AP1000严重事故下的氢气源项及消氢措施分析

 采用一体化严重事故分析工具,建立包括主热传输系统、专设安全设施、安全壳系统的AP1000的事故分析模型。根据AP1000概率安全评价选取典型事故序列,同时叠加相关安全系统失效的严重事故进程进行模拟,结果表明,中破口始发严重事故压力容器内会产生624kg的氢气,安全壳隔间有氢气燃烧的风险。同时,建立氢气控制系统模型,选取热段中破口始发(MB-LOCA)的严重事故序列,分析氢气控制系统的消氢效果,结果表明,氢气控制系统可以有效地将氢气浓度控制在安全限值以内,采用64个点火器叠加2个非能动氢气复合器(PARs)可以有效降低点火次数。     

核电厂严重事故序列选取准则探讨

严重事故的预防和缓解是新一代核电厂的重要安全问题。本文主要讨论核电厂严重事故研究和管理中确定严重事故主导事故序列时应考虑的准则问题,包括定性和定量准则以及准则相应的意义。以此为基础,本文整理形成一套推荐中国核电厂进行严重事故主导序列筛选时采用的准则,并以1000MW非能动先进压水堆(AP1000)标准设计为研究对象进行应用尝试。分析表明,严重事故选取准则应从定性和定量两方面阐述。从定性的角度,严重事故的选取应根据核电厂状态划分,在超设计基准事故范围内,选取可能导致堆芯损伤和安全壳旁路,并且在后果上具有包络性的事故序列。从定量的角度,应确定导致核电厂严重事故风险的绝对筛选值和相对筛选值,同时还要包络陡边效应,补充确定论分析和工程经验的成果结论。根据建议准则选取的AP1000严重事故主导序列与其概率安全分析报告中进行重点分析的严重事故序列基本吻合。     

浅谈AP1000核电密封油系统对氢气纯度的影响分析

AP1000核电发电机组采用双流环式密封油系统,在运行过程中普遍存在氢气纯度下降快,补氢量大和氢气纯度参数只能维持在较低状态下的问题,影响机组的安全性和经济性。该文从设备结构以及系统设计方面进行深入分析,论述密封油系统与氢气纯度的关系,找出导致氢气纯度下降的根本原因,并提出可行的改善措施,对分析处理同类核电机组可能出现的类似问题具有一定的借鉴意义。     

氢气复合器与点火器消氢效率与安全性

氢气点火器与氢气复合器是两种消除严重事故安全壳内氢气的设备。以火焰加速准则和燃爆转变准则为基础,利用GA SFLOW程序对影响氢气点火器与复合器的消氢效率和使用安全性的因素:水蒸气浓度和氢气释放速率,进行了研究。结果表明,水蒸气能够有效抑制氢气火焰加速和氢气从燃烧向爆炸的转变;在氢气释放速率较高的情况下,氢气复合器不能够快速有效地消除氢气;采取氢气复合器结合点火器的方式可以安全、有效地降低氢气燃烧带来的风险。     

CPR1000全厂断电事故模拟及主泵轴封破口敏感性分析

全厂断电事故是导致核电厂发生严重后果的重要事件之一.采用模块化事故分析程序对CPR1000全厂断电事故进行建模与分析,计算一回路压力、压力容器水位、堆芯温度等参数,详细分析了事故进程.分析结果显示:全厂断电事故会导致反应堆压力容器在高压下失效,这将会有安全壳直接加热的风险;同时,事故过程中会产生大量氢气,这部分氢气会逐步迁移到安全壳或者辅助厂房中,从而带来氢气爆炸的风险.针对全厂断电时主泵容易出现轴封破口这一问题,选取了早、中、晚3个时期的事故序列,对轴封破口发生时间做敏感性分析.结果表明,早期破口会加速严重事故的进程,而较晚时间发生破口,尤其是事故中期发生破口能较好地延缓压力容器损毁进程.相关数据可为有关人员防范和缓解严重事故提供参考.     

AP1000和M310安全系统的比较与分析

简述了AP1000的非能动堆芯冷却系统的功能、组成和发生失水事故时的非能动安全注入过程,以及M310安全注入系统的功能、组成和安注过程,分析了AP1000非能动堆芯冷却系统的主要优点。     

包壳相关行为对严重事故进程的影响分析

严重事故工况下,锆合金包壳与水剧烈反应,产生氢气并释放大量热量,会导致堆芯熔化。熔化的锆合金包壳发生共晶反应,二氧化铀与二氧化锆在低于其熔点时发生熔化,将对堆芯熔毁事故进程产生显著影响。本文使用一体化严重事故分析程序,研究百万千万级压水堆核电站发生全场断电叠加破口事故下,包壳行为对严重事故进程的影响。分析结果表明,锆水反应精细化计算模型修改后,全场断电叠加大破口事故下堆芯产氢量减少24.1 Kg;共晶反应能够加速熔融物向下封头迁移同时延长堆芯失效时间。     

福清核电厂严重事故下氢气可燃性控制方案分析

日本福岛核事故后,针对其氢气爆炸会带来安全壳失效和放射性物质外泄的严重后果,给出了福清核电厂严重事故下氢气可燃性控制方案的分析,提供了各个方案的介绍,使用方法,由此带来的优点和副作用,以初步确定根据氢气爆炸的风险大小。帮助操纵员认识氢气可燃控制方案,并可恰当地选择方案中最合适的缓解事故后果的措施,给出了相应建议和意见。     

AP1000压水堆功率控制模式浅析

反应堆功率控制是维持反应堆稳定的核心控制,该文通过结合反应堆反应性控制的基本原理对AP1000采用的功率控制模式进行了简要的介绍,分析了AP1000核功率控制关于功率水平和功率分布的控制方式及约束条件,功率水平控制系统从低功率控制和高功率控制两个部分展开,功率分布则主要分析其轴向功率的控制信号及其限制条件。同时简要减少了反应堆功率控制模块中的快速降功率功能。最后将AP1000反应堆功率控制模式与其他模式进行了对比,在功率水平和功率分布调节方面进行了比较分析。     

CP600压水堆核电厂严重事故现象与纵深防御

<正>压水堆核电厂严重事故是指严重性超过设计基准事故并造成核反应堆堆芯明显恶化的事故工况,可能由安全系统多重故障引起,并导致堆芯明显恶化,危及多层或所有用于防止放射性物质释放的屏障的完整性。压水堆核电厂严重事故的一般现象及其演变过程如下:1)堆芯裸露(1)堆芯裸露;(2)裸露区热量导出效率降低。2)氢气产生(1)包壳温度达到982~1204℃时,明显产生氢气,锆水反应产生热量,随着温度上升,反应速率增加;(2)包壳温度达到1427℃时,锆水反应成为自动催化反应,化学热超过衰变热成为堆芯加热主要部分。3)堆芯融化及压力容器内的重新定位(1)堆芯材料的重新定位:     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the