Search results for "Nuclear Energy"

Bold ambition, blunted agency? : Examining top management perspectives on a circular economy transition in Finland

2022

The circular economy is proposed as a company-driven means to further sustainability transitions. Top managers have a critical role in fostering the circular economy as they are responsible for shaping and implementing a company's sustainability strategy and performance. In this paper, we adopt a microfoundations perspective to enhance our understanding of the influence of top managers as agents of the sustainability transition to the circular economy. In a qualitative research study, we interviewed 34 top managers of Finnish companies that are actively pursuing the circular economy. The main implication of our study is in exploring the role of top managers, as they engage in actively struc…

A Monte Carlo-aided design of a modular 241Am-Be neutron irradiator

2013

Monte Carlo studies aimed at designing a modular 241Am-Be neutron irradiator for testing neutron detectors and personal dosimeters and processing large volume samples are reported in this study. The evaluation of the shapes and thicknesses of the moderator and shielding materials was carried out by a MCNP5 Monte Carlo simulation code. The reliability of the simulation was experimentally verified by the activation of gold foils and TLD dosimeter measurements in an irradiation cell placed at the center of the test configuration.

Single Event Transients and Pulse Quenching Effects in Bandgap Reference Topologies for Space Applications

2016

An architectural performance comparison of bandgap voltage reference variants, designed in a $0.18~\mu \text {m}$ CMOS process, is performed with respect to single event transients. These are commonly induced in microelectronics in the space radiation environment. Heavy ion tests (Silicon, Krypton, Xenon) are used to explore the analog single-event transients and have revealed pulse quenching mechanisms in analogue circuits. The different topologies are compared, in terms of cross-section, pulse duration and pulse amplitude. The measured results, and the explanations behind the findings, reveal important guidelines for designing analog integrated circuits, which are intended for space appli…

'We have a solution': Delivering on the promise to take national responsibility for nuclear waste management

2022

We examine the realization of the umbrella promise to assume national responsibility for the final disposal of spent nuclear fuel. Three case studies are used to illustrate how Finland delivers on the promise to take care of its own nuclear waste - a promise that has greatly contributed to the legitimacy of nuclear power in Finland. The article shows how this promise is being challenged by new competitors, business visionaries, and the public. The case studies illustrate the tensions between those who made the promise and the actors who interpret and mobilize the promise for varying purposes and under changing circumstances. We investigate techno-scientific promises by looking at debates ab…

Radiation Response of Ce-Codoped Germanosilicate and Phosphosilicate Optical Fibers

2016

We report an experimental investigation on the effects of Ce-codoping in determining the radiation response of germanosilicate and phosphosilicate Optical Fibers (OFs) in the UV-Visible domain and up to doses of $1~\hbox{MGy}({\rm SiO}_{2})$ . We show that the addition of Ce strongly impacts the Radiation Induced Attenuation (RIA) of both types of fibers. In the first case the radiation induced losses increase, whereas in the second one decrease. By combining the online RIA measurements with the Electron Paramagnetic Resonance (EPR) ones, we are able to infer the basic microscopic mechanisms taking place under irradiation, which involve the cerium codopant and some of the known Ge-related o…

On-Line Characterization of Gamma Radiation Effects on Single-Ended Raman Based Distributed Fiber Optic Sensor

2016

We report distributed temperature measurements based on Raman scattering performed during steady state $\gamma $ -ray irradiation at a dose rate of 1 kGy( ${\rm SiO}_{2}$ )/h and up to a total ionizing dose (TID) of $\sim 0.1\ \hbox{MGy}$ . We characterize on-line the evolution of the performances of a single-ended Raman distributed temperature sensor (RDTS) during the $\gamma $ -ray exposure of different classes of commercial multimode fibers (MMFs) acting as the sensing element. RDTS is influenced by the radiation-induced attenuation (RIA) phenomena leading to both large errors in the temperature measurements and a diminution of the useful sensing length. The amplitude of the radiation-in…

'Energiemix' versus 'Energiewende' : competing conceptualisations of nuclear energy policy in the German parliamentary debates of 1991-2001

2016

Single Event Upsets Induced by Direct Ionization from Low-Energy Protons in Floating Gate Cells

2017

Floating gate cells in advanced NAND Flash memories, with single-level and multi-level cell architecture, were exposed to low-energy proton beams. The first experimental evidence of single event upsets by proton direct ionization in floating gate cells is reported. The dependence of the error rate versus proton energy is analyzed in a wide energy range. Proton direct ionization events are studied and energy loss in the overlayers is discussed. The threshold LET for floating gate errors in multi-level and single-level cell devices is modeled and technology scaling trends are analyzed, also discussing the impact of the particle track size. peerReviewed

Measurements of Low-Energy Protons using a Silicon Detector for Application to SEE Testing

2021

A silicon detector with a fast electronics chain is used for the dosimetry of protons in the range 0.5-5 MeV at the Centro Nacional de Aceleradores (CNA) 3 MV Tandem laboratory in Seville, Spain. In this configuration, measurements can be performed in pulsed mode, using a digitizer to record event-by-event proton energy depositions. The distributions of deposited energy were obtained thanks to a calibration with an alpha source. Measurements of flux and deposited energy are used to enable single event effect (SEE) testing on selected static random access memories (SRAMs).

Higher-order energy density functionals in nuclear self-consistent theory

2011

In this thesis consisting of two publications and an overview part, a study of two aspects of energy density functionals has been performed. Firstly, we have linked the next-to-next-to-next-to-leading order nuclear energy density functional to a zero-range pseudopotential that includes all possible terms up to sixth order in derivatives. Within the Hartree-Fock approximation, the quasi-local nuclear Energy Density Functional (EDF) has been calculated as the average energy obtained from the pseudopotential. The direct reference of the EDF to the pseudopotential acts as a constraint that allows for expressing the isovector coupling constants functional in terms of the isoscalar ones, or vice …