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There are many tapes of nuclear power plants (NPPs) in operation and under construction in China, involving M310 reactor, VVER reactor, AP1000 reactor and HPR1000 reactor and so on. The design concepts of each type nuclear power plant are quite different, including active nuclear power plant and passive nuclear power plant, second-generation reactor and third-generation reactor. Their designs for preventing internal flooding are also very different, either through physical isolation or by adding flood prevention barrier, but each reactor type nuclear power plant has its own advantages in flood prevention. In order to further improve the internal flooding prevention ability of nuclear power plants in China, this paper makes a comparative study on the internal flooding prevention design of several mainstream tapes of nuclear power plants in China, and gives the advantages of each nuclear power plant in the internal flooding prevention design. By drawing on the design advantages of other reactor type nuclear power plants and using the analysis method of probabilistic safety assessment (PSA), this paper quantitatively evaluates the improvement of the ability of reactor type nuclear power plant that our company participated in the design or construction to resist internal flooding risk after considering these design optimization, and gives targeted design improvement suggestions.

土壤不仅能够产生、排放温室气体N2O，还具有截留、吸收、转化N2O的能力。土壤消耗N2O已经成为很重要的一种降低大气N2O浓度的途径，但目前关于土壤N2O消耗过程及其微生物调控机制的系统研究较为缺乏。试验以浅表层水稻土柱（0-5 cm）为研究对象，通过外源添加N2O气体研究N2O迁移通过淹水土柱的动态过程，以及N2O消耗能力与氧化亚氮还原酶基因丰度变化和其他土壤养分含量变化的联系，揭示浅表层水稻土N2O消纳量与N2O还原微生物之间的耦合关系。结果显示，淹水厌氧条件下5 cm土壤深度外源添加的N2O迁移通过浅表层土柱后，仅有7.17-9.80%部分逸散出土表，表明0-5 cm淹水水稻土层具有极强的N2O截留能力（90%以上）而减少N2O净排放量。排放出土表的N2O也可被淹水土柱继续吸收消耗，且吸收转化速率随N2O浓度增加而大幅提高，最高可达到3896.75 μg N m-2 h-1。与此同时，土壤DOC含量大量消耗，含nosZI基因的反硝化微生物数量显著增长（P < 0.01），而nosZII基因丰度的无显著变化。说明高浓度N2O添加能够促进淹水土壤N2O吸收消耗能力，此刺激作用可能主要由含nosZI基因的N2O还原微生物进行调控。浅表层土壤强大的N2O吸收消耗功能可进一步深入系统研究，为实践温室气体减排提供理论基础。

As coal and gas outburst is a frequent disaster and its mechanism still unclear, consistent numerical modeling is indispensable to enable further investigations owing to difficulties in field observation. As gas-bearing coal with outburst proneness is considered a granular material, the outburst phenomenon is described by a solid-fluid transition that is developed in gas-bearing coal. Inter particle meso-contacts become bondless while the gas-bearing coal is sufficiently degraded. The solid-fluid transition occurs in case of the vanishing second-order work ( d 2 w ) when the gas pressure threshold ( p t ) is satisfied. A unified model for describing the consistent process of outburst is established herein. Finite elements method with Lagrangian integration points (FEMLIP) is used to model solid-fluid transition behavior of gas-bearing coal. The numerical results present the entire process of the outburst and satisfies a four-stage description. The unified model for outburst is beneficial for the study of the outburst mechanism.

A full scope Probabilistic Safety Assessment (PSA) is developed for CAP1400 and some design modification was performed based on the CAP1400 PSA insights. In this paper, a brief introduction of CAP1400 PSA is presented, including analysis method, procedure, results and insights obtained and design improvements. The CAP1400 PSA includes internal events level 1 PSA, low power and shutdown PSA, level 2 PSA, level 3 PSA, internal fire PSA, internal flooding PSA, seismic margin analysis and seismic PSA, etc. The CAP1400 PSA is developed based on PSA methods acknowledged internationally and in compliance with the requirement of PSA related standards, such as ASME PSA standards and Chinese PSA standards. The design improvements derived from PSA results are also introduced in this paper, including design change of passive core cooling system (PXS), diverse design of instrument and control system, design change of in-vessel retention (IVR) of molten core debris, installation of very early warning fire detection system and design change of flooding protection of PXS valves.

In response to the energy crisis, global warming, and climate changes, microalgae have received a great deal of attention as a biofuel feedstock. Due to a high lipid content in microalgal cells, microalgae present as a promising alternative source for the production of biodiesel. Environmental and culturing condition variations can alter lipid production as well as chemical compositions of microalgae. Therefore, application of the strategies to activate lipid accumulation opens the door for lipid overproduction in microalgae. Until now, many original studies regarding the approaches for enhanced microalgal lipid production have been reported in an effort to push forward the production of microalgal biodiesel. However, the current literature demonstrates fragmented information available regarding the strategies for lipid production improvement. From the systematic point of view, the review highlights the main approaches for microalgal lipid accumulation induction to expedite the application of microalgal biodiesel as an alternative to fossil diesel for sustainable environment. Of the several strategies discussed, the one that is most commonly applied is the design of nutrient (e.g., nitrogen, phosphorus, and sulfur) starvation or limitation. Other viable approaches such as light intensity, temperature, carbon dioxide, salinity stress, and metal influence can also achieve enhanced microalgal lipid production.