CPR1000机组加热器控制线缆感应电问题分析及处理

国内某CPR1000 核电机组在调试过程中发现清污机加热器控制线缆在断电情况下存在电压,威胁人员和设备安全.试验人员通过试验确认电压为附近带电线缆所产生的感应电,通过增加中间继电器、改用直流控制的措施进行了改造,降低了感应电,在实现设备正常功能的同时保证了人员和设备安全.本研究系统地梳理了影响感应电的因素及解决感应电的...     

直流X射线模拟电缆X射线响应的可行性

本文对电缆X射线辐照响应的机理和模拟方法进行了研究,分析了电缆直流和脉冲X射线辐照响应的异同。建立了带状电缆X射线辐照响应一维计算模型,该模型包含电缆屏蔽层和介质层间隙、介质层瞬态辐射感应电导率等计算模型,模拟了带状电缆直流和脉冲X射线辐照电流响应。模拟结果表明,在X射线注量相同的条件下,电缆直流和方波脉冲X射线响应具有类似的波形特征及相同的间隙电压。因此,在该计算模型描述的电缆X射线辐照响应机制下,可利用直流X射线开展相应的脉冲X射线辐照响应机制模拟。     

浅议大亚湾和岭澳核电厂严重事故管理导则

介绍了大亚湾和岭澳核电厂严重事故管理导则,重点是大亚湾和岭澳核电厂严重事故管理导则的组成和特点,并对福岛核事故后大亚湾和岭澳核电厂所做的改进进行了介绍.     

屏蔽电缆X射线辐照非线性效应模拟

本文分析了X射线辐照电缆的物理过程,建立了电缆介质层辐射感应电导率(RIC)和间隙效应计算模型,采用有限元方法模拟了电缆X射线辐照非线性效应,给出了诺顿等效电流源(NCD)的非线性响应规律。模拟结果表明,仅考虑RIC效应时,随着X射线注量的增加,NCD幅度存在明显的饱和现象,波形宽度逐渐变窄;仅考虑间隙效应时,NCD幅度近似正比于间隙宽度;当同时考虑两种效应时,间隙效应将会大幅抵消RIC对NCD的影响。因此,在预估核爆环境下屏蔽电缆的X射线辐照响应时,需综合考虑RIC和间隙非线性效应的影响。     

基于正交试验的核主泵导叶水力性能数值优化

为提高核主泵整机水力性能,实现叶轮、导叶与环形压水室的最优匹配,以AP1000核主泵为研究对象,保持叶轮与蜗壳几何参数不变,选择导叶进口冲角、导叶包角和导叶出口角为正交试验方法的3个因素,并根据各因素的值确定取值范围。基于雷诺时均N-S方程、RNGk-ε湍流模型和SIMPLEC算法,应用CFD技术对核主泵进行了正交试验和数值优化。正交试验和因素显著性分析表明:额定工况下,优化后的模型泵较原模型泵扬程提高0.55m、效率提高0.66%;小流量工况下,优化后的杨程和效率提升更加明显;导叶包角和导叶出口角对泵水力性能的影响较为显著,导叶流道扩散程度决定了导叶流道的水力损失;导叶进口冲角、导叶出口角和导叶包角之间的相互作用对泵水力性能的影响不显著,可忽略。对导叶包角的研究表明,在小流量工况下,导叶包角与泵的效率呈正比,在大流量工况下,导叶包角与泵的效率呈反比。     

CPR1000核电厂全厂断电事故情况下严重事故缓解措施有效性研究

福岛核事故发生后,国内外对严重事故更加重视,严重事故管理导则SAMG的编制和实施已成为监管要求。在建核电厂首次装料前,要制定并实施严重事故管理导则,定期对导则进行修订并验证严重事故管理指南和缓解措施的有效性。本文在调研其他核电机组严重事故缓解措施的基础上,利用严重事故仿真验证系统(VVS),选取全厂断电(Station Blackout,简称SBO)加一回路大破口事故作为CPR1000机组的重要严重事故序列,研究了反应堆功率运行(RP)模式下严重事故缓解措施PSAMG的有效性,重点研究了机组在NS/RRA模式下发生严重事故后,现有导则SSAMG缓解措施的有效性,为CPR1000机组严重事故管理导则SSAMG的完善提供参考。     

2MeV He~+离子注入修复太赫兹发射源

为修复因加载过高外置偏压而被击穿的太赫兹光电导天线的发射晶体,采用离子注入法对光电导间隙区域进行了2 MeV He+离子注入处理.经过1016 ions/cm2 He+璃子处理后,光电导天线的电阻由约800 Ω变为60 MΩ,基本恢复到了击穿前的水平.通过对比辐照前后太赫兹发射源在空气气氛中的时域谱和频域谱,发现离子辐照后太赫兹信号强度有了十分明显的增强,时域光谱峰值信号电流由辐照前的2 nA增加到了辐照后的8 nA,峰值功率增幅超过了一个量级,且发现处理后光电导天线的频谱相对于辐照前有了明显的展宽.     

国外PSA技术标准和应用导则适用性评价

介绍了国际上对PSA开发质量和应用过程进行规范的技术标准和导则,以ASME标准和RG1.174、RG1.177为例,对这些标准和导则的适用性进行了分析,并结合我国的PSA开发与应用趋势,提出了建立我国技术标准和导则的建议。     

核电站立式泵组结构共振叠加摩擦故障的诊断分析和治理研究

立式长轴深井泵由于其导轴承位于筒体内部，无法安装振动传感器，从而使其发生故障后不能及时发现。本文通过对某核电站大型立式泵组导轴承故障引起电机振动突然增大的振动故障进行了数据分析，识别出振动异常信号产生的原因，研究了结构共振叠加导轴承摩擦故障的信号特点，为核电站同类型泵组的振动治理提供参考。     

从切尔诺贝利事故看核电站质量保证工作的重要性

本文从核电站质量保证角度对苏联切尔诺贝利核电站事故进行分析后指出,只要严格遵守核电站质量保证安全法规和导则、事故是可以避免的。最后还介绍了国际原子能机构成员国吸取切尔诺贝利核电站事故教训后,今后计划和建议采取的一系列措施。     

Energy transfer mechanisms in LMR rod bundles under mixed convection conditions

The energy transfer mechanisms operative under mixed convection conditions in heated rod arrays are identified. The relative importance of these various mechanisms of energy transfer has been assessed and is presented in regime maps which allow the designer and experimentalist to rapidly assess the characteristics of an operating regime and the capabilities needed in an analysis tool to treat such a regime. Azimuthal heater rod conduction is important for boron nitride insulated rods typically utilized in out-of-pile sodium tests. Therefore the comparison of energy transfer mechanisms necessitated the development of a correlation for azimuthal heater rod conduction. This correlation has been derived from a physical model formulated to describe this conduction effect. The proposed correlation has been tested against experimental data from out-of-pile tests and has been proven accurate for predicting the azimuthal heater rod conduction effect in LMR rod bundles.     

Simulation of the Process of Arc Energy-Effect in High Voltage Auto-Expansion SF6 Circuit Breaker

A new magnetic hydro-dynamics （MHD） model of arc in H.V. auto-expansion SF6 circuit breaker that takes into consideration nozzle ablation due to both radiation and thermal conduction is presented in this paper. The effect of PTFE （polytetrafluorethylene） vapor is considered in the mass, momentum and energy conservation equations of the constructed model. Then, the gas flow fields with and without conduction considered are simulated. By comparing the aforementioned two results, it is indicated that the arc＇s maximal temperature with conduction considered is 90 percent of that without considering conduction.     

Rewetting front propagation under anticipated operational occurrences for boiling water reactors – development of two-dimensional analytical model

An analytical model to predict a rewetting velocity applicable to high pressure and high flow rate condition during anticipated operational occurrences (AOOs) is developed by applying Wiener–Hopf technique coupled with appropriate kernel substitutions. The model considers the effects of enhanced cooling in the vicinity to liquid film front termed “precursory cooling” and heat input from fuel pellets on back side of wall as boundary conditions of a heat conduction equation. A simplified two-dimensional model neglecting an effect of axial heat conduction is also proposed. It is found through the comparison among the models and experimental data that the contribution of the heat conduction in the wall-depth direction is essential in the prediction of the rewetting velocity at the thermal-hydraulic condition simulating AOOs and the axial heat conduction has little influence when an enhanced heat transfer coefficient in the dried-out region is appropriately given as a function of distance from the liquid film front.     

Electronic Transport in Insulating Films

This paper gives a brief review of various electronic transport processes in insulating films. The topics include a brief consideration of energy bands and the concepts of extended and localized states; the properties of traps with emphasis on Shockley-Reed theory; the space-charge limitation of currents for one-carrier injection; the bulk trap limitation of currents including hopping conduction, the Poole-Frenkel effect, and field emission from traps; and ionic conduction.     

Transient Heat Transfer Analysis of a Layer by Considering the Effect of Radiation

The transient heat transfer analysis of a layer has been studied much less than the steady state. However, transient temperature distribution resulted from including radiation and conduction simultaneously, is significantly different from those obtained by considering conduction alone. In order to include the effect of radiation heat transfer, we must insert the gradient of radiative flux in the energy equation. For this purpose, a variety of multi-flux methods have been suggested. A simplified procedure is the two-flux method, which is the one used in the present paper. This paper is focused on one-dimensional transient heat transfer of a layer using Finite Difference Method. To this end, a computer implementation has been written, which is based on implicit finite difference formulation and is capable of considering effect of radiation. By subjecting the layer to various boundary conditions, the effect of variation of refractive index and scattering on transient temperature distribution is discussed.     

导热对不均匀边界放热及最大热流影响的分析和试验

文章阐述了导热和几何尺寸对平均传热系数和最大局部热流的影响,对之进行了分析并提供了研究试验的结果。计算分析和试验都是针对环形流道进行的。流道内侧为肋化管,外侧为光滑管。为进行计算分析,专门发展了二维计算程序“CONDU”。分析表明:导热和几何尺寸对平均传热系数和最大局部热流有重要影响。相似性分析表明,对于实践中有重要意义的某些场合,有必要引进一个与导热和几何尺寸有关的修正函数。此分析的主要结果已得到实验的证实。     

The effect of thermal diffusion from fuel pellets on rewetting of overheated water reactor pins

This paper presents the results of a finite difference solution of a conduction equation for the rewetting of a hot tube containing a filler material. The results show that the effect of a filler is always to reduce the rewetting velocity compared with an empty tube and reasonable agreement is obtained with previous experimental work. The effects of a gas gap on the rewetting of a UO₂-filled Zircaloy tube are discussed. A simple physical model is also presented which shows that the dominant parameter in determining the effect of a filler is (kpc)^1/2. It is suggested that previous theories for rewetting rate derived for empty tubes can be modified to include the effects of a filler by the use of a conduction correction term.     

Dynamic stabilization of D—T burn in Tokamak reactors

A simple,engineeringly feasible dynamic method is supposed to control the deuterium-tritium burn process in Tokamak reactors operated in an advanced scenario.The thermal transport of the D-T plasma is described by an anomalous thermal conduction which is a radially increasing function and the central conduction value is proportional to the central temperature of the plasma.The dynamic external heating power is selected to be inversely proportional to certain power function of this temperature,As a result,the D-T burn can undergo in controllable way in different temperature regimes with different power output.Anomalous alpha particle transport effect is taken into account.It can affect the resultant plasma equilibrium ,the reactor efficency,the operation mode and so on.     

Calculated effect of radially asymmetric heat generation on temperature and heat flux distribution in a fuel rod

The effect of radially asymmetric heat generation on the temperature and heat flux distribution in a fuel rod is evaluated. Based on practical assumptions, the temperature distribution in power reactor fuel can be obtained between reasonable limits by solving the steady-state heat conduction equation with asymmetric heat generation.     

燃料棒周向导热对超临界水堆堆芯子通道分析的影响

本文在子通道程序的燃料棒模型中引入三维导热方程,使该模型能用来模拟燃料棒的周向导热情况。采用改造后的子通道程序对混合谱超临界水堆设计中的两种燃料组件结构进行计算分析,研究燃料棒周向导热对超临界水堆燃料组件子通道分析的影响。结果表明：热谱组件的子通道计算中,燃料棒周向导热的影响不能忽略;快谱组件的子通道计算中,燃料棒周向导热的影响基本可忽略。