核电厂仪控系统纵深防御和多样性设计

针对事件发生时用于保护堆芯和限制放射性扩散的功能,核电厂设计有多层次的防御,仪控系统的设计支持这一理念,通过纵深防御和多样性设计,保证保护屏障和措施的完整性和有效性,抵御潜在的共因故障的影响,有利于限制核电厂事故的发展,减轻事故后果,保证反应堆及核电厂设备和人员的安全,防止放射性物质向周围环境的释放。     

核电厂多样化保护系统设计

基于福清核电厂仪表控制系统纵深防御和多样性的现状,阐述了设计多样化保护系统(DAS)的设计流程、设计准则、系统结构和设计要点。福清核电厂1、2号机组事故分析的结果表明,通过设置DAS,缓解了数字化安全级仪表控制系统发生软件共因故障(SWCCF)的后果,提高了核电厂的安全性,是一个应对数字化安全级仪表控制系统发生SWCCF的行之有效的解决方案。     

“华龙一号”数字化仪控系统纵深防御设计

福岛核事故后,核电厂纵深防御的设计理念得到新的发展,纵深防御层次设置和层次间独立性的安全要求进一步提高。而核电厂数字化仪控系统设计除了满足电厂总的纵深防御目标,保证在核电厂各种工况下正确可靠的执行监视、控制和保护功能之外,还需要考虑自身的数字化系统共模故障等问题。为了保证"华龙一号"数字化仪控系统设计始终满足国际最新核安全要求,为核电出海做好技术储备,一方面对国际原子能机构,西欧核监管联合会,美国核管会仪控系统纵深防御相关的最新法规要求和技术见解进行了解读和分析,归纳出共性要求;另一方面详细论述了中核集团"华龙一号"机组仪控系统整体纵深防御设计方案,并对其与前者的符合性进行了分析。通过分析,"华龙一号"仪控设计现有设计方案基本满足国际最新核安全要求,同时如进一步提升多样化保护系统独立性等问题需要在后续设计中予以关注。为"华龙一号"数字化仪控系统设计的持续改进提供了有价值的参考。     

核事故与国内现役核电机组核安全措施

根据核电厂核安全和辐射安全的设计防御准则,对核电史上三次重大事件进行分析,挖掘出核电事故主要因素：人因因素和超过设计值的自然灾害。同时结合国内核电厂的设计参数和运行参数,对发生类似事故进行研究比较,提出必要的预防方案。国内现役核电厂在运行安全技术上,已经可以充分预防人因事故的发生,对于超过设计值的自然灾害及外在因素引起的事故,还应重新考虑安全标准。核电厂在建设和运行过程中,需要充分考虑在极端环境下,如何将核辐射和泄漏的危害程度降低至政府以及公众能够接受的水平。     

核电厂事故保护表设计方法研究

事故保护表（Fault&Protection Schedule）是英国核安全审评中的设计金线,其目的在于呈现所有设计基准工况要求的安全功能,完整地展现核电厂设计。基于国际法律法规调研以及华龙一号GDA审查经验,本文对事故保护表的设计方法及其应用进行研究,事故保护表从事故保护需求出发,通过安全功能分解,明确功能要求,并关联到具体实现保护功能的系统、仪控、电气等实体,呈现了事故保护功能的设计链条,同时能够呈现事故保护功能设计的完整性,为核电厂执照申请及审评提供了一种工具参考。     

核电厂反应堆保护多样性驱动系统功能仿真与验证研究

本文研究了CPR1000核电厂反应堆保护系统的总体结构,对其纵深防御功能进行了分析。在此基础上介绍了软件共因故障及 AP1000核电厂的应对技术———多样性驱动系统（DAS ）。并对基于CPR1000核电厂的DAS基本功能需求和仿真模拟的实现方法进行了研究。以安全壳内主给水系统管道破裂事故瞬态为例,对发生反应堆保护系统共因实效情况下DAS功能的验证、分析过程进行了阐述,证实其功能设置能有效将机组带入安全状态,缓解事故后果。     

秦山三期CANDU核电厂的安全系统和安全分析

加拿大ＣＡＮＤＵ核电厂核反应堆安全原理采用“纵深防御”的概念，并设计中采用了多重性，多样性、隔离、设备鉴定，质量保证以及使用合适的设计法规和标准等设计手段。秦山三期ＣＡＮＤＵ核电厂在缓解事故后果方面设四个专设安全系统以及一套可靠的安全支持系统。     

先进压水堆核电厂多样性驱动系统需求分析结构

核电厂数字化应用需应对软件可能的共因失效所带来的问题。多样性驱动系统（DAS ）用于数字化保护系统软件共因失效（CCF）时缓解和抵御核电厂发生设计基准事件的后果。本研究在核电厂纵深防御与多样性原则的指导下,对先进压水堆核电厂的多样性驱动系统需求进行分析研究,阐明了先进压水堆核电厂多样性驱动系统的设计特性、过程、依据、方法及系统结构。     

陆上反应堆试验工程设计应考虑的几个重要安全问题

简要介绍了陆上反应堆试验工程的建造目的及其与核电厂的设计差异,提出了在设计上需要考虑的安全目标、应急计划、法规标准、纵深防御、超设计基准事故、放射性包容体等几个重要的安全问题,并作了进一步说明。     

核设备和部件的分级

三里岛和切尔诺贝利核电站事故后,人们更加重视核电厂的安全性。为了确保核电厂周围环境和运行安全,压水堆核电厂设置了三道屏障,即燃料元件包壳、压力壳、安全壳。为了给设计制造提供原始依据和保证核电厂安全运行,还将核电厂中的设备和部件划分为不同的核安全等级。     

Sorption methods of separating barium and radium,aluminum and gallum,and zirconium and hafnium

Chromatographic methods of separating elements with very similar properties have now been developed. However, a number of these methods are difficult to use industrially as their throughput is low. The efficiency of chromatographic separation methods could be increased considerably by using appropriate complex formers, which decrease the effective concentration of the ions being separated, and,in the first approximation, this is equivalent to a decrease in the amount of elements being separated. The difference in the formation constants of the complex compounds increases the separation coefficient. By investigating chromatographic separation with the use of various complex formers, we found the optimal conditions for separating barium and radium, zirconium and hafnium, and aluminum and gallium. The throughput of these methods, with respect to the macroelement was 15–60 kg/hr per m² of column cross section.     

医源性电离辐射损伤及其生物医学防护

随着核与辐射技术在医学检查、诊断和治疗领域运用的增加,世界范围受照人群不断增多,医源性辐射已成为人类最主要的人工辐射来源之一。医疗机构和个人在选择利用放射手段获取诊断和治疗利益的同时,需要注意和防护伴随的辐射损伤效应。本文介绍了医源性辐射及其危害、机体组织的辐射损伤特性和类型、辐射生物效应分子及效应调节研究的进展,简要概述目前临床已经使用或最具应用潜力的辐射防护策略。     

Distribution and Fixation of Cesium and Strontium in Zeolite A and Chabazite

The selective removal and fixation of Cs and Sr have been studied in zeolite A and chabazite. Cesium ion was preferentially distributed into chabazite with a high distribution coefficient (K _Cs>10³ cm³·g^?1) in the presence of NaCl (10^?1 mol·dm^?3). The K _Sr values for zeolite A attained about 10³ cm³·g^?1 in the pH range of 8～10, and they gradually decreased with an decrease in pH.

The initial rate of Cs adsorption was fairly fast in chabazite, and the adsorption ratio reached almost 100% within a few hours. The adsorption ratio of Sr in binderless A zeolite reached almost 100% after 15 h. The adsorption of Cs and Sr on these zeolites was followed by Langmuir-type isotherm. Cesium forms of these zeolites recrystallized to pollucite (CsAlSi₂O₆) above 900°C for zeolite A and above 1,200°C for chabazite. As for Sr forms, these zeolites changed to SrAl₂Si₂O₆ above 900°C.

These recrystallized phases were suitable hosts for the immobilization of Cs and Sr in the nuclear waste solutions.     

清洁解控和退役若干动向与新发展

对国际辐射防护协会第 1 0届大会 ( IRPA-1 0 )涉及的清洁解控和退役问题作了论述 ,包括排除、豁免、清洁解控和废物最少化 ;退役工程技术的发展 ,包括去污技术、切割解体技术、探测技术 ;介绍了一个研究堆退役例子和加速器退役 ;最后 ,还论及了退役中受关注的一些问题 ,如 :石墨废物、混凝土废物、重水堆退役的氚防护、退役时间和退役废物量等。     

全国核与辐射安全监管信息系统的研究和建议

文章简要介绍了全国核与辐射安全监管信息系统的前期规划建设情况,包括基本建设内容、系统总体架构、以及工作中发现的影响和制约工作开展的主要问题,并提出了建议。     

Development and diversity and defense-in-depth application of ABWR feedwater pump and controller model

This work developed an advanced boiling water reactor (ABWR) feedwater pump and controller model, which was incorporated into Personal Computer Transient Analyzer (PCTran)-ABWR, a nuclear power plant simulation code. The feedwater pump model includes three turbine-driven feedwater pumps and one motor-driven feedwater pump. The feedwater controller includes a one-element/three-element water level controller and a specific feedwater speed controller for each feedwater pump. The performance tests, including step change of dome pressure, feedwater pumps transfer, inadvertent closure of all turbine control valves, and one feedwater pump trip at 100% power, demonstrate the feasibility of dynamic response of stand-alone model and incorporated model. Furthermore, a diversity and defense-in-depth analysis is performed to demonstrate the feasibility for motor-driven feedwater pump as an emergency core cooling system (ECCS) automatic diverse back-up. In Lungmen nuclear power plant (NPP), a diverse manual initiation means for the high pressure core flooder (HPCF) loop C is designed as the back-up of digitalized engineered safety features actuation system (ESFAS). If the motor-driven feedwater pump (MDFWP) can be an automatic digital diverse back-up for ESFAS, Lungmen NPP would be more robust to defend against software common-cause failure (CCF).     

Plastic and dissipated work and stored energy

This paper depicts one theoretical and experimental method to take into account the energy phenomena, associated with the elasto—plastic deformation process, during the elaboration of behaviour laws. The energy balance definition is examined in order to relate the stored energy of cold work to the hardening state variables. Two experimental approaches are used to study the evolution of the energy balance. The first one uses microcalorimetric technique and the second infrared technique. Several industrial metallic materials are studied by both approaches. Energy data are used to control the validity domain of the classical behaviour laws and to elaborate new more appropriate ones. Therefore, the hardening parameters cannot be identified with the thermodynamical forces. The use of energy considerations allows the definition of new thermodynamical forces and state variables, in the case of isotropic or kinematical hardening.     

Construction and operational experience with small and medium power reactors and expected improvements

Past experience with small and medium power reactors (SMPRs) in the areas of construction and operation is examined in this paper. Current development of SMPRs focuses on passive safety features; larger design and safety margins; reduction of construction periods through simplification, modularization and increased shop fabrication.