PDS-XADS散裂靶热工水力分析

本文对小型加速器驱动的次临界系统（ADS）--PDS-XADS散裂靶进行了热工水力分析。分析的XADS型实验堆基于欧洲PDS-XADS实验项目的设计,使用铅铋合金（LBE）作为冷却剂。散裂靶是ADS的核心部件之一,用以确保反应堆功率维持在指定水平。本文利用计算流体力学软件ANSYS CFX 11.0对散裂靶的下部区域进行热工水力分析。分析采用稳态计算、剪切应力输运（SST）湍流模型,在壁面边界条件处采用自动壁面函数法,针对不同的散裂靶设计进行计算流体力学（CFD）分析,最后根据散裂靶设计限值选择最优设计方案。     

加速器驱动的次临界系统散裂靶泄漏中子谱研究

为研究加速器驱动的次临界系统（ADS）散裂靶的散裂中子学特性,采用Geant4计算不同能量质子轰击铅铋靶产生的泄漏中子产额、能谱、轴向积分分布。模拟得到1 GeV质子对应的靶的优化尺寸及优化后泄漏中子谱,计算结果可为ADS散裂靶件和堆芯设计提供参考。     

ADS熔盐散裂靶中子学性能研究

与传统加速器驱动次临界系统（ADS）采用金属靶作为散裂中子靶的设计不同,加速器驱动次临界熔盐堆（AD-MSRs）采用靶堆一体的设计,直接使用燃料熔盐作为散裂中子靶。由于熔盐靶的中子学性能直接影响AD MSRs的能量放大系数、核废物的嬗变和核燃料增殖的效率,所以本研究基于MCNPX程序,详细计算了高能质子轰击氟盐和氯盐两种熔盐靶产生的散裂中子产额、散裂中子能谱、能量沉积分布以及散裂产物等中子学性能,并与液态Pb和铅铋共熔体（LBE）两种液态金属靶进行了对比。计算结果表明,熔盐靶在散裂中子产额上与液态金属靶有一定的差距,但熔盐靶内能量沉积分布的梯度较小,更有利于靶区的热量导出。与液态Pb和LBE靶相比,熔盐靶的散裂产物中包含更多的气体以及高质量数的α发射体核素。     

周期法测量启明星Ⅱ号散裂靶材料的反应性价值

为验证理论计算程序及相关核数据,将固体散裂靶材料放入ADS启明星Ⅱ号零功率装置（启明星Ⅱ号）的靶区内,采用周期法测量靶区内有、无散裂靶材料的反应性,从而获得净散裂靶材料对应的反应性价值,并与理论计算结果进行比较。结果表明,反应性价值的实验测量结果与理论计算结果符合较好,验证了理论计算的正确性。经实验验证的理论计算程序和核数据可用于ADS次临界反应堆的设计。     

铅散裂中子靶物理特性研究

利用蒙卡程序DCM/CEM对ADS标准散裂中子靶进行了计算。计算了长0.6 m,直径0.2 m的圆柱形208Pb靶,在0.1～1.6 GeV的质子轰击下,Pb靶发生散裂反应产生的中子产额及表面的中子注量、能谱分布以及靶内能量沉积分布,解释了以前的实验结果。计算结果与文献数据、实验数据进行了比较,符合良好,对进一步进行ADS堆芯设计具有较好的理论指导意义。     

ADS熔盐散裂靶中子学性能研究

与传统加速器驱动次临界系统(ADS)采用金属靶作为散裂中子靶的设计不同,加速器驱动次临界熔盐堆(AD-MSRs)采用靶堆一体的设计,直接使用燃料熔盐作为散裂中子靶。由于熔盐靶的中子学性能直接影响AD-MSRs的能量放大系数、核废物的嬗变和核燃料增殖的效率,所以本研究基于MCNPX程序,详细计算了高能质子轰击氟盐和氯盐两种熔盐靶产生的散裂中子产额、散裂中子能谱、能量沉积分布以及散裂产物等中子学性能,并与液态Pb和铅铋共熔体(LBE)两种液态金属靶进行了对比。计算结果表明,熔盐靶在散裂中子产额上与液态金属靶有一定的差距,但熔盐靶内能量沉积分布的梯度较小,更有利于靶区的热量导出。与液态Pb和LBE靶相比,熔盐靶的散裂产物中包含更多的气体以及高质量数的α发射体核素。     

加速器驱动系统靶区流场的数值模拟

在加速器驱动系统（ADS）中,真空质子束流管出口端为一半球面质子束窗,用于隔离束流管和散裂靶。质子束窗表面热负荷很高,有效冷却质子束窗,从而提高靶件寿命和系统安全性是靶件设计的关键。 采用PHOENICS 3.2程序对ADS靶件冷态下的流场进行数值模拟。在贴体坐标（BFC）下生成计算网格,对靶件束窗下方有无导流板时的靶区流场进行了计算。当体积流量为10m3/h时,流体向下流动进入中央流道（靶区）之前发生边界层脱离,并在质子束窗下方两侧形成一对对称的旋涡。两旋涡在靶区中央重叠,形成一股向上较强的回流。这股回流沿质子束窗     

颗粒流散裂靶缩比模型流态实验研究

散裂靶是加速器驱动次临界系统（ADS）的重要组成部分,颗粒流散裂靶是最新提出并经理论计算的一种高功率散裂靶,研究其颗粒流的流动特性对散裂靶的设计优化有重要意义。本文以螺旋提升机为颗粒流驱动装置,搭建一套颗粒流循环回路系统,研究了倾斜段管道的倾斜角度对三维颗粒流从堵塞流向密集流转变的影响。研究发现,随着螺旋提升机提升频率的增加（即颗粒流量的增加）,在散裂靶靶区存在颗粒稀疏流-密集流转变,在靶区附近能形成稳定的密集流。     

基于DEM的重金属颗粒流靶区输运过程研究

基于固体和液体散裂靶,近期国内外研究学者提出了一种新概念重金属颗粒流散裂靶。加速器驱动次临界系统(ADS)中重金属散裂靶在高能质子轰击作用下,出现能量沉积现象,而这些热量必须进行有效冷却以保证ADS的安全性。本文针对这种新概念颗粒流靶对靶区产生的高额热量的导出效果进行了模拟分析。首先采用蒙特卡罗程序计算450 Me V质子束轰击钨靶后能量沉积的空间分布,并将此作为颗粒流的体热源输入,基于计算流体力学-离散单元法(CFD-DEM)耦合方法对ADS靶区两种不同直径颗粒流的输运过程进行了模拟研究。结果表明,随颗粒直径的减小,靶区内温度分布更为均匀,颗粒流的流动特性更接近流体,颗粒导热性能增强;颗粒流靶中热应力可局限在单个颗粒内部而承受更高的能量沉积,具有更高的安全限值以及更广阔的应用前景。     

ADS启明星Ⅱ号散裂靶样品反应性价值测量实验

正工程化ADS反应堆堆芯由散裂靶和金属冷却反应堆堆芯耦合构成,在强外源作用下,存在着强烈的散裂靶与反应堆的耦合效应。根据ADS堆靶耦合的发展需求,在启明星Ⅱ号上设计了不同材料的圆柱型靶材,并开展了散裂靶反应性影响验证实验。靶样品的外包壳为不锈钢,内部可以装入不同的靶材料制成散裂靶,如钨铁镍合金颗粒靶、纯钨靶、纯铅靶等。通过周期法分别给出了不同靶样品的反应性实验测量结果,利用蒙特卡罗程序MONK配合点截面数据库CENDL-3.1给出了不     

Numerical design of a 20 MW lead–bismuth spallation target for an accelerator-driven system

A spallation target system is a key component to be developed for an accelerator-driven system (ADS). It is known that a 15–25 MW spallation target is required for the practical size of an ADS. Although there have been some design studies for small power spallation targets, that is, less than 10 MW, designs of high power target systems for ADS are relatively rare. The design of a 20 MW spallation target is very challenging because more than 60% of the beam power is deposited as heat in a small volume of the target system. In the present work, a numerical design study was performed to get optimal design parameters for a 20 MW spallation target for a 1000 MW ADS. The cylindrical beam tube and the hemispherical beam window were adopted in the basic target design concept with 1 GeV proton energy, and the thermal-hydraulic and the structural analyses were performed with the CFX and ANSYS codes. The beam window diameter and thickness were varied to find the optimal parameter set based on the design criteria: maximum lead–bismuth eutectic (LBE) temperature <500 °C, maximum beam window temperature <600 °C, maximum LBE velocity <2 m/s, and the maximum beam window stress <160 MPa. The results of the present study show that a 40 cm wide proton beam with a uniform beam profile should be adopted for the spallation target of 20 MW power. It was found that a 2.5 mm thick beam window is needed to sustain the mechanical load.     

基于单通道模型的ADS堆芯物理热工耦合计算

利用单通道模型,开发了铅铋冷却加速器驱动次临界系统(ADS)堆芯组件温度和密度分布的热工计算程序,并将该程序与MCNP耦合,建立了物理热工耦合计算方法。利用该方法计算了耦合后的功率及热工参数。结果表明,堆芯组件温度及冷却剂流速满足热工安全限值,堆芯径向功率不均匀系数较大,堆芯设计需进一步优化。     

Design and corrosion study of a closed spallation target module of an accelerator-driven system (ADS)

At the Forschungszentrum Karlsruhe (FZK) the characteristics of an accelerator-driven subcritical reactor system (ADS) are critically evaluated, mainly with respect to the potential of transmutation of minor actinides and long-lived fission products, to the feasibility and to safety aspects. The work is concentrating on system design, neutronics, thermalhydraulics, safety, materials and corrosion. This article describes the FZK approach to design a closed 4 MW(th) spallation target module with a solid beam window and eutectic lead–bismuth (Pb–Bi) as spallation material and cooling fluid, which is going to be implemented in the FZK three-beam concept of an ADS. This multi-beam concept shows significant improvements towards single-beam concepts from the literature with respect to power distribution in the subcritical blanket and thermal loads of heat removal from the beam window and the spallation region. For some selected martensitic and austenitic steels, corrosion tests in static lead are performed to examine their suitability as structural or window materials. Alloying aluminum into the surface layer by high-power electron beam treatment, corrosion can be reduced to nearly zero. One prerequisite to minimize corrosion is a proper oxygen control system (OCS) via the gas-phase to set the oxygen concentration in the liquid Pb–Bi. The dynamic behaviour of this oxygen control system is described. Finally, the KArlsruhe Lead LAboratory (KALLA) is introduced, the objectives of which are technological, thermal-hydraulic and corrosion investigations into the beam window, the spallation target module and the primary system of an ADS.     

Numerical design of a 20 MW lead–bismuth spallation target with an injection tube

A spallation target system is a key component to be developed for an accelerator driven system (ADS). It is known that a 15–25 MW spallation target is required for a practical 1000 MW_th ADS. The design of a 20 MW spallation target is very challenging because more than 60% of the beam power is deposited as heat in a small volume of the target system. In the present work, a numerical design study was performed to obtain the optimal design parameters for a 20 MW spallation target for a 1000 MW_th ADS. A dual injection tube was proposed for a reduction of the lead–bismuth eutectic (LBE) flow rate at the target channel. The results of the present study show that a 30 cm wide proton beam with a uniform beam distribution should be adopted for a spallation target of a 20 MW power. When the dual LBE injection tube is employed, the LBE flow rate could be reduced by a factor of 7 without reducing the allowable beam current.     

可用一台ADS验证装置的150 MeV固态金属散裂中子靶的性质研究

对可以用于中国“加速器驱动洁净核能系统”的入射质子能量为150MeV,束流为3 mA的固态金属靶进行了研究。采用锥型几何结构作为靶的结构,材料选择钨,靶厚度为3 mm,对“靶-束窗”一体化结构进行了研究。研究了泄露中子产额和中子产额,泄露中子的能谱分布和空间分布,散裂碎片的分布以及能量沉积和辐射损伤。     

基于水工质的有窗散裂靶流场分析及实验测量

散裂靶是加速器驱动的次临界系统(ADS)的重要组成部分,有窗散裂靶是唯一经实验验证、测量的液态金属高功率散裂靶,研究有窗靶内工质的流动对散裂靶的设计优化有重要意义。本文以水为工质对有窗靶件进行了可视化实验及数值模拟研究,实验采用粒子图像测速法对靶件可视化部分进行速度场测量,同时利用计算流体力学软件FLUENT对靶件流场进行数值模拟。通过5种湍流模型（标准k-ε模型、RNG k-ε模型、Realk-ε模型、SST k-ω模型、RSM模型）在不同流速下的模拟结果与实验结果的对比分析,表明采用RNG k-ε模型并结合相应的壁面函数能较准确模拟有窗靶内的流动。     

ADS散裂靶件内部自由界面形态的数值模型分析

加速器驱动的次临界系统（ADS）内部的散裂靶件通过加速器装置耦合次临界堆芯。无窗靶件的设计需保证自由界面有着稳定且理想的形状，以避免液态重金属局部过热。为研究无窗靶件内部自由界面的形态，本工作基于开源CFD计算平台OpenFOAM，使用VOF（volumeoffluid）方法追踪自由界面，对无窗靶件内部自由界面的形态和特性进行数值模拟，并将结果与商用软件FLUENT计算结果和实验结果进行对比。同时比较多种湍流模型对计算的影响，推荐出较合适的湍流模型。     

Feasibility of uranium spallation target in accelerator-driven system

A feasibility study on natural uranium spallation target in accelerator-driven system (ADS) for minor actinide (MA) transmutation was performed. As a result of comparative study of uranium and lead-bismuth (PbBi) targets in the bare case without blanket surrounding, it was found that uranium target had better neutron generation performance, but limited by the geometrical size due to high neutron absorption in ²³⁸U. In ADS for MA transmutation, uranium used as target instead of PbBi also absorbs neutrons passing the target area.More realistic concept of pin type uranium spallation target cooled by liquid PbBi was considered aiming at enhancing spallation target performance in terms of neutron generation efficiency and operation temperature. The uranium pin target design had nothing better effects on neutron balance of such system than a conventional PbBi target in ADS and it was concluded that uranium target was not suitable for the full-scale ADS.     

ADS散裂靶产生的放射性毒性

利用SHIELD程序计算不同能量质子照射不同靶产生的散裂产物分布。采用年摄入量限值(ALI)标准定义的放射性毒性，对散裂靶中散裂产物产生的放射性毒性进行研究分析。研究结果表明：散裂产物具有较大的毒性，特别是在加速器驱动的次临界系统(ADS)要求的入射粒子(质子)能量下，产生了一些处于稀土区长寿命的α放射性核素。这些核素若不能在辐射场中被嬗变掉，其毒性将对生物环境产生长期的影响。