HTR-10放射性石墨粉尘取样回路中过滤元件的效率研究

10MW高温气冷实验堆(HTR-10)中石墨构件摩擦磨损不可避免地会产生石墨粉尘,其上可吸附固体裂变核素,可能影响反应堆安全正常运行。为研究石墨粉尘的粒径分布、微观形貌以及其表面的吸附特性,在HTR-10一回路氦净化系统入口建造了配置高性能烧结金属粉末过滤元件的放射性石墨粉尘取样回路。为对放射性石墨粉尘的取样过滤结果进行研究,首先对过滤元件的过滤机理、压降特征以及过滤效率进行分析。设计并搭建实验装置对烧结金属粉末过滤元件的过滤效率进行测量,实验结果表明过滤元件能去除气流中的大部分粉尘,实现对HTR-10一回路氦气中放射性石墨粉尘等悬浮物的高效过滤取样。     

10MW高温气冷堆一回路放射性裂变产物活度测量实验及分析

对10MW高温气冷堆（HTR-10）一回路氦气中放射性裂变产物的组成及活度水平的准确测量，可用以分析研究HTR-10燃料元件释放裂变产物的特征，并可用以推知堆芯所有燃料元件中铀污染水平和燃料颗粒的整体破损率水平，从而可得到HTR-10辐射安全性的直接验证。本工作通过对取样罐氦气中惰性气体核素活度的分析，推测HTR-10一回路活度，并与程序计算值进行了比较。实验测到了^85mKr、⁸⁷Kr、⁸⁸Kr、¹³³Xe、¹³⁵Xe、^135mXe、¹³⁸Xe、⁸⁸Rb、¹³⁸Cs等核素。通过实验测量可推知，燃料元件石墨孔隙中的铀污染份额低于5.7×10^－7。     

HTR-10一回路冷却剂中氚活度的测量

详细介绍了测量10 MW高温气冷试验堆一回路冷却剂中氚活度的方法。设计适用于HTR-10特点的氚收集装置,先后两次收集冷却剂中的氚,制成液样进而用液闪法进行测量,并根据试验结果推算HTR-10一回路冷却剂中氚的总活度。针对两次试验结果进行分析并与理论计算值相比较,验证了理论计算的正确性并由此进一步证明高温气冷堆的燃料包覆颗粒对放射性产物的阻挡作用完好,反应堆对环境的氚释放完全在设计要求范围内,符合相应的国家标准。     

10MW高温气冷堆气体采样分析系统研究

10MW高温气冷堆的氦气净化系统由氧化铜床、分子筛床、低温吸附器等主要净化设备及其它辅助设备组成,气体采样分析系统由气相色谱仪,湿度计、红外分析仪组成。在投入HTR-10使用中,其湿度计和红外分析仪均能达到设计要求,实现了对反应堆一回路氦气中H2O,CO,CO2的连续监测。其气相色谱仪满足设计要求．实现了对反应堆一回路氦气中H2,O2、N2、CH4、CO、CO2的间歇取样分析。     

HTR-10产生石墨粉尘量的估算及其尺寸分布

在10MW高温气冷堆(HTR-10)中,由于石墨构件的磨损会产生石墨粉尘,将影响反应堆的正常运行,石墨粉尘的产生主要来自堆芯、卸料管和装料管3个部位。本文在石墨磨损试验的基础上,保守地估算了HTR-10在正常运行工况下石墨粉尘的产生量(大约为2．74kg／年)。通过质量加权平均,给出了石墨粉尘的体积、面积和直径分布函数。     

HTR-10氦气流中石墨颗粒尺寸的估计

清华大学10MW高温气冷堆（HTR-10）采用石墨结构材料和石墨燃料元件，以及氦气冷却剂。由于结构部件的摩擦和磨损，反应堆一回路氦气流动中不可避免的带有石墨粉尘，这是反应堆设计中必须加以考虑的重要问题之一。本文根据凝并理论和颗粒学中的离散-分区模型（Discrete-Sectional Model,DSM），建立了一种颗粒成长的计算方法，并对其进行了验证；同时运用该方法研究了HTR-10氦气流中石墨颗粒的发展情况，给出了氦气流中石墨颗粒在反应堆正常运行时的尺寸分布，并计算出石墨颗粒直径主要分布于10～20um，平均直径为12.9um。     

HTR-10余热排出系统的建模计算及试验验证

高温气冷堆的余热排出系统为非能动式系统,是一回路舱室冷却系统的组成部分之一。本文建立了10 MW高温气冷实验堆（HTR-10）余热排出系统在反应堆舱室内结构的三维模型,模拟HTR-10运行过程中余热排出系统的工作状况。在HTR-10上进行余热排出系统试验,获得了HTR-10在最高热功率为3 MW条件下余热排出系统的相关数据。将试验数据与模拟结果进行比对,结果表明：模拟结果与试验数据存在偏差。通过分析,提出从模型设计、工况适应性两方面对模型进行优化。     

10MW高温气冷堆氦气流中石墨粉尘的凝并发展

在10MW高温气冷堆中，因球形燃料元件的循环等多种因素，石墨构件摩擦磨损而产生石墨粉尘的现象不可避免。石墨粉尘的粒度很小（约1μm），它在氦气的携带下将在一回路内流动。颗粒的布朗运动使石墨粉尘在流动过程中彼此碰撞而出现石墨粉尘的凝并现象，由此改变了石墨粉尘的粒度分布。本工作采用离散 分区模型，针对10MW高温气冷堆，计算了石墨粉尘在氦气流中的碰撞与凝并状况。计算结果表明，在10MW高温气冷堆中，石墨粉尘的凝并现象不严重。     

高温气冷堆主氦风机惰转特性研究

高温气冷堆主氦风机与压水堆主泵一样,均为反应堆一回路的关键设备.在反应堆正常工况下,两者具有相同的功能要求,但在事故工况时,因反应堆的运行特性不同,其功能要求各异.目前,对压水堆主泵的惰转特性已有大量的实验研究和实际运行结果,但有关主氦风机惰转特性的实验研究与理论研究还很缺乏.本文结合风机的气动特性与高温气冷堆一回路的阻力特性,从理论上研究高温气冷堆主氦风机的惰转特性,建立主氦风机惰转时的流量与转速的预测公式,并给出其数值预测结果,为高温气冷堆设计的初步安全分析提供依据.     

10MW高温气冷实验堆乏燃料元件贮存中放射性裂变产物的安全分析

高温气冷堆乏燃料元件的放射性裂变产物绝大部分滞留在燃料元件中。10MW高温气冷实验堆在设计寿命内将卸出约9万个乏燃料元件，其放射性裂变产物的活度高达1.9×1017Bq，因此正确实施乏燃料元件的贮存，减少放射性裂变产物向环境中释放和进行有效的屏蔽是极其重要的。本文根据乏燃料元件中放射性裂变产物的计算结果和德国高温气冷堆乏燃料元件贮存的经验．对我国10MW高温气冷堆乏燃料元件贮存中放射性裂变产物进行了安全分析。     

The design and thermohydraulics study of the HTR-10 High Temperature Helium Experimental Loop

A High Temperature Helium Experimental Loop (HTHEL) for the purpose of studying the transportation and deposition behavior of solid fission products in high-temperature helium coming from the steam generator (SG) in the 10 MW High Temperature Gas-cooled Test Reactor (HTR-10) is studied and designed. Through the optimal design based on thermohydraulics analysis, the three-sleeve structure of deposition sampling device (DSD) could realize full-length temperature control evenly and simulate the physical environment of the heat transfer tube of SG in the HTR-10 in the sense of thermohydraulics, which could be used to study the original source term in the primary circuit. The simulation of the graphite dust particle trajectories in the DSD are shown and it is elucidated that DSD could also be used to study the behavior of graphite dust in the high temperature helium in the SG of HTR, which will provide deeper understanding for the analysis of source terms of HTR-10.     

HTR-10中石墨粉尘在热气导管中的沉积

分析了10Mw高温气冷堆(HTR-10)中的石墨粉尘在热气导管中的沉积情况,得到了石墨粉尘在热气导管中的沉积率.在分析计算中,考虑了石墨粉尘在热气导管中的紊流沉积和热泳沉积.计算结果发现,石墨粉尘在热气导管中的沉积量非常小,其主要原因是氦气的流速较高.     

10MW高温气冷实验堆氦气安全阀的设计与性能试验

10MW高温气冷实验堆(HTR-10)一回路安全泄放系统安装了两台核一级氦气安全阀，对反应堆一回路进行超压保护，是保证HTR-10安全的重要设备之一。本文介绍了氦气安全阀的设计要求、结构特点及性能要求，并按相关规范要求对其性能进行了实验验证。结果表明，安全阀的性能满足设计要求。     

Fission product release and its environment impact for normal reactor operations and for relevant accidents

The radioactive concentration in the primary loop and the radioactive release for both normal operations and accidents for the HTR-10 are calculated and presented in the paper. The coated-particle fuel is used in the HTR-10, which has good performance of retaining fission products. Therefore the radioactive concentration in the primary loop of the HTR-10 is very low, and the amount of radioactive release to the environment is also very small for both normal operation and accident conditions. The radiation doses to the public caused by radioactive release for both normal operations and accidents are given in the paper. The results show that the maximum individual effective dose to the public due to the release of airborne radioactivity during normal operations is only 1.4×10⁻⁴ mSv a⁻¹, which is much lower than the dose limit (1 mSv a⁻¹) stipulated by Chinese National Standard GB8703-86. For depressurization accident and water ingress accident, the maximum individual whole-body doses to man are only 7.7×10⁻² and 2.0×10⁻¹ mSv, thyroid doses only 1.7×10⁻¹ and 1.1 mSv, respectively. They are much lower than the prescribed minimum of emergency intervention level (whole-body dose: 5 mSv, thyroid dose: 50 mSv) for sheltering measures stipulated by the Chinese Nuclear Safety Criterion HAD002/03. The conclusion is that the environmental impact is very small for normal operations and accidents for the HTR-10, and the requirements stipulated in the Chinese Nuclear Safety Criterions are satisfied perfectly.     

10MW高温气冷堆蒸汽发生器传热管束应力分析

10MW高温气冷堆蒸汽发生器（SG）传热管是带放射性的一回路与无放射性的给水蒸汽二回路的屏障。管束的破裂将会引起二回路的水蒸汽进入一回路,从而导致堆芯压力的升高和放射性产物的外泄,因此确保传热管的完整性是十分必要的。传热管的结构采用小弯曲半径的螺旋管结构,对于这种无法进行体积性在役检查的螺旋管,利用破前漏思想确保传热管的完整性是一个重要的选择。本文利用管道有限元程序PIPESTRESS对高温气冷堆蒸汽发生器传热管的应力进行了计算,得到了传热管的最大应力和应力与材料的不利组合位置。     

氦气试验回路中的氦净化

为了减少结构材料的腐蚀并验证高温气冷实验堆中的氦净化工艺，在氦气试验回路中设置了氦净化系统并进行了试验。试验结果表明，净化流量为５０ｍ＾３／ｈ的主要由分子筛和深活性炭床组成的氦净化系统，能把氦中２００００ｃｍ＾３／ｍ＾３的化学杂质净化到７６ｃｍ＾３／ｍ＾３以下。所采用的氦中痕量杂质分析测量技术达到１０＾－１ｃｍ＾３／ｍ＾３精度。     

The experimental study on the helium circulator of HTR-10

The helium circulator is a key component of 10 MW high temperature gas-cooled reactor (HTR-10), which has the helium coolant circulate inside the primary loop of the reactor. Before delivery, the performance experiment of the circulator was carried out in the factory at 0.426 MPa, 250 °C nitrogen condition. In the paper, by using dimensional methodology, the experiment results are converted to those on 3.0 MPa, 250 °C helium condition which is real working condition on the reactor. Then the circulator performances are analyzed. Finally, the operating performances on HTR-10 are predicted. The paper concludes that the circulator design was made correctly and the performances are satisfied with HTR-10 operating requirements.     

Model of particle resuspension in turbulent flows

The graphite dust generated in an HTR/PBMR during normal reactor operation is deposited inside the primary system and becomes radioactive due to sorption of fission products. A significant amount of radioactive dust may be resuspended and released to the environment in case of LOCA. Therefore accurate particle resuspension models are required for HTR/PBMR safety analyses.Thermal-hydraulic safety analyses of HTR/PBMR type reactors are typically performed using computer codes such as FLOWNEX, MELCOR, or SPECTRA. None of these codes currently includes a well-tested mechanistic resuspension model.The resuspension model based on the Vainshtein model has been developed and implemented into the SPECTRA thermal-hydraulic system code. The resuspension model formulation has been extended in such way that other formulations, for example the Rock’n Roll model, may easily be defined and used within the general model framework.Several test calculations were performed, including comparisons of the numerical SPECTRA results with the analytical solutions obtained by means of MathCAD. Furthermore, comparisons with the experimental results of the Reeks and Hall, and STORM experiments were made. It was concluded that the model gives satisfactory results for a number of tests.