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431.
432.
基于“多重屏障原理”的深地质处置是国内外公认的处置高放射性核废物的合适方法。本文从处置库建造与运行对环境的影响及环境对处置库反作用两方面探讨高放废物深地质处置中涉及的有关环境问题,并指出为确保处置库的长期安全性,必须特别注重选址及多因素耦合作用研究。 相似文献
433.
Federal regulations governing the disposal of high-level radioactive waste in deep, geologic repositories require an assessment of performance over thousands of years. Because of the long regulatory period involved and the complex nature of the events and processes of interest, prediction of the performance of the disposal system will inevitably include uncertainties. These uncertainties come from a variety of sources, and some are quantifiable and others are not. This paper discusses these uncertainties and outlines approaches for their treatment. Recommendations for the potential resolution of current limitations in the treatment of uncertainties in performance assessment are made. Some general issues, as well as a suggested approach for incorporating expert judgment into quantitative performance assessment analysis, are discussed also.This paper was presented (by title) at Emerging Concepts, MGUS-87 Conference, Redwood City, California, 13–15 April 1987. 相似文献
434.
阐明了研究区水地质条件及地下水化学特征;通过水地球化学计算,研究了地下水与固相间的反应趋势;模拟了地下水垂向流动过程中发生的水岩作用;进而从水地球化学角度对预选场地高放废物地质处置的适宜性作出初步评价。 相似文献
435.
Z. X. Zhang S. Q. Kou X. C. Tan P.-A. Lindqvist 《Rock Mechanics and Rock Engineering》2003,36(1):39-61
Summary
This paper presents the testing methods used and the results obtained in an investigation of the cutter forces on a Boretec
DS 1.6 boring machine during field boring in ?sp? Hard Rock Laboratory. Two button cutters, one front cutter and one gauge
cutter, were used in the field measurements. A total of 6 strain gauges were bonded on the shaft of each cutter. And each
group of two gauges was used to measure a one-orthogonal cutter force component, i.e. the normal force, tangential force,
and side force, respectively. In order to measure the cutter forces successfully, a telemetry system composed of a transmitter
and a receiver was employed to transfer the signals from the strain gauges to a computer.
A three-direction-loading system was employed in the laboratory calibration so as to solve the force-coupling problem appearing
in the cutter force measurements. Correspondingly, a mathematical treatment of the force-coupling problem was performed. Then,
by means of the established testing system, which was proved successful in the laboratory, the normal force, tangential force,
and side force of the two button cutters on the boring machine were measured in the field. In addition, the penetration rate,
thrust, and rotation speed of the boring machine were also recorded in the field. The results show the following. (1) A force-coupling
phenomenon really exists and it should be considered. (2) All three directional force components always show quite a high
peak value every few seconds. (3) The cutter forces of the front cutter are always much larger than the respective cutter
forces of the gauge cutter. Moreover, as expected, the normal force of each cutter is much larger than the tangential force
and side force of the cutter in question.
Received October 5, 2001; accepted June 25, 2002; Published online November 19, 2002 相似文献
436.
Summary Currently under study by the Department of Energy are the geologic and hydrologic characteristics of the ash-flow deposits under Yucca mountain at the Nevada test site. Of interest at this site is the potential for disposal of high-level radioactive wastes in the unsaturated zone of the densely welded portions of the tuffs. These studies include the preformance-assessment of barriers and seals for boreholes, ramps, drifts and shafts at the Yucca mountain site. In-situ tests on standard Type II Portland cement and microfine cement as grout materials have been performed on a similar rock type to Yucca Mountain's near Superior Arizona. The tests were performed in a vertical borehole drilled in highly fractured and densely welded tuff (brown unit of Apache Leap) through a series of pressurized grout applications. Packer flow tests prior to and after each grout application measure the effectiveness of the grout application in reducing the permeability of the rock surrounding the borehole. Overall the grout applications have reduced the permeability of the test hole by three orders of magnitude. 相似文献
437.
为了降低废弃物及废弃煤矿对环境的污染,提出了废弃煤矿废弃物灌注技术的可行性。分析了可灌注废弃物的种类,讨论了目标地层的选择原则。提出采用可控充填、低压充填以及高压灌注等3阶段液力充填方法对废弃煤矿进行废弃物灌注。为保证工程顺利施工,需要检测灌注压力、压裂裂缝、地面隆起等情况,并控制灌注混合物的特性。初步分析表明,对废弃煤矿进行废弃物灌注具有技术可行性。 相似文献
438.
439.
In order to know the mechanism of groundwater transport and the variation of ion concentrations in the near-field of the high-level radioactive waste repository, the whole process was simulated by EOS3 module of TOUGHREACT. Generally, the pH and cation concentrations vary obviously in the near-field saturated zone due to interaction between groundwater and bentonite. Moreover, the simulated results showed that calcite precipitation could not cause obvious variations in the porosity of media in the near-filed if the chemical components and their concentrations of groundwater and bentonite pore water are similar to those used in this study. 相似文献
440.
Fettweis M Baeye M Francken F Lauwaert B Van den Eynde D Van Lancker V Martens C Michielsen T 《Marine pollution bulletin》2011,62(2):258-269
The impact of continuous disposal of fine-grained sediments from maintenance dredging works on the suspended particulate matter concentration in a shallow nearshore turbidity maximum was investigated during dredging experiment (port of Zeebrugge, southern North Sea). Before, during and after the experiment monitoring of SPM concentration using OBS and ADV altimetry was carried out at a location 5 km west of the disposal site. A statistical analysis, based on the concept of populations and sub-sampling, was applied to evaluate the effect. The data revealed that the SPM concentration near the bed was on average more than two times higher during the dredging experiment. The disposed material was mainly transported in the benthic layer and resulted in a long-term increase of SPM concentration and formation of fluid mud layers. The study shows that SPM concentration can be used as an indicator of environmental changes if representative time series are available. 相似文献