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Publikationer (10 of 106) Visa alla publikationer
Jansson, P., Schillebeeckx, P., Zencker, U. & Cobos, J. (2019). EURAD: SFC WP: Spent Fuel Characterisation and Evolution Until Disposal. In: : . Paper presented at Euradwaste ’19, 4-7 June 2019, Pitesti, Romania.
Öppna denna publikation i ny flik eller fönster >>EURAD: SFC WP: Spent Fuel Characterisation and Evolution Until Disposal
2019 (Engelska)Konferensbidrag, Poster (med eller utan abstract) (Övrigt vetenskapligt)
Nyckelord
nuclear fuel, characterization, back-end
Nationell ämneskategori
Subatomär fysik
Forskningsämne
Fysik med inriktning mot tillämpad kärnfysik
Identifikatorer
urn:nbn:se:uu:diva-389524 (URN)
Konferens
Euradwaste ’19, 4-7 June 2019, Pitesti, Romania
Tillgänglig från: 2019-07-17 Skapad: 2019-07-17 Senast uppdaterad: 2019-08-09Bibliografiskt granskad
Zsolt, E., Mishra, V., Grape, S., Branger, E., Jansson, P. & Caldeira Balkeståhl, L. (2019). Investigating the gamma and neutron radiation around quivers for verification purposes. In: : . Paper presented at ESARDA Symposium 2019.
Öppna denna publikation i ny flik eller fönster >>Investigating the gamma and neutron radiation around quivers for verification purposes
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2019 (Engelska)Konferensbidrag, Muntlig presentation med publicerat abstract (Övrigt vetenskapligt)
Abstract [en]

Before encapsulation of spent nuclear fuel in a geological repository, the fuels need to be verified fors afeguards purposes. This requirement applies to all spent fuel assemblies, including those with properties or designs that are especially challenging to verify. One such example are quivers, a new type of containers used to hold damaged spent fuel rods. After placing damaged rods inside the quivers, they are sealed with a thick lid and the water is removed. The lid is thick enough to significantly reduce the amount of the gamma radiation penetrating through it, which can make safeguards verification from the top using gamma techniques difficult.

In this paper we make a first feasibility study related to safeguards verification of quivers, aimed at investigating the gamma and neutron radiation field around a quiver using a simplified quiver geometry. The nuclide inventory of the rods placed in the quiver is calculated with Serpent and Origen-Arp, and the radiation transport is modeled with Serpent. The objective is to assess the capability of existing non-destructive assay instruments, measuring the gamma and/or neutron radiation from the object, to verify the content for nuclear safeguards purposes. The results show that the thick quiver lid attenuates the gamma radiation, thereby making gamma-radiation based verification from above the quiver difficult. Verification using neutron instruments above the quiver, or gamma and/or neutron instruments on the side may be possible. These results are in agreement with measurements of a BWR quiver using a DCVD, performed by the authors.

Nyckelord
quiver, safeguards verification, gamma radiation, neutron radiation, spent fuel, PWR, modeling
Nationell ämneskategori
Subatomär fysik
Forskningsämne
Fysik med inriktning mot tillämpad kärnfysik
Identifikatorer
urn:nbn:se:uu:diva-389765 (URN)
Konferens
ESARDA Symposium 2019
Tillgänglig från: 2019-07-24 Skapad: 2019-07-24 Senast uppdaterad: 2019-07-24
Branger, E., Grape, S., Jansson, P. & Jacobsson Svärd, S. (2019). On the inclusion of light transport in prediction tools for Cherenkov light intensity assessment of irradiated nuclear fuel assemblies. Journal of Instrumentation, 14, Article ID T01010.
Öppna denna publikation i ny flik eller fönster >>On the inclusion of light transport in prediction tools for Cherenkov light intensity assessment of irradiated nuclear fuel assemblies
2019 (Engelska)Ingår i: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 14, artikel-id T01010Artikel i tidskrift (Refereegranskat) Published
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.

Nyckelord
Nuclear safeguards, Geant4, Cherenkov light, DCVD, Nuclear fuel
Nationell ämneskategori
Subatomär fysik
Forskningsämne
Fysik med inriktning mot tillämpad kärnfysik
Identifikatorer
urn:nbn:se:uu:diva-357151 (URN)10.1088/1748-0221/14/01/T01010 (DOI)000457930800001 ()
Forskningsfinansiär
Strålsäkerhetsmyndigheten, SSM2012-2750Swedish National Infrastructure for Computing (SNIC), p2007011
Tillgänglig från: 2018-08-13 Skapad: 2018-08-13 Senast uppdaterad: 2019-03-05Bibliografiskt granskad
Janssens, W., Niemeyer, I., Aregbe, Y., Bonino, F., Funk, P., Hildingsson, L., . . . Vince, A. (2019). Outcome and Actions of the 2019 Reflection Group of the European Safeguards Research and Development Association (ESARDA). In: : . Paper presented at INMM 60:th Annual Meeting.
Öppna denna publikation i ny flik eller fönster >>Outcome and Actions of the 2019 Reflection Group of the European Safeguards Research and Development Association (ESARDA)
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2019 (Engelska)Konferensbidrag, Publicerat paper (Övrigt vetenskapligt)
Abstract [en]

The European Safeguards Research and Development Association (ESARDA), founded in 1969, is a voluntary association of European organizations formed to foster, advance and harmonize research and development (R&D) in the area of nuclear safeguards. It provides a forum for the exchange of information and ideas between nuclear facility operators, safeguards national authorities, regional and international inspectorates, and individuals engaged in safeguards-related research and development. Today ESARDA includes 33 Parties from within the European Union. In addition, a further eight laboratories, authorities, operators and academic institutions from outside the EU have joined ESARDA as Associate Members, while the Association signed Memoranda of Understanding with the Asia-Pacific Safeguards Network and the African Commission on Nuclear Energy, and a Letter of Intent with the Institute for Nuclear Materials Management.

ESARDA seeks to maintain a dynamic approach to the developing priorities, while ensuring that its activities continue to anticipate future needs, which is why the Association periodically undertakes a formal Reflection Group exercise. In the last 2 years, the Reflection Group, RG2019, worked along the following objectives:

  1. develop a roadmap to improve and enhance the quality, effectiveness and efficiency of safeguards and non-proliferation in Europe and abroad; and
  2. ensure that the future activities of ESARDA are both consistent with the Association’s purpose, as stated in the ESARDA Agreement, and address the needs of the ESARDA members and/or stakeholders.

In the report, finalized before the ESARDA Symposium in May 2019, three specific goals were identified:

  1. establish short term ESARDA priorities (2019 to 2024) and prepare a roadmap - i.e. WHAT;
  2. define ESARDA’s long-term future (2019-2050) activities based on the new landscape in Europe and internationally - to be reviewed before 2025 to establish the next 5 year plan; and
  3. review the ESARDA organization, and discuss HOW ESARDA can achieve the identified objectives and implement the identified roadmap.

A World Café on these topics was organized and held during the 2019 Symposium. In this paper, the key outcomes and results of the ESARDA Reflection Group 2019 are presented, including their relevance for the international partners of ESARDA.

Nationell ämneskategori
Subatomär fysik
Forskningsämne
Fysik med inriktning mot tillämpad kärnfysik
Identifikatorer
urn:nbn:se:uu:diva-392277 (URN)
Konferens
INMM 60:th Annual Meeting
Tillgänglig från: 2019-09-02 Skapad: 2019-09-02 Senast uppdaterad: 2019-09-02
Branger, E., Grape, S. & Jansson, P. (2019). Verifying PWR assemblies with rod cluster control assembly inserts using a DCVD. ESARDA Bulletin (58), 35-40
Öppna denna publikation i ny flik eller fönster >>Verifying PWR assemblies with rod cluster control assembly inserts using a DCVD
2019 (Engelska)Ingår i: ESARDA Bulletin, ISSN 1977-5296, nr 58, s. 35-40Artikel i tidskrift (Refereegranskat) Published
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.

Nyckelord
DCVD, partial defect verification, Rod cluster control assembly, Cherenkov light, Geant4, nuclear fuel
Nationell ämneskategori
Subatomär fysik
Forskningsämne
Fysik med inriktning mot tillämpad kärnfysik
Identifikatorer
urn:nbn:se:uu:diva-388553 (URN)
Tillgänglig från: 2019-07-01 Skapad: 2019-07-01 Senast uppdaterad: 2019-07-01
Branger, E., Grape, S., Jansson, P. & Jacobsson Svärd, S. (2018). Experimental evaluation of models for predicting Cherenkov light intensities from short-cooled nuclear fuel assemblies. Journal of Instrumentation, 13, Article ID P02022.
Öppna denna publikation i ny flik eller fönster >>Experimental evaluation of models for predicting Cherenkov light intensities from short-cooled nuclear fuel assemblies
2018 (Engelska)Ingår i: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 13, artikel-id P02022Artikel i tidskrift (Refereegranskat) Published
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.

Nyckelord
Cherenkov detectors; Search for radioactive and fissile materials; Simulation methods and programs; Radiation calculation
Nationell ämneskategori
Subatomär fysik
Forskningsämne
Fysik
Identifikatorer
urn:nbn:se:uu:diva-346692 (URN)10.1088/1748-0221/13/02/P02022 (DOI)000425937900001 ()
Forskningsfinansiär
Strålsäkerhetsmyndigheten, SSM2012-2750Swedish National Infrastructure for Computing (SNIC), p2007011
Tillgänglig från: 2018-03-20 Skapad: 2018-03-20 Senast uppdaterad: 2018-08-17Bibliografiskt granskad
Branger, E., Grape, S., Jansson, P. & Jacobsson Svärd, S. (2018). Experimental study of background subtraction in Digital Cherenkov Viewing Device measurements. Journal of Instrumentation, 13(8), Article ID T08008.
Öppna denna publikation i ny flik eller fönster >>Experimental study of background subtraction in Digital Cherenkov Viewing Device measurements
2018 (Engelska)Ingår i: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 13, nr 8, artikel-id T08008Artikel i tidskrift (Refereegranskat) Published
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.

Nyckelord
Nuclear safeguards, Cherenkov light, DCVD, Nuclear fuel
Nationell ämneskategori
Subatomär fysik
Forskningsämne
Fysik med inriktning mot kärnfysik
Identifikatorer
urn:nbn:se:uu:diva-357150 (URN)10.1088/1748-0221/13/08/T08008 (DOI)000442556100001 ()
Forskningsfinansiär
Strålsäkerhetsmyndigheten, SSM2012-2750Swedish National Infrastructure for Computing (SNIC), p2007011
Tillgänglig från: 2018-08-13 Skapad: 2018-08-13 Senast uppdaterad: 2019-08-01Bibliografiskt granskad
Branger, E., Grape, S., Jansson, P. & Jacobsson, S. (2018). Improved Cherenkov Light Prediction Model for Enhanced DCVD Performance. In: : . Paper presented at IAEA Symposium on International Safeguards: Building Future Safeguards Capabilities 5–8 November 2018, Vienna, Austria.
Öppna denna publikation i ny flik eller fönster >>Improved Cherenkov Light Prediction Model for Enhanced DCVD Performance
2018 (Engelska)Konferensbidrag, Publicerat paper (Övrigt vetenskapligt)
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.

Nyckelord
DCVD, Nuclear Fuel, Nuclear Safeguards
Nationell ämneskategori
Subatomär fysik
Identifikatorer
urn:nbn:se:uu:diva-367334 (URN)
Konferens
IAEA Symposium on International Safeguards: Building Future Safeguards Capabilities 5–8 November 2018, Vienna, Austria
Forskningsfinansiär
Strålsäkerhetsmyndigheten, SSM2012-2750Swedish National Infrastructure for Computing (SNIC), p2007011
Tillgänglig från: 2018-11-30 Skapad: 2018-11-30 Senast uppdaterad: 2019-03-07Bibliografiskt granskad
Bourva, L. & Jansson, P. (Eds.). (2018). International Workshop on Numerical Modelling of NDA Instrumentation and Methods for Nuclear Safeguards: (NM-NDA-IMNS18). Paper presented at International Workshop on Numerical Modelling of NDA Instrumentation and Methods for Nuclear Safeguards, Luxembourg, May 16-17, 2018. European Safeguards Research & Development Association (ESARDA)
Öppna denna publikation i ny flik eller fönster >>International Workshop on Numerical Modelling of NDA Instrumentation and Methods for Nuclear Safeguards: (NM-NDA-IMNS18)
2018 (Engelska)Proceedings (redaktörskap) (Övrigt vetenskapligt)
Ort, förlag, år, upplaga, sidor
European Safeguards Research & Development Association (ESARDA), 2018. s. 151
Nationell ämneskategori
Subatomär fysik
Forskningsämne
Fysik med inriktning mot tillämpad kärnfysik
Identifikatorer
urn:nbn:se:uu:diva-366710 (URN)
Konferens
International Workshop on Numerical Modelling of NDA Instrumentation and Methods for Nuclear Safeguards, Luxembourg, May 16-17, 2018
Tillgänglig från: 2018-11-23 Skapad: 2018-11-23 Senast uppdaterad: 2019-07-25Bibliografiskt granskad
Jansson, P. (2018). Nonproliferation and nuclear fuel cycle back-end research at Uppsala University, Sweden: Special Seminar at PNNL.
Öppna denna publikation i ny flik eller fönster >>Nonproliferation and nuclear fuel cycle back-end research at Uppsala University, Sweden: Special Seminar at PNNL
2018 (Engelska)Övrigt (Övrigt vetenskapligt)
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.

Förlag
s. 59
Nyckelord
tomography, geological disposal, KBS-3, DCVD, back-end, gamma scanning, nuclear, MVA
Nationell ämneskategori
Subatomär fysik
Forskningsämne
Fysik med inriktning mot tillämpad kärnfysik
Identifikatorer
urn:nbn:se:uu:diva-340081 (URN)
Anmärkning

Presentation given at a Special Seminar on 2018-01-25 in the Radiation Detection & Nuclear Sciences Group at Pacific Northwest National Laboratory, USA.

Tillgänglig från: 2018-01-25 Skapad: 2018-01-25 Senast uppdaterad: 2018-02-01Bibliografiskt granskad
Organisationer
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0002-3136-5665

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