Modeling shallow marine carbonate depositional systems

Geological Process Models (GPMs) have been used in the past to simulate the distinctive stratigraphies formed in carbonate sediments, and to explore the interaction of controls that produce heterogeneity. Previous GPMs have only indirectly included the supersaturation of calcium carbonate in seawater, a key physicochemical control on carbonate production in reef and lagoon environments, by modifying production rates based on the distance from open marine sources. We here use the residence time of water in the lagoon and reef areas as a proxy for the supersaturation state of carbonate in a new process model, Carbonate GPM. Residence times in the model are calculated using a particle-tracking algorithm. Carbonate production is also controlled by water depth and wave power dissipation. Once deposited, sediment can be eroded, transported and re-deposited via both advective and diffusive processes. We show that using residence time as a control on production might explain the formation of non-ordered, three-dimensional carbonate stratigraphies by lateral shifts in the locus of carbonate deposition on timescales comparable to so-called 5th-order sea-level oscillations. We also show that representing supersaturation as a function of distance from open marine sources, as in previous models, cannot correctly predict the supersaturation distribution over a lagoon due to the intricacies of the flow regime.     

Modeling spent TRISO fuel for geological disposal: corrosion and failure under oxidizing conditions in the presence of water

High temperature gas reactors (HTGRs) are being considered for near term deployment in the United States under the GNEP program and farther term deployment under the Gen IV reactor design (U.S. DOE Nuclear Energy Research Advisory Committee, 2002). A common factor among current HTGR (prismatic or pebble) designs is the use of TRISO coated particle fuel. TRISO refers to the three types of coating layers (pyrolytic carbon, porous carbon, and silicon carbide) around the fuel kernel, which is both protected and contained by the layers. While there have been a number of reactors operated with coated particle fuel, and extensive amount of research has gone into designing new HTGRs, little work has been done on modeling and analysing the degradation rates of spent TRISO fuel for permanent geological disposal. An integral part of developing a spent fuel degradation modeling was to analyze the waste form without taking any consideration for engineering barriers. A basic model was developed to simulate the time to failure of spent TRISO fuel in a repository environment. Preliminary verification of the model was performed with comparison to output from a proprietary model called GARGOYLE that was also used to model degradation rates of TRISO fuel. A sensitivity study was performed to determine which fuel and repository parameters had the most significant effect on the predicted time to fuel particle failure. Results of the analysis indicate corrosion rates and thicknesses of the outer pyrolytic carbon and silicon carbide layers, along with the time dependent temperature of the spent fuel in the repository environment, have a significant effect on the time to particle failure. The thicknesses of the kernel, buffer, and IPyC layers along with the strength of the SiC layer and the pressure in the TRISO particle did not significantly alter the results from the model. It can be concluded that a better understanding of the corrosion rates of the OPyC and SiC layers, along with increasing the quality control of the OPyC and SiC layer thicknesses, can significantly reduce uncertainty in estimates of the time to failure of spent TRISO fuel in a repository environment.     

地下金属矿山地质工程灾害分析与防治

分析了国内矿山工程地质灾害的现状与类型,并在此基础上提出了其控制与治理措施。实践表明,实行以预防为主的控制方针,可有效地预防工程地质灾害的发生。     

Institutionalized knowledge conflict in assessing the possible contributions of H2 to a sustainable energy system for the Netherlands

This paper reports on a stakeholder dialogue project on the possible contribution of hydrogen to the Dutch energy transition. Dialogue methodology aims at articulating and exploring competing perspectives, including views that are in the margin of the energy policy subsystem. Three dialogue groups explored trajectories labeled Hydrogen for Transport, Hydrogen for the Built Environment and Hydrogen in the existing natural gas grid. The groups identified barriers and opportunities for the trajectories through back casting and assessed its pros and cons as compared to a non-hydrogen alternative. Referees from abroad contributed to a confrontation workshop, where the groups exchanged and discussed their first findings. The dialogue reveals that stakeholders are strongly divided with respect to small-scale domestic as well as the concept of a flexible natural gas infrastructure. We find a conflict between knowledge claims that either support or challenge the status quo. This is referred to as institutionalized knowledge conflict.     

基于Surpac的地质数据库的建立与应用

对澳大利亚SSI公司开发的三维可视化矿山工程软件Surpac地质数据库的功能进行了介绍,根据系统所需数据库结构,结合陕西某铅锌矿的实际情况,对该矿的地质数据库表结构进行定义,构建了地质数据库,着重介绍了地质数据库的应用,对促进Surpac软件在我国金属矿山的应用具有重要意义。     

国外地质勘探报告解读要点

对国内外地质勘探报告中确定地基容许承载力的方法进行了对比，并对地基承栽力的修正系数进行了分析。     

大庆油田多学科油藏研究一体化平台研制

多学科油藏研究一体化平台是基于Windows操作系统、以局域网络为传输通道、以开发数据库和精细地质研究成果为基础的多学科工作平台。本文扼要介绍了平台的研发背景、总体思路、开发环境,详细描述了数据共享、精细地质建模、精细油藏数值模拟及三维可视化的功能设计与实现方法,最后客观评价了平台的优势与不足。     

高校科研项目立项的模糊综合评判方法及应用

应用模糊综合评判方法对高等学校科研项目立项的评审工作进行了理论探讨 ,并举例说明此方法的应用。     

国外几例高放废物地质处置设施选址探讨

根据《高放废物地质处置中长期研发规划指南》所提出的“三步走” 战略, 我国高放废物地质处置项目正处在试验与选址阶段。本文通过总结国外高放废物地质处置项目的建设过程, 总结正反两方面的经验, 认为我国高放废物地质处置项目应采用分阶段决策的选址方案, 健全法律法规, 明确政府、监管方、实施者及公众的角色, 各方保持持续沟通和对话。