Rome, Italy..
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Correia, C. M. B.
    Univ Coimbra, Dept Fis, LIBPhys UC, P-3004516 Coimbra, Portugal..
    Goncalves, B.
    Univ Lisbon, Inst Super Tecn, Inst Plasmas & Fusao Nucl, P-1049001 Lisbon, Portugal..
    Esposito, B.
    ENEA, CR Frascati, Dipartimento FSN, Via E Fermi,45 Frascati, I-00044 Rome, Italy..
    Real-time software tools for the performance analysis of the ITER Radial Neutron Camera2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 1001-1005Article in journal (Refereed)
    Abstract [en]

    The Radial Neutron Camera (RNC) diagnostic is a neutron detection system with multiple collimators aiming at characterizing the neutron emission that will be produced by the ITER tokamak. The RNC plays a primary role for basic and advanced plasma control measurements and acts as backup for system machine protection measurements. During the RNC system level design phase the following real-time data processing algorithms were developed to assess RNC data throughput needs and measurement performances: (i) real-time data compression block (ii) real-time calculation of the neutron emissivity radial profile, based on Tikhonov regularization, starting from the line-integrated measurements, the line-of-sight geometry and using the magnetic flux information [1] (iii) real-time calculation of the neutron emissivity profile using a priori trained neural networks, the line-integrated measurements and the magnetic flux information (the best output from different neural networks being evaluated by a figure of merit that maps the neutron emissivity profile to the original line-integrated measurements) [21]. This paper presents results for the processing times of the various algorithms and their minimum control cycle for different conditions, such as number of lines of sight, number of magnetic flux surfaces and measurement error on the line integrated RNC measurements.

  • 11.
    Cufar, Aljaz
    et al.
    Jozef Stefan Inst, Reactor Phys Dept, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia..
    Lengar, Igor
    Jozef Stefan Inst, Reactor Phys Dept, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia..
    Kodeli, Ivan
    Jozef Stefan Inst, Reactor Phys Dept, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia..
    Milocco, Alberto
    Culham Sci Ctr, Culham Ctr Fus Energy, Abingdon OX14 3DB, Oxon, England..
    Sauvan, Patrick
    UNED, ETS Ingn Ind, Dept Ingn Energet, C Juan del Rosal 12, Madrid 28040, Spain..
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Snoj, Luka
    Jozef Stefan Inst, Reactor Phys Dept, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia..
    Comparison of DT neutron production codes MCUNED, ENEA-JSI source subroutine and DDT2016In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 109, p. 164-168Article in journal (Refereed)
    Abstract [en]

    As the DT fusion reaction produces neutrons with energies significantly higher than in fission reactors, special fusion-relevant benchmark experiments are often performed using DT neutron generators. However, commonly used Monte Carlo particle transport codes such as MCNP or TRIPOLI cannot be directly used to analyze these experiments since they do not have the capabilities to model the production of DT neutrons. Three of the available approaches to model the DT neutron generator source are the MCUNED code, the ENEA-JSI DT source subroutine and the DDT code. The MCUNED code is an extension of the well-established and validated MCNPX Monte Carlo code. The ENEA-JSI source subroutine was originally prepared for the modelling of the FNG experiments using different versions of the MCNP code (-4, -5, -X) and was later extended to allow the modelling of both DT and DD neutron sources. The DDT code prepares the DT source definition file (SDEF card in MCNP) which can then be used in different versions of the MCNP code. In the paper the methods for the simulation of the DT neutron production used in the codes are briefly described and compared for the case of a simple accelerator-based DT neutron source.

  • 12.
    Drenik, A.
    et al.
    Max Planck Inst Plasma Phys, Garching, Germany; Jozef Stefan Inst, Ljubljana, Slovenia.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, Nataliia
    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.
    Eriksson, Jacob
    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.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    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.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    Natl Ctr Nucl Res NCBJ, Otwock, Poland.
    Analysis of the outer divertor hot spot activity in the protection video camera recordings at JET2019In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 139, p. 115-123Article in journal (Refereed)
    Abstract [en]

    Hot spots on the divertor tiles at JET result in overestimation of the tile surface temperature which causes unnecessary termination of pulses. However, the appearance of hot spots can also indicate the condition of the divertor tile surfaces. To analyse the behaviour of the hot spots in the outer divertor tiles of JET, a simple image processing algorithm is developed. The algorithm isolates areas of bright pixels in the camera image and compares them to previously identified hot spots. The activity of the hot spots is then linked to values of other signals and parameters in the same time intervals. The operation of the detection algorithm was studied in a limited pulse range with high hot spot activity on the divertor tiles 5, 6 and 7. This allowed us to optimise the values of the controlling parameters. Then, the wider applicability of the method has been demonstrated by the analysis of the hot spot behaviour in a whole experimental campaign.

  • 13. Fonnesu, N.
    et al.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, Nataliia
    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.
    Eriksson, Jacob
    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.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    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.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    Shutdown dose rate measurements after the 2016 Deuterium-Deuterium campaign at JET2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 136, p. 1348-1353Article in journal (Refereed)
    Abstract [en]

    The EUROfusion Work Package JET3 programme, established to enable the technological exploitation of the JET experiments over the next years, includes, within the NEXP subproject, a novel Shutdown Dose Rate (SDR) experiment. Considering its ITER-relevance, SDR experiments at JET represent a unique opportunity to validate the numerical tools for ITER nuclear analysis, through the comparison between numerical predictions and measured quantities (C/E). Within this framework, two active gamma dosimeters based on spherical air-vented ionization chambers (ICs) have been installed in ex-vessel positions close to the horizontal ports of the tokamak in Octants 1 and 2. The first JET campaign exploited in the novel SDR experiment is the latest 5-week Deuterium-Deuterium campaign (c36b), which achieved the best results in recent years in terms of high power operation. The present work is dedicated to the analysis of dose rate measurements carried out during this campaign and after shutdown. Proper correction factors are evaluated and applied to the instrument reading, while influence quantities and error sources are analyzed in order to calculate the overall experimental uncertainty.

  • 14.
    Giacomelli, L.
    et al.
    CNR, Ist Fis Plasma P Caldirola, Milan, Italy.
    Rigamonti, D.
    CNR, Ist Fis Plasma P Caldirola, Milan, Italy.
    Nocente, M.
    Univ Milano Bicocca, Dipartimento Fis G Occhialini, Milan, Italy.
    Rebai, M.
    CNR, Ist Fis Plasma P Caldirola, Milan, Italy.
    Tardocchi, M.
    CNR, Ist Fis Plasma P Caldirola, Milan, Italy.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    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.
    Franke, T.
    Max Planck Inst Plasma Phys, Garching, Germany;EUROfus Power Plant Phys & Technol PPPT Dept, Garching, Germany.
    Biel, W.
    Forschungszentrum Julich, Inst Energy & Climate Res, Julich, Germany;Univ Ghent, Dept Appl Phys, Ghent, Belgium.
    Conceptual studies of gamma ray diagnostics for DEMO control2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 136, p. 1494-1498Article in journal (Refereed)
    Abstract [en]

    The future tokamak demonstration fusion reactor (DEMO) will operate at unprecedented physical and technological conditions where high reliability of the system components is required. The conceptual study of a suite of DEMO diagnostics is on-going. Among these, a Gamma-Ray Spectrometric Instrument (GRSI) is being investigated to assess its performance and information quality in view of DEMO control. The GRSI foresees radial orthogonal multi-line of sight viewing DEMO plasma across its poloidal section as a further development of the Gamma-Ray Camera of JET and of the Radial Gamma-Ray Spectrometers proposed for ITER but with stricter technological constraints. These include surface availability in the Tritium Breeding Blankets of DEMO vessel inner wall for diagnostics collimators openings, diagnostics distance from the plasma, neutron irradiation and activation of the reactor structures. On DEMO the gamma-ray (gamma) emission from DT plasmas consists of T(d,gamma)He-5 (E gamma = 16.63 MeV) and T(p,gamma)He-4 (E gamma = 19.81 MeV) reactions which for their high E gamma would allow in principle for background-free measurements. This work reports the assessment on the GRSI diagnostic capability. Reactions cross sections are assessed and used for the calculations of the reactions gamma emission energy spectrum under DEMO DT plasma conditions and compared with 14 MeV neutron emissions before and after the GRSI collimator. Investigation of the GRSI gamma spectrometers performance is also presented. Measurement of the gamma emission intensity of T(d,gamma)He-5 can be in principle used as an independent assessment of DEMO DT plasmas fusion power.

  • 15.
    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.

  • 16. Kresina, Michal
    et al.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, Nataliia
    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.
    Eriksson, Jacob
    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.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    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.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    Preparation for commissioning of materials detritiation facility at Culham Science Centre2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 136, p. 1391-1395Article in journal (Refereed)
    Abstract [en]

    The Materials Detritiation Facility has been designed to thermally treat solid non-combustible radioactive waste produced during operations of the Joint European Torus (JET) that is classified as Intermediate Level Waste in the UK due to its tritium inventory (> 12 kBq/g). The waste will be thermally treated in a retort furnace at temperatures up to 1000 degrees C under a flowing air atmosphere to reduce its tritium inventory sufficiently to allow its disposal at a lower waste category via existing disposal routes. The gaseous flow from the furnace will be processed via a bubbler system, where released tritium will be trapped in water. Commissioning of the facility will be divided into two main parts: inactive and active. The main purpose of the inactive commissioning is to verify that all components and safety systems of the facility are installed, tested and operated properly and within their operational limits. Several trials of the furnace with non-radioactive materials will be performed to verify its temperature profile, and to verify operation of the gaseous process line. During the active commissioning, small amounts of tritium-contaminated material will be introduced into the facility and used for active trials. The tritium inventory in this material has been selected based on the As low as reasonably practicable (ALARP) principle, to ensure that the activity levels are sufficient to fully test the control instrumentation and pose minimal risk to operators during commissioning. Overall, four active trials will be performed with carbon-based and Inconel materials with total tritium inventories of 1MBq, 3GBq, 20GBq and 26GBq. Tritium levels in the bubblers as well as in aerial discharge from the facility will be monitored. Furthermore, all materials used in the active trials will be sampled and analyzed to verify the performance of the process and confirm that a major part of tritium inventory can be removed from materials by the process.

  • 17.
    Lengar, Igor
    et al.
    Jozef Stefan Inst, Reactor Phys Dept, Jamova 39, SI-1000 Ljubljana, Slovenia.;Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, Oxon, England..
    Cufar, Aljaz
    Jozef Stefan Inst, Reactor Phys Dept, Jamova 39, SI-1000 Ljubljana, Slovenia.;Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, Oxon, England..
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, Oxon, England..
    Batistoni, Paola
    ENEA, Via E Fermi 45, I-00044 Rome, Italy.;Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, Oxon, England..
    Popovichev, Sergey
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England.;Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, Oxon, England..
    Snoj, Luka
    Jozef Stefan Inst, Reactor Phys Dept, Jamova 39, SI-1000 Ljubljana, Slovenia.;Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, Oxon, England..
    Syme, Brian
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England.;Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, Oxon, England..
    Vila, Rafael
    CIEMAT, Lab Nacl Fus, Madrid, Spain.;Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, Oxon, England..
    Stankunas, Gediminas
    Lithuanian Energy Inst, Lab Nucl Installat Safety, Breslaujos Str 3, LT-44403 Kaunas, Lithuania.;Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, Oxon, England..
    Radiation damage and nuclear heating studies in selected functional materials during the JET DT campaign2016In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 109, p. 1011-1015Article in journal (Refereed)
    Abstract [en]

    A new Deuterium-Tritium campaign (DTE2) is planned at JET in the next years, with a proposed 14 MeV neutron budget of 1.7 x 10(21), which is nearly an order of magnitude higher than any previous DT campaigns. The neutron and gamma ray fields inside the JET device during DT plasma operations at specific locations have previously been evaluated. It is estimated that a total neutron fluence on the first wall of JET of up to 10(20) n/m(2) could be achieved, which is comparable to the fluence occurring in ITER at the end of life in the rear part of the port plug, where several diagnostic components will be located. The purpose of the present work is to evaluate the radiation damage and nuclear heating in selected functional materials to be irradiated at JET during DT plasma operation. These quantities are calculated with the use of the MCNP6 code and the FISPACT II code. In particular the neutron and gamma ray fields at specific locations inside the JET device, dedicated to material damage studies, were characterized. The emphasis is on a potential longterm irradiation station located close to the first wall at outboard midplane, offering the opportunity to irradiate samples of functional materials used in ITER diagnostics, to assess the degradation of the physical properties. The radiation damage and the nuclear heating were calculated for selected materials irradiated in these positions and for the neutron flux and fluence expected in DTE2. The studied candidate functional materials include, among others, Sapphire, YAG, ZnS, Spinel, Diamond. In addition the activation of the internal irradiation holder itself was calculated with FISPACT. Damage levels in the range of 10(-5) dpa were found. 2016 EURATOM.

  • 18.
    Lengar, Igor
    et al.
    EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England;Jozef Stefan Inst, Jamova Cesta 39, Ljubljana, Slovenia.
    Cufar, Aljaz
    EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England;Jozef Stefan Inst, Jamova Cesta 39, Ljubljana, Slovenia.
    Radulovic, Vladimir
    EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England;Jozef Stefan Inst, Jamova Cesta 39, Ljubljana, Slovenia.
    Batistoni, Paola
    EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England;ENEA, I-00044 Rome, Italy;CCFE, Abingdon OX14 3DB, Oxon, England.
    Popovichev, Sergey
    EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England;CCFE, Abingdon OX14 3DB, Oxon, England.
    Packer, Lee
    EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England;CCFE, Abingdon OX14 3DB, Oxon, England.
    Ghani, Zamir
    EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England;CCFE, Abingdon OX14 3DB, Oxon, England.
    Kodeli, Ivan A.
    EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England;Jozef Stefan Inst, Jamova Cesta 39, Ljubljana, Slovenia.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England.
    Snoj, Luka
    EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England;Jozef Stefan Inst, Jamova Cesta 39, Ljubljana, Slovenia.
    Activation material selection for multiple foil activation detectors in JET TT campaign2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 136, p. 988-992Article in journal (Refereed)
    Abstract [en]

    In the preparation for the Deuterium-Tritium campaign, JET will operate with a tritium plasma. The T + T reaction consists of two notable channels: (1) T + T -> He-4 + 2n, (2) T + T -> He-5 + n -> He-4 + 2n. The reaction channel (1) is the reaction with the highest branching ratio and a continuum of neutron energies being produced. Reaction channel (2) produces a spectrum with a peak at 8.8 MeV. A particular problem is the ratio between the individual TT reaction channels, which is highly dependent on the energy of the reacting tritium ions. There are very few measurements on the TT spectrum and the study at JET would be interesting. The work is focused on the determination of the spectral characteristics in the TT plasma discharges, especially on the presence of the 8.8 MeV peak, a consequence of channel (2) of the TT reaction. The possibility to use an optimized set of activation materials in order to target the measurement of the 8.8 MeV peak is studied. The lower limit of detection for the channel (2) ratio within the TT reaction is estimated and the influence of DT source neutrons, which are a consequence of deuterium traces in the plasma, is investigated.

  • 19.
    Lengar, Igor
    et al.
    Culham Sci Ctr, EUROfus Consortium, Abingdon, Oxon, England;Jozef Stefan Inst, Reactor Phys Div, Jamova Cesta 39, Ljubljana, Slovenia.
    Zohar, Andrej
    Culham Sci Ctr, EUROfus Consortium, Abingdon, Oxon, England;Jozef Stefan Inst, Reactor Phys Div, Jamova Cesta 39, Ljubljana, Slovenia.
    Batistoni, Paola
    Culham Sci Ctr, EUROfus Consortium, Abingdon, Oxon, England;ENEA, Fus Tech Unit, Via E Fermi 45, I-00044 Frascati, Italy;Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England.
    Popovichev, Sergey
    Culham Sci Ctr, EUROfus Consortium, Abingdon, Oxon, England;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. Culham Sci Ctr, EUROfus Consortium, Abingdon, Oxon, England.
    Characterization of JET neutron field in irradiation locations for DD, DT and TT plasmas2019In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 146, p. 1967-1970Article in journal (Refereed)
    Abstract [en]

    The neutron fluxes and spectra were characterized for four locations close to the plasma and related to activation experiments, as the preparation for the upcoming experimental campaigns in JET. The focus was on the study of a variance reduction technique in order to obtain statistically significant results in the parts of the neutron energy spectra, important for irradiation experiments. The DD, DT and TT plasmas were studied with the Monte Carlo hybrid method and the use of the ADVANTG program for generation of weight windows as variance reduction method to accelerate Monte Carlo simulations. The calculations were optimized to obtain low statistical uncertainties for all energy bins in the 640 energy group structure and for all three plasma sources. This included the acceleration of calculations for reaction rates of capture reactions, i.e. in the thermal flux region in irradiation positions on the first wall. Speed-ups due to use of the hybrid method in excess of two orders of magnitude were found with respect to analog calculations despite the vicinity of the plasma source.

  • 20. Moro, F.
    et al.
    Esposito, B.
    Marocco, D.
    Villari, R.
    Petrizzi, L.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    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.
    Gatu Johnson, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dapena, M.
    Neutronic calculations in support of the design of the ITER High Resolution Neutron Spectrometer2011In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 86, no 6-8, p. 1277-1281Article in journal (Refereed)
    Abstract [en]

    This paper presents the results of neutronic calculations performed to address important issues related to the optimization of the ITER HRNS (High resolution Neutron Spectrometer) design, in particular concerning the definition of the collimator and the choice of the detector system. The calculations have been carried out using the MCNP5 Monte Carlo code in a full 3-D geometry. The HRNS collimation system has been included in the latest MCNP ITER 40 model (Alite-4). The ITER scenario 2 reference DT plasma fusion neutron source peaked at 14.1 MeV with Gaussian energy distribution has been used. Neutron fluxes and energy spectra (>1 MeV) have been evaluated at different positions along the HRNS collimator and at the detector location. The noise-to-signal ratio (i.e. the ratio of collided to uncoilided neutrons), the breakdown of the collided spectrum into its components, the dependency on the first wall aperture and the gamma-ray spectra at the detector position have also been analyzed. The impact of the results on the design of the HRNS diagnostic system is discussed.

  • 21.
    Moro, Fabio
    et al.
    ENEA, Dept Fus & Nucl Safety Technol, I-00044 Rome, Italy..
    Marocco, D.
    ENEA, Dept Fus & Nucl Safety Technol, I-00044 Rome, Italy..
    Esposito, B.
    ENEA, Dept Fus & Nucl Safety Technol, I-00044 Rome, Italy..
    Flammini, D.
    ENEA, Dept Fus & Nucl Safety Technol, I-00044 Rome, Italy..
    Podda, S.
    ENEA, Dept Fus & Nucl Safety Technol, I-00044 Rome, Italy..
    Villari, R.
    ENEA, Dept Fus & Nucl Safety Technol, I-00044 Rome, Italy..
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Nuclear analysis of the ITER radial neutron camera architectural options2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 1033-1038Article in journal (Refereed)
    Abstract [en]

    The ITER Radial Neutron Camera (RNC) is a multichannel detection system hosted in the Equatorial Port Plug 1 (EPP 1) designed to provide information on the neutron source total strength arid emissivity profiles. It consists of two sub-systems: the ex-port line-of-sights (LOSs), covering the plasma core, embedded in a massive shielding block located in the Port Interspace, and the in-port LOSs distributed in two removable cassettes integrated inside the Port Plug. Presently, the RNC layout development process is undergoing a System Level Design phase: several preliminary architectural options based on a System Engineering work have been defined: a detailed nuclear analysis of these options has been performed through radiation transport calculations with the MCNP Monte Carlo code. The radiation environment at the detectors positions has been fully characterized through the evaluation of the expected neutron spectra and the secondary gamma background and the analysis of the 3D radiation maps. MoreOver, the impact of a reduced ex-port shielding block on the neutron and gamma spectra has been investigated. The results of the present study provide guidelines for the development of the RNC final design and the necessary data for the measurement performance analysis.

  • 22. Obryk, Barbara
    et al.
    Batistoni, Paola
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Syme, Brian D.
    Popovichev, Sergey
    Stamatelatos, Ion E.
    Vasilopoulou, Theodora
    Bilski, Pawel
    Thermoluminescence measurements of neutron streaming through JET Torus Hall ducts2014In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 89, no 9-10, p. 2235-2240Article in journal (Refereed)
    Abstract [en]

    Thermoluminescence detectors (TLD) were used for dose measurements at JET. Several hundreds of LiF detectors of various types, standard LiF:Mg,Ti and highly sensitive LiF:Mg,Cu,P were produced. LiF detectors consisting of natural lithium are sensitive to slow neutrons, their response to neutrons being enhanced by Li-6-enriched lithium or suppressed by using lithium consisting entirely of Li-7. Pairs of (LiF)-Li-6/(LiF)-Li-7 detectors allow distinguishing between neutron/non-neutron components of a radiation field. For detection of neutrons of higher energy, polyethylene (PE-300) moderators were used. TLDs, located in the centre of cylindrical moderators, were installed at eleven positions in the JET hall and the hall labyrinth in July 2012, and exposure took place during the last two weeks of the experimental campaign. Measurements of the gamma dose were obtained for all positions over a range of about five orders of magnitude variation. As the TLDs were also calibrated in a thermal neutron field, the neutron fluence at the experimental position could be derived. The experimental results are compared with calculations using the MCNP code. The results confirm that the TLD technology can be usefully applied to measurements of neutron streaming through JET Torus Hall ducts.  

  • 23. Oya, Yasuhisa
    et al.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, F.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, N.
    Ericsson, G.
    Eriksson, Jacob
    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.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, The Svedberg Laboratory.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Sjöstrand, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, M.
    Zychor, I.
    Correlation of surface chemical states with hydrogen isotope retention in divertor tiles of JET with ITER-Like Wall2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 132, p. 24-28Article in journal (Refereed)
    Abstract [en]

    To understand the fuel retention mechanism correlation of surface chemical states and hydrogen isotope retention behavior determined by XPS (X-ray photoelectron spectroscopy) and TDS (Thermal desorption spectroscopy), respectively, for JET ITER-Like Wall samples from operational period 2011-2012 were investigated. It was found that the deposition layer was formed on the upper part of the inner vertical divertor area. At the inner plasma strike point region, the original surface materials, W or Mo, were found, indicating to an erosion-dominated region, but deposition of impurities was also found. Higher heat load would induce the formation of metal carbide. At the outer horizontal divertor tile, mixed material layer was formed with iron as an impurity. TDS showed the H and D desorption behavior and the major D desorption temperature for the upper part of the inner vertical tile was located at 370 degrees C and 530 degrees C. At the strike point region, the D desorption temperature was clearly shifted toward higher release temperatures, indicating the stabilization of D trapping by higher heat load

  • 24.
    Santos, B.
    et al.
    Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, Nataliia
    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.
    Eriksson, Jacob
    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.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    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.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zoletnik, S.
    Natl Ctr Nucl Res, Otwock, Poland.
    Control and data acquisition software upgrade for JET gamma-ray diagnostics2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 128, p. 117-121Article in journal (Refereed)
    Abstract [en]

    The Joint European Torus (JET), the largest magnetic confinement plasma physics experiment in operation, has a large amount of key diagnostics for physics exploration and machine operation, which include several Gamma Ray Diagnostics. The Gamma-Ray Spectrometer (GRS), Gamma Camera (GC) and Gamma-Ray Spectrometer Upgrade (GSU) diagnostics have similar Control and Data Acquisition Systems (CDAQ) based on the Advanced Telecommunication Computing Architecture standard, featuring Field Programmable Gate Arrays for data processing and management. During past JET-EP2 enhancements, the GRS and GC diagnostics were successfully installed and commissioned. However, the installed CDAQ software that interfaces these diagnostics to JET Control and Data Acquisition System is different, requiring higher maintenance costs. Benefiting from the Gamma Camera Upgrade (GCU) and new GSU installation and commissioning, the upgrading of the software and controller hardware used in the GRS and GC was evaluated, aiming at software standardization between all three diagnostics for easier maintenance. This paper describes the software standardization process between the diagnostics towards the usage of the same CDAQ software as well as the same Operating System (OS) for the controllers, which allows the operator to minimize the maintenance time, avoiding the need for system specific expertise. The rationale behind the choice of MARTe framework as CDAQ software and Scientific Linux as OS will also be presented.

  • 25.
    Sias, G.
    et al.
    Univ Cagliari, Elect & Elect Engn Dept, Cagliari, Italy.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Klimek, Iwona
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Wodniak, Iwona
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Yadykin, D.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, Nataliia
    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.
    Eriksson, Jacob
    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.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    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.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    Natl Ctr Nucl Res NCBJ, Otwock, Poland.
    A locked mode indicator for disruption prediction on JET and ASDEX upgrade2019In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 138, p. 254-266Article in journal (Refereed)
    Abstract [en]

    The aim of this paper is to present a signal processing algorithm that, applied to the raw Locked Mode signal, allows us to obtain a disruption indicator in principle exploitable on different tokamaks. A common definition of such an indicator for different machines would facilitate the development of portable systems for disruption prediction, which is becoming of increasingly importance for the next tokamak generations. Moreover, the indicator allows us to overcome some intrinsic problems in the diagnostic system such as drift and offset. The behavior of the proposed indicator as disruption predictor, based on crossing optimized thresholds of the signal amplitude, has been analyzed using data of both JET and ASDEX Upgrade experiments. A thorough analysis of the disruption prediction performance shows how the indicator is able to recover some missed and tardy detections of the raw signal. Moreover, it intervenes and corrects premature or even wrong alarms due to, e.g., drifts and/or offsets.

  • 26.
    Snoj, Luka
    et al.
    Jozef Stefan Inst, Reactor Phys Div, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia..
    Lengar, Igor
    Jozef Stefan Inst, Reactor Phys Div, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia..
    Cufar, Aljaz
    Jozef Stefan Inst, Reactor Phys Div, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia..
    Syme, Brian
    Culham Sci Ctr, Culham Ctr Fus Energy, Abingdon OX14 3DB, Oxon, England..
    Popovichev, Sergey
    Culham Sci Ctr, Culham Ctr Fus Energy, Abingdon OX14 3DB, Oxon, England..
    Batistoni, Paola
    ENEA CR Frascati, Via E Fermi 45, I-00044 Rome, Italy..
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Neutronic analysis of JET external neutron monitor response2016In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 109, p. 99-103Article in journal (Refereed)
    Abstract [en]

    The power output of fusion devices is measured in terms of the neutron yield which relates directly to the fusion yield. JET made a transition from Carbon wall to ITER-Like Wall (Beryllium/Tungsten/Carbon) during 2010-11. Absolutely calibrated measurement of the neutron yield by JET neutron monitors was ensured by direct measurements using a calibrated Cf-252 neutron source (NS) deployed by the in-vessel remote handling system (RHS) inside the JET vacuum vessel. Neutronic calculations were required in order to understand the neutron transport from the source in the vacuum vessel to the fission chamber detectors mounted outside the vessel on the transformer limbs of the tokamak. We developed a simplified computational model of JET and the JET RHS in Monte Carlo neutron transport code MCNP and analyzed the paths and structures through which neutrons reach the detectors and the effect of the JET RHS on the neutron monitor response. In addition we performed several sensitivity studies of the effect of substantial massive structures blocking the ports on the external neutron monitor response. As the simplified model provided a qualitative picture of the process only, some calculations were repeated using a more detailed full 3D model of the JET tokamak.

  • 27. Snoj, Luka
    et al.
    Trkov, Andrej
    Lengar, Igor
    Popovichev, Sergey
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Syme, Brian
    Calculations to support JET neutron yield calibration: Neutron scattering in source holder2012In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 87, no 11, p. 1846-1852Article in journal (Refereed)
    Abstract [en]

    After the coated CFC wall to ITER-Like Wall (Beryllium/Tungsten/Carbon) transition in 2010-11, confirmation of the neutron yield calibration will be ensured by direct measurements using a calibrated 252Cf neutron source deployed by the in-vessel remote handling boom and Mascot manipulator inside the JET vacuum vessel. The paper describes preliminary calculations and the results of numerical study of the effect of source holder on neutron detector response. The source baton was designed in such a way, that it does not significantly affect the neutron spectrum, angular neutron flux distribution or activation detector response. All effects are approximately equal to or less than 1%. The largest disturbance to the neutron flux angular distribution and to the neutron spectrum arises from the source capsule. Hence one should obtain as much information as possible about the capsule and the 252Cf source material in order to avoid additional systematic errors.

  • 28.
    Stancar, Ziga
    et al.
    Jozef Stefan Inst, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia.
    Gorelenkova, Marina
    Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08544 USA.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eriksson, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Buchanan, James
    Culham Ctr Fus Energy, Abingdon OX14 3DB, Oxon, England.
    Snoj, Luka
    Jozef Stefan Inst, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia.
    Generation of a plasma neutron source for Monte Carlo neutron transport calculations in the tokamak JET2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 136, p. 1047-1051Article in journal (Refereed)
    Abstract [en]

    The connection between plasma physics and neutronics is crucial for the understanding of the operation and performance of modern and future tokamak devices. Neutrons are one of the primary carriers of information on the plasma state and represent the basis for various plasma diagnostic systems as well as measurements of fusion power, tritium breeding studies, evaluations of tokamak structural embrittlement and the heating of water inside the fusion device's walls. It is therefore important that the birth of neutrons in a plasma and their transport from inside the tokamak vessel to the surrounding structures is well characterized. In this paper a methodology for the modelling of the neutron emission on the tokamak JET is presented. The TRANSP code is used to simulate the total neutron production as well as 2D neutron emission profiles for a JET plasma discharge. The spectra of the fusion neutrons are computed using the DRESS code. The computational results are analysed in an effort to create a plasma neutron source generator, which is to be used for Monte Carlo neutron transport computations.

  • 29. Stankunas, G.
    et al.
    Syme, D. B.
    Popovichev, S.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Batistoni, P.
    Safety analyses in support of neutron detector calibration operations at JET2014In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 89, no 9-10, p. 2204-2209Article in journal (Refereed)
    Abstract [en]

    Neutron detectors in fusion devices need to be calibrated to provide the absolute neutron yield and the fusion power produced in fusion reactions. A new in situ calibration of the JET neutron detectors was recently performed using a Cf-252 neutron source with intensity of about 2.7 x 10(8) n/s. The source was delivered to the JET facility within a transport flask and the surface radiation levels must fall within transport regulations. Some contingency scenarios required transfer of the source into special shields: the operational shield and the auxiliary shield. In this paper we describe the neutron calculations that have been carried out to evaluate the dose rate leakage from the shields which may contain the neutron source. The calculations have been performed using accurate modelling of the neutron and gamma ray emission from the Cf-252 source, and from the three shields. The differences on calculated dose rates deriving from the use of different flux-to-dose conversion factors have also been investigated. A comparison of dose rates calculated and measured is presented from the bare source (in cell) and with the source within its transport flask. 

  • 30. Syme, D. B.
    et al.
    Popovichev, S.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lengar, I.
    Snoj, L.
    Sowden, C.
    Giacomelli, L.
    Hermon, G.
    Allan, P.
    Macheta, P.
    Plummer, D.
    Stephens, J.
    Batistoni, P.
    Prokopowicz, R.
    Jednorog, S.
    Abhangi, M. R.
    Makwana, R.
    Fusion yield measurements on JET and their calibration2014In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 89, no 11, p. 2766-2775Article in journal (Refereed)
    Abstract [en]

    The power output of fusion experiments and fusion reactor-like devices is measured in terms of the neutron yields which relate directly to the fusion yield. In this paper we describe the devices and methods used to make the new in situ calibration of JET in April 2013 and its early results. The target accuracy of this calibration was 10%, just as in the earlier JET calibration and as required for ITER, where a precise neutron yield measurement is important, e.g., for tritium accountancy. We discuss the constraints and early decisions which defined the main calibration approach, e.g., the choice of source type and the deployment method. We describe the physics, source issues, safety and engineering aspects required to calibrate directly the Fission Chambers and the Activation System which carry the JET neutron calibration. In particular a direct calibration of the Activation system was planned for the first time in JET. We used the existing JET remote-handling system to deploy the Cf-252 source and developed the compatible tooling and systems necessary to ensure safe and efficient deployment in these cases. The scientific programme has sought to better understand the limitations of the calibration, to optimise the measurements and other provisions, to provide corrections for perturbing factors (e.g., presence of the remote-handling boom and other non-standard torus conditions) and to ensure personnel safety and safe working conditions. Much of this work has been based on an extensive programme of Monte-Carlo calculations which, e.g., revealed a potential contribution to the neutron yield via a direct line of sight through the ports which presents individually depending on the details of the port geometry.

  • 31.
    Vasilopoulou, T.
    et al.
    NCSR Demokritos, Inst Nucl & Radiol Sci & Technol, Energy & Safety, Athens, Greece.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, Nataliia
    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.
    Eriksson, Jacob
    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.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    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.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    Natl Ctr Nucl Res NCBJ, Otwock, Poland.
    Improved neutron activation dosimetry for fusion2019In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 139, p. 109-114Article in journal (Refereed)
    Abstract [en]

    Neutron activation technique has been widely used for the monitoring of neutron fluence at the Joint European Torus (JET) whereas it is foreseen to be employed at future fusion plants, such as ITER and DEMO. Neutron activation provides a robust tool for the measurement of neutron fluence in the complex environment encountered in a tokamak. However, activation experiments previously performed at JET showed that the activation foils used need to be calibrated in a real fusion environment in order to provide accurate neutron fluence data. Triggered by this challenge, an improved neutron activation method for the evaluation of neutron fluence at fusion devices has been developed. Activation assemblies similar to those used at JET were irradiated under 14 MeV neutrons at the Frascati Neutron Generator (FNG) reference neutron field. The data obtained from the calibration experiment were applied for the analysis of activation foil measurements performed during the implemented JET Deuterium-Deuterium (D-D) campaign. The activation results were compared against thermoluminescence measurements and a satisfactory agreement was observed. The proposed method provides confidence on the use of activation technique for the precise estimation of neutron fluence at fusion devices and enables its successful implementation in the forthcoming JET Deuterium-Tritium (D-T) campaign.

  • 32. Victoria, M.
    et al.
    Dudarev, S.
    Boutard, J. L.
    Diegele, E.
    Laesser, R.
    Almazouzi, A.
    Caturla, M. J.
    Fu, C. C.
    Källne, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Malerba, L.
    Nordlund, K.
    Perlado, M.
    Rieth, A.
    Samaras, A.
    Schaeublin, R.
    Singh, B. N.
    Willaime, F.
    Modelling irradiation effects in fusion materials2007In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 82, no 15-24, p. 2413-2421Article in journal (Refereed)
    Abstract [en]

    We review the current status of the European fusion materials modelling programme. We describe recent findings and outline potential areas for future development. Large-scale density functional theory (DFT) calculations reveal the structure of the point defects in alpha-Fe, and highlight the crucial part played by magnetism. The calculations give accurate migration energies of point defects and the strength of their interaction with He atoms. Kinetic models based on DFT results reproduce the stages of radiation damage recovery in iron, and stages of He-desorption from pre-implanted iron. Experiments aimed at validating the models will be carried out in the future using a multi-beam ion irradiation facility chosen for its versatility and rapid feedback.

  • 33.
    Villari, R.
    et al.
    ENEA, Fus & Technol Nucl Safety & Secur, I-00044 Frascati, Rome, Italy.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, Nataliia
    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.
    Eriksson, Jacob
    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.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    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.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    Shutdown dose rate neutronics experiment during high performances DD operations at JET2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 136, p. 1545-1549Article in journal (Refereed)
    Abstract [en]

    A novel Shutdown dose rate benchmark experiment has been performed at Joint European Torus (JET) machine during the last high performance Deuterium-Deuterium (DD) campaign in preparation of future high Deuterium Tritium experiment (DTE2). On-line continuous gamma dose rate measurements were performed for four months at two ITER relevant ex-vessel positions close to Radial Neutron Camera and on the top of ITER-like Antenna using high-sensitive ionization chambers. Decay gamma spectra at the shutdown were also collected using High Purity Germanium spectrometer to identify dominant radionuclides contributing to the dose. Neutron fluence measurements during operations were performed as well using activation foils assembly installed close to ionization chambers. The measurements are performed to validate shutdown dose rate tools used in ITER. This paper presents the experimental assembly and measurements analyses.

  • 34. Villari, R.
    et al.
    Batistoni, P.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Manning, A.
    Moro, F.
    Petrizzi, L.
    Popovichev, S.
    Syme, D. B.
    Shutdown dose rate benchmark experiment at JET to validate the three-dimensional Advanced-D1S method2012In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 87, no 7-8, p. 1095-1100Article in journal (Refereed)
    Abstract [en]

    The paper describes a new benchmark, performed as a preliminary experiment on JET tokamak during the last shutdown. Dose rate has been measured with different dosimeters along the axis of the main horizontal port of Octant 1, from the plasma centre to 1 m outside the port at various times after shutdown. The activation dose from the horizontal neutron camera, moved outside the torus hall during the shutdown, has also been assessed. The measured values have been compared with dose rates calculated using an Advanced-D1S method in which new computation capabilities have been introduced, such as dose rate spatial mesh map and automated time behaviour. Measurements along the axis of the horizontal port are well predicted by the calculation. With few exceptions, the D1S estimation is within the error of the measurements. The activation of the horizontal camera is underestimated by a factor of 2. However, more accurate measurements are needed to reduce the uncertainties. The Advanced-D1S method, the results and implications of the benchmark are presented and discussed.

1 - 34 of 34
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