Assessment of effectiveness of geologic isolation systems. Test case release consequence analysis for a spent fuel repository in bedded salt

Geologic and geohydrologic data for the Paradox Basin have been used to simulate movement of ground water and radioacrtive contaminants from a hypothetical nuclear reactor spent fuel repository after an assumed accidental release. The pathlines, travel times and velocity of the ground water from the repository to the discharge locale (river) were determined after the disruptive event by use of a two-dimensional finite difference hydrologic model. The concentration of radioactive contaminants in the ground water was calculated along a series of flow tubes by use of a one-dimensional mass transport model which takes into account convection, dispersion, contaminant/media interactions and radioactive decay. For the hypothetical site location and specific parameters used in this demonstration, it is found that Iodine-129 (I-129) is tthe only isotope reaching the Colorado River in significant concentration. This concentration occurs about 8.0 x 10/sup 5/ years after the repository has been breached. This I-129 ground-water concentration is about 0.3 of the drinking water standard for uncontrolled use. The groundwater concentration would then be diluted by the Colorado River. None of the actinide elements reach more than half the distance from the repository to the Colorado River in the two-million year model run time. This exercise demonstrates that the WISAP model system is applicable for analysis of contaminant transport. The results presented in this report, however, are valid only for one particular set of parameters. A complete sensitivity analysis must be performed to evaluate the range of effects from the release of contaminants from a breached repository

Explaining extreme events of 2011 from a climate perspective

International audienc

Reflections on Place and Place-making in the Cities of China

This article is about the small spaces of the city we call 'places'. Places are shaped by being lived in; they are spaces of encounter where the little histories of the city are played out. They are, of course, also shaped by the state through planning, supervision, ordinances, and so forth. The patterns and rhythms of life in the small spaces of the city are therefore not simply a straightforward projection of civil life. Places are also sites of resistance, contestation, and actions that are often thought to be illegal by the (local) state. After introducing the concept of place, the remainder of this article is a reflection on places and place-making (but also place-breaking) in urban China. Because the patterns and rhythms of urban life have continuity, however, my approach to their study was historical. The story told here is roughly divided into four major periods: Imperial China, Republican China, the People's Republic under Mao Zedong, and the reform period from about 1980 onward. I then return to the concepts of place and place-making with which I began, summarizing my findings and suggesting some topics for further research. Copyright (c) 2007 The Author. Journal Compilation (c) 2007 Joint Editors and Blackwell Publishing Ltd.