| 1. |
- Ahlin, Kristina, et al.
(författare)
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Antecedents and neuroimaging patterns in cerebral palsy with epilepsy and cognitive impairment: a population-based study in children born at term
- 2017
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Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - : Wiley. - 1600-0412 .- 0001-6349. ; 96:7, s. 828-836
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Tidskriftsartikel (refereegranskat)abstract
- Introduction. Antecedents of accompanying impairments in cerebral palsy and their relation to neuroimaging patterns need to be explored. Material and methods. A population-based study of 309 children with cerebral palsy born at term between 1983 and 1994. Prepartum, intrapartum, and postpartum variables previously studied as antecedents of cerebral palsy type and motor severity were analyzed in children with cerebral palsy and cognitive impairment and/or epilepsy, and in children with cerebral palsy without these accompanying impairments. Neuroimaging patterns and their relation to identified antecedents were analyzed. Data were retrieved from the cerebral palsy register of western Sweden, and from obstetric and neonatal records. Results. Children with cerebral palsy and accompanying impairments more often had low birthweight (kg) (odds ratio 0.5, 95% confidence interval 0.3-0.8), brain maldevelopment known at birth (p = 0.007, odds ratio infinity) and neonatal infection (odds ratio 5.4, 95% confidence interval 1.04-28.4). Moreover, neuroimaging patterns of maldevelopment (odds ratio 7.2, 95% confidence interval 2.9-17.2), cortical/subcortical lesions (odds ratio 5.3, 95% confidence interval 2.3-12.2) and basal ganglia lesions (odds ratio 7.6, 95% confidence interval 1.4-41.3) were more common, wheras white matter injury was found significantly less often (odds ratio 0.2, 95% confidence interval 0.1-0.5). In most children with maldevelopment, the intrapartum and postpartum periods were uneventful (p
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| 2. |
- Ahlin, Kristina, et al.
(författare)
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Antecedents of cerebral palsy according to severity of motor impairment.
- 2016
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Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - : Wiley. - 1600-0412 .- 0001-6349. ; 95:7, s. 793-802
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to determine whether antecedents and neuroimaging patterns vary according to the severity of motor impairment in children with cerebral palsy. Material and methods. A population-based study in which all 309 term-born children with spastic and dyskinetic cerebral palsy born between 1983 and 1994 and 618 matched controls were studied. Antecedents were retrieved from obstetric records. Information on neuroimaging was retrieved from the cerebral palsy Register of Western Sweden. Cases were grouped by severity of motor impairment: mild (walks without aids), moderate (walks with aids) or severe (dependent on wheelchair). Binary logistic regression, the Cochran-Armitage test for trends, interaction analyses and interrelationship analyses were performed. Results. Antecedents associated with mild motor impairment were antepartum (placental weight, maternal weight and antibiotic therapy) or intrapartum and postpartum adverse events (meconium-stained amniotic fluid, low Apgar score, admission to neonatal intensive care unit and neonatal encephalopathy). Antecedents associated with severe motor impairment were antepartum (congenital infection, small head circumference and brain maldevelopment) or intrapartum and postpartum (emergency cesarean section and maternal antibiotic therapy). Comparisons between mild and severe motor impairment revealed congenital infection, maldevelopment, neonatal encephalopathy and meconium aspiration syndrome significantly more often in the group with severe motor impairment (p
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| 3. |
- Andersson, Peter, 1981-, et al.
(författare)
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Neutron Tomography Using Mobile Neutron Generators for Assessment of Void Distributions in Thermal Hydraulic Test Loops
- 2015
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Konferensbidrag (refereegranskat)abstract
- Detailed knowledge of the lateral distribution of steam (void) and water in a nuclear fuel assembly is of great value for nuclear reactor operators and fuel manufacturers, with consequences for both reactor safety and economy of operation. Therefore, nuclear relevant two-phase flows are being studied at dedicated thermal-hydraulic test loop, using twophase flow systems ranging from simplified geometries such as heated circular pipes to full scale mock-ups of nuclear fuel assemblies. Neutron tomography (NT) has been suggested for assessment of the lateral distribution of steam and water in such test loops, motivated by a good ability of neutrons to penetrate the metallic structures of metal pipes and nuclear fuel rod mock-ups, as compared to e. g. conventional X-rays, while the liquid water simultaneously gives comparatively good contrast. However, these stationary test loops require the measurement setup to be mobile, which is often not the case for NT setups. Here, it is acknowledged that fast neutrons of 14 MeV from mobile neutron generators constitute a viable option for a mobile NT system. We present details of the development of neutron tomography for this purpose at the division of Applied Nuclear Physics at Uppsala University. Our concept contains a portable neutron generator, exploiting the fusion reaction of deuterium and tritium, and a detector with plastic scintillator elements designed to achieve adequate spatial and energy resolution, all mounted in a light-weight frame without collimators or bulky moderation to allow for a mobile instrument that can be moved about the stationary thermal hydraulic test sections. The detector system stores event-to-event pulse-height information to allow for discrimination based on the energy deposition in the scintillator elements. Experimental results from the tomographic assessment of axially symmetric test objects are shown, as well as simulation results from a scaled up version of the instrument for nonsymmetrical objects in quarter fuel-bundle size objects. In conclusion, the application of tomography on inch-wide vertical pipes has been experimentally demonstrated and simulation results indicate that tomography of the void distribution in nonsymmetrical vertical flows in quarter BWR fuel bundles is also feasible.
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| 4. |
- Bacelis, Jonas, 1984, et al.
(författare)
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Literature-Informed Analysis of a Genome-Wide Association Study of Gestational Age in Norwegian Women and Children Suggests Involvement of Inflammatory Pathways
- 2016
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:8
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Tidskriftsartikel (refereegranskat)abstract
- Background Five-to-eighteen percent of pregnancies worldwide end in preterm birth, which is the major cause of neonatal death and morbidity. Approximately 30% of the variation in gestational age at birth can be attributed to genetic factors. Genome-wide association studies (GWAS) have not shown robust evidence of association with genomic loci yet. We separately investigated 1921 Norwegian mothers and 1199 children from pregnancies with spontaneous onset of delivery. Individuals were further divided based on the onset of delivery: initiated by labor or prelabor rupture of membranes. Genetic association with ultrasound- dated gestational age was evaluated using three genetic models and adaptive permutations. The top-ranked loci were tested for enrichment in 12 candidate gene-sets generated by text-mining PubMed abstracts containing pregnancy-related keywords. The six GWAS did not reveal significant associations, with the most extreme empirical p = 5.1 x 10(-7). The top loci from maternal GWAS with deliveries initiated by labor showed significant enrichment in 10 PubMed gene-sets, e.g., p = 0.001 and 0.005 for keywords "uterus" and "preterm" respectively. Enrichment signals were mainly caused by infection/inflammation-related genes TLR4, NFKB1, ABCA1, MMP9. Literature-informed analysis of top loci revealed further immunity genes: IL1A, IL1B, CAMP, TREM1, TFRC, NFKBIA, MEFV, IRF8, WNT5A. Our analyses support the role of inflammatory pathways in determining pregnancy duration and provide a list of 32 candidate genes for a follow-up work. We observed that the top regions from GWAS in mothers with labor-initiated deliveries significantly more often overlap with pregnancy-related genes than would be expected by chance, suggesting that increased sample size would benefit similar studies.
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| 5. |
- Bergek, Anna, 1973, et al.
(författare)
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Technological innovation systems in contexts: Conceptualizing contextual structures and interaction dynamics
- 2015
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Ingår i: Environmental Innovation and Societal Transitions. - : Elsevier BV. - 2210-4224 .- 2210-4232. ; 16, s. 51-64
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Tidskriftsartikel (refereegranskat)abstract
- This paper addresses interactions between technological innovation systems (TIS) and wider "context structures". While TIS studies have always considered various kinds of contextual influences, we suggest that the TIS framework can be further strengthened by a more elaborated conceptualization of TIS context structures and TIS-context interactions. For that purpose, we identify and discuss four especially important types of context structures: technological, sectorial, geographical and political. For each of these, we provide examples of different ways in which context structures can interact with a focal TIS and how our understanding of TIS dynamics is enhanced by considering them explicitly. Lessons for analysts are given and a research agenda is outlined.
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| 6. |
- Branger, Erik, 1988-, et al.
(författare)
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Comparison of prediction models for Cherenkov light emissions from nuclear fuel assemblies
- 2017
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 7. |
- Branger, Erik, 1988-, et al.
(författare)
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Experimental evaluation of models for predicting Cherenkov light intensities from short-cooled nuclear fuel assemblies
- 2018
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 8. |
- Branger, Erik, 1988-, et al.
(författare)
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Experimental study of background subtraction in Digital Cherenkov Viewing Device measurements
- 2018
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 13:8
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 9. |
- Branger, Erik, 1988-, et al.
(författare)
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Improved Cherenkov Light Prediction Model for Enhanced DCVD Performance
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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| 10. |
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| 11. |
- Branger, Erik, 1988-, et al.
(författare)
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Investigating the Cherenkov light production due to cross-talk in closely stored nuclear fuel assemblies in wet storage
- 2018
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Ingår i: ESARDA Bulletin. - : European Commission Joint Research Centre. - 1977-5296. ; :57, s. 66-74
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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| 12. |
- Branger, Erik, 1988-, et al.
(författare)
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On Cherenkov light production by irradiated nuclear fuel rods
- 2017
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 12
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 13. |
- Branger, Erik, 1988-, et al.
(författare)
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On the inclusion of light transport in prediction tools for Cherenkov light intensity assessment of irradiated nuclear fuel assemblies
- 2019
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 14. |
- Brodin, Ola, et al.
(författare)
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Pharmacokinetics and Toxicity of Sodium Selenite in the Treatment of Patients with Carcinoma in a Phase I Clinical Trial: The SECAR Study
- 2015
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Ingår i: Nutrients. - : MDPI. - 2072-6643. ; 7:6, s. 4978-4994
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Tidskriftsartikel (refereegranskat)abstract
- Background: Sodium selenite at high dose exerts antitumor effects and increases efficacy of cytostatic drugs in multiple preclinical malignancy models. We assessed the safety and efficacy of intravenous administered sodium selenite in cancer patients refractory to cytostatic drugs in a phase I trial. Patients received first line of chemotherapy following selenite treatment to investigate altered sensitivity to these drugs and preliminary assessment of any clinical benefits. Materials and Methods: Thirty-four patients with different therapy resistant tumors received iv sodium selenite daily for consecutive five days either for two weeks or four weeks. Each cohort consisted of at least three patients who received the same daily dose of selenite throughout the whole treatment. If 0/3 patients had dose-limiting toxicities (DLTs), the study proceeded to the next dose-level. If 2/3 had DLT, the dose was considered too high and if 1/3 had DLT, three more patients were included. Dose-escalation continued until the maximum tolerated dose (MTD) was reached. MTD was defined as the highest dose-level on which 0/3 or 1/6 patients experienced DLT. The primary endpoint was safety, dose-limiting toxic effects and the MTD of sodium selenite. The secondary endpoint was primary response evaluation. Results and Conclusion: MTD was defined as 10.2 mg/m(2), with a calculated median plasma half-life of 18.25 h. The maximum plasma concentration of selenium from a single dose of selenite increased in a nonlinear pattern. The most common adverse events were fatigue, nausea, and cramps in fingers and legs. DLTs were acute, of short duration and reversible. Biomarkers for organ functions indicated no major systemic toxicity. In conclusion, sodium selenite is safe and tolerable when administered up to 10.2 mg/m(2) under current protocol. Further development of the study is underway to determine if prolonged infusions might be a more effective treatment strategy.
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| 15. |
- Bry, Kristina, 1953, et al.
(författare)
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Gastric fluid cytokines are associated with chorioamnionitis and white blood cell counts in preterm infants.
- 2015
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Ingår i: Acta Paediatrica, International Journal of Paediatrics. - : Wiley. - 0803-5253 .- 1651-2227. ; 104:6, s. 575-580
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Tidskriftsartikel (refereegranskat)abstract
- AimThe aim of this study was to determine whether the concentration of cytokines in the gastric fluid at birth was associated with chorioamnionitis or funisitis and with the white blood cell counts of very premature newborns.MethodsWe retrieved gastric fluid from 27 preterm infants with a gestational age of
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| 16. |
- Davour, Anna, et al.
(författare)
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Applying image analysis techniques to tomographic images of irradiated nuclear fuel assemblies
- 2016
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Ingår i: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549 .- 1873-2100. ; 96, s. 223-229
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 17. |
- Davour, Anna, 1975-, et al.
(författare)
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Image analysis methods for partial defect detection using tomographic images on nuclear fuel assemblies
- 2015
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A promising non-destructive assay method for verification of irradiated nuclear fuel is gammatomography, i.e. the use of measurements of the gamma radiation field around a nuclear fuel assembly to reconstruct detailed information about the internal source distribution.Typically, tomographic reconstructions result in two-dimensional images of cross sections of the fuel. We demonstrate how such images can be searched for fuel rods using a template matching technique, which is a method commonly used in the field of image analysis. In this case, a template or mask corresponding to the size and shape of a fuel rod is translated across the image in order to find the region with the highest reconstructed activity, which is assumed to correspond to the location of a fuel rod in the image. This is done iteratively, allowing no overlap of the rods. By defining the threshold between background and fuel rod objects in the image, we can identify and count the fuel rods using no other assumptions than the rod radius.Thus the rod identification procedure provides a possible means to verify whether all fuel rods arepresent, and it may also be implemented to identify the fuel type of the measured assembly. Theprocedure is robust in cases of irregularities, such as assembly bow or torsion, or the dislocation ofindividual fuel rods in the measured cross section.Here we demonstrate fuel rod identification procedure, using authentic images collected with a tomographic measurement device on commercial fuel assemblies. The results show that image analysis can support tomographic partial defect verification of irradiated nuclear fuel assemblies, even on the single fuel rod level.
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| 18. |
- Grape, Sophie, 1982-, et al.
(författare)
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Forskning inom teknisk kärnämneskontroll vid Uppsala universitet under 2014–2015
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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| 19. |
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| 20. |
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| 21. |
- Hallingström, Maria, et al.
(författare)
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Proteomic Analysis of Early Mid-Trimester Amniotic Fluid Does Not Predict Spontaneous Preterm Delivery
- 2016
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:5
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Tidskriftsartikel (refereegranskat)abstract
- Objective The aim of this study was to identify early proteomic biomarkers of spontaneous preterm delivery (PTD) in mid-trimester amniotic fluid from asymptomatic women. This is a case-cohort study. Amniotic fluid from mid-trimester genetic amniocentesis (14-19 weeks of gestation) was collected from 2008 to 2011. The analysis was conducted in 24 healthy women with subsequent spontaneous PTD (cases) and 40 randomly selected healthy women delivering at term (controls). An exploratory phase with proteomics analysis of pooled samples was followed by a verification phase with ELISA of individual case and control samples. The median (interquartile range (IQR: 25th; 75th percentiles) gestational age at delivery was 35+5 (33+6-36+6) weeks in women with spontaneous PTD and 40+0 (39+1-40+5) weeks in women who delivered at term. In the exploratory phase, the most pronounced differences were found in C-reactive protein (CRP) levels, that were approximately two-fold higher in the pooled case samples than in the pooled control samples. However, we could not verify these differences with ELISA. The median (25th; 75th IQR) CRP level was 95.2 ng/mL (64.3; 163.5) in women with spontaneous PTD and 86.0 ng/mL (51.2; 145.8) in women delivering at term (p = 0.37; t-test). Proteomic analysis with mass spectrometry of mid-trimester amniotic fluid suggests CRP as a potential marker of spontaneous preterm delivery, but this prognostic potential was not verified with ELISA.
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| 22. |
- Hellesen, Carl, 1980-, et al.
(författare)
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Nuclear Spent Fuel Parameter Determination using Multivariate Analysis of Fission Product Gamma Spectra
- 2017
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Ingår i: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549 .- 1873-2100. ; 110, s. 886-895
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 23. |
- Holcombe, Scott, et al.
(författare)
-
A Novel gamma emission tomography instrument for enhanced fuel characterization capabilities within the OECD Halden Reactor Project
- 2015
-
Ingår i: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549 .- 1873-2100. ; 85, s. 837-845
-
Tidskriftsartikel (refereegranskat)abstract
- Gamma emission tomography is a method based on gamma-ray spectroscopy and tomographic reconstruction techniques, which can be used for rod-wise characterization of nuclear fuel assemblies without dismantling the fuel. By performing a large number of measurements of the gamma-ray flux intensity around a fuel assembly using a well-collimated gamma-ray detector, the internal source distribution in the assembly may be reconstructed using tomographic algorithms. If a spectroscopic detection system is used, different gamma-ray emitting isotopes can be selected for analysis, enabling nondestructive fuel characterization with respect to a variety of fuel parameters. In this paper, we describe a novel gamma emission tomography instrument, which has been designed, constructed and tested at the Halden Boiling Water Reactor (HBWR). The device will be used to characterize fuel assemblies irradiated in the HBWR as part of ongoing nuclear fuel research conducted within the OECD Halden Reactor Project (HRP). As compared to single-rod gamma scanning, where the fuel is dismantled and the gamma radiation from each rod is measured separately, handling time associated with characterizing the fuel can be significantly reduced when using the gamma emission tomography device. Furthermore, because gamma emission tomography enables rod-wise fuel characterization without dismantling, even instrumented experimental fuel assemblies may be characterized repeatedly throughout the fuel's lifetime, with limited risk of damaging the fuel or its instrumentation. Accordingly, the capabilities of fuel characterization within the OECD HRP are expected to be strongly enhanced by the deployment of this device. Here, the gamma-tomographic method and the experimental setup are demonstrated through experimental measurements of the fuel stack and gas plenum regions of a nine-rod HBWR fuel assembly configuration, where four rods had a burnup of approximately 26 MWd/kgUO(2) and five rods had a burnup of approximately 50 MWd/kgUO(2). Tomographic images are presented, which show the applicability for assessment of fission gas contents in the gas plena and of fission products in the fuel stack. Furthermore, neutron activation products are analyzed, which give additional information on construction material properties.
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| 24. |
- Holcombe, Scott, et al.
(författare)
-
Determination of the Rod-wise Fission Gas Release Fraction in a Complete Fuel Assembly Using Non-destructive Gamma Emission Tomography
- 2016
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 837, s. 99-108
-
Tidskriftsartikel (refereegranskat)abstract
- A gamma tomography instrument has been developed at the Halden Boiling Water Reactor (HBWR) in cooperation between the Institute for Energy Technology, Westinghouse (Sweden) and Uppsala University. The instrument is used to record the gamma radiation field surrounding complete fuel assemblies and consists of a shielded enclosure with fixtures to accurately position the fuel and detector relative to each other. A High Purity Germanium detector is used for acquiring high-resolution spectroscopic data, allowing for analysis of multiple gamma-ray peaks. Using the data extracted from the selected peaks, tomographic reconstruction algorithms are used to reproduce the corresponding spatial gamma-ray source distributions within the fuel assembly. With this method, rod-wise data can be can be deduced without the need to dismantle the fuel.In this work, the tomographic device has been experimentally benchmarked for non-destructive rod-wise determination of the Fission Gas Release (FGR) fraction. Measurements were performed on the fuel-stack and gas-plenum regions of a complete fuel assembly, and quantitative tomographic reconstructions of the measurement data were performed in order to determine the rod-wise ratio of 85Kr in the gas plenum to 137Cs in the fuel stack. The rod-wise ratio of 85Kr/137Cs was, in turn, used to calculate the rod-wise FGR fraction. In connection to the tomographic measurements, the fuel rods were also measured individually using gamma scanning in order to provide an experimental benchmark for the tomographic method.Fuel rods from two donor driver fuel assemblies were placed into a nine-rod HBWR driver fuel assembly configuration. In order to provide a challenging measurement object and thus an appropriate benchmark for the tomographic method, five rods were taken from an assembly with a burnup of 51 MWd/kgUO2, and four rods were from an assembly with a burnup of 26 MWd/kgUO2. At the time of the measurements, the nine rods had cooled for approximately 22 years. All fuel rods had operated at high linear heat rates (around 70 kW/m), thus leading to relatively high FGR fractions. Here, the FGR fraction was determined to be ~24% in the high-burnup rods, and ~17% in the low-burnup rods. The tomography measurement results were in good agreement with the results from individual rod scanning, demonstrating the feasibility of tomography for this application. The capability of tomography to assess individual fuel rods without the need to dismantle the assembly can be particularly valuable in cases of fuels that do not allow disassembly, such as experimental HBWR fuel fitted with extensive instrumentation.
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| 25. |
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| 26. |
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| 27. |
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| 28. |
- Jacobsson, Staffan, 1951, et al.
(författare)
-
Bidrag till handlingsplan för havsbaserad vindkraft i Sverige - För säkrad eltillförsel, stabiltklimat och industriell utveckling
- 2015
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Världen behöver ställa om produktionen av el till ett system med inga eller ringa utsläpp av växthusgaser. Både Världsbanken (2014) och International Energy Agency (IEA,2013) varnar i starka ordalag för en temperaturhöjning långt utöver 2 grader vilket understryker betydelsen av en politik som säkerställer att en omvandling sker i tid. Tillutmaningen läggs åldrande kärnkraftverk samt en förväntad ökad efterfrågan på el inom transportsektorn och för att ersätta gas för uppvärmning. En teknik som EUkommissionenhar stora förväntningar på, och som främst britter, tyskar och danskar investerar mycket i, är havsbaserad vindkraft. I detta bidrag argumenterar vi för att Sverige bör följa dessa länder och bygga ut den havsbaserade vindkraften som ett komplement till andra tekniker som använder förnyelsebara energikällor. Vi diskuterar även vilka hinder som måste överbryggas för att en utbyggnad skall ske i tid och åtgärder som kan vidtas för att säkra en utbyggnad.Sveriges potential är stor. Om 3 000 km2 används för havsbaserad vindkraft, 5 MW installeras per km2 och kraftverken har 40 % kapacitetsfaktor, blir årsproduktionendrygt 50 TWh. Många företag har sett denna potential och projekt som befinner sig i olika delar av tillståndsprocessen skulle kunna producera 26 TWh. I debatten argumenteras emellertid ofta att nya investeringar i förnybar energiteknik inte behövs då i) Sverige har en nettoexport av el och ii) vi med lätthet uppfyller 2020 målen. Denna tidshorisont är emellertid för kort jämfört med de långa ledtider som finns i utbyggnaden av ny kapacitet och vi kan inte heller betrakta Sverige som en isolerad ö. Vi måste istället blicka framåt några decennier och ut mot övriga EU när vi analyserar önskvärdheten av att investera i havsbaserad vindkraft. Vi uppmärksammar då risken att det kan uppstå ett större produktionsgap i Sverige. Även för Nordpool-området finns denna risk och för EU som helhet är det förväntade produktionsgapet mycket stort. En utbyggd havsbaserad vindkraft kan bidra till att säkerställa att Sverige och Nordpoolområdet får ett kraftsystem som kan leverera omfattande mängder el till rimliga priser när de åldrande kärnkraftverken läggs ner. Potentialen är så stor att Sverige även kan ge ett viktigt bidrag till att uppnå EU:s klimatmål genom en ökad elexport. Detta bidrag skall inte ses som att vi blir ”världens samvete” utan förenas med nya affärsmöjligheter då Sverige synes kunna producera havsvindel till en låg kostnad i förhållande tillinstallationer i Nordsjön. Detta är det starkaste skälet till en utbyggnad i Sverige och ett utnyttjande av denna svenska komparativa fördel passar väl in i EUs tankar om enEnergiunion.Det är tänkbart att en kapacitet att producera 30 TWh havsbaserad vindel kan finnas på plats i Sverige år 2035. För att möjliggöra nödvändiga investeringar måste dock en rad hinder överbryggas. Det viktigaste hindret är brist på incitament att investera och det behövs ett styrmedel som på ett trovärdigt sätt leder till de omfattande investerin
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| 29. |
- Jacobsson, Staffan, 1951, et al.
(författare)
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Improving the European Commission's analytical base for designing instrument mixes in the energy sector: Market failures versus system weaknesses
- 2017
-
Ingår i: Energy Research and Social Science. - : Elsevier BV. - 2214-6296. ; 33, s. 11-20
-
Tidskriftsartikel (refereegranskat)abstract
- © 2017 Elsevier Ltd. To limit global warming to 1.5-2°C, EU needs to eliminate emissions of CO 2 equivalents over the next decades, which necessitates that a range of new technologies develop, mature and diffuse on a massive scale. To create conditions for this, effective instrument mixes have to be designed and implemented. However, the choice of such mixes depends on the analytical rationale for policy intervention. The purpose of this paper is, therefore, to scrutinize the analytical base of the EU Commission, contrast it with the work of classical economists and recent innovation scholars, and draw lessons for how effective mixes of policy instruments may be identified. We show that the Commission's focus on market failures, static efficiency and technology neutrality does not cover all possible obstacles and leads it to neglect the centrality of dynamic efficiency and the structural build-up of innovation systems around new technologies.
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| 30. |
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| 31. |
- Jacobsson, Staffan, 1951, et al.
(författare)
-
Lessons from Germany’s ”Energiewende”
- 2015
-
Ingår i: Fagerberg, J., Laestadius, S. and Martin, B., (2015) (eds): The Triple Challenge: Europe a New Age, Oxford University Press.
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 32. |
- Jacobsson, Staffan, 1970-, et al.
(författare)
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Outcomes of the JNT 1955 Phase I Viability Study of Gamma Emission Tomography for Spent Fuel Verification
- 2017
-
Ingår i: ESARDA Bulletin. - 1977-5296. ; :55, s. 10-28
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 33. |
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| 34. |
- Jacobsson Svärd, Staffan, 1970-, et al.
(författare)
-
Applicability of a set of tomographic reconstruction algorithms for quantitative SPECT on irradiated nuclear fuel assemblies
- 2015
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 783, s. 128-141
-
Tidskriftsartikel (refereegranskat)abstract
- A fuel assembly operated in a nuclear power plant typically contains 100–300 fuel rods, depending on fuel type, which become strongly radioactive during irradiation in the reactor core. For operational and security reasons, it is of interest to experimentally deduce rod-wise information from the fuel, preferably by means of non-destructive measurements. The tomographic SPECT technique offers such possibilities through its two-step application; (1) recording the gamma-ray flux distribution around the fuel assembly, and (2) reconstructing the assembly׳s internal source distribution, based on the recorded radiation field. In this paper, algorithms for performing the latter step and extracting quantitative relative rod-by-rod data are accounted for.As compared to application of SPECT in nuclear medicine, nuclear fuel assemblies present a much more heterogeneous distribution of internal attenuation to gamma radiation than the human body, typically with rods containing pellets of heavy uranium dioxide surrounded by cladding of a zirconium alloy placed in water or air. This inhomogeneity severely complicates the tomographic quantification of the rod-wise relative source content, and the deduction of conclusive data requires detailed modelling of the attenuation to be introduced in the reconstructions. However, as shown in this paper, simplified models may still produce valuable information about the fuel.Here, a set of reconstruction algorithms for SPECT on nuclear fuel assemblies are described and discussed in terms of their quantitative performance for two applications; verification of fuel assemblies׳ completeness in nuclear safeguards, and rod-wise fuel characterization. It is argued that a request not to base the former assessment on any a priori information brings constraints to which reconstruction methods that may be used in that case, whereas the use of a priori information on geometry and material content enables highly accurate quantitative assessment, which may be particularly useful in the latter application.Two main classes of algorithms are covered; (1) analytic filtered back-projection algorithms, and (2) a group of model-based or algebraic algorithms. For the former class, a basic algorithm has been implemented, which does not take attenuation in the materials of the fuel assemblies into account and which assumes an idealized imaging geometry. In addition, a novel methodology has been presented for introducing a first-order correction to the obtained images for these deficits; in particular, the effects of attenuation are taken into account by modelling the response for an object with a homogeneous mix of fuel materials in the image area. Neither the basic algorithm, nor the correction method requires prior knowledge of the fuel geometry, but they result in images of the assembly׳s internal activity distribution. Image analysis is then applied to deduce quantitative information.Two algebraic algorithms are also presented, which model attenuation in the fuel assemblies to different degrees; either assuming a homogenous mix of materials in the image area without a priori information or utilizing known information of the assembly geometry and of its position in the measuring setup for modelling the gamma-ray attenuation in detail. Both algorithms model the detection system in detail. The former algorithm returns an image of the cross-section of the object, from which quantitative information is extracted, whereas the latter returns conclusive relative rod-by-rod data.Here, all reconstruction methods are demonstrated on simulated data of a 96-rod fuel assembly in a tomographic measurement setup. The assembly was simulated with the same activity content in all rods for evaluation purposes. Based on the results, it is argued that the choice of algorithm to a large degree depends on application, and also that a combination of reconstruction methods may be useful. A discussion on alternative analysis methods is also included.
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| 35. |
- Jacobsson Svärd, Staffan, 1970-, et al.
(författare)
-
Tomographic determination of spent fuel assembly pin-wise burnup and cooling time for detection of anomalies
- 2015
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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| 36. |
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| 37. |
- Jansson, Peter, 1971-, et al.
(författare)
-
A platform for feed-forward and follow-up of students' progression in oral presentation within a study programme
- 2015
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Didactic research has shown that feedforward has a positive effect on students' experience of their progression in oral presentation. However, studies also show that students often experience a lack of feedback from teachers and audience attending their presentations and consequently they lack an experience of progression.In this work we present a platform for structured documentation and follow-up of students' progress of skills in oral presentation that has been been implemented within the bachelor programme in nuclear engineering at Uppsala University. The platform provides efficient communication of feedback and feedforward to the students over this one-year programme, involving several courses and teachers.The platform is implemented within the system for learning and study administration that is used by students and staff at Uppsala University ("Student Portal"). It consists of an interface where the students and teachers have an overview of progress made in all individual courses at the programme. For each course that includes an oral presentation, there is a folder where each student uploads a self assessment. In the same folder, the teachers upload their feedback as well as the feedback provided by fellow students for each oral presentation. Self assessments and feedback provide feedforward for future oral presentations. The platform was implemented in August 2014, and it has now been in use for one year within the nuclear engineering programme. Lessons learned from using the platform are presented in this work.In order to study the effects of implementing this platform, a questionnaire was distributed to the students for the purpose of collecting information regarding their experience of giving oral presentation, their perceived skill level and their experience of practising oral presentations. The same questionnaire was distributed to the students on three occasions: before, during and after the first year of using the platform. Results from analysis of data are presented, showing that the students have experienced progression during this year.
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| 38. |
- Karlsson, Sofia A., et al.
(författare)
-
The impact of a changed legislation on reporting of adverse drug reactions in Sweden, with focus on nurses' reporting
- 2015
-
Ingår i: European Journal of Clinical Pharmacology. - : Springer Science and Business Media LLC. - 0031-6970 .- 1432-1041. ; 71:5, s. 631-636
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: In March 2007, a legislative amendment was issued in Sweden compelling nurses to report all suspected adverse drug reactions (ADRs) to the national pharmacovigilance system. The aims of this study were to describe the status of ADR reporting, before and after the implementation of the legislative changes, and to describe the general characteristics of suspected ADRs reported by nurses. Methods: The Swedish pharmacovigilance system during the study period constituted six regional centres responsible for the handling of all spontaneous ADR reports within their region. In this study, we identified all individual ADR reports from 2005 and 2010, analysed in depth the ADR reports from two regional centres and collated information about the reporter and the nature of the reported ADR. Results: From the two regional centres, a total of 898 and 1074 reports were submitted in 2005 and 2010 respectively. Nurses submitted 31% (275 reports) of the reports in 2005 and 24% (260 reports) in 2010. Nurses' reporting of serious ADRs was 3% (seven reports) in 2005 and 7% (17 reports) in 2010 with reporting of unlabelled ADRs at 4% (11 reports) in 2005 and 17% (45 reports) in 2010. Most of the serious and/or unlabelled reactions were related to vaccine administration (14 reports in 2005 and 36 reports in 2010). Conclusions: The overall ADR reporting by nurses did not appear to increase after the change in reporting legislation. The proportion of serious and/or unlabelled ADRs reported by nurses did however appear to increase during the same period. Taken together, our data suggests that further pro-active measures should be considered in order to involve nurses in the reporting of suspected ADRs.
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| 39. |
- Lauber, V., et al.
(författare)
-
The politics and economics of constructing, contesting and restricting socio-political space for renewables - The German Renewable Energy Act
- 2016
-
Ingår i: Environmental Innovation and Societal Transitions. - : Elsevier BV. - 2210-4224. ; 18, s. 147-163
-
Tidskriftsartikel (refereegranskat)abstract
- © 2015 Elsevier B.V. All rights reserved. This paper addresses the politics and economics of constructing, contesting and reducing the "socio-political space" for renewables connected to the German Renewable Energy Act (EEG). The political discourse is traced, revealing a gulf between "fit and conform" versus "stretch and transform" narratives. The former focus on short-term consumer costs, short learning periods and cost reductions from R&D rather than from market formation. The latter focus on total costs and acknowledge the need for lengthy learning periods and market formation to reduce costs. The version of the "fit and conform" narrative which recently became dominant, misrepresents the EEG surcharge, exaggerates the "burden" by ignoring external costs of fossil generation and doesn't consider inter-generational equity issues. This reflects the defensive reactions of a politically entrenched industry caught in a process of creative destruction, appealing to political actors such as the European Commission by invoking Europe's industrial competitiveness and (ideologically shared) technology-neutral policies.
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| 40. |
- Markard, J., et al.
(författare)
-
The technological innovation systems framework: Response to six criticisms
- 2015
-
Ingår i: Environmental Innovation and Societal Transitions. - : Elsevier BV. - 2210-4224. ; 16:Sept., s. 76-86
-
Tidskriftsartikel (refereegranskat)abstract
- The technological innovation systems framework (TIS) is widely used to study the emergence and growth of new technological fields and industries. At the same time, it has been criticized for a number of issues and innovation scholars have made suggestions of how to improve the framework. In this viewpoint, we respond to six areas of criticism: (1) TIS context, (2) system delineation, (3) spatial aspects, (4) transitions, (5) politics, and (6) policy recommendations. We point to promising conceptual developments of how to address shortcomings and highlight needs for further research. We also discuss the prospects of the TIS approach for the analysis of socio-technical transitions. The TIS framework, in our view, has the potential to outgrow its original scope - explaining the dynamics and performance of a technological field - and to address many of the issues relevant when studying transitions.
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| 41. |
- Martinik, Tomas, et al.
(författare)
-
Simulation of differential die-away instrument's response to asymmetrically burned spent nuclear fuel
- 2015
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 788, s. 79-85
-
Tidskriftsartikel (refereegranskat)abstract
- Previous simulation studies of differential die-away (DDA) instrument's response to active interrogation of spent nuclear fuel from a pressurized water reactor (PWR) yielded promising results in terms of its capability to accurately measure or estimate basic spent fuel assembly (SFA) characteristics, such as multiplication, initial enrichment (IE) and burn-up (BU) as well as the total plutonium content. These studies were however performed only for a subset of idealized SFAs with a symmetric BU with respect to its longitudinal axis. Therefore, to complement the previous results, additional simulations have been performed of the DDA instrument’s response to interrogation of asymmetrically burned spent nuclear fuel in order to determine whether detailed assay of SFAs from all 4 sides will be necessary in real life applications or whether a cost and time saving single sided assay could be used to achieve results of similar quality as previously reported in case of symmetrically burned SFAs.The results of this study suggest that DDA instrument response depends on the position of the individual neutron detectors and in fact can be split in two modes.The first mode, measured by the back detectors, is not significantly sensitive to the spatial distribution of fissile isotopes and neutron absorbers, but rather reflects the total amount of both contributors as in the cases of symmetrically burned SFAs. In contrary, the second mode, measured by the front detectors, yields certain sensitivity to the orientation of the asymmetrically burned SFA inside the assaying instrument. This study thus provides evidence that the DDA instrument can potentially be utilized as necessary in both ways, i.e. a quick determination of the average SFA characteristics in a single assay, as well as a more detailed characterization involving several DDA observables through assay of the SFA from all of its four sides that can possibly map the burn-up distribution and/or identify diversion or replacement of pins.
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| 42. |
- Miremadi, I., et al.
(författare)
-
Assessing the performance of energy innovation systems: Towards an established set of indicators
- 2018
-
Ingår i: Energy Research and Social Science. - : Elsevier BV. - 2214-6296. ; 40, s. 159-176
-
Tidskriftsartikel (refereegranskat)abstract
- Energy innovation is essential for tackling climate change. However, an established set of indicators, that can support policy makers in their design of policy mixes, has not been developed for evaluating the performance of energy innovation systems. The purpose of this study is, therefore, to list and classify a large set of indicators of the performance of energy innovation systems at sectoral and technological levels. 120 listed indicators are evaluated using four usefulness criteria, demonstrating significant weaknesses in the available indicators. The indicators are also classified according to an innovation process categorization to see if they cover all aspects of an innovation system along the entire innovation chain. In order to illustrate their application, the Nordic countries are selected for an analysis at the sectoral level, demonstrating a variety in the dynamics of energy innovation systems among these countries. At the level of an individual technology, we show how 90 indicators match the seven functions in a technological innovation system and how they, therefore, can guide policy by helping to analyze the strength of each function. Policy making may be further supported by an understanding of the dynamic relations between different indicators. Finally, recommendations for further research are given.
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| 43. |
- Nordqvist, Mahsa, et al.
(författare)
-
Timing of probiotic milk consumption during pregnancy and effects on the incidence of preeclampsia and preterm delivery: a prospective observational cohort study in Norway
- 2018
-
Ingår i: BMJ Open. - : BMJ. - 2044-6055 .- 2044-6055. ; 8:1
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives To investigate whether the timing of probiotic milk intake before, during early or late pregnancy influences associations with preeclampsia and preterm delivery. Design Population based prospective cohort study. Setting Norway, between 1999 and 2008. Participants 70 149 singleton pregnancies resulting in live-born babies from the Norwegian Mother and Child Cohort Study (no chronic disease, answered questionnaires, no placenta previaicerclage/serious malformation of fetus, first enrolment pregnancy). Only nulliparous women (n=37 050) were included in the preeclampsia analysis. Both iatrogenic and spontaneous preteml delivery (between gestational weeks 22+0 and 36+6) with spontaneous term controls (between gestational weeks 39+0 and 40+6) were included in the preterm delivery analysis resulting in 34 458 cases. Main outcome measures Adjusted OR for preeclampsia and preterm delivery according to consumption of probiotic milk at three different time periods (before pregnancy, during early and late pregnancy). Results Prohiotic milk intake in late pregnancy (but not before or in early pregnancy) was significantly associated with lower preeclampsia risk (adjusted OR: 0.80 (95% Cl 0.68 to 0.94)p-value: 0.007). Prohiotic intake during early (but not before or during late pregnancy) was significantly associated with lower risk of preterm delivery (adjusted OR: 0.79 (0.64 to 0.97)p-value: 0.03). Conclusions In this observational study, we found an association between timing of probiotic milk consumption during pregnancy and the incidence of the adverse pregnancy outcomes preeclampsia and preterm delivery. If future randomised controlled trials could establish a causal association between probiotics consumption and reduced risk of preeclampsia and preterm delivery, recommending probiotics would he a promising public health measure to reduce these adverse pregnancy outcomes.
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| 44. |
- Raven, R., et al.
(författare)
-
The politics of innovation spaces for low-carbon energy: Introduction to the special issue
- 2016
-
Ingår i: Environmental Innovation and Societal Transitions. - : Elsevier BV. - 2210-4224. ; 18, s. 101-110
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- © 2015 Elsevier B.V. All rights reserved. Energy systems around the globe face multiple, major pressures to transform into more sustainable ones. Over the past decades numerous, potentially sustainable energy innovations have been proposed, studied, developed and implemented to varying degrees. In the field of transition studies, scholars have used the notion of 'protective space' to study how such innovations emerge, grow, survive and decline over time, but few take an explicit political perspective on these dynamics. This editorial briefly reviews why such a perspective is necessary, and, on the basis of the contributions in this special issue, what it could entail in evolutionary, relational and institutional terms. The paper ends with six lessons for those involved in sustainable innovation advocacy.
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| 45. |
- Smith, Eric L., et al.
(författare)
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A Viability Study of Gamma Emission Tomography for Spent Fuel Verification : JNT 1955 Phase I Technical Report
- 2016
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Rapport (refereegranskat)abstract
- The potential for gamma emission tomography (GET) to detect partial defects within a spent nuclear fuel assembly is being assessed through a collaboration of Support Programs to the International Atomic Energy Agency (IAEA). In the first phase of this study, two safeguards verification objectives have been identified. The first is the independent determination of the number of active pins that are present in the assembly, in the absence of a priori information about the assembly. The second objective is to provide quantitative assay 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 has been evaluated across a range of fuel types, burnups, and cooling times, and with a target total interrogation time of less than 60 minutes. This evaluation of GET viability for safeguards applications was 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. Instrument response data were processed using a variety of tomographic-reconstruction and image-processing methods, and scoring metrics specific to each of the verification objectives were used to predict performance. This report describes the analysis framework and metrics used to predict tomographer performance, the design of a “universal” GET (UGET) instrument intended to support the full range of verification scenarios envisioned by the IAEA, and a comparison of predicted performance for the notional UGET design and an optimized variant of an existing IAEA instrument.
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| 46. |
- Timpka, Toomas, et al.
(författare)
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Lifetime history of sexual and physical abuse among competitive athletics (track and field) athletes : cross sectional study of associations with sports and non-sports injury
- 2019
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Ingår i: British Journal of Sports Medicine. - : BMJ PUBLISHING GROUP. - 0306-3674 .- 1473-0480. ; 53:22, s. 1412-
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Tidskriftsartikel (refereegranskat)abstract
- Objective To examine associations between lifetime sexual and physical abuse, and the likelihood of injury within and outside sport in athletes involved in competitive athletics. Methods A cross sectional study was performed among the top 10 Swedish athletics athletes using 1 year prevalence of sports and non-sports injuries as the primary outcome measure. Associations with sociodemographic characteristics, lifetime abuse history and training load were investigated. Data were analysed using simple and multiple logistic regression models. Results 11% of 197 participating athletes reported lifetime sexual abuse; there was a higher proportion of women (16.2%) than men (4.3%) (P=0.005). 18% reported lifetime physical abuse; there was a higher proportion of men (22.8%) than women (14.3%) (P=0.050). For women, lifetime sexual abuse was associated with an increased likelihood of a non-sports injury (OR 8.78, CI 2.76 to 27.93; P<0.001). Among men, increased likelihood of a non-sports injury was associated with more frequent use of alcoholic beverages (OR 6.47, CI 1.49 to 28.07; P=0.013), while commencing athletics training at >13 years of age was associated with a lower likelihood of non-sports injury (OR 0.09, CI 0.01 to 0.81; P=0.032). Lifetime physical abuse was associated with a higher likelihood of sports injury in women (OR 12.37, CI 1.52 to 100.37; P=0.019). Among men, athletes with each parents with <= 12 years formal education had a lower likelihood of sustaining an injury during their sports practice (OR 0.37, CI 0.14 to 0.96; P=0.040). Conclusions Lifetime sexual and physical abuse were associated with an increased likelihood of injury among female athletes. Emotional factors should be included in the comprehension of injuries sustained by athletes.
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| 47. |
- Timpka, Toomas, et al.
(författare)
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Protocol Design for Large-Scale Cross-Sectional Studies of Sexual Abuse and Associated Factors in Individual Sports : Feasibility Study in Swedish Athletics
- 2015
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Ingår i: Journal of Sports Science and Medicine (JSSM). - : JOURNAL SPORTS SCIENCE & MEDICINE, MEDICAL FACULTY ULUDAG UNIV, DEPT SPORTS MEDICINE, BURSA, TURKEY. - 1303-2968. ; 14:1, s. 179-187
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Tidskriftsartikel (refereegranskat)abstract
- To ensure health and well-being for their athletes, sports organizations must offer preventive measures against sexual abuse. The aim of this study was to design and evaluate feasibility of a research protocol for cross-sectional epidemiological studies of sexual abuse in athletics. Examination of the requirements on the study of sexual abuse in athletics was followed by iterated drafting of protocol specifications and formative evaluations. The feasibility of the resulting protocol was evaluated in a national-level study among elite athletics athletes (n = 507) in Sweden. The definition of sexual abuse, the ethical soundness of the protocol, reference populations and study of co-morbidity, and the means for athlete-level data collection were identified as particularly complex issues in the requirements analyses. The web-based survey defined by the protocol facilitates anonymous athlete self-reporting of data on exposure to sexual abuse. 198 athletes (39%) fully completed the feasibility survey. 89% (n = 177) reported that they agreed with that the questions in the survey were important, and 95% (n = 189) reported that they answered truthfully to all questions. Similarly, 91% (n = 180) reported that they did not agree with that the questions were unpleasant for them. However, 16% (n = 32) reported that they did not find the survey to be of personal value, and 12% (n = 23) reported that the survey had caused them to think about issues that they did not want to think about. Responding that participation was not personally gratifying was associated with training more hours (p = 0.01). There is a scarcity of research on the prevention of sexual abuse in individual sports. The present protocol should be regarded as a means to overcome this shortcoming in athletics. When implementing the protocol, it is necessary to encourage athlete compliance and to adapt the web-based survey to the particular infrastructural conditions in the sports setting at hand.
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| 48. |
- Verma, Vasudha, 1988-, et al.
(författare)
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Feasibility Study of Self Powered Neutron Detectors in Fast Reactors for Detecting Local Change in Neutron Flux Distribution
- 2015
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Ingår i: Feasibility Study of Self Powered Neutron Detectors in Fast Reactors for Detecting Local Change in Neutron Flux Distribution.
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Konferensbidrag (refereegranskat)abstract
- Neutron flux monitoring systems form an integral part of the design of a Generation IV sodium cooled fast reactor. Diverse possibilities of detector systems have to be investigated with respect to practicality and feasibility according to the detection parameters. In this paper, we demonstrate the feasibility of using self powered neutron detectors as in-core detectors in fast reactors for detecting local changes in the neutron flux distribution. We show that the gamma contribution from fission products decay and activation of structural materials and sodium is very small compared to the fission gammas. Thus, it is possible for the in-core SPND signal to follow changes in local neutron flux as they are proportional to each other. This implies that the signal from an in-core SPND can provide dynamic information on the neutron flux perturbations occuring inside the reactor core.
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| 49. |
- Verma, Vasudha, 1988-, et al.
(författare)
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Neutron flux monitoring with in-vessel fission chambers to detect an inadvertent control rod withdrawal in a sodium-cooled fast reactor
- 2016
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Ingår i: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549 .- 1873-2100. ; 94, s. 487-493
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Tidskriftsartikel (refereegranskat)abstract
- The neutron flux monitoring system forms an integral part of the safety design of a Generation IV sodium-cooled fast reactor. During the initial design phase of the neutron flux monitoring system, one needs to explore various detector locations and configurations. Diverse possibilities of the detector system installation should be studied for different locations in the reactor vessel in order to detect any perturbations in the core. In this paper, we investigate the possibility of placing fission chambers beyond the lateral neutron shield, ex-core but in-vessel and study the detectability of an inadvertent control rod withdrawal with these fission chambers. A generic core design of a Generation IV 1500 MWth French sodium-cooled fast reactor is used for the study, and calculations are performed with the Monte Carlo code SERPENT2. We propose certain design changes that are needed to be incorporated, w.r.t. the facilitation of neutron transport to this ex-core location.We are able to show that there is a detectable signature in the fission chambers following an inadvertent control rod withdrawal in the core. The equally-spaced azimuthal detectors are able to follow changes in the neutron flux distribution in the core. This study helps us to analyze multiple detector locations and give the general trends for monitoring indications to detect any perturbations in the core.
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| 50. |
- Verma, Vasudha, 1988-, et al.
(författare)
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Self Powered Neutron Detectors as in-core detectors for Sodium-cooled Fast Reactors
- 2017
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 860, s. 6-12
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Tidskriftsartikel (refereegranskat)abstract
- Neutron flux monitoring system forms an integral part of the design of a Generation IV sodium cooled fast reactor. Diverse possibilities of detector system installation must be studied for various locations in the reactor vessel in order to detect any perturbations in the core. Results from a previous paper indicated that it is possible to detect changes in neutron source distribution initiated by an inadvertent withdrawal of outer control rod with in-vessel fission chambers located azimuthally around the core. It is, however, not possible to follow inner control rod withdrawal and precisely know the location of the perturbation in the core. Hence the use of complimentary in-core detectors coupled with the peripheral fission chambers is proposed to enable robust core monitoring across the radial direction.In this paper, we assess the feasibility of using self-powered neutron detectors (SPNDs) as in-core detectors in fast reactors for detecting local changes in the power distribution when the reactor is operated at nominal power. We study the neutron and gamma contributions to the total output current of the detector modelled with Platinum as the emitter material. It is shown that this SPND placed in an SFR-like environment would give a sufficiently measurable prompt neutron induced current of the order of 600 nA/m. The corresponding induced current in the connecting cable is two orders of magnitude lower and can be neglected. This means that the SPND can follow in-core power fluctuations. This validates the operability of an SPND in an SFR-like environment.
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