钠冷快堆钠池火事故数值模拟

为了估计和预测钠火事故的后果，构建了以“有火焰薄层”为理论基础的燃烧模型和热传输模型，给出了程序计算结果与试验值的比较。比较结果证实，该计算结果可信、模型合理。程序可用来分析和预测钠池火事故。     

Behaviors of Impurities in Liquid Sodium, (III)

Some fundamental studies for removing hydrogen from liquid sodium by a molten salt extraction were carried out. Alkali chloride eutectics LiCl-KCl and LiCl-KCl-NaCl (chlinak) were chosen because of their relatively low melting points, and the properties of these eutectics related to reactivities and mutual solubilities between the salts and liquid sodium were examined experimentally. From the comparison of the solubility of sodium in molten eutectics it was decided to employ chlinak for extracting hydrogen from sodium.

The difference in hydrogen concentration in sodium before mixing of the two liquid phases and after equilibrium indicated that the molar distribution ratio of hydrogen between molten chlinak and sodium was more than 10 at 400°C and decreased with increasing temperature.

From these results, it was found that hydrogen was preferentially extracted into the molten salt phase, and deduced that molten salt extraction with molten chlinak was a feasible process for removing hydrogen from liquid sodium.     

Behaviors of Impurities in Liquid Sodium, (II)

The behavior of hydrogen in liquid sodium containing relatively large amounts of oxygen were investigated with the aid of the hydrogen sensor of niobium membrane. The partial pressure of the hydrogen in liquid sodium at hot zone of a cold-trapped natural circulation sodium loop was measured as functions of temperatures of the cold trap and the hot zone of the loop. It was observed that at constant cold trap temperature the partial pressure of hydrogen in sodium increases with increasing the hot zone temperature. This study also showed that, keeping the temperature of hot zone constant, a logarithmic plot of hydrogen concentration calculated from the equilibrium hydrogen partial pressure vs. the reciprocal temperature of cold trap yields a straight line whose slope is nearly equal to that on the solubility of sodium hydroxide in sodium. Finally, it was observed that the permeation of hydrogen in sodium through a niobium membrane is a process controlled by diffusion. But the permeability for hydrogen in niobium is a few-hundredths smaller than that in literature, owing to the oxide film on the membrane surface.     

快堆钠回路水锤程序开发与应用

研究开发了快堆钠回路水锤分析专用程序WHA。该程序在一维特征线法（MOC）传统的压力波传播数学模型中补充了钠腔－气腔外边界模型,并采用气泡离散模型模拟低压液柱分离中的蒸汽穴的生成与溃灭。程序用FORTRAN90语言对快堆实验钠回路ESPRESSO中由于阀门的快速开启与关闭引起的压力波传播进行了分析计算。计算结果表明：将钠腔－气腔引入水锤压力波传播的数学模型进行程序计算的结果是合理的。     

我国的快堆技术发展和实验快堆

随着我国核电技术的发展,自主研制钠冷快中子增殖堆十分必要。本文介绍了我国在研究开发快堆技术方面的历史和实验快堆的设计原则、设计简介和安全特性。     

小波变换在快堆蒸汽发生器声学泄漏检测中的应用

根据在清华大学液态金属实验室实验钠回路上得到的实验数据，采用基于小波变换的奇异性检测理论进行快堆蒸汽发生器水／水蒸气泄漏的故障诊断研究。结果表明：此方法使得声学泄漏探测系统的灵敏度得到了提高，且对泄漏发生时间的定位十分准确，是快堆蒸汽发生器水／水蒸气泄漏检测的有效方法。     

液钠沸腾两相流流型与临界热流密度(CHF)机理实验研究

通过大量的液态金属钠临界热流密度 (CHF)的实验研究 ,结合液钠两相传热流动特性及液钠的物性特点 ,分析了起始沸腾流型 ,泡状流 ,块状流 ,环状流和双向环状流的热工水力特性 ;并从实验结果出发 ,深入分析了液钠发生临界热流密度时的气泡爆炸和液膜撕裂或局部蒸干的两种传热恶化机理     

Density Wave Instability of Sodium Boiling Two-phase Flow in a Vertical Annulus at Low Pressure

Experiments of density wave instability in a sodium boiling two-phase flow in an annulus were carried out with the parameters of heat flux from 80 to 976kW/m², inlet subcooling from 25.6 to 226.8°C, mass flow rate from 7.92 to 68.9 kg/h, and system pressure from 2,600 Pa to 0.06 MPa. It was found that the density wave instability occurred in the case of low exit quality, and the oscillation of flow rate was so large that the flow would be reversal. The lower inlet temperature, the higher system pressure and the larger mass flow rate could result in a more stable boiling two-phase flow. The oscillation period of the instability increased with the system pressure and the inlet subcooling, but it decreased with the mass flow rate. A correlation for the onset condition of the density wave instability was obtained from the experimental data.     

快堆燃料组件抗震分析流体附加质量计算方法研究

浸没在液态钠中的快堆堆芯组件在地震作用下发生振动,可能导致组件结构损坏或堆芯结构变形,从而影响反应堆结构完整性和安全.流体使该振动表现为强烈的非线性,因此,研究地震引起的流固耦合效应对快堆抗震分析十分重要.本文主要研究流固耦合问题中附加质量的计算方法,该方法由Westergaard首先提出,是一种考虑水体对结构作用的简化动力学计算方法,它将动水压力等效成质量附加在结构上,质量等效原则自提出在各行业得到广泛应用,但缺乏详细理论推导.本文首先推导出附加质量公式,并对该公式进行有效性分析;接着对单根和两根组件用CASTEM在空气和水中进行建模;最后将频率、碰撞力分别与试验值比较.结果表明,计算值和试验值吻合.     

超功率下金属燃料钠冷快堆的动态仿真

编制了计算金属燃料钠冷快堆在超功率事故下的动态过程的仿真程序ＭＦＴＯＰ，并对它对美国池式钠冷快堆ＥＢＲ－Ⅱ在启动和功率运行工况下的反应引入事故瞬态进行了大量的分析计算，所得结果与国外大型程序ＮＡＴＤＥＭＯ的相应预测结果符合良好。本程序可用于其它钠冷快堆的超功率瞬态计算。     

Method for Determining Degassing Constant of Xenon in Liquid Sodium

A method for determining the xenon degassing constant from liquid sodium to the cover gas by measuring the ¹³⁵Xe and ^135mXe release rate ratios, which were produced by the decay of ¹³⁵I in liquid sodium, was investigated using the Toshiba inpile fission product loop. Release rate ratios of ¹³⁵Xe to ^135mXe showed values of 9.9~7.6 at a sodium temperature range of 240~390°C and degassing constant of 1.2 × 10^?3-2.6 × 10^?3 sec^?1, which correspond to degassing half-life of 9.7~4.4 min, were obtained. This method is found to be effective for the determination of fission gas degassing constant, which has a corresponding half-life between several minutes to 40 min and will be useful for the study of fission gas transport phenomena in liquid sodium systems.     

基于小波独立成分分析的核动力装置冗余传感器故障在线诊断方法研究

针对核动力装置传感器的在线故障诊断问题,提出一种基于小波独立成份分析(WAV-ICA)的冗余传感器故障在线诊断方法。利用小波分解对测量信号进行高频滤波,消除电子噪声和传输噪声的影响,选取所关注的独立成分进行参数估计,并进行独立成分分析(ICA),从而实现对固定偏差、突变故障以及漂移故障的在线检测;利用稳压器5路冗余压力测量数据对该方法的故障检测效果进行验证,并与简单分析法(SA)和直接ICA方法进行对比分析。结果表明,该方法能有效地在线检测固定偏差和漂移故障,具有误诊率低、鲁棒性强、受单通道故障影响小的特点。     

失热阱下池式钠冷快堆的瞬态计算

本文采用简便实用的微机化数学模型,选用解刚性方程组很有效的 STIFF 数值积分法,编制了计算失热阱下池式钠冷快堆主回路系统动态过程的程序 WPRMY1。该程序可在微机上运行,对 EBR-Ⅱ 两个失热阱瞬态的计算结果,与国外大型程序 NATDEMO 的相应计算值以及可获得的部分试验数据符合良好。     

快堆钠设备清洗方法综述

钠冷快堆在运行和退役期间必须对钠设备进行清洗除钠,国际上采用的清洗方法包括水蒸汽清洗法、水雾清洗法、醇清洗法和真空蒸馏法等六种主要清洗法,本文系统地概述了每种清洗法的清洗原理、特点、应用范围和缺陷,为不同环境下、不同结构形式的钠设备清洗方法的选择提供了参考价值.     

快堆在我国未来核电事业发展中的战略地位

根据到下世纪中(2050年)我国能源和电力需求预测,分析了快堆在我国未来核电事业发展中的战略地位。     

钠冷氧化物燃料快堆嬗变MA研究

研究了次量锕系核素(MA)在钠冷氧化物燃料快堆中嬗变的基本物理特性。结果表明,MA核素加入堆芯燃料中后对堆芯动态参数和反应性反馈会产生显著的影响,如:βeff会有所减小、多普勒负反馈会显著减弱以及钠空泡反应性正反馈会显著增强。添加MA所带来的收益是燃耗反应性损失减小,且一定量的MA被嬗变掉,同时MA裂变也有相应的能量产出。MA嬗变的本质在于MA的焚毁,MA的焚毁比消耗与其所占全堆的裂变份额(包括由其转换的238Pu的裂变)成正比,为此相同MA裂变份额下的堆芯安全参数成为MA嬗变快堆设计的关键点。研究表明,堆芯小型化能够有效地减小堆芯的钠空泡反应性正反馈,同时对MA的焚毁比消耗影响较小。     

Oxygen Diffusion Analysis of Lead-Bismuth-Cooled Natural-Circulation Reactor

Lead-Bismuth Eutectic (LBE) coolant has been selected as one of the possible options for fast breeder reactors (FBR). To control a corrosion of structural materials in LBE is a key issue for LBE-cooled reactor feasibility, so that oxygen concentration is necessary to be controlled in the appropriate range.

A concentration diffusion analysis code (COCOA: Concentration COntrol Analysis code) was developed to evaluate diffusivity and controllability of oxygen in the LBE-cooled natural-circulation reactor design. The controllability was investigated through the sensitivity surveys on two ordinary models of oxygen control (ON-OFF and PID methods) and detection regions of oxygen concentration, which is referred in the control system.

It is concluded that the oxygen concentration should be detected at the center of the secondary vortex near the inner shell for both control methods to decrease the peak concentration below the upper constraint. The PID control method can decrease the peak concentration 400 s faster than the ON-OFF control method, when concentration is detected at the center of the vortex. It is also concluded that the diffusion and the equilibrium coefficients in LBE have negligible effects on the oxygen controllability through the sensitivity survey. It is prospected that oxygen concentration control is possible even in the natural-circulation reactor.     

钠冷快堆燃料破损定位方法综述

反应堆燃料元件破损后,为了确保运行安全和及时处理破损事故,必须对破损的燃料组件进行定位操作。本文广泛调研了国际上钠冷快堆中采用的各种燃料破损定位方法,介绍了定位原理,评析各种方法的应用范围和缺陷,展望了燃料破损定位技术的研发趋势,为我国钠冷快堆燃料破损定位方法的选择提供了参考依据。     

基于丝壁电离室的数字化氚在线测量系统的研制

涉氚场所中的氚浓度在线测量是保障工作安全顺利进行的有力条件。针对涉氚场所中氚主要以氚气形式存在的特点,设计并研制了一套数字化氚在线测量系统。该系统采用补正极原理设计了丝壁电离室,消除了氚在进入电离室前产生的电离离子对测量结果的影响;开发了数字化信号处理系统,可自控获取、处理及显示过程中的氚浓度。系统在氚靶生产过程中得以应用,结果表明,丝壁的设计使得电离室室壁氚吸附产生的记忆效应减小到1%以内,系统中的氚浓度能够在线实时准确测量、显示,能很好地满足涉氚场所氚在线测量的要求。