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  • 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.
    Bourva, Ludovic
    et al.
    International Atomic Energy Agenca (IAEA).
    Jansson, PeterUppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    International Workshop on Numerical Modelling of NDA Instrumentation and Methods for Nuclear Safeguards: (NM-NDA-IMNS18)2018Conference proceedings (editor) (Other academic)
  • 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.
    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.

  • 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.
    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.

  • 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.
    Verifying PWR assemblies with rod cluster control assembly inserts using a DCVD2019In: ESARDA Bulletin, ISSN 1977-5296, no 58, p. 35-40Article in journal (Refereed)
    Abstract [en]

    One of the instruments available to authority inspectors to measure and characterize the Cherenkov light emissions from irradiated nuclear fuel assemblies in wet storage is the Digital Cherenkov Viewing Device (DCVD). Based on the presence, characteristics and intensity of the Cherenkov light, the inspectors can verify that an assembly under study is not a dummy object, as well as perform partial defect verification of the assembly.

    PWR assemblies are sometimes stored with a rod cluster control assembly (RCCA) inserted, which affects the Cherenkov light production and transport in the assembly. Such an insert will also block light from exiting the top of the fuel assembly, which will affect the light distribution and intensity of the Cherenkov light emissions. Whether or not this constitutes a problem when verifying the assemblies for gross or partial defects with a DCVD has not previously been investigated thoroughly.

    In this work, the Cherenkov light intensity of a PWR 17x17 assembly with two different RCCA inserts were simulated and analysed, and compared to the Cherenkov light intensity from an assembly without an insert. For the studied assembly and insert types, the DCVD was found to be able to detect partial defects on the level of 50% in all studied cases with similar performance, though with a higher measurement uncertainty due to the reduced intensity when an RCCA insert is present. Consequently, for the studied assembly and insert types, assemblies with inserts can be verified with the same methodology as used for assemblies without inserts, with similar partial defect detection performance.

    The simulation approach used also made it possible to investigate the minimum Cherenkov light intensity reduction resulting from partial defects of other levels than 50%, in the PWR 17x17 fuel assembly with and without RCCA inserts. The results for the simulations without an insert were in agreement with previous results, despite differences in substitution patterns, substitution materials, modeling software and analysis approach.

  • 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, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Improved Cherenkov Light Prediction Model for Enhanced DCVD Performance2018Conference paper (Other academic)
    Abstract [en]

    The Digital Cherenkov Viewing Device (DCVD) is an instrument used to verify irradiated nuclear fuel assemblies in wet storage based on the fuel’s Cherenkov light emissions. The DCVD is frequently used for partial defect verification, verifying that 50% or more of an assembly has not been diverted. The verification methodology is based on comparison of the measured Cherenkov light intensity to a predicted intensity, based on operator declarations.

    For the last five years, a dedicated PhD project at Uppsala University has been aiming at enhancing and improving the verification capabilities when using the DCVD. The project is now approaching its end, and this paper summarizes the comprehensive work performed regarding improving the prediction capabilities.

    A new prediction model has been developed, considering more fuel assembly details to ensure more accurate predictions. With the new model, the irradiation history of an assembly, the assembly design and the contributions from gamma and beta decays are taken into account. The model has also been extended to account for the radiation from neighbouring fuel assemblies, which can enter the assembly being measured and contribute to the measured Cherenkov light. The performance of the prediction model and the neighbour intensity prediction model has been validated against fuel measurements by the IAEA at a PWR facility with short-cooled fuel. The results show that the new model offers an improved prediction capability, allowing the fuel inventory to be verified with no fuel assemblies being identified as outliers requiring additional investigation. A simplified version of the prediction model will be implemented in the next DCVD software version, making it available to IAEA inspectors.

    This development of the DCVD capabilities are in line with the fourth theme of the IAEA safeguards symposium, “Shaping the future of safeguards implementation”, by resolving challenges related to the DCVD and by extending the capabilities of the instrument.

  • 7.
    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.

  • 8.
    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 study of background subtraction in Digital Cherenkov Viewing Device measurements2018In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 13, no 8, article id T08008Article in journal (Refereed)
    Abstract [en]

    The Digital Cherenkov Viewing Device (DCVD) is an imaging tool used by authority inspectors for partial defect verification of nuclear fuel assemblies in wet storage, i.e. to verify that part of an assembly has not been diverted. One of the currently adopted verification procedures is based on quantitative measurements of the assembly's Cherenkov light emissions, and comparisons to an expected intensity, calculated based on operator declarations. A background subtraction of the intensity data in the recorded images is necessary for accurate quantitative measurements. The currently used background subtraction is aimed at removing an electronics-induced image-wide offset, but it is argued here that the currently adopted procedure may be insufficient.

    It is recommended that a standard dark-frame subtraction should be used, to remove systematic pixel-wise background due to the electronics, replacing the currently used offset procedure. Experimental analyses show that a dark-frame subtraction would further enhance the accuracy and reliability of DCVD measurements. Furthermore, should ageing of the CCD chip result in larger systematic pixel-wise deviations over time, a dark-frame subtraction can ensure reliable measurements regardless of the age of the CCD chip. It can also help in eliminating any adverse effects of malfunctioning pixels. In addition to the background from electronic noise, ways to compensate for background from neighbouring fuel assemblies and ambient light are also discussed.

  • 9.
    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)
  • 10.
    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.
    On the inclusion of light transport in prediction tools for Cherenkov light intensity assessment of irradiated nuclear fuel assemblies2019In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 14, article id T01010Article in journal (Refereed)
    Abstract [en]

    The Digital Cherenkov Viewing Device (DCVD) is a tool used to verify irradiated nuclear fuel assemblies in wet storage by imaging the Cherenkov light produced by the radiation emitted from the assemblies. It is frequently used for partial defect verification, verifying that part of an assembly has not been removed and/or replaced. In one of the verification procedures used, the detected total Cherenkov light intensities from a set of assemblies are compared to predicted intensities, which are calculated using operator declarations for the assemblies.

    This work presents a new, time-efficient method to simulate DCVD images of fuel assemblies, allowing for estimations of the Cherenkov light production, transport and detection. Qualitatively, good agreement between simulated and measured images is demonstrated. Quantitatively, it is shown that relative intensity predictions based on simulated images are within 0.5% of corresponding predictions based solely on the production of Cherenkov light, neglecting light transport and detection. Consequently, in most cases it is sufficient to use predictions based on produced Cherenkov light, neglecting transport and detection, thus substantially reducing the time needed for simulations.

    In a verification campaign, assemblies are grouped according to their type, and the relative measured and predicted intensities are compared in a group. By determining transparency factors, describing the fraction of Cherenkov light that is blocked by the top plate of an assembly, it is possible to adjust predictions based on the production of Cherenkov light to take the effect of the top plate into account. This procedure allows assemblies of the same type bit with different top plates to be compared with increased accuracy. The effect of using predictions adjusted with transparency factors were assessed experimentally on a set of Pressurized Water Reactor 17x17 assemblies having five different top plate designs. As a result of the adjustment, the agreement between measured and predicted relative intensities for the whole data set was enhanced, resulting in a reduction of an RMSE from 14.1% to 10.7%. It is expected that further enhancements may be achieved by introducing more detailed top-plate and spacer descriptions.

    The full text will be freely available from 2020-02-01 00:00
  • 11. 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)
  • 12.
    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.

  • 13.
    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.

  • 14.
    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.

  • 15.
    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.

  • 16.
    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)
  • 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.
    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.

  • 18.
    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)
  • 19.
    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.

  • 20.
    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.

  • 21.
    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)
  • 22.
    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.

  • 23.
    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.

  • 24.
    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.

  • 25.
    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)