Enhancements to PWR SAMG since Fukushima

Plant specific Severe Accident Management Guidelines are provided to give guidance to plant staff to respond to a severe accident, to protect containment, minimise fission product releases and prioritise equipment recovery efforts while bringing the plant to a controlled stable condition. This paper presents and discusses the enhancements that have been made particularly to widely implemented SAMG based on the Westinghouse Owners Group generic model (now part of the PWR Owners Group) since the Fukushima accident. Although U.S. and European responses to the accident may seem at first sight to be different, in fact, the enhancements needed to SAMG in order to address lessons learned were quite consistent. How to deal with loss of d.c. power and / or instrumentation, long term loss of a.c. power (much longer than had previously been considered), multiple unit severe accidents, accidents in the fuel pool, accidents from shutdown initial plant conditions and other issues and conditions that occurred during the event and which we must learn from? This paper presents results of a number of projects aimed at providing SAMG enhancements to address these issues, some originating in the U.S. and some in Europe. Main enhancements addressing lessons learned from Fukushima are described. The paper also summarises and describes an ongoing project to develop a fully revised generic SAMG specifically applicable to PWR plants in Europe (and also applicable to other designs, such as VVER) which benefits from all these efforts and will provide a single integrated and updated basis for plants with mitigation systems typical in Europe (often different from the US) to update their SAMG

The 1980 US/Canada wheat and barley exploratory experiment. Volume 2: Addenda

Three study areas supporting the U.S./Canada Wheat and Barley Exploratory Experiment are discussed including an evaluation of the experiment shakedown test analyst labeling results, an evaluation of the crop proportion estimate procedure 1A component, and the evaluation of spring wheat and barley crop calendar models for the 1979 crop year

The backwash effect on SQL skills grading

This paper examines the effect of grading approaches for SQL query formulation on students' learning strategies. The way that students are graded in a subject has a significant impact on their learning approach, and it is crucial that graded tasks are carefully designed and implemented to inculcate a deep learning experience, An online examination system is described and evaluated. Copyright 2004 ACM

The Crackle of Contemporaneity

There comes a time to move beyond asking the broad question “What is contemporaneity?” to consider more acute ways in which this question can be traced and signalled. We consider the notion of signal to be particularly appropriate in the consideration of contemporaneity, since signals are a constitutive element of contemporary infrastructures and our experience of time even if they are relatively undetectable. They operate underneath human perceptual thresholds as carriers, controllers, and codes, while also surfacing into perceptual and semiotic registers, as signs across various media—textual, visual, and, of course, sonic—all the while accessible as traces. Perhaps in this way it is possible to experience contemporaneity at a range of different scales— from the microtemporal to the planetary—to register both our closeness and distance from it (Agamben 2009), and to exemplify how times come together disjunctively in the present

Density Matrix Renormalization Group in the Heisenberg Picture

In some cases the state of a quantum system with a large number of subsystems can be approximated efficiently by the density matrix renormalization group, which makes use of redundancies in the description of the state. Here we show that the achievable efficiency can be much better when performing density matrix renormalization group calculations in the Heisenberg picture, as only the observable of interest but not the entire state is considered. In some non-trivial cases, this approach can even be exact for finite bond dimensions.Comment: version to appear in PRL, acronyms in title and abstract expanded, new improved numerical example