uu.seUppsala University Publications
Change search
Refine search result
123 1 - 50 of 103
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the 'Create feeds' function.
  • 1.
    Axelsson, Anders
    et al.
    The Swedish Defence Research Agency.
    Andersson, Per
    The Swedish Defence Research Agency.
    Elmgren, Klas
    The Swedish Defence Research Agency.
    Jansson, Peter
    The Swedish Defence Research Agency.
    Olsson, Nils
    The Swedish Defence Research Agency.
    Ringbom, Anders
    The Swedish Defence Research Agency.
    Wilhelmsen-Rolander, Katarina
    The Swedish Defence Research Agency.
    Fast neutron analysis at the Swedish Defence Research Agency (FOI)2003Conference paper (Other academic)
  • 2.
    Branger, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Comparison of prediction models for Cherenkov light emissions from nuclear fuel assemblies2017In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 12, article id P06007Article in journal (Refereed)
    Abstract [en]

    The Digital Cherenkov Viewing Device (DCVD) is a tool used by nuclear safeguards inspectors to verify irradiated nuclear fuel assemblies in wet storage based on the Cherenkov light produced by the assembly. Verification that no rods have been substituted in the fuel, so-called partial-defect verification, is made by comparing the intensity measured with a DCVD with a predicted intensity, based on operator fuel declaration. The prediction model currently used by inspectors is based on simulations of Cherenkov light production in a BWR 8x8 geometry. This work investigates prediction models based on simulated Cherenkov light production in a BWR 8x8 and a PWR 17x17 assembly, as well as a simplified model based on a single rod in water. Cherenkov light caused by both fission product gamma and beta decays were considered.The simulations reveal that there are systematic differences between the models, most noticeably with respect to the fuel assembly cooling time. Consequently, a prediction model that is based on another fuel assembly configuration than the fuel type being measured, will result in systematic over or underestimation of short-cooled fuel as opposed to long-cooled fuel. While a simplified model may be accurate enough for fuel assemblies with fairly homogeneous cooling times, the prediction models may differ by up to 18 \,\% for more heterogeneous fuel. Accordingly, these investigations indicate that the currently used model may need to be exchanged with a set of more detailed, fuel-type specific models, in order minimize the model dependant systematic deviations.

  • 3.
    Branger, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    On Cherenkov light production by irradiated nuclear fuel rods2017In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 12, article id T06001Article in journal (Refereed)
    Abstract [en]

    Safeguards verification of irradiated nuclear fuel assemblies in wet storage is frequently done by measuring the Cherenkov light in the surrounding water produced due to radioactive decays of fission products in the fuel. This paper accounts for the physical processes behind the Cherenkov light production caused by a single fuel rod in wet storage, and simulations are presented that investigate to what extent various properties of the rod affect the Cherenkov light production. The results show that the fuel properties has a noticeable effect on the Cherenkov light production, and thus that the prediction models for Cherenkov light production which are used in the safeguards verifications could potentially be improved by considering these properties.It is concluded that the dominating source of the Cherenkov light is gamma-ray interactions with electrons in the surrounding water. Electrons created from beta decay may also exit the fuel and produce Cherenkov light, and e.g. Y-90 was identified as a possible contributor to significant levels of the measurable Cherenkov light in long-cooled fuel. The results also show that the cylindrical, elongated fuel rod geometry results in a non-isotropic Cherenkov light production, and the light component parallel to the rod's axis exhibits a dependence on gamma-ray energy that differs from the total intensity, which is of importance since the typical safeguards measurement situation observes the vertical light component. It is also concluded that the radial distributions of the radiation sources in a fuel rod will affect the Cherenkov light production.

  • 4.
    Branger, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    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.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Investigating the Cherenkov light production due to cross-talk in closely stored nuclear fuel assemblies in wet storage2017Conference paper (Other academic)
    Abstract [en]

    The Digital Cherenkov Viewing Device (DCVD) is one of the tools available to a safeguards inspector performing verifications of irradiated nuclear fuel assemblies in wet storage. One of the main advantages of safeguards verification using Cherenkov light is that it can be performed without moving the fuel assemblies to an isolated measurement position, allowing for quick measurements. One disadvantage of this procedure is that irradiated nuclear fuel assemblies are often stored close to each other, and consequently gamma radiation from one assembly can enter a neighbouring assembly, and produce Cherenkov light in the neighbour. As a result, the measured Cherenkov light intensity of one assembly will include contributions from its neighbours, which may affect the safeguards conclusions drawn.

    In this paper, this so-called near-neighbour effect, is investigated and quantified through simulation. The simulations show that for two fuel assemblies with similar properties stored closely, the near-neighbour effect can cause a Cherenkov light intensity increase of up to 3% in a measurement. For one fuel assembly surrounded by identical neighbour assemblies, a total of up to 14% of the measured intensity may emanate from the neighbours. The relative contribution from the near-neighbour effect also depends on the fuel properties; for a long-cooled, low-burnup assembly, with low gamma and Cherenkov light emission, surrounded by short-cooled, high-burnup assemblies with high emission, the measured Cherenkov light intensity may be dominated by the contributions from its neighbours.

    When the DCVD is used for partial-defect verification, a 50% defect must be confidently detected. Previous studies have shown that a 50% defect will reduce the measured Cherenkov light intensity by 30% or more, and thus a threshold has been defined, where a ≥30% decrease in Cherenkov light indicates a partial defect. However, this work shows that the near-neighbour effect may also influence the measured intensity, calling either for a lowering of this threshold or for the intensity contributions from neighbouring assemblies to be corrected for. In this work, a method is proposed for assessing the near-neighbour effect based on declared fuel parameters, enabling the latter type of corrections.

  • 5.
    Branger, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Experimental evaluation of models for predicting Cherenkov light intensities from short-cooled nuclear fuel assemblies2018In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 13, article id P02022Article in journal (Refereed)
    Abstract [en]

    The Digital Cherenkov Viewing Device (DCVD) is a tool used by nuclear safeguards inspectors to verify irradiated nuclear fuel assemblies in wet storage based on the recording of Cherenkov light produced by the assemblies. One type of verification involves comparing the measured light intensity from an assembly with a predicted intensity, based on assembly declarations. Crucial for such analyses is the performance of the prediction model used, and recently new modelling methods have been introduced to allow for enhanced prediction capabilities by taking the irradiation history into account, and by including the cross-talk radiation from neighbouring assemblies in the predictions.

    In this work, the performance of three models for Cherenkov-light intensity prediction is evaluated by applying them to a set of short-cooled PWR 17x17 assemblies for which experimental DCVD measurements and operator-declared irradiation data was available; (1) a two-parameter model, based on total burnup and cooling time, previously used by the safeguards inspectors, (2) a newly introduced gamma-spectrum-based model, which incorporates cycle-wise burnup histories, and (3) the latter gamma-spectrum-based model with the addition to account for contributions from neighbouring assemblies.

    The results show that the two gamma-spectrum-based models provide significantly higher precision for the measured inventory compared to the two-parameter model, lowering the standard deviation between relative measured and predicted intensities from 15.2% to 8.1% respectively 7.8%.

    The results show some systematic differences between assemblies of different designs (produced by different manufacturers) in spite of their similar PWR 17x17 geometries, and possible ways are discussed to address such differences, which may allow for even higher prediction capabilities. Still, it is concluded that the gamma-spectrum-based models enable confident verification of the fuel assembly inventory at the currently used detection limit for partial defects, being a 30% discrepancy between measured and predicted intensities, while some false detection occurs with the two-parameter model. The results also indicate that the gamma-spectrum-based prediction methods are accurate enough that the 30% discrepancy limit could potentially be lowered.

    The full text will be freely available from 2019-03-01 15:24
  • 6.
    Branger, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Improving the prediction model for Cherenkov light generation by irradiated nuclear fuel assemblies in wet storage for enhanced partial-defect verification capability2015Conference paper (Other academic)
  • 7. Bäcklin, Anders
    et al.
    Håkansson, Ane
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Radiation Sciences.
    Jacobsson, Staffan
    Characterization of irradiated LWR fuel assemblies with long cooling time by means of gamma-ray measurements1998Conference paper (Refereed)
  • 8.
    Davour, Anna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. OECD Halden Reactor Project, Halden, Norway.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Holcombe, Scott
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. OECD Halden Reactor Project, Halden, Norway.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Troeng, Mats
    Applying image analysis techniques to tomographic images of irradiated nuclear fuel assemblies2016In: Annals of Nuclear Energy, ISSN 0306-4549, E-ISSN 1873-2100, Vol. 96, p. 223-229Article in journal (Refereed)
    Abstract [en]

    In this paper we present a set of image analysis techniques used for extraction of information from cross-sectional images of nuclear fuel assemblies, achieved from gamma emission tomography measurements. These techniques are based on template matching, an established method for identifying objects with known properties in images.

    We demonstrate a rod template matching algorithm for identification and counting of the fuel rods present in the image. This technique may be applicable in nuclear safeguards inspections, because of the potential of verifying the presence of all fuel rods, or potentially discovering any that are missing.

    We also demonstrate the accurate determination of the position of a fuel assembly, or parts of the assembly, within the imaged area. Accurate knowledge of the assembly position enables detailed modelling of the gamma transport through the fuel, which in turn is needed to make tomographic reconstructions quantifying the activity in each fuel rod with high precision.

    Using the full gamma energy spectrum, details about the location of different gamma-emitting isotopes within the fuel assembly can be extracted. We also demonstrate the capability to determine the position of supporting parts of the nuclear fuel assembly through their attenuating effect on the gamma rays emitted from the fuel. Altogether this enhances the capabilities of non-destructive nuclear fuel characterization.

  • 9.
    Favalli, Andrea
    et al.
    Los Alamos National Laboratory, Los Alamos, NM, USA.
    Vo, Duc
    Los Alamos National Laboratory, Los Alamos, NM, USA.
    Grogan, B.
    Oak Ridge National Laboratory, Oak Ridge, TN, USA.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Liljenfeldt, Henrik
    Oak Ridge National Laboratory, Oak Ridge, TN, USA.
    Mozin, Vladimir
    Lawrence Livermore National Laboratory, Livermore, CA, USA.
    Schwalbach, Peter
    European Commission, DG Energy, Euratom Safeguards Luxemburg, Luxemburg.
    Sjöland, Anders
    Swedish Nuclear Fuel and Waste Management Company.
    Tobin, S.J.
    Los Alamos National Laboratory, Los Alamos, NM, USA.
    Trellue, Holly
    Los Alamos National Laboratory, Los Alamos, NM, USA.
    Vaccaro, Stefano
    European Commission, DG Energy, Euratom Safeguards Luxemburg, Luxemburg.
    Determining initial enrichment, burnup, and cooling time of pressurized-water-reactor spent fuel assemblies by analyzing passive gamma spectra measured at the Clab interim-fuel storage facility in Sweden2016In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 820, p. 102-111Article in journal (Refereed)
    Abstract [en]

    The purpose of the Next Generation Safeguards Initiative (NGSI)–Spent Fuel (SF) project is to strengthen the technical toolkit of safeguards inspectors and/or other interested parties. The NGSI–SF team is working to achieve the following technical goals more easily and efficiently than in the past using nondestructive assay measurements of spent fuel assemblies: (1) verify the initial enrichment, burnup, and cooling time of facility declaration; (2) detect the diversion or replacement of pins; (3) estimate the plutonium mass [which is also a function of the variables in (1)]; (4) estimate the decay heat; and (5) determine the reactivity of spent fuel assemblies. Since August 2013, a set of measurement campaigns has been conducted at the Central Interim Storage Facility for Spent Nuclear Fuel (Clab), in collaboration with Swedish Nuclear Fuel and Waste Management Company (SKB). One purpose of the measurement campaigns was to acquire passive gamma spectra with high-purity germanium and lanthanum bromide scintillation detectors from Pressurized Water Reactor and Boiling Water Reactor spent fuel assemblies. The absolute 137Cs count rate and the 154Eu/137Cs, 134Cs/137Cs, 106Ru/137Cs, and 144Ce/137Cs isotopic ratios were extracted; these values were used to construct corresponding model functions (which describe each measured quantity’s behavior over various combinations of burnup, cooling time, and initial enrichment) and then were used to determine those same quantities in each measured spent fuel assembly. The results obtained in comparison with the operator declared values, as well as the methodology developed, are discussed in detail in the paper.

  • 10.
    Grape, Sophie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Åberg Lindell, Matilda
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    New perspectives on nuclear power - Generation IV nuclear energy systems to strengthen nuclear non-proliferation and support nuclear disarmament2014In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 73, p. 815-819Article in journal (Refereed)
    Abstract [en]

    Recently, nuclear power has received support from environmental and climate researchers emphasizing the need to address factors of global importance such as climate change, peace and welfare. Here, we add to previous discussions on meeting future climate goals while securing safe supplies of energy by discussing future nuclear energy systems in the perspective of strengthening nuclear non-proliferation and aiding in the process of reducing stockpiles of nuclear weapons materials.

    New nuclear energy systems, currently under development within the Generation IV (Gen IV) framework, are being designed to offer passive safety and inherent means to mitigate consequences of nuclear accidents. Here, we describe how these systems may also be used to reduce or even eliminate stockpiles of civil and military plutonium—the former present in waste from today׳s reactors and the latter produced for weapons purposes. It is argued that large-scale implementation of Gen IV systems would impose needs for strong nuclear safeguards. The deployment of Safeguards-by-Design principles in the design and construction phases can avoid draining of IAEA resources by enabling more effective and cost-efficient nuclear safeguards, as compared to the current safeguards implementation, which was enforced decades after the first nuclear power plants started operation.

  • 11.
    Grape, Sophie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    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.
    Branger, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Forskning inom teknisk kärnämneskontroll vid Uppsala universitet under 2014–20152016Report (Other academic)
    Abstract [sv]

    Uppsala universitet har inom ramen för olika avtal med SSM under 2014-2015 bedrivit ett omfattande forskningsprogram inom kärnämneskontroll. Forskningsprogrammet har under denna tid innefattat 3 doktorander med dedikerade forskningsprojekt och ett flertal seniora forskare som helt eller delvis har varit engagerade inom kärnämneskontroll.

    Denna rapport uppmärksammar särskilt fyra forskningsområden av hög relevans för den globala kärnämneskontrollen, vilka benämns; DCVD, Next Generation Safeguards Initiative, verifiering av atypiska bränsleobjekt och Generation IV kärnkraftsystem. Även andra forskningsaktiviteter har genomförts inom ramen för forskningsprogrammet, vilka dock ligger utanför redovisningen i denna rapport.

    Under perioden 2014-2015 producerades inom forskningsprogrammet 9 artiklar som skickats till vetenskapliga tidskrifter med peer-review-granskning. Därutöver gjordes medvetna satsningar på att lyfta fram forskningen på de arenor som är av störst betydelse för det internationella kärnämneskontrollarbetet, d.v.s. på de symposier och möten som arrangeras av FN:s internationella atomenergiorgan (IAEA), det europeiska samarbetsorganet ESARDA och den amerikanska organisationen INMM. Vid dessa internationella konferenser publicerades ytterligare 15 vetenskapliga artiklar med unikt innehåll under perioden. En publikationslista med samtliga forskningsarbeten som producerats under perioden redovisas i denna rapport.

  • 12.
    Grape, Sophie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Österlund, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Students’ approaches to learning from other students’ oral presentations2013Conference paper (Other academic)
    Abstract [en]

    A phenomenographic study has been performed in order to investigate students’ approaches to learning from other students’ oral presentations in the context of a compulsory seminar on nuclear accidents in the third year of the nuclear engineering programme at Uppsala University.

  • 13.
    Grape, Sophie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson SVärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Österlund, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Students’ Approaches to Learning from Other Students’ Oral Presentations2015Conference paper (Other academic)
  • 14.
    Grogan, B.
    et al.
    Oak Ridge National Laboratory, USA.
    Favalli, Andrea
    Los Alamos National Laboratory, Los Alamos, NM, USA.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Liljenfeldt, Henrik
    Oak Ridge National Laboratory, Oak Ridge, TN, USA.
    Mozin, Vladimir
    Lawrence Livermore National Laboratory, Livermore, CA, USA.
    Schwalbach, Peter
    European Commission, DG Energy, Euratom Safeguards Luxemburg, Luxemburg.
    Sjöland, Anders
    Swedish Nuclear Fuel and Waste Management Company.
    Tobin, Stephen
    Los Alamos National Laboratory, Los Alamos, NM, USA.
    Trellue, Holly
    Los Alamos National Laboratory, Los Alamos, NM, USA.
    Vaccaro, Stefano
    European Commission, DG Energy, Euratom Safeguards Luxemburg, Luxemburg.
    Vo, Duc
    Los Alamos National Laboratory, Los Alamos, NM, USA.
    NDA Measurement Analysis of Spent Nuclear Fuel Assemblies at the SwedishClab Facility Using the INDEPTH Code2016Conference paper (Other academic)
    Abstract [en]

    A project to research the application of non-destructive assay (NDA) to spent fuel assemblies is underwayamong a team comprised of the European Commission, DG Energy, Directorate Safeguards; the SwedishNuclear Fuel and Waste Management Company; Uppsala University; and US national laboratories (LosAlamos National Laboratory, Lawrence Livermore National Laboratory, and Oak Ride NationalLaboratory). The research goals of this project combine safeguards goals (detection of missing/substitutedfuel pins and verification of operator declarations) and non-safeguards goals (estimation of decay heat andreactivity of each assembly). The final objective of this project is to quantify the capability of severalintegrated NDA instruments being developed to meet the aforementioned safeguards and non-safeguardsgoals using combined signatures of neutron, gamma-ray, and decay heat.

    In support of these goals, passive gamma and neutron measurements were made on 50 spent fuelassemblies at the Swedish Central Interim Storage Facility for Spent Nuclear Fuel (Clab) using high-purity germanium and Fork detectors. The Oak Ridge National Laboratory (ORNL) Inverse DepletionTheory (INDEPTH) code was used to reconstruct the spent fuel parameters (initial enrichment, burnup,and cooling time) for each assembly. INDEPTH uses a gradient-based search technique—combined withthe ORIGEN code for forward depletion calculations—to find the spent fuel parameters that result inpassive gamma and neutron outputs that best match the measurements. The results of the INDEPTHcalculations are presented and compared to the operator declarations (trusted in this case) in order toassess how accurately these parameters can be determined using current passive gamma and neutronmeasurements. These results will provide a baseline which can be used to assess whether and by howmuch new safeguards instruments being developed for NDA measurements can improve the accuracy ofreconstructed fuel parameter values.

  • 15.
    Hellesen, Carl
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Håkansson, Ane
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Improved proliferation resistance of fast reactor blankets manufactured from spent nuclear fuel2013Conference paper (Other academic)
    Abstract [en]

    In this paper we investigate how a blanket manufactured from recycled light water reactor (LWR)waste, instead of depleted uranium (DU), could potentially improve the non- proliferationcharacteristics. The blanket made from LWR waste would from the start of operation contain a fractionof plutonium isotopes unsuitable for weapons production. As 239Pu is bred in the blanket it istherefore always mixed with the plutonium already present.

    We use a Monte Carlo model of the advanced burner test reactor (ABTR) as reference design, andthe proliferation resistance of the blanket material is evaluated for two criteria, spontaneous neutronemission and decay heat. We show that it is possible to achieve a production of plutonium withproliferation resistance comparable to light water reactor waste with a burnup of 50MWd/kg.

  • 16.
    Hellesen, Carl
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Håkansson, Ane
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Improving the proliferation resistance of generation IV fast reactor fuel cycles using blankets manufactured from spent nuclear fuel.2013Conference paper (Other academic)
  • 17.
    Hellesen, Carl
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Åberg Lindell, Matilda
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Nuclear Spent Fuel Parameter Determination using Multivariate Analysis of Fission Product Gamma Spectra2017In: Annals of Nuclear Energy, ISSN 0306-4549, E-ISSN 1873-2100, Vol. 110, p. 886-895Article in journal (Refereed)
    Abstract [en]

    In this paper, we investigate the application of multivariate data analysis methods to the analysis of gamma spectroscopy measurements of spent nuclear fuel (SNF). Using a simulated irradiation and cooling of nuclear fuel over a wide range of cooling times (CT), total burnup at discharge (BU) and initial enrichments (IE) we investigate the possibilities of using a multivariate data analysis of the gamma ray emission signatures from the fuel to determine these fuel parameters. This is accomplished by training a multivariate analysis method on simulated data and then applying the method to simulated, but perturbed, data.

    We find that for SNF with CT less than about 20 years, a single gamma spectrum from a high resolution gamma spectrometer, such as a high-purity germanium spectrometer, allows for the determination of the above mentioned fuel parameters.

    Further, using measured gamma spectra from real SNF from Swedish pressurized light water reactors we were able to confirm the operator declared fuel parameters. In this case, a multivariate analysis trained on simulated data and applied to real data was used.

  • 18.
    Hellesen, Carl
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Wolniewicz, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Håkansson, Ane
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Österlund, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Transient Simulation of Gas Bubble in a Medium Sized Lead Cooled Fast Reactor2014In: Proceedings of the International Conference on Physics of Reactors (PHYSOR 2014) / [ed] Kenya Suyama, Takanori Sugawara, Kenichi Tada, Go Chiba and Akio Yamamoto, 2014Conference paper (Other academic)
    Abstract [en]

    A common problem for many liquid metal cooled fast reactor designs is the positive void worth of the coolant. In this context, an advantage of lead cooled fast reactors is the high temperature of coolant boiling. In contrast to sodium cooled fast reactors this, in practice, precludes coolant boiling. However, partial voiding of the core could result from e.g. gas bubbles entering the core from below. This would introduce a positive reactivity, if the bubble is large enough.

     

    In this paper we model this type of event using a point kinetics code coupled to a heat transport code. The reactivity parameters are obtained from a Monte Carlo code. The 300 MWth reactor design Alfred is used as a test case. We show that in general the reactor design studied is robust in such events, and we conclude that small bubbles a measureable Power oscillation would occur. For very large bubbles there exist a possibility of core damage. The cladding is the most sensitive part.

  • 19.
    Håkansson, Ane
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Kärnfysik.
    Andersson, Camilla
    Bäcklin, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Kärnfysik.
    Jacobsson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Kärnfysik.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Kärnfysik.
    Tomography as a means for Experimental Verification of the Integrity of Irradiated Nuclear Fuel1997Conference paper (Refereed)
  • 20.
    Håkansson, Ane
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Radiation Sciences.
    Bäcklin, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Radiation Sciences.
    Jacobsson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Radiation Sciences.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Radiation Sciences.
    An experimental study of the neutron emission from spent PWR fuel1997Report (Other academic)
    Abstract [en]

    Measurements of the thermal and epithermal neutron emission from eleven 15x15 and fourteen 17x17 PWR fuel assemblies have been performed. In the measurements a FORK detector supplied by Euroatom was utilised. The neutron flux was observed to depend on the burnup to approximately the fourth power. Also the strong dependence on initial enrichment could be verified. The latter dependency suggests a possible method to determine the initial enrichment. Such a method is considered as an important feature of safeguard as well as in fuel processing at the planned encapsulation plant for spent nuclear fuel.

  • 21.
    Håkansson, Ane
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Radiation Sciences.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Radiation Sciences.
    Digital behandling av linjärpulser från en CdTe-detektor: en förstudie1997Report (Other academic)
    Abstract [en]

    The neccesary treatment of the linear pulses from a CdTe detector in order to improve the energy resolution for gamma-ray spectroscopy is normally performed by using analogue technique. In this paper we suggest two methods based on digital treatment of the detector pulses. Significant features of the methods are the improvement of the energy resolution, the fact that virtually no dead time is introduced in the detector system and the simpler handling of such systems. The paper describes the underlying idea of the methods, computer simulations of detector system and actual measurements. Preliminary results show that an improvement of the energy resolution of a factor of 2 to 5, depending on the method, used is achieved.

  • 22.
    Ianakiev, Kiril
    et al.
    Los Alamos National Laboratory.
    Swinhoe, Martyn
    Los Alamos National Laboratory.
    Iliev, M.L.
    Los Alamos National Laboratory.
    Tobin, Stephen
    Los Alamos National Laboratory.
    Sjöland, Anders
    Swedish Nuclear Fuel and Waste Management Company.
    Liljenfeldt, Henrik
    Swedish Nuclear Fuel and Waste Management Company.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Underwater Testing of Detectors and Electronics Hardware for Spent Fuel Measurements2015Conference paper (Other academic)
    Abstract [en]

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

  • 23.
    Jacobsson, S
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Backlin, A
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hakansson, A
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    A tomographic method for experimental verification of the integrity of spent nuclear fuel2000In: Applied Radiation and Isotopes, ISSN 0969-8043, E-ISSN 1872-9800, Vol. 53, no 4-5, p. 681-689Article in journal (Refereed)
    Abstract [en]

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

  • 24. Jacobsson, Staffan
    et al.
    Bäcklin, Anders
    Håkansson, Ane
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Radiation Sciences.
    A tomographic method for experimental verification of the integrity of a spent nuclear fuel assembly1997Conference paper (Other academic)
  • 25.
    Jacobsson, Staffan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics.
    Håkansson, Ane
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics.
    Andersson, Camilla
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics.
    Bäcklin, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics.
    A Tomographic Method for Experimental Verification of the Integrity of Spent Nuclear Fuel1999In: 4th Topical Meeting on Industrial Radiation and Radioisotope Measurement Applications, IRRMA'99: October 3-7, 1999, Velvet Cloak Inn, Raleigh, North Carolina, USA, American Nuclear Society, 1999Conference paper (Refereed)
  • 26.
    Jacobsson, Staffan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Håkansson, Ane
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson, Camilla
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Bäcklin, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    A Tomographic Method for Verification of the Integrity of Spent Nuclear Fuel1998Report (Other academic)
    Abstract [en]

    A tomographic method for experimental investigation of the integrity of usedLWR fuel has been developed. It is based on measurements of the gamma radiation fromthe fission products in the fuel rods. A reconstruction code of the algebraic type has beenwritten. The potential of the technique has been examined in extensive simulationsassuming a gamma-ray energy of either 0.66 MeV (137Cs) or 1.27 MeV (154Eu).The resultsof the simulations for BWR fuel indicate that single fuel rods or groups of rods replacedwith water or fresh fuel can be reliably detected independent of their position in the fuelassembly using 137Cs radiation. For PWR fuel the same result is obtained with the exceptionof the most central positions. Here the more penetrable radiation from 154Eu must be used inorder to allow a water channel to be distinguished from a fuel rod.

    The results of the simulations have been verified experimentally for a 8x8 BWRfuel assembly. Special equipment has been constructed and installed at the interim storageCLAB. The equipment allows the mapping of the radiation field around a fuel assemblywith the aid of a germanium detector fitted with a collimator with a vertical slit. Theintensities measured in 2 520 detector positions were used as input for the reconstructioncode used in the simulations. The results agreed very well with the simulations and revealedsignificantly a position containing a water channel in the central part of the assembly.

  • 27.
    Jacobsson, Staffan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Håkansson, Ane
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson, Camilla
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Bäcklin, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    A Tomographic Method for Verification of the Integrity of Spent Nuclear Fuel1998Report (Other academic)
  • 28.
    Jacobsson, Staffan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Håkansson, Ane
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Bäcklin, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    A Tomographic Method for Verification of the Integrity of Spent Nuclear Fuel Assemblies - II: Experimental Investigation2001In: Nuclear Technology, ISSN 0029-5450, Vol. 135, no 2, p. 146-153Article in journal (Refereed)
    Abstract [en]

    A tomographic method for verification of the integrity of used light water reactor fuel has been experimentally investigated. The method utilizes emitted gamma rays from fission products in the fuel rods. The radiation field is recorded in a large number of positions relative to the assembly, whereby the source distribution is reconstructed using a special-purpose reconstruction code.

    An 8 × 8 boiling water reactor fuel assembly has been measured at the Swedish interim storage (CLAB), using installed gamma-scanning equipment modified for the purpose of tomography. The equipment allows the mapping of the radiation field around a fuel assembly with the aid of a germanium detector fitted with a collimator with a vertical slit. Two gamma-ray energies were recorded: 662 keV (137Cs) and 1274 keV (154Eu). The intensities measured in 2520 detector positions were used as input for the tomographic reconstruction code. The results agreed very well with simulations and significantly revealed a position containing a water channel in the central part of the assembly.

  • 29.
    Jacobsson, Staffan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Smith, Eric
    Pacific Northwest National Laboratory, USA.
    White, Timothy A.
    Pacific Northwest National Laboratory, USA.
    Mozin, Vladimir
    Lawrence Livermore National Laboratory, Livermore, CA, USA.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Davour, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Trellue, Holly
    Los Alamos National Laboratory, Los Alamos, NM, USA.
    Deshmukh, Nikhil
    Pacific Northwest National Laboratory, USA.
    Miller, Erin
    Pacific Northwest National Laboratory, Richland, USA.
    Wittman, Richard
    Pacific Northwest National Laboratory, Richland, USA.
    Honkamaa, Tapani
    STUK – Radiation and Nuclear Safety Authority,Helsinki, Finland.
    Vaccaro, Stefano
    European Commission, DG Energy, Euratom Safeguards Luxemburg, Luxemburg.
    Ely, James
    International Atomic Energy Agency (IAEA), Vienna, Austria.
    Outcomes of the JNT 1955 Phase I Viability Study of Gamma Emission Tomography for Spent Fuel Verification2017In: ESARDA Bulletin, ISSN 1977-5296, no 55, p. 10-28Article in journal (Refereed)
    Abstract [en]

    The potential for gamma emission tomography (GET) to detect partial defects within a spent nuclear fuel assembly has been assessed within the IAEA Support Program project JNT 1955, phase I, which was completed and reported to the IAEA in October 2016. Two safeguards verification objectives were identified in the project; (1) independent determination of the number of active pins that are present in a measured assembly, in the absence of a priori information about the assembly; and (2) quantitative assessment of pin-by-pin properties, for example the activity of key isotopes or pin attributes such as cooling time and relative burnup, under the assumption that basic fuel parameters (e.g., assembly type and nominal fuel composition) are known. The efficacy of GET to meet these two verification objectives was evaluated across a range of fuel types, burnups and cooling times, while targeting a total interrogation time of less than 60 minutes.

    The evaluations were founded on a modelling and analysis framework applied to existing and emerging GET instrument designs. Monte Carlo models of different fuel types were used to produce simulated tomographer responses to large populations of "virtual" fuel assemblies. The simulated instrument response data were then processed using a variety of tomographic-reconstruction and image- processing methods, and scoring metrics were defined and used to evaluate the performance of the methods.

    This paper describes the analysis framework and metrics used to predict tomographer performance. It also presents the design of a "universal" GET (UGET) instrument intended to support the full range of verification scenarios envisioned by the IAEA. Finally, it gives examples of the expected partial-defect detection capabilities for some fuels and diversion scenarios, and it provides a comparison of predicted performance for the notional UGET design and an optimized variant of an existing IAEA instrument.

  • 30.
    Jacobsson Svärd, Staffan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Davour, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Holcombe, Scott
    OECD Halden Reactor Project.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Tomographic determination of spent fuel assembly pin-wise burnup and cooling time for detection of anomalies2015Conference paper (Other academic)
    Abstract [en]

    The IAEA has initiated Member States’ Support Program project JNT A 1955 to assess the partial defect detection capabilities of gamma emission tomography (GET) for spent nuclear fuel assembly verification. The GET technique is based on measurements of the gamma-ray flux distribution around a spent fuel assembly using dedicated, tomographic equipment and subsequent reconstruction of the internal source distribution using tomographic algorithms applied on the recorded data. One of the verification objectives identified for the project is the quantitative measurement of pin-by-pin properties, e.g. burnup and/or cooling time, for the detection of anomalies and/or verification of operator-declared data. For this objective, reconstruction algorithms that return quantitative, isotopic pin-by-pin data are applied.

    Previously, GET measurements performed on commercial nuclear fuel assemblies in Sweden have proven capable of determining the relative pin-by-pin power distribution with high precision in BWR fuel with short cooling time, based on the measured distribution of the gamma-ray emitting fission product 140Ba/La in the fuel. In the current project, the capabilities of GET to determine additional pin-wise fuel parameters in additional fuel types are being assessed. The evaluations are based on Monte Carlo simulations of the emission of gamma-rays from the fuel and their detection in a tomographic measurement device.

    This paper describes the algorithms used for reconstructing quantitative pin-wise data and the results that are anticipated with this technique. It is argued that detailed modelling of the gamma-ray attenuation through the highly inhomogeneous mix of strongly-attenuating fuel rods and less-attenuating surrounding water (wet storage) or air (dry storage) is required to yield high precision in the reconstructed data. The burnup distribution assessment would be based on the recording of 662-keV gamma radiation from 137Cs, whereas the assessment of both burnup and cooling time simultaneously requires the GET measurement and pin-wise reconstruction of at least two isotopes, which puts constraints on the measurement equipment used.

  • 31.
    Jacobsson Svärd, Staffan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Håkansson, Ane
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Bäcklin, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Radiation Sciences.
    Osifo, Otasowie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Radiation Sciences.
    Willman, Christofer
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Radiation Sciences.
    Tomography for partial-defect verification: experiences from measurements using different devices2006In: ESARDA Bulletin, ISSN 0392-3029, Vol. 33, p. 15-25Article in journal (Refereed)
    Abstract [en]

    Three devices of different types have been used in tomographic measurements for the purpose of partial-defect verification on the single-rod level. The devices range from a laboratory device used in measurements on a fuel model to an in-pool device used in measurements on irradiated fuel in a fuel-handling pool.

    The tomographic technique accounted for in this paper involves measurements of the gamma-ray flux distribution around a fuel assembly followed by computer-aided reconstruction of the internal source distribution. The results are rod-by-rod values of the relative concentrations of selected gamma-emitting isotopes. Also cross-sectional images are obtained.

    The tomographic technique presented here has proven to be robust and reliable. In laboratory experiments on a fuel model, reconstructions of relative rod-by-rod activities have been obtained with 1.5 % accuracy (1 σ). Using an in-pool device in measurements on fuel with a cooling time of about 4 weeks, data on fuel rods have been obtained in agreement with production-code calculations. Furthermore, tomographic images of good quality have been acquired.

    The applicability of the tomographic technique for partial-defect verification on the single-rod level has been investigated and demonstrated. The gamma-ray source concentration reconstructed in a position corresponding to a removed or replaced rod has been significantly lower than that of normal rods.

    Finally, requirements and properties of a device for tomographic measurements on nuclear fuel are discussed. It is argued that the use of a detector system with high energy resolution and high peak efficiency in connection to spectroscopic peak analysis is beneficial.

  • 32.
    Jacobsson Svärd, Staffan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Kärnfysik.
    Håkansson, Ane
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Kärnfysik.
    Bäcklin, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Kärnfysik.
    Osifo, Otasowie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Kärnfysik.
    Willman, Christofer
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Kärnfysik.
    Jansson, Peter
    Non-destructive experimental determination of the pin-power distribution in nuclear fuel2003Conference paper (Other academic)
    Abstract [en]

    A need for validation of modern core-analysis codes with respect to the calculated pin-power distribution has been recognized. A non-destructive experimental method for such validation has been developed, based on a tomographic technique. Each axial node of the fuel assembly is measured separately and the relative pin-by-pin content of the direct fission product Ba-140 is determined. Investigations performed so far indicate that 1-2% (1 σ) accuracy can be obtained.

    A measuring device has been constructed which, when fully equipped, is designed to measure a complete BWR assembly in 25 axial nodes within an eight-hour work shift. The applicability of the constructed device has been demonstrated in measurements at the Swedish BWR Forsmark 2 on irradiated fuel with a cooling time of 4-5 weeks. Data from the core-analysis code POLCA-7 have been compared to measured pin-by-pin contents of Ba-140. An agreement of 3.1% (1 σ) has been demonstrated.

    As compared to the conventional method, involving gamma scanning of individual fuel pins, this method does not require the fuel to be disassembled. Neither does the fuel channel have to be removed. The cost per measured fuel pin is in the order of 20 times lower than the conventional method.

  • 33.
    Jacobsson Svärd, Staffan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Håkansson, Ane
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Kärnfysik.
    Bäcklin, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Kärnfysik.
    Osifo, Otasowie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Kärnfysik.
    Willman, Christofer
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Kärnfysik.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Kärnfysik.
    Nondestructive Experimental Determination of the Pin-Power Distribution in Nuclear Fuel Assemblies2005In: Nuclear Technology, ISSN 0029-5450, Vol. 151, no 1, p. 70-76Article in journal (Refereed)
    Abstract [en]

    A need for validation of modern production codes with respect to the calculated pin-power distribution has been recognized. A nondestructive experimental method for such validation has been developed based on a tomographic technique. The gamma-ray flux distribution is recorded in each axial node of the fuel assembly separately, whereby the relative rod-by-rod content of the fission product 140Ba is determined. Measurements indicate that 1 to 2% accuracy (1 sigma) is achievable.

    A device has been constructed for in-pool measurements at reactor sites. The applicability has been demonstrated in measurements at the Swedish boiling water reactor (BWR) Forsmark 2 on irradiated fuel with a cooling time of 4 to 5 weeks. Data from the production code POLCA-7 have been compared to measured rod-by-rod contents of 140Ba. An agreement of 3.1% (1 sigma) has been demonstrated.

    It is estimated that measurements can be performed on a complete BWR assembly in 25 axial nodes within an 8-h work shift. As compared to the conventional method, involving gamma scanning of individual fuel rods, this method does not require the fuel to be disassembled nor does the fuel channel have to be removed. The cost per measured fuel rod is estimated to be an order of magnitude lower than the conventional method.

  • 34.
    Jacobsson Svärd, Staffan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Smith, Eric
    Pacific Northwest National Laboratory, USA.
    White, Timothy A.
    Pacific Northwest National Laboratory, USA.
    Mozin, Vladimir
    Lawrence Livermore National Laboratory, Livermore, CA, USA.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Davour, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Trellue, Holly
    Los Alamos National Laboratory, Los Alamos, NM, USA.
    Deshmukh, Nikhil
    Pacific Northwest National Laboratory, USA.
    Wittman, Richard
    Pacific Northwest National Laboratory, USA.
    Honkamaa, Tapani
    STUK – Radiation and Nuclear Safety Authority, Finland.
    Vaccaro, Stefano
    European Commission, DG Energy, Euratom Safeguards Luxemburg, Luxemburg.
    Ely, James
    International Atomic Energy Agency.
    Outcomes of the JNT 1955 Phase I Viability Study of Gamma EmissionTomography for Spent Fuel Verification2017Conference paper (Other academic)
    Abstract [en]

    The potential for gamma emission tomography (GET) to detect partial defectswithin a spent nuclear fuel assembly has been assessed within the IAEA SupportProgram project JNT 1955, phase I, which was completed and reported to theIAEA in October 2016. Two safeguards verification objectives were identified inthe project; (1) independent determination of the number of active pins that arepresent in a measured assembly, in the absence of a priori information about theassembly, and; (2) quantitative assessment of pin-by-pin properties, for examplethe activity of key isotopes or pin attributes such as cooling time and relativeburnup, under the assumption that basic fuel parameters (e.g., assembly typeand nominal fuel composition) are known. The efficacy of GET to meet these twoverification objectives was evaluated across a range of fuel types, burnups andcooling times, while targeting a total interrogation time of less than 60 minutes.The evaluations were founded on a modelling and analysis framework applied toexisting and emerging GET instrument designs. Monte Carlo models of differentfuel types were used to produce simulated tomographer responses to largepopulations of “virtual” fuel assemblies. The simulated instrument response datawere then processed using a variety of tomographic-reconstruction and image-processing methods, and scoring metrics were defined and used to evaluate theperformance of the methods.

    This paper describes the analysis framework and metrics used to predicttomographer performance. It also presents the design of a “universal” GET(UGET) instrument intended to support the full range of verification scenariosenvisioned by the IAEA. Finally, it gives examples of the expected partial-defectdetection capabilities for some fuels and diversion scenarios, and it provides acomparison of predicted performance for the notional UGET design and anoptimized variant of an existing IAEA instrument.

  • 35.
    Jacobsson Svärd, Staffan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    White, Timothy A.
    Pacific Northwest National Laboratory.
    Smith, Eric
    Pacific Northwest National Laboratory.
    Mozin, Vladimir
    Lawrence Livermore National Laboratory, USA.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Davour, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Holcombe, Scott
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Trellue, Holly
    Los Alamos National Laboratory.
    Deshmukh, N.
    Pacific Northwest National Laboratory.
    Wittman, R. S.
    Pacific Northwest National Laboratory.
    Gamma-ray Emission Tomography: Modelling and evaluation of partial-defect testing capabilities2014Conference paper (Other academic)
    Abstract [en]

    Assessment of gamma emission tomography (GET) for spent nuclear fuel verification is the task in IAEA MSP project JNT1955. In line with IAEA Safeguards R&D plan 2012-2023, the aim of this effort is to “develop more sensitive and less intrusive alternatives to existing NDA instruments to perform partial defect tests on spent fuel assemblies prior to transfer to difficult to access storage". The current viability study constitutes the first phase of three, with evaluation and decision points between each phase. Two verification objectives have been identified; (1) counting of fuel pins in tomographic images without any a priori knowledge of the fuel assembly under study, and (2) quantitative measurements of pin-by-pin properties, e.g. burnup, for the detection of anomalies and/or verification of operator-declared data.

    Previous measurements performed in Sweden and Finland have proven GET highly promising for detecting removed or substituted fuel pins (i.e. partial defects) in BWR and VVER-440 fuel assemblies even down to the individual fuel pin level. The current project adds to previous experiences by pursuing a quantitative assessment of the capabilities of GET for partial defect detection, across a broad range of potential IAEA applications, fuel types, and fuel parameters. A modelling and performance-evaluation framework has been developed to provide quantitative GET performance predictions, incorporating burn-up and cooling-time calculations, Monte Carlo radiation-transport and detector-response modelling, GET instrument definitions (existing and notional) and tomographic reconstruction algorithms, which use recorded gamma-ray intensities to produce cross-sectional images of the source distribution in the fuel assembly or conclusive pin-by-pin data. The framework also comprises image-processing algorithms and performance metrics that recognize the inherent trade-off between the probability of detecting missing pins and the false-alarm rate. Here, the modelling and analysis framework is described and preliminary results are presented. 

  • 36.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Converged results from Geant4 calculations of pin-by-pin contributions to 137Cs gamma radiation flux at Clab2017Data set
    Abstract [en]

    A set of Geant4 calculations have been performed in reference [1] in which the gamma radiation flux through the opening of the collimator slit in the nuclear fuel gamma scanning equipment installed at the Swedish interim storage for used nuclear fuel (Clab) was calculated. This dataset contains data aggregated from the data in [1]. Specifically, the most converged gamma flux together with its calculated statistical uncertainty for each nuclear fuel rod is presented here.

    [1] Jansson P.; "Results from Geant4 calculations of pin-by-pin contributions to 137Cs gamma radiation flux at Clab"; URL: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-316271; 2016

  • 37.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Radiation Sciences.
    Determination of the residual thermal power in spent nuclear fuel from gamma-ray measurements1996Report (Other academic)
    Abstract [en]

    A method of determining the decay heat in spent nuclear fuel using the gamma radiation from 137Cs is presented. The method is useful for fuel assemblies with a cooling time longer than 5 years. Experimental tests of the method are presented for eleven 8x8 BWR fuel assemblies with cooling times in the range 5 to 15 years. The decay heat is determined with a 3.5 % error for these assemblies. Simulations with the code Origen2.1 shows that this uncertainty can be expected to be reduced for fuel assemblies with cooling times of the order of 40 years.

  • 38.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Digital Pulse Processing in HPGe Gamma-ray Spectroscopy: Supplement to the spring 2013, 2016 & 2017 courses on Activity Measurements with Germanium Detectors2017Book (Other academic)
    Abstract [en]

    A summary of basic digital signal processing systems is provided. Methods currently used in gamma-ray spectroscopy based on digital techniques are summarized. A list of references regarding digital spectroscopy is provided to guide the reader to relevant work.

  • 39.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Geant4 simulation results for the designed UGET-v1 tomographic measurement device.2016Data set
    Abstract [en]

    Results from simulations performed with Geant4 for the UGET v1 of a tomographic measurement device, designed in the UGET project.

  • 40.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Nonproliferation and nuclear fuel cycle back-end research at Uppsala University, Sweden: Special Seminar at PNNL2018Other (Other academic)
    Abstract [en]

    A brief overview of Uppsala University and the Department of Physics and Astronomy will be followed by a presentation of current research activities within the Division of Applied Nuclear Physics. Special attention will be given to on-going research in two sub-groups; Research for Nuclear Nonproliferation and research for the needs of the Swedish Nuclear Fuel and Waste Management company that is responsible for managing all the used nuclear fuel in Sweden, including encapsulation and deep geological disposal.

    After the more organizational overview, the research performed within the research group regarding single photon gamma emission tomography (GET) of nuclear fuel assemblies will be presented both from a historical perspective and from the perspective of what is currently ongoing. Specifically, the work currently ongoing within the Swedish support program to IAEA Safeguards regarding GET will be presented.

  • 41.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Results from Geant4 calculations of energy deposition from gamma- and neutron radiation emitted from selected cases of used boiling water reactor nuclear fuel assemblies in a KBS-3 type deep geological repository2017Data set
    Abstract [en]

    Monte Carlo calculations, using the Geant4 framework version 10.02, of energy deposition from gamma- and neutron radiation emitted from boiling water reator (BWR) fuel assemblies in a KBS-3 type deep geological repository for used nuclear fuel have been performed. This dataset contains the results of the calculations. Three fuel rods were arbitrarily selected as source rods for 662 keV and 2.75 MeV gamma- and neutron radiation, respectively. For each of the six cases, the energy deposited in a 3-dimensional (x,y,z) mesh with 1 cm resolution was calculated and tallied as function of the type of particle that deposited the energy.

  • 42.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Results from Geant4 calculations of pin-by-pin contributions to 137Cs gamma radiation flux at Clab2016Data set
    Abstract [en]

    A set of Geant4 calculations have been performed in which the gamma radiation flux through the opening of the collimator slit in the nuclear fuel gamma scanning equipment installed at the Swedish interim storage for used nuclear fuel. Two types of boiling water reactor (BWR) and two types of pressurized water reactor (PWR) nuclear fuel assemblies were used in the calculations. For each fuel type and for each individual pin in each fuel assembly type, the contribution to the gamma flux was calculated for a 137Cs source with 662 keV gamma radiation. Some calculations were performed without a fuel assembly but instead using a point source with 137Cs  located at various positions in the collimator slit.

    This dataset contains the results of the calculations in the format of structured query language (SQL).

  • 43.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics.
    Studies of Nuclear Fuel by Means of Nuclear Spectroscopic Methods2002Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The increasing demand for characterization of nuclear fuel, both from an operator and authority point of view, motivates the development of new experimental and, preferable, non-destructive methods. In this thesis, some methods based on nuclear spectroscopic techniques are presented.

    Various parameters of irradiated fuel are shown to be determined with high accuracy and confidence by utilizing gamma-ray scanning, tomography and passive neutron assay.

    Specifically, fuel parameters relevant for a secure storage of spent nuclear fuel in a long-term repository, such as e.g. burnup and decay heat, are shown to be determined with adequate accuracy. The techniques developed are expected to be implemented in the planned encapsulation facility in Sweden.

    Also, a device for tomographic measurements of the spatial distribution of thermal power in nuclear fuel assemblies has been built, tested and evaluated. The device utilizes single photon emission computed tomography (SPECT) in order to reconstruct the gamma-ray source distribution within a fuel assembly. The device is expected to be an important tool for validating reactor core simulators regarding new fuel designs.

    For safeguards purposes, two experimental methods for verifying the integrity, i.e. the possible loss of fissile material from a nuclear fuel assembly, are presented. Verification of integrity is shown to be possible on an individual fuel rod level.

  • 44.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics.
    Studies of Nuclear fuel by means of Nuclear Spectroscopy Methods2000Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This paper which is a thesis for the title teknologie licentiat is a summary text of several works performed by the author regarding spectroscopic measurements on spent nuclear fuel. Methods for determining the decay heat of spent nuclear fuel by means of gammaray spectroscopy and for verifying the integrity of nuclear fuel by means of tomography is presented. A summary of work performed regarding gammaray detector technology for studies of fission gas release is presented.

  • 45.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    The proposed SPIRE project: Challenge, Scope and Impact2016Conference paper (Other academic)
    Abstract [en]

    Time is progressing towards 2025 when the vision of IGD-TP is to have an operating geological disposal facility in Europe, only nine years remains. As mature national programs are developing details on what is needed regarding characterisation of spent nuclear fuel, i.e. determining source terms to decay heat, criticality or dose rates, it becomes more evident that the uncertainties associated with such parameters and the underlying knowledge of source terms have large impacts on economy and safety of interim storage and deep geological facilities.

    With the Spent fuel characterization Program for the Implementation of (geological) Repositories (SPIRE), we try to address remaining issues for spent fuel characterization in relation to its storage, both short term and long term. We attack the operators' challenge both from a measurement and simulation point of view, including development of both old a new measurement techniques, enhancing the precision and reliability with which parameters of the fuel can be calculated and perform validation and verification efforts in this context.

    We believe that spent fuel characterization is an important contribution to enabling the vision of the IGD-TP.

  • 46.
    Jansson, Peter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    White, Timothy A.
    Pacific Northwest National Laboratory.
    Mozin, Vladimir
    Lawrence Livermore National Laboratory.
    Monte Carlo simulations of a Universal Gamma-Ray Emission Tomography Device2015Conference paper (Other academic)
    Abstract [en]

    A design of a universal gamma-ray emission tomography (UGET) device has been definedwithin the IAEA MSSP project JNT1955 in order to evaluate partial defect detectioncapabilities when using tomography on used nuclear fuel assemblies. The design isintended to allow for fuel assembly verification using single photon emission tomographyon a broad range of fuel assembly types and fuel parameters.

    In this paper, results from a set of Monte Carlo radiation transport simulations for the UGETdesign are presented. In these simulations, two cases are studied, each of them with a PWR fuel, in one case the complete fuel assembly and in the other with 11 missing rods.The characteristic features of the design are presented including expected performancerequirements on the gamma-ray collimator and detector system, supported by thesimulation results. In addition, the agreement between the two simulation tools used, Geant4 and MCNP, indicate that any of the two can give satisfactory accuracy for this purpose.

  • 47.
    Jansson, Peter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Håkansson, Ane
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    A laboratory device for developing analysis tools and methods for gamma emission tomography of nuclear fuel2013Conference paper (Other academic)
    Abstract [en]

    Tomography is a measurement technique that images the inner parts of objects using only external measurement. It is widely used within the field of medicine, and may become important also for nuclear fuel verification where inspectors can obtain information from fuel assemblies’ inner sections without dismantling them.

    At Uppsala University, Sweden, a laboratory device has been built for investigating the tomographic measurement techniques on nuclear fuel. The device is composed of machinery to position model fuelrods, activated with Cs-137, in a fuel assembly pattern according to the user's choice. The gamma radiation from the model fuel assembly is collimated to a set of detectors that record the radiation intensity in various positions around the fuel model. Reconstruction of the gamma activity distribution within the fuel model is performed off-line.

    The objective for constructing the laboratory device was to support the development of tomographic techniques for nuclear fuel diagnostics as well as for nuclear safeguards purposes. The device allows for evaluating the performance of different data-acquisition setups, measurement schemes and reconstruction algorithms, since the activity content of each fuel rod is well known.

    For safeguards purposes, the device is unique in its capability to model various fuel geometries and configurations of partial defects. The latter includes removed, empty and substituted fuel rods. It is well suited for developing tomographic techniques that are optimized for partial defect detection. It also allows for development of analysis tools necessary to quantify detection limits.

    Here, we describe the capabilities of the laboratory device and elaborate on how the device may be used to support the nuclear safeguards community with the development of unattended gamma emission tomography.

  • 48.
    Jansson, Peter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Tobin, Steve
    Los Alamos National Laboratory.
    Liljenfeldt, Henrik
    Swedish Nuclear Fuel and Waste Management Company.
    Experimental Comparison between High Purity Germanium and Scintillator Detectors for Determining Burnup, Cooling Time and Decay Heat of Used Nuclear Fuel2014Conference paper (Other academic)
    Abstract [en]

    A experimental study of the gamma-ray energy spectra from used nuclear fuel has been performed. Four types of detectors were used to measure spectra from three PWR used fuel assemblies stored at the interim storage for used fuel in Sweden, CLAB: HPGe, LaBr3, NaI and BGO.

    The study was performed in the context of used fuel characterization for the back end of the fuel cycle in Sweden. Specifically, the purpose was to evaluate the behaviour of the different scintillator detectors (LaBr3, NaI and BGO) and their ability to be used instead of HPGe detectors when determining spent fuel parameters such as burnup, cooling time and decay heat of the used fuel.

    This paper presents results from the experimental study and an analysis of the capability of the detectors for used fuel characterization. The results shown are important when designing systems for used fuel characterization, e.g. for determining decay heat or fuel parameters concerning safeguards.

  • 49.
    Jansson, Peter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Radiation Sciences. Kärnfysik.
    Håkansson, Ane
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Radiation Sciences. Kärnfysik.
    Bäcklin, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Radiation Sciences. Kärnfysik.
    Calculations of the Neutron Flux Outside BWR 8×8 Spent-Fuel Assemblies and the Sensitivity to Fuel Pin Diversion2004In: Nuclear Technology, ISSN 0029-5450, E-ISSN 1943-7471, Vol. 146, no 1, p. 58-64Article in journal (Refereed)
    Abstract [en]

    The possibility of detecting replaced fuel rods in a spent-fuel assembly by means of measurement of the emitted neutron- and gamma-ray radiation has been investigated by computer simulations. The radiation field outside a boiling water reactor 8 × 8 fuel assembly with varying patterns of fuel rods replaced with lead dummies was calculated using a simple model for the source distribution and the Monte Carlo code MCNP-4C for the radiation field. In particular, the sensitivity of the thermal neutron field as measured in a Fork detector to various replacement patterns was investigated. The results suggest a detection limit of 5% of the fuel mass replaced, i.e., 3 out of 63 rods, independently of the pattern of the replaced rods.

  • 50. Jansson, Peter
    et al.
    Håkansson, Ane
    Bäcklin, Anders
    Detection of Partial Defects in irradiated BWR fuel assemblies. A Preliminary Study.2002Conference paper (Refereed)
    Abstract [en]

    The possibility of detecting partial defects in spent BWR fuel assemblies by means of measure- ments of the emitted neutron and gamma-ray radiation has been the subject in a preliminary study. Computer simulations have been made both for the case of removed rods and the case of replacement by dummy rods. The focus was put on the replacement scenario in which verica- tion by using weighing techniques is not possible. Using the Origen-S code, the source strength for a typical 8x8 BWR fuel assembly was calculated. For various geometrical patterns of the replaced rods, the radiation eld outside the fuel assembly was calculated with the Monte Carlo code MCNP-4C.

    The results suggest that neutron measurements alone, signicantly can reveal if 3 % or more of the total ssile material has been replaced. In a case where operator-declared data are unavailable or assumed incorrect, an anomalous neutron signal will indicate erroneously stated burnup and/or replaced fuel rods. An inspector is then either forced to use an indirect method such as gamma scanning to verify the burnup or tomography in order to directly verify a possible partial defect.

123 1 - 50 of 103
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf