用银激活计数器测量快脉冲中子

本文介绍了银激活计数器测量等离子体焦点快脉冲中子的原理，用加速器Ｄ－Ｄ中子作标准中子源，采用饱和照射方式对探头进行了标定。在探测距离６０ｃｍ，给出探头定标系数η＝（２．６０土０．３２）×１０￣４中子／计数。误差分析表明，作与不作散射中子校正，实际测量焦点中子的相对标准误差小于２０％和３０％。最后给出了测量焦点中子的部分结果。     

基于康普顿散射本底扣除的航空γ能谱测量谱线比大气氡校正方法

大气氡子体释放的γ射线严重影响航空γ能谱测量结果,而谱线比大气氡校正方法是航空γ能谱测量大气氡校正数学方法中校正效果较好的一种。本文在此方法的基础上提出了基于快速傅里叶变换扣除散射射线的谱线比大气氡校正方法,研究了改进后新谱线比法不同组分校正系数和高度之间的关系,建立了新谱线比大气氡校正数学模型,并提出了校正系数的地面饱和模型刻度技术。改进后的谱线比大气氡校正方法的适用性及其校正系数的刻度效率得到了提高,节省了谱线比方法应用成本,解决了传统谱线比大气氡校正方法中校正系数采用谱形拟合方法导致物理含义丢失的问题。     

活性炭吸附测氡法静态吸附系数测量研究

建立了一种简便的静态吸附系数的测量方法,并对相关活性炭吸附氡的静态吸附系数进行测量,将测量结果与相同条件下动态吸附法测量的相应结果进行对比。从比较结果来看,静态吸附系数K_s与动态吸附系数K_d的比值恒定,接近于1。这种方法可用于活性炭种类的筛选和吸附条件的初期探索,可为最终活性炭吸附的工程条件的选择和确定节省大量的初期工作。此外,此方法也可为其他吸附材料对氡吸附系数的初步测量及相关测量研究提供一种简单快速的测定方法。     

电离室充不同气体的饱和特性实验研究

对体积为1 L的球形不锈钢高气压电离室,用实验方法测量了5种气体（Ar、N2、He、Kr和Xe）的饱和特性.本文主要介绍了测量方法及其结果.结果表明,在相同的充气压力下,He气最容易饱和,Xe气最不容易饱和,Ar气和N2气的饱和电压相近.     

煤样射气系数的测定及其影响因素的探讨

介绍了煤样氡射气系数测量方法,应用该方法测量了全国不同地区多个煤样的氡射气系数。根据测量结果分析了镭-226比活度、煤样粒径、样品含水率等因素对氡射气系数的影响,研究结果表明:氡的射气系数与煤样中镭-226比活度没有相关性;但与样品的粒径有关,且随粒径减小而增大;样品含水率对测量结果有明显影响,当样品含水率5%时,氡的射气系数随着含水率的增加而增加,当样品含水率5%时呈下降趋势。     

IP板测量γ射线辐射场参数研究

将IP板应用到γ射线辐射场测量中,测量参考辐射场射野的二维分布,给出射野尺寸及均匀度,结果与电离室扫场结果一致;基于IP板对γ射线测量结果,对IP板的衰退特性作研究,结果显示IP板适用于短周期剂量监测,并由实验得到了由信号衰退造成的测量结果修正系数;IP板对单能γ射线的吸收剂量响应的线性拟合的确定系数R2=0.999 77,得到了IP板的137Csγ吸收剂量响应的剂量率依赖关系,并给出了剂量率修正系数。     

中国先进研究堆功率反应性系数测量

中国先进研究堆(CARR)功率反应性系数测量试验的目的是获得CARR堆芯满装载时功率反应性系数,为CARR安全运行提供数据参考。试验采用控制棒棒栅效率刻度法。3次试验的测量结果均为负值且与温度反应性系数不矛盾,满足验收准则的要求。文中对引起偏差的原因进行了深入分析,考虑到CARR日后运行的实际情况,选用第3次试验的测量结果为CARR堆芯满装载时的功率反应性系数。     

放射性气溶胶测量中能量补偿系数时间特性研究

为进一步提高能量甄别法测定放射性气溶胶测量结果的准确性,开展了能量补偿系数的时间依赖特性研究。根据核素在滤膜上的衰变规律对补偿系数的时间特性进行了全面分析,研究了取样时间、等待时间和测量时间对其的影响,并进行了测量验证,获取在实验条件下最佳的时间分配组合,可为放射性气溶胶快速测量工作提供参考。     

双色平面激光诱导荧光法测温技术研究

讨论双色平面激光诱导荧光法(PLIF)在测量流体温度分布中的应用,激光染料分别选择具有负温度系数的RhB和具有正温度系数的Fl27。通过片光系统将激光束整形为平面片光,由此激发激光染料发出特定波长的荧光,根据荧光的强度信息进一步得出平面温度场的分布。对双色PLIF中涉及的相关技术问题进行探讨,如染色剂的光谱特性以及光谱的分离。标定的温度高于常压条件下水的饱和温度,表明双色平面激光诱导荧光技术可用于涉及相变过程中的温度场测量。     

基于静电探针测量对双潘宁离子源的弧特性研究

本文介绍了采用静电探针的逐点测量法和锯齿波扫描测量法来测量离子源放电中等离子体参数,在此基础上利用静电探针所测量的离子饱和流信号作为控制部分反馈变量,使用闭环控制对22厘米双潘宁离子源的等离子体进行调节,并且利用探针所测量的结果对弧特性进行了初步的分析.     

Hydrogen transport through interface between gas bubbling and liquid breeders

An experimental study was performed to investigate hydrogen transport under conditions of gas bubbling into the liquid breeders of Li, Pb–17Li and Flinak. Gas of H₂ or high-purity Ar at 0.1 MPa was injected into the liquid breeders using an I-shape nozzle. Then, the H₂ partial pressure in the cover gas under transition state was measured by a solid electrolyte sensor. Variations of the partial pressure in the exhaust gas were compared with a numerical model to describe hydrogen transfer through the bubble–liquid interface. The experimental rates of hydrogen transport in the liquid breeders were correlated in terms of a mass-transfer coefficient for the hydrogen transport under gas bubbling. The overall mass-transfer coefficient for H₂ charging was compared with that for Ar purging. The coefficient for the recovery was about 10 times lower than that of the charging in the respective cases of the Pb–17Li and the Flinak.     

曝气装置结构对多孔板鼓泡特性的影响

气泡体积是决定鼓泡式过滤器性能的重要参数，当使用多孔板作为曝气装置时，孔板结构和气腔状态会对生成气泡体积产生影响。本文采用可视化方法实验研究孔板结构、气腔状态对多孔板鼓泡特性的影响规律。结果表明，气腔无水状态下多孔板鼓泡效果更好；使用有效鼓泡时间能很好地表征多孔板的鼓泡性能；仅当气体流量处于0.35～0.7 L/min、孔间距小于6 mm时，孔间距对多孔板鼓泡性能产生影响；多孔板孔数的确定应保证生成的气泡体积处于气腔控制区。     

Analysis of the critical active species for methylene blue decoloration in a dielectric barrier discharge plasma system

In the paper, a hybrid gas–liquid dielectric barrier discharge (DBD) plasma system was set up to treat a methylene blue (MB) solution. The effects of the change of the carrier gas, the gas bubbling rate and different kinds of scavenger addition, including sodium carbonate (Na₂CO₃), para benzoquinone (p-BQ), triethylenediamine and sodium dihydrogen phosphate (NaH₂PO₄), on the MB decoloration were reviewed to clarify the critical active species for the dye decoloration in the DBD plasma system. The obtained results show that higher decoloration of the MB solution could be achieved when O₂ was used as the carrier gas, which could be 100% after 20 min discharge treatment, and the result confirmed the crucial effect of O₃ in the MB decoloration. Based on the experiments of the scavenger addition, it could be concluded that O₂⁻ and ¹O₂ were two other important reactive oxygen species (ROS) for the MB decoloration. The results of the higher chemical oxygen demand removal and faster disappearance of the characteristic peak of the MB from the UV–vis analysis under O₂ bubbling conditions also proved the critical effect of the ROS formed by O₂ on the MB decoloration.     

钍基液态燃料熔盐实验堆氙毒分析

熔盐堆作为第四代核能系统堆型之一,液态燃料形态的特点使其可以实现在线处理和在线添料。为了提高中子经济性可以利用在线处理的氦鼓泡法,将氦气通入反应堆一回路,去除堆芯内的裂变气体(如Xe、Kr)。基于钍基熔盐液态堆(Thorium Molten Salt Reactor-Liquid Fuel1,TMSR-LF1)概念设计,结合熔盐实验堆(Molten Salt Reactor Experiment,MSRE)氙毒模型,分析了鼓泡法去除氙毒中~(135)Xe扩散规律和去除效率对氙毒的影响,并给出了对应的初始有效增殖因子的变化规律。分析结果表明,虽然存在~(135)Xe会大量向石墨扩散的可能性,但是鼓泡法仍然可以有效去除TMSR-LF1堆芯内的~(135)Xe,减小堆芯毒性,提高反应性。     

Decontamination factors and release rates of UO2 particles from boiling pools of sodium

A semi-mechanistic model for calculating solid radionuclide release rates from boiling or bubbling pools of sodium was developed. The influence of particle spacial and size distributions on the decontamination of the releases was analysed and found significant. Decontamination factors are shown as a function of pool depth, bubbling characteristics and particle size distribution. The calculation of a decontamination factor for estimating the source term of large scale hypothetical core disruptive accidents is presented. The decontamination factor for a large scale accident was found to be two orders of magnitude greater than results obtained from small scale experiments conducted with uniform particle distributions.     

Dissolved oxygen control and monitoring implementation in the liquid lead-bismuth eutectic loop: HELIOS

A 12 m tall LBE coolant loop, named as HELIOS, has been developed by thermal-hydraulic scaling of the PEACER-300MWe. Thermo-hydraulic experiment and materials test are the principal purposes of HELIOS operation. In this study, an yttria stabilized zirconia (YSZ) based oxygen sensor that was hermetically sealed for long-term applications using the electromagnetically swaged metal-ceramic joining method, have been developed for high temperature oxygen control application over a long period of time. The rugged electrode design has been calibrated to absolute metal-oxide equilibrium by using a first principle of detecting pure metal-oxide transition using electrochemical impedance spectroscopy (EIS). During the materials tests in HELIOS, dissolved oxygen concentration was administered at the intended condition of 10⁻⁶ wt% by direct gas bubbling with Ar + 4%H₂, Ar + 5%O₂ and/or pure Ar while corrosion tests were conducted for up to 1000 h with inspection after each 333 h. During the total 1000 h corrosion test, oxygen concentration was measured by oxygen sensor. The result confirmed that the direct gas bubbling method is a viable and practical option for controlling oxygen concentration in large loops including HELIOS.     

高温气冷堆备用停堆装置新型供料器分析与试验

吸收球停堆装置参与球床型高温气冷堆的堆芯反应性调节控制,实现反应堆冷停堆,供料器是数百万个6 mm吸收球从堆芯反射层被气力输送回到贮球罐的起点,吸收球在供料器中被气流悬浮、加速,需研究不同结构型式的供料器的输送性能及可靠性.利用Fluent软件对新型流化管式供料器进行了数值模拟分析,获得速度、压力分布场,同时进行了空气介质常温流动供料器试验研究.模拟计算得到供料器局部阻力系数约为5.1,试验测得供料器局部阻力系数为5.7,结果在工程应用可接受的范围内.     

Flow Transition Characteristics in 5×5 Rod Bundle Channel

The special geometric structure of the rod bundle channel can induce complicated flow transition of the coolant, and investigation on the flow transition rules is sufficiently important. In the current study, experimental and numerical study on the flow transition characteristics in the 5×5 rod bundle channel was carried out. Experiments were performed to obtain the variation characteristics of the resistance coefficient and CFD simulation was performed using different turbulence models in ANSYS Fluent. The results show that the simulation with SST k-ω turbulence model agrees well with the experimental data. The simulated turbulence intensity and resistance coefficient at different measurement locations and in different flow conditions were compared. For different subchannels, the turbulence intensity and the resistance coefficient are higher in the center subchannel than those in the edge subchannel. For the same subchannel, the turbulence intensity and the shear stress in the subchannel center are higher than those in the subchannel edge. This result indicates that the turbulence intensity, shear stress and resistance coefficient in the rod bundle are not uniform due to the influence of the wall surface. This non-uniform spatial interaction makes the transition point obscure.     

5×5棒束通道内流动转捩特性研究

棒束通道的特殊结构导致其内部流动转捩情况较为复杂，探究其内部流动转捩规律具有重要意义。本文针对棒束通道内的流动转捩特性开展实验与CFD模拟研究，通过实验获得了棒束通道内沿程阻力系数的变化规律；采用不同湍流模型进行了数值模拟。结果表明，SST k-ω模型能较好地反映实验结果。进一步对比了不同雷诺数工况下通道内不同位置的沿程阻力系数与湍流强度，发现对于不同子通道，中心子通道湍流强度与沿程阻力系数高于边角子通道；对于同一子通道，子通道中心处湍流强度与壁面切应力高于子通道边缘处。这一结果说明，受壁面影响，棒束内湍流强度、壁面切应力、阻力特性具有不均匀性，这些空间上的不均匀性相互作用会引起总体上棒束转捩点不明显。     

Bubble-induced circulation and associated boundary heat transfer

The mechanism of heat transfer from a bubbling liquid pool to an inclined side wall is considered. The process is relevant to the question of Mark-I liner melt-through due to contact with a high-temperature melt of reactor core materials, the bubbling being due to the decomposition of the concrete floor. We demonstrate experimentally that the recirculation caused by the two-phase lift creates a single-phase (liquid) boundary-layer flow along the inclined boundary which is responsible for heat transfer. An initial attempt to analytically quantify this process is also presented.