This thesis presents a whole-core benchmark of the European Pressurized Reactor (EPR) using multiple transport methods. The core specifications were taken directly from the Final Safety Analysis Report (FSAR) submitted to the Nuclear Regulatory Commission (NRC) and the reactor was modeled in a stylized manner while maintaining full heterogeneity at the pin and assembly level. The geometry and material specifications are given as well as problem-specific cross sections for 2, 4, and 8 energy group calculations. Cross sections were generated using HELIOS, a lattice depletion code based on the Collision Probability Method (CPM). The multi-group cross sections were utilized in the reference calculation, COMET calculation, and response function generation. The reference solution was obtained via an MCNP model identical to the one implemented in COMET. Specific steps towards constructing and running a COMET calculation are outlined. Detailed results including assembly eigenvalues, core eigenvalues, and pin fission densities are presented.

The reported lifetime in an in-beam neutron lifetime experiment performed at NIST was tn = (886.3 ± 3.4) s. The largest source of uncertainty was the efficiency of the neutron flux monitor (0.3% relative uncertainty). The flux monitor operates by counting charged particles produced when neutrons impinge on a 6Li foil. Its efficiency was calculated from the 6Li thermal neutron cross section, the solid angle subtended by the charged particle detectors, and the amount of neutron-absorbing material present on the foil. An absolute black neutron detector for cold neutron beams has been developed to measure the efficiency without the need to know these quantities. The flux monitor efficiency is measured to a precision of 0.052% using this direct calibration technique. This calibration removes the largest barrier to a 1 s neutron lifetime measurement with the beam technique. It is hoped that this data can also be used to re-evaluate the current NIST neutron lifetime value, reduce its uncertainty, and remove the dependence on evaluated nuclear data files. There is also the possibility for a direct measurement of the 6Li thermal neutron cross section.

In zukünftigen kerntechnischen Anlagen können die Materialien Blei und Bismut eine größere Rolle spielen als heute. Für die Planung dieser Anlagen werden verlässliche Wirkungsquerschnittsdaten benötigt. Insbesondere der Neutronentransport in einem Blei-Spallationstarget eines beschleunigergetriebenen unterkritischen Reaktors hängt stark von den inelastischen Streuquerschnitten im Energiebereich von 0,5 MeV bis 6 MeV ab. In den vergangenen 20 Jahren wurden elastische und inelastische Neutronenstreuquerschnitte mit hoher Präzision für eine Vielzahl von Elementen am PTB-Flugzeitspektrometer gemessen. Zur Erzeugung der Neutronen wurde hauptsächlich die D(d,n)-Reaktion genutzt. Aufgrund des Q-Wertes der Reaktion und der verfügbaren Deuteronenenergien können Neutronen im Energiebereich von 6 MeV bis 16 MeV erzeugt werden. Die Messung von Wirkungsquerschnitten bei niedrigeren Energien erfordert somit die Verwendung einer anderen neutronenerzeugenden Reaktion. Hierfür wurde die 15N(p,n)15O-Reaktion ausgewählt, da sie die Erzeugung monoenergetischer Neutronen bis zu einer Energie von 5,7 MeV erlaubt. In dieser Arbeit wird die 15N(p,n)-Reaktion auf ihre Eignung als Quelle monoenergetischer Neutronen in Streuexperimenten untersucht. Die Untersuchung der Reaktion beinhaltet die Messung von differentiellen Wirkungsquerschnitten für ausgewählte Energien und die Auswahl von optimalen Targetbedingungen. Differentielle elastische und inelastische Neutronenstreuquerschnitte wurden unter Anwendung der Flugzeitmethode für Blei bei vier Energien zwischen 2 MeV und 4 MeV gemessen. Eine Bleiprobe mit natürlicher Isotopenzusammensetzung wurde verwendet. Für den Nachweis der gestreuten Neutronen wurden NE213 Flüssigszintillatoren verwendet, deren Nachweiswahrscheinlichkeit gut bekannt ist. Winkelintegrierte Wirkungsquerschnitte wurden mit einem Legendre-Polynomfit unter Verwendung der Methode der kleinsten Quadrate bestimmt. Zusätzlich erfolgten Messungen für die isotopenreinen Streuproben 209Bi und 181Ta bei 4 MeV Neutronenenergie. Die Ergebnisse werden mit denen früherer Experimente und aktuellen Evaluationen verglichen. / In future nuclear facilities, the materials lead and bismuth can play a more important role than in today’s nuclear reactors. Reliable cross section data are required for the design of those facilities. In particular the neutron transport in the lead spallation target of an Accelerator-Driven Subcritical Reactor strongly depends on the inelastic neutron scattering cross sections in the energy region from 0.5MeV to 6 MeV. In the recent 20 years, elastic and inelastic neutron scattering cross sections were measured with high precision for a variety of elements at the PTB time-of-flight spectrometer. The D(d,n) reaction was primarily used for the production of neutrons. Because of the Q value of the reaction and the available deuteron energies, neutrons in the energy range from 6MeV to 16MeV can be produced. For the cross section measurement at lower energies, however, another neutron producing reaction is required. The 15N(p,n)15O reaction was chosen, as it allows the production of monoenergetic neutrons with up to 5.7MeV energy. In this work, the 15N(p,n) reaction was studied with focus on the suitability as a source for monoenergetic neutrons in scattering experiments. This includes the measurement of differential cross sections for the neutron producing reaction and the choice of optimum target conditions. Differential elastic and inelastic neutron scattering cross sections were measured for lead at four energies in the region from 2MeV to 4MeV incident neutron energy using the time-offlight technique. A lead sample with natural isotopic composition was used. NE213 liquid scintillation detectors with well-known detection efficiencies were used for the detection of the scattered neutrons. Angle-integrated cross sections were determined by a Legendre polynomial expansion using least-squares methods. Additionally, measurements were carried out for isotopically pure 209Bi and 181Ta samples at 4MeV incident neutron energy. Results are compared with other measurements and recent evaluations.

This project explores the 'maternal migration effect'. Following migration to a high-income country with a low maternal mortality rate, we assume that some immigrant women’s reliance upon maternal practices that respond to a low-income, high-mortality context can adversely affect care-seeking and utilization of treatment facilities. At highest risk in the United Kingdom and Sweden are those from Africa's Horn, particularly Somali women who have experienced diasporic migration. By applying constructivist qualitative methods as proxies for medical anthropology, we propose a framework for identifying socio-cultural factors, and then we explore how these can influence the western facility-based maternity care encounter. Study 1 proposes a conceptual framework to understand why sub-Saharan African immigrants might experience adverse childbirth outcomes in western settings. Analysis was guided by 'naturalistic inquiry method' to explore delay-causing socio-cultural factors to optimal maternity treatment. Delays can result from (a) broken trust underlying women’s late-booking or refusal of treatment interventions, and care provider frustration; (b) over-reliance on poorly-functioning interpreter services that deny women’s access to medical expertise; and (c) mutual broken trust and miscommunication, and limited development of guidelines for treatment avoidance. Limited coherence exists in the perspectives between women and providers about caesarean section and other interventions, refusal of treatment, and coping strategies following adverse birth outcomes. Care providers' held misconceptions about women’s preferences for gender- and ethnic-congruence. Women preferred competent care. Congruent language was identified as the key ingredient for optimal culture-sensitive care. Study 2 applied 'grounded dimensional analysis' and 'functional narrative analysis' to explore pre-migration socio-cultural factors that influence Somali parents' childbearing in Sweden. Women’s delayed care-seeking continues, despite that childbearing is still perceived as life-threatening. Decision-making is shared between the couple. Men more than women trust care providers to fill gaps in their knowledge. The postpartum period showed that fathers play an important role. "Aftercare" concerns include unarticulated sexual aversion combined with loss of traditional kin support. Women's autonomy is enhanced but greater necessity exists for intimate partner communication and reliance upon professional care services. Medical anthropology can provide a complementary instrument for developing qualitative evidence-based strategies that target prevention of adverse childbirth outcomes in European countries.

This poststructuralist qualitative study explored the discourses constructing women’s choice for a caesarean section in the absence of clinical indications, in the talk and texts of women, midwives, an obstetrician, professional journals and the media publications. The study affirms inscriptions surrounding choice in childbirth are shaped discursively through a multiplicity of discourses underpinned by social and institutional practices. With advances in technology, childbearing women have a greater variety of options from which to choose. Controversial, is the option of a caesarean section, regardless of clinical need. The issue is depicted in both professional and popular discourse as contentious, complex and contradictory. Its momentum into the 21st century, as a new object of obstetric discourse, has been played out on a number of platforms. In this thesis I draw from the theoretical ideas of French philosopher Michel Foucault, to examine this complex debate. I argue there is a volatile moment in the history of childbirth in which an explosion of discourses have sculptured choice for a caesarean, in the absence of clinical indications, out of a repartee of autonomy, convenience, desire, fear and risk. In this precarious moment, new meanings joust with the old on a shifting terrain awash with rhetoric that co-opts, competes, and contradicts to bring about a caché of mutable ‘truths’. Whether caesarean, as an optional extra, can be explained in terms of a libertarian imperative, an embodiment of lifestyle, the satiation of desire, the attenuation of fear or the avoidance of risk, the democratisation of this choice has exposed a pathologising paradox, whereupon the normal emerges as the abnormal, and the abnormal emerges as the normal. The deconstruction of choice through a poststructuralist lens has enabled insight into how contradiction and contest befall the ‘order of things ’ and in so doing, provides new openings for contemplating the discursive positioning of women through the competing discourses of childbirth.

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No description available.

This poststructuralist qualitative study explored the discourses constructing women’s choice for a caesarean section in the absence of clinical indications, in the talk and texts of women, midwives, an obstetrician, professional journals and the media publications. The study affirms inscriptions surrounding choice in childbirth are shaped discursively through a multiplicity of discourses underpinned by social and institutional practices. With advances in technology, childbearing women have a greater variety of options from which to choose. Controversial, is the option of a caesarean section, regardless of clinical need. The issue is depicted in both professional and popular discourse as contentious, complex and contradictory. Its momentum into the 21st century, as a new object of obstetric discourse, has been played out on a number of platforms. In this thesis I draw from the theoretical ideas of French philosopher Michel Foucault, to examine this complex debate. I argue there is a volatile moment in the history of childbirth in which an explosion of discourses have sculptured choice for a caesarean, in the absence of clinical indications, out of a repartee of autonomy, convenience, desire, fear and risk. In this precarious moment, new meanings joust with the old on a shifting terrain awash with rhetoric that co-opts, competes, and contradicts to bring about a caché of mutable ‘truths’. Whether caesarean, as an optional extra, can be explained in terms of a libertarian imperative, an embodiment of lifestyle, the satiation of desire, the attenuation of fear or the avoidance of risk, the democratisation of this choice has exposed a pathologising paradox, whereupon the normal emerges as the abnormal, and the abnormal emerges as the normal. The deconstruction of choice through a poststructuralist lens has enabled insight into how contradiction and contest befall the ‘order of things ’ and in so doing, provides new openings for contemplating the discursive positioning of women through the competing discourses of childbirth.

This poststructuralist qualitative study explored the discourses constructing women’s choice for a caesarean section in the absence of clinical indications, in the talk and texts of women, midwives, an obstetrician, professional journals and the media publications. The study affirms inscriptions surrounding choice in childbirth are shaped discursively through a multiplicity of discourses underpinned by social and institutional practices. With advances in technology, childbearing women have a greater variety of options from which to choose. Controversial, is the option of a caesarean section, regardless of clinical need. The issue is depicted in both professional and popular discourse as contentious, complex and contradictory. Its momentum into the 21st century, as a new object of obstetric discourse, has been played out on a number of platforms. In this thesis I draw from the theoretical ideas of French philosopher Michel Foucault, to examine this complex debate. I argue there is a volatile moment in the history of childbirth in which an explosion of discourses have sculptured choice for a caesarean, in the absence of clinical indications, out of a repartee of autonomy, convenience, desire, fear and risk. In this precarious moment, new meanings joust with the old on a shifting terrain awash with rhetoric that co-opts, competes, and contradicts to bring about a caché of mutable ‘truths’. Whether caesarean, as an optional extra, can be explained in terms of a libertarian imperative, an embodiment of lifestyle, the satiation of desire, the attenuation of fear or the avoidance of risk, the democratisation of this choice has exposed a pathologising paradox, whereupon the normal emerges as the abnormal, and the abnormal emerges as the normal. The deconstruction of choice through a poststructuralist lens has enabled insight into how contradiction and contest befall the ‘order of things ’ and in so doing, provides new openings for contemplating the discursive positioning of women through the competing discourses of childbirth.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.