| 1. |
- Ringborg, U, et al.
(författare)
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The Swedish Council on Technology Assessment in Health Care (SBU) systematic overview of radiotherapy for cancer including a prospective survey of radiotherapy practice in Sweden 2001 - Summary and conclusions
- 2003
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Ingår i: Acta Oncologica. - : Informa UK Limited. - 1651-226X .- 0284-186X. ; 42:5-6, s. 357-365
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Tidskriftsartikel (refereegranskat)abstract
- A systematic assessment of radiotherapy for cancer was conducted by The Swedish Council on Technology Assessment in Health Care (SBU) and published in 1996. The assessment reviewed the scientific literature up to 1993 on the use of radiotherapy in the treatment of solid tumours. and estimated the costs associated with radiotherapy It also described the current practise of radiotherapy in Sweden 1992 and compared practise with scientific knowledge. The SBU has now conducted a follow-up study on radiotherapy for cancer, including a review of the scientific literature from 1994 and a prospective survey of radiotherapy practise in Sweden 2001. The following conclusions were drawn: The role of radiotherapy as an important form of treatment for cancer with both curative and palliative intent has been further confirmed. The use of radiotherapy in Sweden has increased and is now at the internationally recommended level. Radiotherapy in Sweden is mostly given in accordance with the scientific evidence but may still be underutilized in certain situations. The resources for radiotherapy are being utilized more efficiently The costs of radiotherapy are still 5% of the total cost of cancer care, while the cost of an individual treatment (fraction) has decreased. The need for radiotherapy capacity will increase. In addition, half of the treatment equipment will have to be replaced in the next few years.
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| 11. |
- Bremberg, ER, et al.
(författare)
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An evaluation of pharmacist contribution to an oncology ward in a Swedish hospital
- 2006
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Ingår i: Journal of oncology pharmacy practice : official publication of the International Society of Oncology Pharmacy Practitioners. - : SAGE Publications. - 1078-1552. ; 12:2, s. 75-81
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Tidskriftsartikel (refereegranskat)abstract
- Aim. The aim of this project was to establish the importance of a pharmacist in the health-care team in improving drug use in an oncology ward in the Department of Oncology, Karolinska University Hospital, Stockholm, Sweden. Methods and patients. The pharmacist participated in the medical round in the mornings and worked as a member of the health-care team. Drug-related problems (DRPs) were identified by drug chart reviews based on data from medical files, laboratory tests and interviews with patients and/or relatives. A questionnaire to physicians and nurses was used to evaluate their experiences of the pharmacist’s contribution to the oncology ward. Results. In total, 114 DRPs were identified in 58 patients. For each DRP, the pharmacist gave proposals for solutions. Sixty-eight suggestions out of 114 (59.6%) were implemented by the physician. Two suggestions (1.8%) were partly followed. For 32 suggestions (28.0%) it was unclear if they had caused any change in medication. Twelve suggestions (10.5%) were not followed. Most of the physicians and nurses acknowledged the pharmacist’s contribution to improved drug use in the ward. Conclusion. A pharmacist can improve drug use in an oncology ward as a member of the health-care team. The pharmacist contributes with a systematic focus on the patient from a drug perspective.
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| 18. |
- Insulander Björk, Klara L, 1982, et al.
(författare)
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Study of Thorium-Plutonium Fuel for Possible Operating Cycle Extension in PWRs
- 2013
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Ingår i: Science and Technology of Nuclear Installations. - : Hindawi Limited. - 1687-6075 .- 1687-6083. ; 2013
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Tidskriftsartikel (refereegranskat)abstract
- Computer simulations have been carried out to investigate thepossibility of extending operating cycle length in the PressurisedWater Reactor Ringhals 3 by the use of thorium-plutonium oxidefuel. The calculations have been carried out using tools andmethods that are normally employed for reload design and safetyevaluation in Ringhals 3. The 3-batch reload scheme and the powerlevel have been kept unchanged, and a normal uranium oxide fuelassembly designed for a 12-month operating cycle in this reactoris used as a reference. The use of plutonium as the fissile component reduces the worth ofcontrol rods and soluble boron, which makes it necessary to modifythe control systems. The delayed neutron fraction is low comparedwith the reference, but simulations and qualitative assessments ofrelevant transients indicate that the reactor could still beoperated safely. Differences in reactivity coefficients are mainlybeneficial for the outcome of transient simulations for thethorium based fuel. A 50% extension of the current 12-month operating cycle length should be possible with thorium-plutonium mixed oxide fuel, given an upgrade of the control systems. More detailed simulations have to be carried out for some transients in order to confirm the qualitative reasoning presented.
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| 19. |
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| 20. |
- Lau, Cheuk Wah, 1985, et al.
(författare)
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Conceptual study of axial offset fluctuations upon stepwise power changes in a thorium-plutonium core to improve load-following conditions
- 2014
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Ingår i: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549 .- 1873-2100. ; 72, s. 84-89
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Tidskriftsartikel (refereegranskat)abstract
- The increased share of renewable energy, such as wind and solar power, will increase the demand for load-following power sources, and nuclear reactors could be one option. However, during rapid load-following events, traditional UOX cores could be restricted by the volatile oscillation of the power distribution. Therefore, a conceptual study on stability properties of Th-MOX PWR concerning axial offset power excursion during load-following events are investigated and discussed. The study is performed in SIMULATE-3 for a realistic PWR core (Ringhals-3) at the end of cycle, where the largest amplitude of the axial offset oscillations is expected. It is shown that the Th-MOX core possesses much better stability characteristics and shorter reactor dead time compared with a traditional UOX core, and the main reasons are the lower sensitivity to perturbations in the neutron spectrum, lower xenon poisoning and lower thermal neutron flux.
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| 21. |
- Lau, Cheuk Wah, 1985, et al.
(författare)
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Feasibility Study of 1/3 Thorium-Plutonium Mixed Oxide Core
- 2014
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Ingår i: Science and Technology of Nuclear Installations. - : Hindawi Limited. - 1687-6075 .- 1687-6083. ; 2014:Art. no. 709415
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Tidskriftsartikel (refereegranskat)abstract
- Thorium-plutonium mixed oxide (Th-MOX) fuel has become one of the most promising solutions to reduce a large and increasing plutonium stockpile. Compared with traditional uranium-plutonium mixed oxide (U-MOX) fuels, Th-MOX fuel has higher consumption rate of plutonium in LWRs. Besides, thorium based fuels have improved thermomechanical material properties compared with traditional U-MOX fuels. Previous studies on a full Th-MOX core have shown reduced efficiency in reactivity control mechanisms, stronger reactivity feedback, and a significantly lower fraction of delayed neutrons compared with a traditional uranium oxide (UOX) core. These problems complicate the implementation of a full Th-MOX core in a similar way as for a traditional U-MOX core. In order to reduce and avoid some of these issues, the introduction of a lower fraction of Th-MOX fuel in the core is proposed. In this study, one-third of the assemblies are Th-MOX fuel, and the rest are traditional UOX fuel. The feasibility study is based on the Swedish Ringhals-3 PWR. The results show that the core characteristics are more similar to a traditional UOX core, and the fraction of delayed neutrons is within acceptable limits. Moreover, the damping of axial xenon oscillations induced by control rod insertions is almost 5 times more effective for the 1/3 Th-MOX core compared with the standard core.
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| 22. |
- Lau, Cheuk Wah, 1985, et al.
(författare)
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Improvement of LWR thermal margins by introducing thorium
- 2012
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Ingår i: Progress in Nuclear Energy. - : Elsevier BV. - 0149-1970. ; 61, s. 48-56
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Tidskriftsartikel (refereegranskat)abstract
- The use of thorium in pressurized water reactor fuel assemblies is investigated in this paper. The novelty of the reported work is to study a fuel design primarily intended to control the excess of reactivity at beginning of life, and flatten the intra-assembly power distribution rather than converting fertile Th-232 into fissile U-233. The fuel assembly is a traditional 17 x 17 pressurized water reactor fuel design. The majority of the fuel pins contain a mixture of uranium and thorium oxides, while a few fuel pins contain a mixture between uranium and gadolinium oxides. The calculation were performed by two-dimensional transport calculations with the Studsvik Scandpower CASMO-4E code in order to determine the main neutronic properties of the new fuel design, compared with the traditional uranium-based fuel assembly containing gadolinium used as reference. The majority of the neutronic properties of the uranium-thorium-based fuel assembly were similar to the reference fuel assembly. The Doppler and the moderator temperature coefficients of reactivity were found to be appreciably more negative in the uranium-thorium-based design, but still within acceptable limits. One advantage of this new uranium-thorium-based design is a reduction of the pin peak power at beginning of life, because of smaller amount of gadolinium being used. This is important from an operational and safety viewpoint, since the margin to departure from nucleate boiling becomes larger. Consequently, this new type of thorium-based fuel assembly shows advantageous properties for use in power-uprated cores.
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| 23. |
- Lau, Cheuk Wah, 1985, et al.
(författare)
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Improvement of the thermal margins in the Swedish Ringhals-3 PWR by introducing new fuel assemblies with thorium
- 2012
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Ingår i: Proc. Int. Conf. on Advances in Reactor Physics – Linking Research, Industry, and Education (PHYSOR 2012), Knoxville, TN, USA, April 15-20, 2012, American Nuclear Society. - 9781622763894 ; 5, s. 4041-4055
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Konferensbidrag (refereegranskat)abstract
- Thorium is a fertile material and most of the past research has focused on breeding thorium to fissile material. In this paper, the focus is on using thorium to improve the thermal margins by homogeneously distributing thorium in the fuel pellets. A proposed uranium-thorium-based fuel assembly is simulated for the Swedish Ringhals-3 PWR core in a realistic demonstration. All the key safety parameters, such as isothermal temperature coefficient of reactivity, Doppler temperature of reactivity, boron worth, shutdown margins and fraction of delayed neutrons are studied in this paper, and are within safety limits for the new core design using the uranium- thorium-based fuel assemblies. The calculations were performed by the two-dimensional transport code CASMO-4E and the two group steady-state three dimensional nodal code SIMULATE-3 from Studsvik Scandpower. The results showed that the uranium-thorium-based fuel assembly improves the thermal margins, both in the pin peak power and the local power (Fq). The improved thermal margins would allow more flexible core designs with less neutron leakage or could be used in power uprates to offer efficient safety margins.
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| 24. |
- Lau, Cheuk Wah, 1985, et al.
(författare)
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Investigation of the Equilibrium Core Characteristics for the Ringhals-3 PWR with Improved Thermal Margins Using Uranium-thorium Fuel
- 2013
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Ingår i: Proceedings of ICAPP 2013. ; , s. 8-
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Konferensbidrag (refereegranskat)abstract
- Nowadays, PWR core thermal margins have decreased because of higher enrichment of U-235 in the fuel assemblies to achieve higher discharge burnup, higher core power to improve economical competiveness, and reduction of fast neutron leakage to prevent rapid ageing of the pressure vessel. Thus, a new uranium-thorium-based fuel assembly is proposed for improving the thermal margins. The proposed fuel is simulated for the Swedish Ringhals-3 PWR equilibrium core in a realistic demonstration. The difference between the uranium-thorium and traditional fuel assemblies is the fuel pellets composition. In the uranium-thorium fuel assembly, 7 weight percentage of thorium oxide is added to some of the fuel pellets. In those fuel pellets, the enrichment is kept below 5 % enrichment of U-235 in order to avoid extra certification on transport, management and storage.The two most significant results showed in this paper are the improved pin peak power, and the axial offset in the core. The pin peak power margin could be improved by 75 % by using the uranium-thorium-based fuel compared with the reference core containing traditional fuel assemblies. The maximum axial offset was decreased by 33 % using the uranium-thorium-based fuel compared with the reference core. The improved thermal margins in the core would allow more flexible core designs with less neutron leakage, or could be used for power uprates while guaranteeing sufficient safety margins.
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| 25. |
- Lau, Cheuk Wah, 1985, et al.
(författare)
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Reducing axial offset and improving stability in PWRs by using uranium-thorium fuel
- 2014
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Ingår i: Progress in Nuclear Energy. - : Elsevier BV. - 0149-1970. ; 76, s. 137-147
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Tidskriftsartikel (refereegranskat)abstract
- The axial offset (AO) is a parameter used to monitor the core axial power distribution, and is important for safe reactor operation. Previous works have showed that a new type uranium-thorium (U-Th) based fuel assembly could be used to achieve a more homogenous radial power distribution, and thereby improve the thermal margins in the core. In this paper, it is shown that a core containing U-Th fuel assemblies also reduces the AO and improves the core stability. For an equilibrium U-Th core, the maximum AO could be reduced by 33%, and the minimum AO could be reduced by 8% compared with a standard uranium core. In the U-Th core, the maximum AO was influenced by the more negative moderator temperature coefficient of reactivity, while the minimum AO is mainly affected by the more homogenous radial power distribution. These findings conclude that the U-Th core displays a more homogenous power distribution both axially and radially, thus offering better thermal margins for power uprates and flexible power operation. Moreover, xenon oscillations in the core due to perturbations induced by the control rods are 30% more effectively damped for the U-Th core compared with the standard core, improving the stability in AO. © 2014 Elsevier Ltd. All rights reserved.
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| 26. |
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| 27. |
- Litvinchuk, A. P., et al.
(författare)
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Optical and electronic properties of metal doped thermoelectric Zn4Sb3
- 2008
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 103:12
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Tidskriftsartikel (refereegranskat)abstract
- Optical and electronic properties of metal (Pb, Bi, Sn, and In) doped Zn4Sb3 are reported in the temperature range 80-300 K, which covers the beta, alpha, and alpha(') structural phases of this thermoelectric material. Metal doping alters the subtle balance between Zn disorder and Zn deficiency present in beta-Zn4Sb3 and changes its low temperature structural behavior. Analysis of infrared reflection data shows that the formation of ordered alpha'-Zn4Sb3 is accompanied by a substantial increase in the free charge-carrier concentration. In contrast, for samples where doping suppresses the occurrence of the low temperature alpha'-phase, the free charge-carrier concentration is only weakly temperature dependent. Different degrees of structural disorder in doped beta-Zn4Sb3 and the ordering processes at low temperatures leading to alpha- and alpha'-Zn4Sb3 are also recognized in the charge-carrier dynamics.
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| 28. |
- Mihai, Oana, 1975, et al.
(författare)
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The effect of water on methane oxidation over Pd/Al2O3 under lean, stoichiometric and rich conditions
- 2017
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Ingår i: Catalysis Science and Technology. - : Royal Society of Chemistry (RSC). - 2044-4753 .- 2044-4761. ; 7:14, s. 3084-3096
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the effect of oxygen concentration and the presence of water on methane oxidation were examined over a Pd/Al2O3 catalyst. The physicochemical properties of the catalyst were investigated in detail using BET, XRD, STEM, O-2-TPO and CH4-TPR. Ramping experiments from 150 to 700 degrees C were conducted using rich, stoichiometric and lean gas mixtures in the absence and presence of water. It was found that increasing the oxygen concentration in a dry atmosphere resulted in higher methane oxidation activity, which can be connected to the facilitation of palladium oxide formation. The TPO data showed that only minor amounts of PdO up to 700 degrees C were decomposed; however, in the stoichiometric and rich reaction mixture, PdO was still decomposed because of the oxygen limitation. This fact resulted in a "negative activation" during cooling, with increased activity because of palladium re-oxidation. Moreover, methane steam reforming and water gas shift reactions were important reactions under rich conditions over the metallic palladium sites. A significant inhibiting effect of water on the Pd-catalyst with loss of methane activity was found. Interestingly, the inhibition effect was much greater using high oxygen concentration in the gas mixture (500 ppm CH4, 8% O-2, 5% H2O) than that at lower oxygen levels (800-1200 ppm) and we propose that the hydroxyl species formation, which blocks the active sites, are facilitated by a large oxygen excess. In addition, the re-oxidation of palladium occurring during the cooling ramp in dry feed using rich and stoichiometric gas mixtures was also significantly suppressed in the presence of a large amount of water. Thus, water impedes the oxidation of palladium, which significantly deactivates the Pd catalyst.
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| 29. |
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| 32. |
- Nylén, H., et al.
(författare)
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O KVV Auger emission versus resonant photoemission at the O K edge of high-Tc superconductors
- 1998
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Ingår i: Physica C: Superconductivity and its Applications. - 0921-4534. ; 300:3-4, s. 161-170
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Tidskriftsartikel (refereegranskat)abstract
- Photoelectron spectroscopy results on single crystals of the superconductors Bi2Sr2CaCu2O8,Bi2Sr 2CuO6, Ba0.6K0.4BiO3 and the semiconductor Ba0.9K0.1BiO3 are reported for the photon energy region around the O K absorption threshold. The development of the O-KVV Auger structure has been carefully monitored as a function of photon energy. A non-monotonic behavior displaying a feature at a constant binding energy of about 14 eV was found for Bi2Sr2CaCu2O8 and Bi2Sr2CuO6 in a narrow photon energy region of 1 eV at the main edge of the O K absorption spectrum around 530 eV. The corresponding enhancement, connected with the autoionization of O 2 p states, is absent in Ba1-xKxBiO3 in contrast to Bi2Sr2CaCu2O8 and Bi2Sr2CuO6. The resonant enhancement is more pronounced for Bi2Sr2CuO6 as compared to Bi2Sr2CaCu2O8, which can be explained by a lower charge carrier concentration in the former case, leading to a more localized nature of intermediate O 2 p states. The model parameters Cu d-d and O p-p Coulomb interactions and the charge transfer energy Δ are estimated from the experiments.
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| 33. |
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| 38. |
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| 39. |
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| 41. |
- Qvarford, M., et al.
(författare)
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X-ray absorption study of oxygen in the high-Tc superconductor Bi2Sr2CaCu2O8 near the interfaces to Cu, Ag and Au
- 1996
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Ingår i: Physica C: Superconductivity and its Applications. - : Elsevier BV. - 0921-4534 .- 1873-2143. ; 265:1-2, s. 113-120
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Tidskriftsartikel (refereegranskat)abstract
- The influence on O 2p holes in single crystalline Bi2Sr2CaCu2O8 upon the interface formation to Cu, Ag and Au has been studied by O K edge X-ray absorption measurements. It was found that Cu reduces the amount of doping induced O 2p holes significantly in the vicinity of the interface, whereas Ag and Au gave a much smaller reduction of these states. Photoemission spectra confirmed previous findings that Cu causes a strong chemical reaction at the Bi-O surface of Bi2Sr2CaCu2O8, in contrast to Ag and Au which induced only a minimal reaction. The results support the opinion that the Bi-O layers are essential for the doping of the Cu-O2 layers in Bi2Sr2CaCu2O8.
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| 42. |
- Sadokhina, Nadezda, 1985, et al.
(författare)
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An Experimental and Kinetic Modelling Study for Methane Oxidation over Pd-based Catalyst: Inhibition by Water
- 2017
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Ingår i: Catalysis Letters. - : Springer Science and Business Media LLC. - 1572-879X .- 1011-372X. ; 147:9, s. 2360-2371
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Tidskriftsartikel (refereegranskat)abstract
- The water inhibition of methane oxidation over a bimetallic Pt-Pd on CeO2-Al2O3 catalyst was investigated and the experimental data were used to develop a kinetic model, consisting of only three reaction steps. In the model, the water effect was assigned to the adsorption of H2O on surface sites, as well as to the formation and accumulation of surface hydroxyl groups. These two effects were accounted by the model, which could well describe the experimental data obtained under various conditions.
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| 43. |
- Sadokhina, Nadezda, 1985, et al.
(författare)
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The influence of gas composition on Pd-based catalyst activity in methane oxidation - inhibition and promotion by NO
- 2017
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Ingår i: Applied Catalysis B: Environmental. - : Elsevier BV. - 0926-3373 .- 1873-3883. ; 200, s. 351-360
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Tidskriftsartikel (refereegranskat)abstract
- The individual influence, as well as the combined effect of H2O and NO on the activity of Pd/Al2O3, PtPd/Al2O3 and PtPd/CeAl2O3 catalysts in complete methane oxidation under lean conditions were investigated. Under temperature-programmed ramping experiments the activity was severely inhibited in the presence of 5 vol.% H2O in the reaction mixture. We propose that this is due to blocking by both water and hydroxyl species. Under the influence of NO without water in the gas flow, it was found that the methane oxidation activity was partly suppressed, due to blocking of active sites. Indeed TPD performed after ramping experiments showed NOx storage on the catalyst. Contrary to the negative effect of NO in the dry case, the promotional NO effect on the activity was observed when water was co-fed, comparing the case with only water presence. The promotional NO effect was confirmed with isothermal experiments, where e.g. the methane conversion decreased from initial 96% to 25% after 10 h of exposure in CH4-O-2-H2O mixture at 450 degrees C over the Pd/Al2O3 sample, while the decrease was only from 88% to 60% when catalyst was exposed to CH4-O-2-H2O-NO mixture. We propose that the reason is that the NO reacts with the hydroxyl species to form HNO2, which reduces the water deactivation effect.
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| 44. |
- Tjernberg, O, et al.
(författare)
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Evidence of pseudogap related core level shifts in Bi2Sr2Ca1-xYxCu2O8+delta
- 1997
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 79:3, s. 499-502
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Tidskriftsartikel (refereegranskat)abstract
- Photoelectron spectroscopy data from Bi2Sr2Ca1-xYxCu2O8+delta Single crystals, for x = 0, 0.16, and 0.55, are presented. It is shown that there are core level shifts related to the opening of a pseudogap and that similar shifts are observed at the opening of the superconducting gap in optimally doped samples. This result is in agreement with pair formation above T-c as suggested by V.J. Emery and S.A. Kivelson [Nature (London) 374, 434 (1995)].
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| 45. |
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| 46. |
- Zakharov, A. A., et al.
(författare)
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Metal-dielectric transition in Ba0.6K0.4BiO3-y single crystals studied by scanning photoelectron microscopy
- 1997
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Ingår i: Physical Review B (Condensed Matter). - 0163-1829. ; 56:10
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure of Ba0.6K0.4BiO3-y single crystals has been studied using a scanning photoelectron microscope with a lateral resolution in the one micrometer range. It is possible to change the oxygen content (y) and convert the surface from the metallic to the dielectric state presumably by breaking the Bi-O bonds by using the focused zero-order light to irradiate the sample surface. The electronic states close to the Fermi level after such a treatment show a different doping dependence as compared to the case of potassium doping. By imaging the surface on the micrometer scale we find significant variations in the valence band intensity over the surface and observe a rather large intensity of the density of states close to the Fermi level. This will have a large impact on the discussions of dynamical lattice distortion and pseudogap behavior in the metallic phase.
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