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News Article | December 16, 2015

Dear authors, reviewers, readers of The Journal of Nuclear Materials In January 2016, the Journal of Nuclear Materials will go through a very important editorial transition. Dr Louis Mansur, who has been an editor and then the Chairman of the Editors for over 25 years will be stepping down. For the past eighteen month, I have been working to prepare for this transition. I want to take this opportunity to thanks the current editorial team again for their service to the journal and the nuclear materials community: Drs Louis Mansur (ORNL, USA), Roger Stoller(ORNL, USA), Takeo Muroga (NIFS, Japan), Toru Ogawa (Nagaoka University of Technology, Japan), Malcolm Griffiths (CNL, Canada) and Stephane Gin (CEA, France). It is my pleasure to announce that Prof. Gary Was from the University of Michigan will be assuming the role of Editor-in-Chief. He will lead a core team of Senior Editors along side Prof. Steve Zinkle, UT/ORNL Governor's Chair at the University of Tennessee, Prof. Shigeharu Ukai from Hokkaido University and Dr. David Petti from Idaho National Laboratory. Each of the Senior Editors will be supported by a team of 2–3 Associate Editors. The current list of Associate editor is K. Fukuya (Institute of Nuclear Engineering, Fukui, Japan), Q. Huang (Institute of Nuclear Energy Safety Technology, CAS, China), M. Preuss (University of Manchester, UK), N. Dacheux (Université de Montpellier / CEA, France), L. Snead (Massachusetts Institute of Technology, USA),Y. Dai (Paul Scherrer Institute, Switzerland), Jean-Paul Crocombette (CEA France), Lorenzo Malerba (SCK-CEN, Belgium), with C. Stanek (LANL, USA) expected to join very soon. The overall editorial team should comprise 12 members as of 1st January 2016, with an expectation that it will grow to 13 in the first months of 2016. The team therefore encompassed a broad expertise on the various topics of interest to the journal. This extended editorial team will allow us to develop a strategy to better serve the nuclear materials community. We expect that most of the editors will be present at the forthcoming NuMAT 16 conference in Montpellier in November 2016, and please make your way to the conference if you wish to meet and exchange your views with them.

News Article | September 14, 2016

Looking for food that could be harvested by astronauts far from Earth, researchers focused on spirulina, which has been harvested for food in South America and Africa for centuries. ESA astronaut Samantha Cristoforetti ate the first food containing spirulina in space and now the knowledge is being applied to a pilot project in Congo as a food supplement. Preparing for long missions far from Earth, astronauts will need to harvest their own food. ESA's Micro-Ecological Life Support System Alternative team, or MELiSSA, is looking at creating a closed ecosystem that continuously recycles waste into food, oxygen and water. The Arthrospira bacteria – better known as spirulina – have been a staple part of MELiSSA for many years because they is easy to grow and multiply rapidly. The bacteria turn carbon dioxide into oxygen and can be eaten as a delicious protein-rich supplement. They are also highly resistant to radiation found in outer space. During his stay on the International Space Station mission, ESA astronaut Andreas Mogensen tested cereal bars containing spirulina collected through MELiSSA's system to ensure they taste good in space. A Belgian partner in the Melissa project, the SCK·CEN research centre, has been involved since the early days. Their research into spirulina investigated aspects of the bacteria such as gene expression, enzyme activity, how they absorb light, how they move during growth and how they ingest nutrients. This unparalleled knowledge is now being applied around the Congo town of Bikoro. The staple diet in this region is cassava, which supplies very little protein, so spirulina could supplement the local diet with much-needed protein as well as vitamin A and iron. The pilot phase is looking at growing spirulina in tubs of water with potassium bicarbonate and other ingredients that can be found locally. Under sunlight and regular stirring, the tubs are easy for harvesting and provide for a family of six. The spirulina is dried and powdered, with 10 grams sprinkled on food each day enough to satisfy most dietary requirements – adding a slightly saltier taste to a dish. Employees from the SCK·CEN research centre are working with local entrepreneurs to help make the system a success after beginning in one village. Experiments are also planned on the Space Station because nobody knows how some of the organisms in the MELiSSA system will grow in space. A series of experiments will fly the Arthrospira bacteria and cultivate them in the Biolab facility in ESA's Columbus laboratory to see how they adapt to weightlessness. "When we started working on MELiSSA over 25 years ago we were inspired by ecosystems such as found around lake Chad 1500 km to the north of Bikoro," concludes Christophe. "It is fitting that our work creating a circular ecosystem is now helping the local population as well as future astronauts in space." Explore further: Edible algae—coming to a rooftop near you?

Filliatre P.,CEA Cadarache Center | Filliatre P.,French Atomic Energy Commission | Vermeeren L.,SCK | Vermeeren L.,French Atomic Energy Commission | And 6 more authors.
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2011

The fission chambers that provide in-core measurements of the neutron flux in nuclear reactors are also sensitive to the γ-ray flux. According to experimental data, this contribution can be dominant in current mode. We present a calculation route, relying on a description of the physical phenomena, that compute the γ-ray signal in a fission chamber, coming directly from the γ-ray flux, and indirectly from the neutron flux and activated structures. We use it in a working example for which we show that the main contribution of the γ-ray flux to the signal comes from the interaction of the γ-rays with the electrodes. The relative contribution of gammas created by neutron interactions in the detector is small. The comparison of this example with experimental results yields a good qualitative agreement: the γ-ray signal may dominate in current mode, but is effectively suppressed in fluctuation mode. This calculation route will be useful for the design of fission chambers to be operated under high neutron and γ-ray flux. © 2011 Elsevier B.V. All rights reserved.

Noynaert L.,SCK | Verwaest I.,SCK | Libon H.,Belgonucleaire | Cuchet J.-M.,Tractebel Engineering
Proceedings of the International Conference on Radioactive Waste Management and Environmental Remediation, ICEM | Year: 2013

Decommissioning of nuclear facilities is a complex process involving operations such as detailed surveys, decontamination and dismantling of equipment's, demolition of buildings and management of resulting waste and nuclear materials if any. This process takes place in a well-developed legal framework and is controlled and followed-up by stakeholders like the Safety Authority, the Radwaste management Agency and the Safeguards Organism. In the framework of its nuclear waste and decommissioning program and more specifically the decommissioning of the BR3 reactor, SCK•CEN has developed different software tools to secure the waste and material traceability, to support the sound management of the decommissioning project and to facilitate the control and the follow-up by the stakeholders. In the case of Belgium, it concerns the Federal Agency for Nuclear Control, the National Agency for radioactive waste management and fissile material and EURATOM and IAEA. In 2005, BELGONUCLEAIRE decided to shutdown her Dessel MOX fuel fabrication plant and the production stopped in 2006. According to the final decommissioning plan ("PDF") approved by NIRAS, the decommissioning works should start in 2008 at the earliest. In 2006, the management of BELGONUCLEAIRE identified the need for an integrated database and decided to entrust SCK•CEN with its development, because SCK•CEN relies on previous experience in comparable applications namely already approved by authorities such as NIRAS, FANC and EURATOM. The main objectives of this integrated software tool are: • simplified and updated safeguards • waste & material traceability • computerized documentation • support to project management • periodic & final reporting to waste and safety authorities. The software called DASAO (Database for Safeguards, Waste and Decommissioning) was successfully commissioned in 2008 and extensively used from 2009 to the satisfaction of BELGONUCLEAIRE and the stakeholders. SCK•CEN is now implementing a simplified release of the software for the management of the decommissioning of the THETIS reactor. Its decommissioning will start in March 2013 and will be completed by the end of 2014. NOMENCLATURE • A1X, A2X, A3X radioactive waste categories defined by NIRAS/ONDRAF respectively βγ-waste, α suspected waste, α-bearing waste • FANC/AFCN: Federal Agency for Nuclear Control • EURATOM: European Control Agency • INP: Inventory of Nuclear Liability • NIRAS/ONDRAF: National Organism of Radioactive waste and Fissile Material • ZB-batch: This a batch containing decommissioning radioactive waste, packed in 200 l drum (type ALDRUM) and belonging to the A3X waste category. • WDM: "Waste Drum Monitoring" : system used for the radiological characterization of 200 liter drums containing A3X waste Copyright © 2013 by ASME.

Ooms L.,SCK | Maris P.,SCK | Noynaert L.,SCK
Proceedings of the International Conference on Radioactive Waste Management and Environmental Remediation, ICEM | Year: 2013

The Thetis research reactor on the site of the Nuclear Sciences Institute of the Ghent University has been in operation from 1967 until December 2003. This light-water moderated graphite-reflected low-enriched uranium pool-type reactor has been used for various purposes e.g. The production of radioisotopes and activation analyses. During the first years its core power was 15 kW. In the early '70, a core enlargement allowed for operation at typically 150 kW, while the maximum was allowed to be 250 kW In September 2007, Ghent University entrusted to SCK•CEN the management of the back-end of the spent fuel and the decommissioning of the reactor. In 2010, the spent fuel was removed from the reactor and transported to Belgoprocess for cementation in 400 l drums and interim storage awaiting final disposal. This activity allows tackling the decommissioning of the reactor. The objective is to complete its decommissioning by the end of 2014. In the framework of the decommissioning of the Thetis reactor, SCK•CEN set-up the final decommissioning plan and the decommissioning licensing file. These documents include among others a radiological inventory of the reactor. The graphite moderator blocks, the control and the safety pates, the liner of the pool were modeled to assess the activation products (isotopic vector and intensity). At the end of the unloading of the reactor in 2010 a brief mapping of the equipment's and internals of the reactor pool was performed. In 2012, we realized a more detailed mapping. These results confirmed those performed earlier and allowed to confirm the assumptions made in the final decommissioning plan. We set-up the terms of reference for the first decommissioning phase of the reactor namely the dismantling of the reactor i.e. reactor pool, circuits and rabbit system, equipment's and ventilation ducts. The removal of asbestos is also included into this phase. We conducted the selection process and the awarding of this decommissioning job. We gained the decommissioning license in May 2012. We also prepared the software tool allowing managing the decommissioning project by updating the inventory and recording the progress, the characterization measurements and the material and waste production. This software allows also to trace all the material streams and to report to the Authorities. This software is a simplified release of the ones developed by SCK•CEN in the framework of other decommissioning projects like BR3 and Belgonucleaire. The dismantling of the reactor i.e. reactor pool, circuits and rabbit system, will be performed in 2013. In 2014, it is planned to map all the surfaces of the infrastructure to highlight residual contamination of floor, walls and ceiling. The contaminated surfaces will be decontaminated and controlled. The objective is to reach the free release of the reactor building and laboratories by the end of 2014. Copyright © 2013 by ASME.

Salvagnini E.,Medical Imaging Research Center | Bosmans H.,Medical Imaging Research Center | Struelens L.,SCK | Marshall N.W.,Medical Imaging Research Center
Medical Physics | Year: 2013

Purpose: The aim of this paper was to illustrate the value of the new metric effective detective quantum efficiency (eDQE) in relation to more established measures in the optimization process of two digital mammography systems. The following metrics were included for comparison against eDQE: detective quantum efficiency (DQE) of the detector, signal difference to noise ratio (SdNR), and detectability index (d′) calculated using a standard nonprewhitened observer with eye filter. Methods: The two systems investigated were the Siemens MAMMOMAT Inspiration and the Ho-logic Selenia Dimensions. The presampling modulation transfer function (MTF) required for the eDQE was measured using two geometries: a geometry containing scattered radiation and a low scatter geometry. The eDQE, SdNR, and d′ were measured for poly(methyl methacrylate) (PMMA) thicknesses of 20, 40, 60, and 70 mm, with and without the antiscatter grid and for a selection of clinically relevant target/filter (T/F) combinations. Figures of merit (FOMs) were then formed from SdNR and d′ using the mean glandular dose as the factor to express detriment. Detector DQE was measured at energies covering the range of typical clinically used spectra. Results: The MTF measured in the presence of scattered radiation showed a large drop at low spatial frequency compared to the low scatter method and led to a corresponding reduction in eDQE. The eDQE for the Siemens system at 1 mm -1 ranged between 0.15 and 0.27, depending on T/F and grid setting. For the Hologic system, eDQE at 1 mm-1 varied from 0.15 to 0.32, again depending on T/F and grid setting. The eDQE results for both systems showed that the grid increased the system efficiency for PMMA thicknesses of 40 mm and above but showed only small sensitivity to T/F setting. While results of the SdNR and d′ based FOMs confirmed the eDQE grid position results, they were also more specific in terms of T/F selection. For the Siemens system at 20 mm PMMA, the FOMs indicated Mo/Mo (grid out) as optimal while W/Rh (grid in) was the optimal configuration at 40, 60, and 70 mm PMMA. For the Hologic, the FOMs pointed to W/Rh (grid in) at 20 and 40 mm of PMMA while W/Ag (grid in) gave the highest FOM at 60 and 70 mm PMMA. Finally, DQE at 1 mm-1 averaged for the four beam qualities studied was 0.44 ± 0.02 and 0.55 ± 0.03 for the Siemens and Hologic detectors, respectively, indicating only a small influence of energy on detector DQE. Conclusions: Both the DQE and eDQE data showed only a small sensitivity to T/F setting for these two systems. The eDQE showed clear preferences in terms of scatter reduction, being highest for the grid-in geometry for PMMA thicknesses of 40 mm and above. The SdNR and d′ based figures of merit, which contain additional weighting for contrast and dose, pointed to specific T/F settings for both systems. © 2013 American Association of Physicists in Medicine.

De Bruyn D.,SCK | Baeten P.,SCK | Larmignat S.,AREVA | Woaye Hune A.,AREVA | Mansani L.,Ansaldo Energia
International Congress on Advances in Nuclear Power Plants 2010, ICAPP 2010 | Year: 2010

SCK'CEN in association with 18 Europeans partners from industry, research centres and academia, responded to the second FP7 (Framework Programme) call from the European Commission to establish a Central Design Team for the design of a Fast Spectrum Transmutation Experimental Facility (FASTEF) able to demonstrate efficient transmutation and associated technology through a system working in subcritical and/or critical mode. The proposal prepared by the consortium coordinated by SCK'CEN has been accepted for funding and the project has started on April 01st, 2009for a period of three years.As a further upgrade of the existing XT-ADS design, performed from 2005 to 2009 in the frame of an FP6 project, based itself on the SCK'CEN MYRRHA 2005 design and described in a companion paper, FASTEF is proposed to be designed to an advanced engineering level for decision to embark for its construction at the horizon of2012-2013 with the following objectives: to be operated as a flexible and high-flux fast spectrum irradiation facility, to be an experimental device to serve as a test-bed for transmutation (by demonstrating the ADS technology and the efficient transmutation of high level waste) andfinally to contribute to the demonstration of the Lead Fast Reactor technology without jeopardizing the two above objectives. The work of the Central Design Team (CDT) has been organised in four technical work packages: definition of specifications, design in sub-critical and critical mode, plant requirements and finally key issues towards realisation. As the first work package, devoted to the FASTEF specifications, has occurred in the first months of the project, this paper is dedicated to a detailed presentation of its conclusions.

Pheron X.,Andra Inc | Pheron X.,CNRS Hubert Curien Laboratory | Girard S.,CEA DAM Ile-de-France | Boukenter A.,CNRS Hubert Curien Laboratory | And 4 more authors.
Optics Express | Year: 2012

The use of distributed strain and temperature in optical fiber sensors based on Brillouin scattering for the monitoring of nuclear waste repository requires investigation of their performance changes under irradiation. For this purpose, we irradiated various fiber types at high gamma doses which represented the harsh environment constraints associated with the considered application. Radiation leads to two phenomena impacting the Brillouin scattering: 1) decreasing in the fiber linear transmission through the radiation-induced attenuation (RIA) phenomenon which impacts distance range and 2) modifying the Brillouin scattering properties, both intrinsic frequency position of Brillouin loss and its dependence on strain and temperature. We then examined the dose dependence of these radiation-induced changes in the 1 to 10 MGy dose range, showing that the responses strongly depend on the fiber composition. We characterized the radiation effects on strain and temperature coefficients, dependencies of the Brillouin frequency, providing evidence for a strong robustness of these intrinsic properties against radiations. From our results, Fluorine-doped fibers appear to be very promising candidates for temperature and strain sensing through Brillouin-based sensors in high gamma-ray dose radiative environments. © 2012 Optical Society of America.

Vandeplassche D.,SCK | Biarrotte J.-L.,Institute Of Physique Nucleaire | Klein H.,Institute For Angewandte Physik | Podlech H.,Institute For Angewandte Physik
IPAC 2011 - 2nd International Particle Accelerator Conference | Year: 2011

Accelerator Driven Systems (ADS) are promising tools for the efficient transmutation of nuclear waste products in dedicated industrial installations, called transmuters. The Myrrha project at Mol, Belgium, placed itself on the path towards these applications with a multipurpose and versatile system based on a liquid Pb-Bi (LBE) cooled fast reactor (70 MWth) which may be operated in both critical and subcritical modes. In the latter case the core is fed by spallation neutrons obtained from a 600 MeV proton beam hitting the LBE coolant/target. The accelerator providing this beam is a high intensity CW superconducting linac which is laid out for the highest achievable reliability. The combination of a parallel redundant and of a fault tolerant scheme should allow obtaining an MTBF value in excess of 250 hours that is required for optimal integrity and successful operation of the ADS. Myrrha is expected to be operational in 2023. The forthcoming 4-year period is fully dedicated to R&D activities, and in the field of the accelerator they are strongly focused on the reliability aspects and on the proper shaping of the beam trip spectrum. Copyright © 2011 by IPAC'11/EPS-AG.

Abderrahim H.A.,SCK | De Bruyn D.,SCK | Van den Eynde G.,SCK | Michiels S.,SCK
Wiley Interdisciplinary Reviews: Energy and Environment | Year: 2014

To be able to answer the worlds' increasing demand for energy, nuclear energy must be part of the energy basket. The generation of nuclear energy produces, besides energy, also high-level nuclear waste, which is nowadays for geological storage. Transmutation of the minor actinides and long-lived fission products that arise from the reprocessing of the nuclear waste can reduce the radiological impact of these radioactive elements. Transmutation can be completed in an efficient way in fast neutron spectrum facilities. Both critical fast reactors and subcritical accelerator driven systems are potential candidates as dedicated transmutation systems. Nevertheless, an accelerator driven system operates in a flexible and safer manner even with a core loading containing a high amount of minor actinides leading to a high more-efficient transmutation approach. © 2013 John Wiley & Sons, Ltd.

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