Search results for "Nuclear energy"
showing 10 items of 614 documents
Bartlett formalism generating functions and Z-transforms in fluctuation and noise theory
1983
Abstract “La theorie des fonctions generatrices s'adapte elle meme et avec la plus grande generalite aux questions des probabilite les plus difficiles.” (Laplace, 1812) “An important part of probability theory consists of the derivation of the probability distribution of the sum of n random variables, each of which obeys a given probability law, and the development of asymptotic forms of these distributions valid for increasing n. Probability generating functions owe their dominant position to the simplification they permit to both problems. Their employment to obtain the successive moments of a probability distribution and to solve the difference equations of probability theory is ancillar…
Statistical physics: Some basic principles of fluctuation and noise theory
1983
Abstract Models have traditionally played a significant role in statistical mechanics. In view of the complexity of the system which statistical mechanics attempt to describe, this is not at all surprising. The study of simplified models has frequently revealed the underlying mathematical structure of many physical questions and in so doing the study of models has contributed directly to a clarification of several paradoxes which beset statistical mechanics. In this paper some of the models which appear to be useful for the discussion of non-equilibrium phenomena are examined in some detail. As usual these models are extremely simplified versions of the actual situations. It is, finally, as…
The roles of the state and social licence to operate? Lessons from nuclear waste management in Finland, France, and Sweden
2019
The concept of social licence to operate (SLO) is an increasingly popular tool for companies to manage their relations with the local communities. SLO is very seldom used in the nuclear sector, which has nevertheless applied similar approaches, under notions such as partnership and participatory governance. This article explores the specific challenges that the application of SLO faces in the nuclear waste management (NWM) sector, by applying an often-used SLO framework of Boutilier and Thomson to illustrative case studies concerning nuclear waste repository projects in Finland, France and Sweden. Among the specificities of this sector, the article focuses on the central roles of the state …
Absolutzählung von radionukliden durch die beta-gamma-koinzidenzmethode mit einem flüssigen szintillator als innerem beta-detektor
1965
Zusammenfassung Fehlerquellen und Genauigkeit der Methode wurden untersucht. Die Ortsabhangigkeit der Zahlausbeuten im β- und γ-Detektor bedingt trotz des grossen Probenvolumens keinen wesentlichen Fehler, wenn die Detektoren symmetrisch angeordnet sind. Dagegen mussen Fehler korrigiert werden, die durch unvollkommenen Nachweis energiearmer Zerfallszweige im β-Detector und durch die γ-Empfindlichkeit des β-Detektors entstehen; dies kann entweder durch graphische Extrapolation oder—allgemeiner—durch Berechnen eines Korrekturfaktors geschehen. Die rechnerische Korrektur wird an typischen Zerfallsschemata erlautert. Fur den statistischen Fehler der Zerfallsrate wird eine Formel angegeben, welc…
Erfassung und auswertung hämodynamicscher funktionsabläufe mit dem neuen I2-kanalfunktionsmeβstand “Mainz”
1970
Zusammenfassung Mit dem 12-Kanalfunktionsmeβstand “Mainz” konnen hamodynamische Funktionsmessungen an 6 verschiedenen Stellen der Korperoberflache vollsimultan durchgefuhrt werden. Die digital gespeicherten Aktivitatsverlaufe werden mit geeigneten Mittelungsverfahren geglattet und die auftretenden Ratenkonstanten, nach halblogarithmischer, analoger Ausgabe, graphisch ermittelt. Komplementare Exponentialverlaufe werden elektronisch differenziert, halblogarithmisch ausgeschrieben und bezuglich der gesuchten Ratenkonstanten wiederum graphisch ausgewertet. Anhand ausgewahlter Beispiele wird gezeigt, wie die registrierten Aktivitatsverlaufe zerlegt und uber geeignete, mathematisch formulierte Mo…
Möglichkeiten der Radiometrischen Bestimmung des Isotopieeffektes
1970
Als ein weiteres Element, bei dem die Moglichkeit besteht, den Isotopieeffekt radiometrisch zu bestimmen, kame147Sm in Frage. Wegen seiner geringen Haufigkeit in der Natur ist147Sm aber von geringer Bedeutung. Auch bei176Lu kommt aus diesem Grunde eine radiometrische Bestimmung des Isotopieeffektes trotz der hohen spezifischen Aktivitat nicht in Frage. Erschwerend wirkt sich aus, das sich die Massenzahl von176Lu nur sehr wenig vom Atomgewicht des Elementes unterscheidet (0.588%). Dieses ist 3–4mal kleiner als bei40K und87Rb (Tab. 2 und Abb. 6).
A constitutive model for the thermo-mechanical behaviour of fusion-relevant pebble beds and its application to the simulation of HELICA mock-up exper…
2007
Abstract Within the framework of the R&D activities promoted by EFDA on the Helium-Cooled Pebble Bed Test Blanket Module to be irradiated in ITER, attention has been focused on the modelling of the thermo-mechanical behaviour of both beryllium and lithiated ceramic pebble beds that are envisaged to be used respectively as neutron multiplier and tritium breeder. This behaviour depends, mainly, on the reactor-relevant conditions, the pebble sizes and the breeder cell geometries and a general constitutive model has not yet been validated, especially for fusion-relevant applications. ENEA-Brasimone and the Department of Nuclear Engineering (DIN) of the University of Palermo have performed inten…
A readout unit for high rate applications
2002
The LHCb readout unit (RU) is a custom entry stage to the readout network of a data-acquisition or trigger system. It performs subevent building from multiple link inputs toward a readout network via a PCI network interface or alternatively toward a high-speed link, via an S-link interface. Incoming event fragments are derandomized, buffered and assembled into single subevents. This process is based on a low-overhead framing convention and matching of equal event numbers. Programmable logic is used both in the input and output stages of the RU module, which may be configured either as a data-link multiplexer or as entry stage to a readout or trigger network. All FPGAs are interconnected via…
Educational programs in nuclear and radiochemistry at the University of Mainz and in Germany
1993
A survey is given of the educational programs at German universities and research institutions. The program at the University of Mainz is outlined in some detail.
Self-Radiolysis of Tritiated Water: Experimental Study and Simulation
2005
Radioactive decay of tritium contained in tritiated water leads to the production of gaseous helium and, through self-radiolysis, to the formation of molecular hydrogen and oxygen. For safety management of tritiated water storage, it is essential to be able to predict pressure increase resulting from this phenomenon. The present study aims to identify the mechanisms that take place in self-radiolysis of chemically pure liquid tritiated water. The evolution of the concentration of hydrogen and oxygen in the gas phase of closed vessels containing tritiated water has been followed experimentally. Simulation of pure water radiolysis has been carried out using data from the literature. In order …