HFETR碘坑后沿启堆临界棒位的估算

本文研究高通量工程试验堆(HFETR)在碘坑内启动反应堆的问题。首先根据反应堆在碘坑内启堆时碘(135I)和氙(135Xe)浓度随时间变化关系推导出了氙毒引入的反应性随时间变化的解析表达式;接着针对HFETR某炉段进行研究,并结合冷却剂温度效应、燃耗及停堆前的棒位,给出估算碘坑后沿启动反应堆的临界棒位的方法;最后基于MATLAB软件开发用于估算碘坑后沿启动反应堆的临界棒位的程序。     

CO对PEMFC性能影响研究

天然气、甲醇等碳氢化合物重整制氢作为燃料正在应用到质子交换膜燃料电池领域。为系统地研究重整气中CO对质子交换膜燃料电池性能的影响,采用热压法自制膜电极,研究了CO浓度、催化剂种类、操作温度、增湿操作等因素对质子交换膜燃料电池性能的影响。实验结果表明:20×10~(-6) CO浓度即能使电池性能显著下降60%~70%;Pt Ru/C催化剂对抗CO中毒的能力较Pt/C催化剂有明显提升,在100×10~(-6) CO浓度下能使性能提高70%;提高工作温度能有效地改善阳极CO中毒状况,在50×10~(-6) CO浓度并加湿的条件下,当操作温度从80℃提高到120℃时电池性能可增加一倍。同时增湿操作有利于改进电池在低浓度CO下的发电性能。     

基于NH3-SCR反应铜基小孔分子筛催化剂Na中毒对比研究

以浸渍法模拟碱金属中毒NH₃-SCR催化剂过程，制备不同Na含量（质量分数）的铜基小孔分子筛Cu/SSZ-13和Cu/SAPO-34，对比研究了二者的碱金属中毒机理。结果表明，外引Na离子均可严重影响两种催化剂的NH₃-SCR催化活性，造成催化剂的晶相结构坍塌，酸性量减少，活性物种减少。不同的是，Na引入量较低（<1.82%）时，Cu/SAPO-34比Cu/SSZ-13具有更强的Na离子耐受性，而当Na含量高于3.48%时，Cu/SAPO-34几乎完全丧失NH₃-SCR催化活性。通过催化剂的结构表征（BET、XRD和SEM）和酸性位表征（DRIFTS、NH₃-TPD和H₂-TPR），研究表明随着Na中毒程度的加深，Cu/SSZ-13的结构破坏是渐变式的，而Cu/SAPO-34的结构破坏是突变式的；Na中毒的机理研究表明，酸性位的减少是Cu/SSZ-13的SCR活性下降的主导原因，结构坍塌是Cu/SAPO-34的SCR活性下降的主导原因。     

Neutron poison distribution in the central reflector to reduce the DLOFC temperature of a Th-LEU fueled OTTO PBMR DPP-400 core

In a previous study using a mixture of thorium and 20 a/o% LEU at 16 gram per fuel sphere heavy metal loading and adjusting the effective fuel enrichment to produce the same amount of cumulative energy per fuel sphere as with the 10 a/o% Low Enriched Uranium (LEU), the maximum Depressurized Loss Of Forced Cooling (DLOFC) temperature was reduced from 2273 to 1925 °C and 1811 °C for a symmetric and asymmetric core, respectively using an once-through-then-out (OTTO) fuelling scheme. This article presents an additional strategy for reducing the maximum DLOFC temperature by placing an optimized distribution of neutron poisons in the central reflector. This strategy produced maximum DLOFC temperatures of 1509 and 1448 °C for the symmetric and the asymmetric cores, respectively. These results are impressive as it means that the less complicated OTTO cycle with its lower capital cost achieved the same cumulative energy produced per fuel sphere than the standard six-pass refuelling scheme and that at substantially lower maximum DLOFC temperatures. Both the addition of the neutron poisons to the central reflector and the creation of a radially asymmetric core resulted in lower burn-ups that had to be reversed by increasing the enrichment of the fuel.     

面向PCA异常检测器的毒害攻击和防御机制

网络流量异常检测对于保证网络稳定高效运行极为重要.目前基于主成分分析(PCA)的全网络异常检测算法虽然发挥了关键作用,但它还存在着受毒害攻击而失效的问题.为此,深入分析了毒害攻击的机制并对其进行了分类,提出了量化毒害流量的两个测度,并给出了3种新的毒害攻击机制;提出了一种基于健壮PCA的异常检测算法RPCA以抵御毒害攻...     

液氯储罐泄漏事故模拟及应对措施

在文章模拟液氯储罐发生泄漏事故,利用数学模型对毒害区域进行了计算,论述了泄漏后采取的紧急措施     

含可燃毒物的压水堆堆芯装料优化

含可燃毒物的压水堆堆芯装料优化是燃料管理优化研究中的难点。应用通常的优化算法效率低、全局性差，特征统计算法更适合求解该优化问题。本研究克服了原特征统计算法装料优化将组件布置(LP)优化和新组件可燃毒物配置(BP)优化脱耦处理的缺陷，对LP和BP同时进行优化，结合堆芯分析程序CYCLE2D，成功地研制了压水堆LP和BP耦合优化程序CSALPBP。用该程序对大亚湾2号机组第10循环进行了堆芯装料优化计算。结果表明：CSALPBP程序具有很高的搜索效率和很好的全局性。     

长寿期压水堆板状燃料组件可燃毒物选型研究

可燃毒物在长寿期压水堆中起着至关重要的作用,板状燃料组件在长寿期压水堆中具有较好的应用前景。本文开展长寿期压水堆板状燃料组件可燃毒物选型及中子学特性研究,对含不同可燃毒物的板状燃料组件进行输运-燃耗计算,筛选出中子学性能较好的可燃毒物。结果表明,采用富集同位素157Gd、167Er和B4C作为可燃毒物时,几乎无反应性惩罚;当采用PACS-J和231Pa作为可燃毒物时,因其自身特性,在寿期末不仅未造成反应性惩罚,且延长了组件寿期,提高了燃料利用率;PACS-J与慢燃耗可燃毒物组合,可获得更优的反应性曲线。由本文结果可知,板状燃料组件可以选用富集同位素157Gd、富集同位素167Er、B4C、231Pa和PACS-J作为可燃毒物,可燃毒物组合可以选用PACS-Er和PACS-Pa两种组合方案。     

燃耗信任制中燃耗计算的敏感性因素研究

在OECD/NEA发布的Phase-IA基准题的基础上,采用SCALE程序包对影响燃耗计算结果的因素进行研究。分析堆芯运行参数以及控制棒和可燃毒物对燃耗计算以及乏燃料系统临界安全的影响,给出各因素保守性结论。     

Applications of Near-infrared Spectroscopy in Food Safety Evaluation and Control: A Review of Recent Research Advances

Food safety is a critical public concern, and has drawn great attention in society. Consequently, developments of rapid, robust, and accurate methods and techniques for food safety evaluation and control are required. As a nondestructive and convenient tool, near-infrared spectroscopy (NIRS) has been widely shown to be a promising technique for food safety inspection and control due to its huge advantages of speed, noninvasive measurement, ease of use, and minimal sample preparation requirement. This review presents the fundamentals of NIRS and focuses on recent advances in its applications, during the last 10 years of food safety control, in meat, fish and fishery products, edible oils, milk and dairy products, grains and grain products, fruits and vegetables, and others. Based upon these applications, it can be demonstrated that NIRS, combined with chemometric methods, is a powerful tool for food safety surveillance and for the elimination of the occurrence of food safety problems. Some disadvantages that need to be solved or investigated with regard to the further development of NIRS are also discussed.