风险指引型设备分级方法研究

风险指引型设备分级是综合确定论和概率论的分析结果对设备进行重新分级的一种方法.它可以使核电厂将资源更合理地分配到安全重要度高的设备上,同时节省大量的采购及其他相关费用.文章介绍了风险指引型设备分级的分析方法和过程,并以大亚湾核电站辅助给水系统为例对这种方法进行了研究.     

PSA的重要度在风险指引型管理中的应用

PSA的重要度分析是核电厂进行风险指引型管理的主要方法之一。本文回顾了几种重要度的定义,重点探讨了FV和RAW重要度的含义,介绍了在役试验和设备分级活动中使用重要度对SSC分类的应用,最后讨论了目前重要度分析的局限性。     

分级方法在核燃料循环设施安全要求中的应用及相关标准浅析

核燃料循环设施类型多样,分级方法在核燃料循环设施中有较广的应用,标准在指导如何分级中发挥了重要作用。文章以IAEA安全标准第SSR-4《核燃料循环设施安全要求》的要求为参考,结合我国核燃料循环设施的安全相关标准要求,简要分析了分级方法在核燃料循环设施分类、物项安全分级、纵深防御等方面的应用,并提出了分级方法相关标准的建议。     

法国CP1-CP2系列核电机组安全重要设备分级的经验反馈

本文介绍了在法国900MWeCP1-CP2系列核电机组定期安全审查中制定安全重要设备清单时确定安全分级所用的原则和方法.除了对分级清单增补机械设备和电气设备项目外,还引入了安全重要的非安全级(IPS-NC)设备的概念、原则和有关要求.     

概率截断对PSA中RAW重要度的影响研究

重要度分析是核电站概率安全评价中一个重要组成部分.本文首先简要介绍了RAW重要度;在详细分析了截断对重要度的影响后,引入了安全风险因子,指出影响该因子的相关因素,同时也提出只有保证安全风险因子在一定的变化范围之内即减少可能丢失的割集,才能最终降低截断对重要度的影响.最后给出一种解决概率截断问题的思路即使用自动概率截断和McFarm相结合的方法,较好地解决了因概率截断而对重要度计算误差问题.     

核电厂风险指引型安全分级方法对比分析

核电厂物项安全分级是核电厂构筑物、系统和设备(SSCs)相关的各项管理和规定的基础。随着核电厂运维经验积累,逐渐发现传统确定论分级方法过于保守,存在优化的空间。风险指引型安全分级在传统分级的基础上应用概率安全分析技术,明确安全重要物项,优化核电厂物项分级。研究国内外风险指引型安全分级方法及其技术路线,梳理总结为设备分级方法、非能动管道部件分级方法,并开展方法对比分析与可行性分析。初步研究表明,我国核电厂具备开展风险指引型安全分级的基础,基于合理可行的方法实现物项分级的优化,在确保核电厂安全水平的前提下提升运维经济性。     

SSG-30安全分级方法介绍及其在CNHCCB TBS中的初步应用

核能系统物项安全分级是划分其抗震等级、设计规范等级以及质保等级的重要基础。国际原子能机构(IAEA)于2014年发布了《Safety Classification for Systems,Structures and Components of Nuclear Power Plant》(No.SSG-30)。相比传统定性的安全分级方法(IAEA在1979年发布的No.50-SG-D1),SSG-30方法根据物项类型和失效后果等标准进行量化分级。本文根据SSG-30的分级导则,研究其在中国氦冷固态增殖实验包层模块系统(China Helium Coolant Ceramic Breeder Test Blanket Module System,CN HCCB TBS)物项安全分级中的初步应用,可为后续聚变能系统物项安全分级奠定基础。     

非压水反应堆一种安全分级方法研究

物项的安全分级是核反应堆安全设计的基础和重要内容。考虑到反应堆各系统和设备对于核安全的重要程度不完全相同,设计中根据其承担的安全功能以及失效后果对反应堆建（构）筑物、系统和设备进行安全分级。随着我国核能科研和工程领域的发展,出现了多种类型的反应堆,其运行参数及系统设计与常规压水堆核电厂有很大区别,我国现有的针对压水堆制定的分级方法无法很好地适用于这类反应堆,导致了其安全分级存在一定困难。本文在分析现行HAD102/03和IAEA SSG-30物项分级方法的基础上,对SSG-30分级方法的思想和过程进行分析,并采用SSG-30的物项分级方法对典型池式反应堆进行安全分级,总结该方法在非常规压水堆上的应用特点,为此类型反应堆的物项分级提供指导。     

核电站常规设备质量保证分级方法

根据系统、规范的质量保证分级方法对设备进行分级,可以合理地分配有限的资源,确保核电站关键设备的质量.本文结合对我国岭澳核电站一期工程项目中常规设备的分级方法的介绍,分析了分级的目的,对岭澳一期项目中常规设备分级中存在的问题,给出了既能实现合理分配资源,又具有较强可操作性的核电厂常规设备分级方法.     

核电厂物项分级及相关标准

本文评述了涉及核电厂物项分级的法规、导则和标准.对不同文件中的安全分级、抗震分类、规范分级、质保分级进行了分析对比.对一些概念,如安全重要物项、安全4级、规范级与核级等进行了阐述、解释并提出了建设.对标准中存在的一些问题提出了看法.     

核电厂主控制室任务分类的初步探讨

本文阐述了主控制室的重要性与发展要求。并对如何在先进控制室设计中实施人因工程原则进行了简单介绍。重点论述了核电厂主控制室任务分析的目的与作用、策略与方法、范围与内容，并对初步的任务分类进行了探讨。     

Numerical simulation of binary collisions using a modified surface tension model with particle method

The binary collision of liquid droplets is of both practical importance and fundamental value in computational fluid mechanics. We present a modified surface tension model within the moving particle semi-implicit (MPS) method, and carry out two-dimensional simulations to investigate the mechanisms of coalescence and separation of the droplets during binary collision. The modified surface tension model improves accuracy and convergence. A mechanism map is established for various possible deformation pathways encountered during binary collision, as the impact speed is varied; a new pathway is reported when the collision speed is critical. In addition, eccentric collisions are simulated and the effect of the rotation of coalesced particle is explored. The results qualitatively agree with experiments and the numerical protocol may find applications in studying free surface flows and interface deformation.     

基于SVM与DT的核电装备制造业供应风险组合预测模型

基于对核电装备制造业供应风险的识别,确立风险预测的指标体系;对国内3家重点核电装备制造企业及其60家供应商进行问卷调查及深度访谈,运用支持向量机与决策树组合的方法建立供应风险的预测模型.实证研究表明,组合预测模型对供应风险预测的精确性优于单一方法的模型,证明了该预测体系的可行性与可靠性,为核电装备制造业供应风险的管理提...     

适用于三级概率安全评价的核反应堆实时风险计算方法

风险监测是反应堆安全监管与核应急决策的重要技术基础。面向核反应堆实时风险的三级概率安全评价（PSA）提出改进的实时风险计算方法,解决传统风险监测器重点集中在一级PSA的堆芯熔毁频率（CDF）计算的问题。针对反应堆运行时的实际系统配置,通过实时风险模型与在线状态监测进行实时事故频率计算,并采用放射性释放事故分类与实时气象下大气扩散方式分别实现了事故源项与场外剂量的实时计算。反应堆风险模型的计算案例验证了本研究方法与流程的有效性,该方法不仅支持堆芯熔毁实时风险计算,而且支持源项释放实时风险与场外剂量实时风险的计算,可为核反应堆安全监管与核应急提供技术支持。     

Strength and ductility of RC beam-column joints of non-safety related structures and recommendations by national standards

Every nuclear facility consists of various structures of varying importance. Standards and design guidelines recommend categorization of these structures based on their importance, safety function that they have to perform, hazard class, etc. In order to economize the designs, the structures that pose only industrial risk are recommended to be designed following the national practice. This paper presents the results of experiments performed on the beam-column joints of such structures to verify their seismic performances. The specimens were full-scale replicas of the joints of the original non safety related structures such as turbine buildings, intake structures and office buildings. The beam-column connections in the original structures either had non-seismic detailing or seismic detailing, but in order to have a comparison, every joint was tested with both types of detailing. The strength and ductility obtained from the experiments for both types was compared with the codal recommended values by different national standards. Conclusions and comments on the suggested values of allowable stresses, assumed ductility values and corresponding strength reduction factors have been made.     

基于二叉决策图的故障树求解法

探讨了二叉决策图(BDD)求解故障树失效概率和最小割集(MCS)的方法,包括如何将故障树转化为BDD、用BDD求解最小割集、利用零压缩二叉决策图(ZBDD)表示最小割集以减少存储空间、基于BDD求解故障树顶事件失效概率.用程序实现了BDD算法,以某电厂PSA模型部分分枝为对象,通过手工计算和RiskSpectrum P...     

Molecular dynamics simulation of intragranular Xe bubble re-solution in UO2

The homogeneous re-solution of Xe fission gas bubbles in UO₂ is investigated by combined Monte Carlo and molecular dynamics simulations. Using a binary collision model, based on the Ziegler-Littmark-Biersack potential [J.F. Ziegler, J.P. Biersack, U. Littmark, The Stopping and Range of Ions in Solids, Stopping and Ranges of Ions in Matter, vol. 1, Pergamon Press, New York, 1984], the recoil energy distribution of fission gas atoms is obtained. An extensive library of fission gas atom displacement cascades is then compiled using molecular dynamic simulations. It used for calculating recoil spectrum averaged quantities. The calculations yield a re-solution parameter for homogeneous re-solution and a displacement distribution of fission gas atoms around the fission gas bubbles. The results disagree considerably from past estimates. The importance of channeling and threshold energy for fission gas escape are discussed.     

基于相依竞争失效模型的主泵多状态可靠性分析

基于核动力主泵运行环境和性能退化机理,考虑自身振动和外部冲击对其性能退化的影响,建立了主泵冲击与退化相依竞争失效过程的可靠度模型。采用该模型计算了考虑性能退化的主泵在振动和外部冲击条件下的退化状态概率和可靠度,为基于使用环境的核动力主泵的多状态可靠性分析提供了一种有效的分析途径。分析结果可为设计变更和维修优化提供决策依据。     

Adsorption Equilibria of Krypton,Xenon, Nitrogen and Their Mixtures on Molecular Sieve 5A and Activated Charcoal

The adsorption equilibria of Kr, Xe and N₂, which are constituents of the off-gas from nuclear reprocessing processes, on representative adsorbents (Molecular Sieve 5A (MS5A) and activated charcoal) were studied. Adsorption experiments were conducted in the temperature range of 77 to 323 K using a packed bed column. The adsorption isotherms for the activated charcoal adsorbent were successfully correlated by the vacancy-solution model. The adsorption isotherms for the MS5A adsorbent were properly correlated by the Langmuir model and the vacancy solution model. The adsorption experiments for the binary component systems (Kr—Xe, Kr—N₂ systems) were also performed, and the results suggest that the coexistence of Xe greatly inhibits the adsorption of Kr. The coexistence of large amounts of N₂ was also found to inhibit the adsorption of Kr. The experimental results for the adsorption equilibrium of binary component systems on the activated charcoal adsorbent were well reproduced by the vacancy solution model without parameter fitting. The binary adsorption equilibrium on the MS5A adsorbent is rather well predicted by the ideal adsorbed solution model without parameter fitting. The use of the vacancy solution model for this adsorption system requires the optimization of parameters, but the binary adsorption equilibrium is well reproduced with the optimized parameters.     

Upgraded acceptance criteria from transient thermography control for the W7-X divertor target elements

The commissioning of plasma-facing component fields needs advanced non-destructive methods to detect in a reliable way the defects, which can impair the component performances and/or integrity during operation. Within this framework, CEA developed a dedicated non-destructive examination method based on active infrared thermography (SATIR facility) to inspect the bonding between armour material and metallic heat sink. Used with successful in the commissioning of the toroidal pump limiter of Tore Supra, this technique was applied in the frame of the pre-series activities of the Wendelstein 7-X high heat flux divertor elements to assess the bonding quality of the delivered components.This paper presents the methodology adopted to define an acceptance criterion based on SATIR test bed possibly applied for a serial inspection of the Wendelstein 7-X elements. Using the well-tried acceptance test based on the DTref_max parameter, the new method includes advanced data post-processing techniques from thermo-signal SATIR and a data merging method to help the decision-making and to optimise the reliability of the binary response expected for a final decision in terms of acceptance test.