今日的尤卡山计划和多重屏障系统的新概念

主要论述了美国尤卡山项目的最新进展和比利时工程屏障研究的新进展。在尤卡山项目新进展方面介绍了尤卡山项目修改的近期计划,以及两个环境评价补充报告和两位民主党参议员参加2008年美国总统竞选时对尤卡山项目的态度。还介绍了比利时为加强高放废物地质处置的安全性而开发的多重屏障的新概念。     

关于尤卡山项目的一些思考

简要论述了美国尤卡山项目研发的历史进程,讨论了该项目目前的进展状态,以及由此引出可供我国高放废物地质处置研发工作值得思考的若干问题.笔者认为,目前尤卡山项目进展受阻的主要原因是政治因素,而不是场址的自然条件和科学技术因素.关于该项目的不同意见之争还将会继续下去,最后可能只有通过进一步的科学论证和法律途径得以解决.     

美国国会批准能源和水利拨款预算案,尤卡山和核研发项目受益

【美国核能研究所网站2003年11月28日报道】2003年11月18日,美国参众两院批准了一项273亿美元的能源和水利开发拨款预算案,从而增加了2004财政年度尤卡山处置库和核研发的费用。总统不久将签署该预算案。2003年11月18日,众议院以387对36票通过了该拨款预算案。当日晚些时候,参议院也一致通过了该预算案。为内华达处置库和相关废物管理计划提供的资金定在5.8亿美元,比政府申请的少1100万美元。2003财年尤卡山经费总计为4.56亿美元。核废物基金将提供1.9亿美元,其余费用来自国防帐户。工业界对这个结果表示欢迎。核能研究所负责政府事务的高级…     

美国核管会可能会推迟对尤卡山项目的审批日期

【法新社华盛顿2004年7月9日报道】美国联邦法院于2004年7月9日做出了支持在尤卡山建造核废物最终处置库的判决,但同时要求该项目必须建立更严格的辐射防护标准。虽然法庭驳回了内华达州政府、地方社团以及环境组织意图推翻尤卡山项目的申请,但尤卡山项目的反对者还是取得了部分胜利。因为法庭判决推翻了环保署(EPA)的公众辐射防护计划,认为EPA为尤卡山制订的1万年的安全年限还不够,并表示政府应当采纳美国国家科学院(NAS)的建议,保证尤卡山最终处置库在一个更长的时间范围内不会出现辐射泄漏。环境保护论者和内华达州政府对它们所取得…     

美国参议院能源委员会通过在尤卡山建造最终处置库的决议

【路透社华盛顿2002年6月5日电】美国参议院能源委员会于2002年6月5日以13票对10票否决了内华达州的反对意见,通过了在尤卡山建造最终处置库的决议。美国参议院能源委员会通过在尤卡山建造最终处置库的决议     

美国国会小组委员会取消轻水增殖堆的费用

美国众议院科学技术委员会的能源研究和生产小组委员会已完成了能源部1981年度费用的审核工作,恢复了政府企图大幅度取消或削减核计划中某些项目的费用。能源研究和生产小组委员会在3月下旬表决通过了向克林奇河增殖反应堆工程继续提供经费,在过去三年中卡特总统曾主张取消该项工程(但没有成功)。小组委员会     

尤卡山项目1995年取得进展但未克服根本性的缺陷

【美国《核燃料》1996年5月20日刊第13页报道】 美国核废物技术审议委员会认为,美国能源部(DOE)的尤卡山项目1995年虽然取得了一些进展,但DOE还没有消除在人们头脑中长期存在的“尤卡山项目效率低”的印象,也没有为这个项目建立一些基本的技术框架。     

美国参议院通过在尤卡山建造最终处置库的决议

【美联社华盛顿2002年7月9日电】 美国参议院于2002年7月9日通过了同意在尤卡山建造最终处置库的决议,这标志着多年来就核废物处置问题进行的政治争论的结束。 美国参议院通过在尤卡山建造最终处置库的决议     

美国核管会2007财年的预算申请

【美国《核新闻》2006年3月刊报道】美国核管会(NRC)2007财年的预算申请总额为7.766亿美元,比2006财年的实际经费增加了4.7%(3500万美元),同时较2006财年的最初预算多出10%以上(7500万美元)。由于预期有电力公司可能会在2007年年底前后为新建核反应堆申请建设运行许可证(COL),因此在2007财年用于核反应堆安全保障的预算将增加4800万美元;与此同时,由于预期能源部(DOE)将推迟提交在内华达州尤卡山建设高放废物最终处置库的申请,因此在2007财年,用于核材料和废物安全项目的预算削减了1300万美元。总体上说,NRC在处理和审议许可证申请的过…     

美国尤卡山处置库项目有重大进展

【欧洲核学会《核新闻网》 1998年 12月2 1日报道】　美国能源部 (DOE)公布了一份期待已久的有关尤卡山科学适用性的评价报告。位于内华达的尤卡山被提议用作国家乏燃料处置库。能源部长 Bill Richardson已将这份报告提交白宫。他说 ,从事尤卡山项目的科学家们经过 15年的研究已证实这个项目“不存在阻力”。因此 ,能源部认为这个项目应该继续进行 ,以期在 2 0 0 1年最后决定是否向美国总统推荐这一场地。 Richardson先生说 ,最终决定将根据“科学适用性和其本身的优势作出 ,而不会出于政治考虑”。该报告主要内容的正式摘要分述如下 :最…     

Fukushima Daiichi fuel debris simulant materials for the development of cutting and collection technologies

Cutting fuel debris (solidified corium) is an important issue for the decommissioning of Fukushima Daiichi Power Station. The main reasons for developing and using suel debris simulants are presented. The relative merits of various types of materials (stainless steel, zircalloy, sintered ceramic, cast-fused zirconia, metal + ceramic, melted inactive simulants, prototypic fuel debris, irradiated fuel debris simulant) that can be used to test debris cutting have been assessed against criteria relevant for the cutting technique itself and also for (radioactive) aerosol and combustible gas generation. Simplified simulants can be used for the development of fuel debris cutting techniques but have limited representativeness so that melted inactive fuel debris simulant must be used to assess the cutting performance. Concerning combustible gas generation, zirconium plates provide an upper bound in term of underwater generation of hydrogen. Finally, for aerosol and dust generation, it appears that non-radioactive simulant cannot correctly represent the aerosol formed during cutting but prototypic fuel debris simulants, using depleted uranium are required. Laser cutting tests have been carried out with several types of simulant materials. Promising results were achieved in term of cutting ability both in air and underwater. Data have also been collected on the released aerosols. Nevertheless, confirmatory experiments with prototypic debris are still needed.     

Cutting performances with new industrial continuous wave ND:YAG high power lasers: For dismantling of former nuclear workshops, the performances of recently introduced high power continuous wave ND:YAG lasers are assessed

Dismantling is a great challenge for nuclear companies which are facing with the cleaning of former nuclear sites. Among the available cutting processes is the multi-kilowatts laser whose power is transmitted through optical fibers. Unlike other cutting processes such as the plasma arc cutting process or the oxy-cutting process, the laser process can be easily implemented by robotic equipments. The mechanised robotic arm carries a laser cutting head to perform, with remote-controlled equipments, the cutting operation.The present study deals with the performances which can be reached with high power continuous wave ND:YAG lasers. The cutting tests were carried out up to 8 kW. The laser power was delivered through a specific power supply chain: a 0.4 mm fiber was transporting the power from the laser to a first interface (coupler) then a second 0.6 mm fiber was bringing the laser power to the cutting head. This solution allowed a power delivery chain whose length could be as high as 100 + 20/50 m. Another advantage of this kind of power supply is that the first fiber can be set in a non-contaminated environment whereas the second fiber lies in the contaminated area. The cutting head used for these tests was a specific tool developed for this laser dismantling work: it is a laser cutting head cooled by pressurized air. This tool was developed with the requirement to be able to sustain a laser power of 14 kW. The pressurized air used to cool the head is also used as cutting gas.The cutting capability was about 10 mm by kW. At the power of 8 kW, austenitic steel plates of thickness 100 mm were cut. These performances were reached with the cut started on the plate's edge. If the cut started in the middle of the plate, the cutting performances were not so high: 8 kW became the power to drill and to cut plates of thickness 40 mm.     

Main achievements of FP-4 research in reactor safety

This summary paper deals with the strategy, the organisation and main achievements of the 67 multi-partner projects cosponsored by the European Union (EU) as ‘indirect actions’ (shared-cost and concerted actions) and co-ordinated under seven clusters, each devoted to one key safety issue in nuclear reactor safety, as they were presented at FISA-99. The fundamental safety objective for nuclear power plants (NPPs) consists in protecting the public and the environment from the harmful effects resulting from ionising radiations. The 4th Euratom framework programme 1994–1998 (FP-4) has been carrying out research with this objective both through ‘indirect actions’ and through ‘direct actions’ in co-operation with the Joint Research Centre of the European Commission (EC). The total cost of this research programme was 62.8 million, out of which 34.2 million was contributed by the EU budget. Besides technological safety requirements, socio-economic aspects are becoming increasingly important due to the level of public and political acceptance and to the economic pressure of deregulated electricity markets. It is shown that research conducted in the Euratom framework may contribute to meet these requirements, thereby maintaining nuclear power as a competitive and sustainable option for the energy policy of the European Union.     

UO2-不锈钢燃料棒的光纤激光切割研究

为验证光纤激光用于燃料组件解体和燃料棒切割的可行性,研究光纤激光用于热物性差别很大的UO2芯块 不锈钢包壳管复合结构的切割和铀芯块的切割质量,本文采用光纤激光切割UO2芯块 316Ti包壳管元件棒,并通过扫描电子显微镜、能谱和X射线衍射对UO2芯块的切断面进行微观表征分析,研究激光切割过程对铀芯块切断的表面微观形貌、元素组成及物相的影响。研究结果表明,光纤激光可用于切割UO2芯块 316Ti包壳管元件棒,激光切割过程虽会造成铀芯块切断面出现大量微孔和碎渣,但不会造成UO2的相变。以上结果表明,光纤激光可用于UO2芯块 316Ti包壳管元件棒的切割,通过后续对激光切割系统的抗辐射屏蔽防护,可应用于乏燃料组件解体和乏燃料棒切割。     

某核电厂主蒸汽管道振动原因分析及解决方案探讨

某核电厂在升功率试验及满功率运行时,发现主控室的噪声超过了设计目标值。经过测量,认为主蒸汽管道振动并通过支撑和贯穿件传播到主控室是造成主控室噪声超标的主要原因之一。本文应用流体力学软件和声学分析软件,采用流声耦合分析的方法,对主蒸汽管道的流场和声场进行了分析。在主蒸汽安全阀支管处和主蒸汽隔离阀空腔中存在着声共振现象,是导致主蒸汽管道振动的主要原因。根据主蒸汽管道振动的原因,可以通过振动源头治理、传播路径治理等方法降低主控室噪声。      

A novel approach of deposition for uniform diamond films on circular saw blades

Uniform diamond films are highly desirable for cutting industries,due to their high performance and long lifetime used on cutting tools.Nevertheless,they are difficult to obtain on cutting tools with complicated shapes,greatly limiting the applications of diamond films.In this study,a novel approach of deposition for uniform diamond films is proposed,on circular saw blades made of cemented carbide using reflectors of brass sheets.Diamond films are deposited using hot filament chemical vapor deposition (HFCVD).A novel concave structure of brass sheets is designed and fabricated,improving the distribution of temperature field,and overcoming the disadvantages of the conventional HFCVD systems.This increases the energy efficiency of use without changing the structure and increasing the cost of HFCVD.The grains are refined and the intensities of diamond peaks are strengthened obviously,which is confirmed by scanning electron microscopy and Raman spectra respectively.     

氚污染金属切割试验

采用铝材切割机及角磨机对未封闭和封闭后的氚污染金属进行切割试验,并通过测量切割过程中氚释放活度和金属中氚残留活度来评估切割过程中氚释放率。结果表明,采用铝材切割机对两种金属切割过程中氚释放率分别≤15%和≤1.5%;采用角磨机进行切割过程中氚释放率分别为≤25%和≤1.5%。     

大亚湾核电站旧导向筒处置方案可行性研究

描述广东大亚湾核电站旧导向筒处置方案的可行性研究，内容包括：处置方案的比较与选择，混凝土包装箱的结构设计和屏蔽设计，旧导向筒装箱操作的的工艺设计，包装箱吊装及运输方案的选择，整个处理过程中涉及到的辐射安全和工业安全的分析评价，以及整个工程的经费概算，结果表明，该旧导向筒处置方案技术上可行，经济上合理，采用此方案，对广东大亚湾核电站是导向筒进行最终处置，既可工省大量经费，也可为我国对核电站产生的不可     

Laser welding and ablation cutting process for hydraulic connections by remote handling in the ITER diagnostic port plug

To assess hydraulic connections between subcomponents of the International Thermonuclear Experimental Reactor (ITER) diagnostic port plug, we investigated the laser welding and ablation cutting process, which can be applied to remote handling maintenance. In this study, laser ablation cutting, which vaporizes a small amount of solid material directly into gas by focusing a laser beam of high-density energy, is adopted in order to overcome the limitation of the normal laser cutting technology that the head should be placed as close to the work piece as possible to blow out melt metal at a distance. Complete cutting of a work piece is obtained by repetitive multi-passes of the laser beam. The welding and cutting process were tested on the sample work pieces and finally on a prototype of a hydraulic connection module for remote handling. The results showed that this process can be a promising candidate for hydraulic connections by remote handling. Furthermore the design of the hydraulic connection module has been updated to resolve some technical difficulties that were found during the test.     

Laser cutting performances for thick steel specimens studied by molten metal removal conditions

Laser cutting performances for thick carbon steel and stainless steel specimens up to 300 mm in thickness were studied to dismantle large steel objects. The cutting performances were summarized based on the assist gas flow rate and the front kerf width, and the range for appropriate cutting conditions was shown. Gas pressure in the kerf region required for molten metal removal was estimated from the pressure loss on the kerf surface, which depended on the gas flow rate and the kerf width. The relation to keep sufficient gas pressure in the kerf well corresponded to the experimental relations for appropriate cutting. Drag force to the molten metal on the kerf surface was also estimated, which varied by the structures and materials. The behaviors such as cavity formation and its expansion in the kerf region at the unsuccessful cutting trials were well explained. The results are informative for the development of the laser cutting technology applied to the thick steel specimen for the nuclear decommissioning.