手套箱气氛中氚化水处理的工艺研究

分子筛吸附柱和热金属镁床是手套箱气氛中氚化水 (HTO)搜集和分解处理的一种有效手段。测试了分子筛柱对气氛中水的吸附性能和热金属镁床对HTO的分解性能。结果表明 :分子筛柱对气氛中水的吸附效率 >99 99% ,在空气中水含量为 3 4× 1 0 - 3～ 4 2× 1 0 - 3条件下 ,未发现吸附柱水的贯穿现象 ;热金属镁床对HTO的分解率 >99 9% ,当金属镁的消耗量大于 80 %时 ,未见分解率明显降低。     

被动式氚取样器性能的实验研究

介绍了核设施工作场所和环境空气中氚化水蒸气HTO的监测,被动式氚取样器在国外已经得到非常广泛的应用,所研制的被动式氚取样器,特别适用于7－30d的长期取样,给出该取样周期内空气中HTO浓度的平均值。     

被动式氚取样器性能的实验研究

目前被动式氘取样器在国外取得了广泛的应用,它是基于气体分子扩散或渗透原理采集空气中氘化水蒸汽（HTO）样品的一种方法。本文对被动式氘取样的工作原理从理论上进行了分析,用水所模拟实验测定了液闪计数瓶顶盖孔板直径分别为Φ2－10mm的几种取样器的扩散系数和等效取样流量,并在现场进行了初步应用。     

新型氚蒸馏装置的研制及性能验证

为提高硅胶吸附法监测环境空气中氚的样品前处理效率,采用铸铝加热方式结合温度自动控制技术,研制了一种用于环境硅胶样品自动化氚水蒸馏的装置。经实验验证,该装置选择250℃的加热温度,15 min的蒸馏冷凝收集时间为硅胶吸附氚化水的最佳解析条件,此时对硅胶中氚化水的平均回收率大于99%,氚记忆效应小于0.2‰,100 g饱和硅胶样品能解析水7～10 ml,满足液闪测量要求,研制的氚水蒸馏装置较以往装置蒸馏效率提高了近3倍,能耗减少约77%。     

反应堆退役废物中氚含量的测定方法研究

本文介绍了反应堆退役废物如不锈钢、碳钢锈垢、合金铝和水池底泥固体样品介质中氚含量的测定方法。建立了高温加湿解析、催化氧化、鼓泡器收集的分析方法，并对该方法中有关参数的确定及测量结果的准确性进行了讨论。     

氚污染金属手套箱退役技术研究

为减少氚污染金属手套箱退役解体过程中氚的二次释放,降低工作人员的辐射危害,减少退役中产生的氚污染废物量,本文针对退役氚污染金属手套箱的解体,设计了氚污染金属手套箱退役解体技术方案,即解体前对氚污染金属手套箱进行初步去污,解体中采用合适的切割技术和相应的防护措施。利用氚污染金属手套箱对该解体方案进行了验证,结果表明,设计的解体方案满足氚污染金属手套箱退役需要。     

氚废气的回收技术研究

采用了高温催化氧化法处理含氚废气。处理过程如下:在干燥氩气(含少量H2)的载带下,含氚废气通过高温催化氧化床转化为氚水,然后用蒸馏水或合适的干燥剂吸收。在400℃,氧化床穿透之前,Hopcalite氧化剂对H2的氧化效率接近100%;在500℃,Hopcalite氧化床对HT的氧化效率大于99%。实验测定了回收氚的分子筛在存放过程中,不同规格分子筛的氚释放系数以及存放条件与释放系数的关系。结果表明,3种分子筛在吸收氚水后的氚释放系数为(1.9～5.5)×10-6d-1·g-1。其中,4A钠型分子筛的氚释放系数最小,5A钙型分子筛的氚释放系数最大;3种分子筛在吸收氚水后释放的氚的化学形式绝大部分是氚化水(HTO),氚气(HT)含量不超过1.2%;含氚分子筛的贮存气氛对氚的再释放有一定影响,在纯氩气中氚释放系数比在含2%氢的氩气中的低。     

分子筛床对氚化水气体过滤效能的研究

为了准确掌握分子筛床在现场的实际防护效果,需要进行含氚(氚化水,HTO)空气穿透实验。将露点一定、氚浓度一定的普通氮气以稳定的流速通过分子筛床,并连续测量气体通过分子筛床前后氚浓度的变化和分子筛床穿透前后的质量变化,从而确定分子筛床在现场实际环境中的防氚效果。实验结果表明,无水分子筛床的氚化水吸附效果最好,4 h之内的过滤效率保持在95%以上,过滤效率高,使用时间长;1/3吸水的分子筛床的吸附效果较好,3 h之内过滤效率保持在90%以上。综合考虑使用舒适度和过滤效能,1/3吸水的分子筛床更适合用于现场的实际氚防护。     

TBM TES手套箱泄漏事故下氚浓度与通风关系研究

为了分析TBM TES室内通风是否能在手套箱发生氚泄漏时控制室内氚浓度在安全剂量值,采用Fluent对手套箱的氚泄漏和扩散进行模拟,得到不同通风下手套箱泄漏时的氚泄漏速率以及室内氚浓度分布,并对比分析了模拟数据与理论数据。结果表明TES手套箱泄漏速率为1.41×10~(-5)g/s和1.02×10~(-5)g/s时,分别为5次/h和8次/h的换气通风能控制室内氚浓度在安全剂量值2.0×10~(10)Bq/m~3内;而氚泄漏速率为1.56×10~(-5)g/s时,3次/h的换气通风不能控制室内氚浓度在安全剂量值内;模拟结果与理论结果相一致。结果为TES通风除氚设计提供了理论依据。     

高压氘氚气氛下不锈钢吸附氚的初步研究

本工作对于氚在不锈钢表面的吸附和解吸行为进行了初步研究.样品在n(D)∶n(T)=1∶1,230℃时,15 MPa下恒温8 h后,接着在27 MPa下恒温6 h的情况下进行了氚的吸附,测量了室温下和加热到1173 K时的解吸氚量和总吸附量.其结果如下:不锈钢的总吸附氚量是857.4 MBq·cm-2,不锈钢的解吸氚量是722.2 MBq·cm-2;在本实验的条件下,在室温和加热条件下,不锈钢所释放的氚中,化学成分主要是HTO和HT两部分,大部分以HT形式存在;不锈钢的自由氚占吸附总氚量的7.34%;不锈钢的热解吸谱存在三个解吸峰,其解吸温度分别为439、530和843K.     

Penetration of tritiated water vapor through hydrophobic paints for concrete materials

Behavior of tritium transfer through hydrophobic paints of epoxy and acrylic-silicon resin was investigated experimentally. The amounts of tritium permeating through their paint membranes were measured under the HTO concentration condition of 2–96 Bq/cm³. Most of tritium permeated through the paints as a molecular form of HTO at room temperature. The rate of tritium permeating through the acrylic-silicon paint was correlated in terms of a linear sorption/release model, and that through the epoxy paint was controlled by a diffusion model. Although effective diffusivity estimated by a diffusion model was obtained 1.1 × 10⁻¹³–1.8 × 10⁻¹³ m²/s for epoxy membranes at the temperature of 21–26 °C, its value was found to be hundreds times larger than that for cement-paste coated with epoxy paint. Hence, resistance of tritium diffusion through interface between cement-paste and the epoxy paint was considered to be the most effective in the overall tritium transfer process. Clarification of tritium transfer behavior at the interface is important to understand the mechanism of tritium transfer in concrete walls coated with various paints.     

Investigation on hydrogen absorption/desorption properties of as-cast La(1-x)MgxNi4.25Al0.75 (x =0.0, 0.1, 0.2, 0.3) alloys for tritium storage

La_((1-x))Mg_xNi_(4.25)Al_(0.75)(x = 0.0, 0.1, 0.2, 0.3)alloys for tritium storage were prepared by a method of electromagnetic induction melting. The crystal structure and hydrogen storage performance of the as-cast alloys were investigated. The results showed that a single phase of La Ni_4Al was in the alloys with x = 0.0 and 0.1 and that LaNi_4Al and second phase of(La,Mg)Ni)_3 and AlNi_3 were in the alloys with x = 0.2 and 0.3. On the other hand, the plateau pressures of P–C isotherms of the alloys were increased with the rise of the x value from 0.2 to 0.3 and the hydrogen storage capacity was obviously degraded simultaneously. It was found that the alloy had faster absorption kinetics as the proportion of Mg increased from 0.1 to 0.3.     

Enrichment of slightly concentrated tritiated water by electrolysis using a palladium cathode coated on ionic solid polymer membrane—Design and results

In nuclear installations, tritiated water is generally produced in the process of detritiation of air circulating in the glove boxes. The goal of this work concerns enrichment of this tritiated water at low concentration by electrolysis. The choice of this electrolyzer was dictated by the passivity of selected materials to the radiolysis in low-level tritiated water and the selectivity of the method avoiding further elimination of tritiated water and moisture before release in environment. According to the results, it is feasible to treat non-negligible volume of low-level tritiated water using a cathodic palladium membrane coated on an ionic solid polymer membrane. Presence of a palladium black deposit on the palladium membrane improves effectiveness. Enrichment in tritiated water depends on the isotopic separation factor, thereby the current and the permeability values.     

Experimental study on the adsorption and desorption of tritium in the graphite materials for HTR-PM

Tritium behavior in the reactor such as production, diffusion and release are accompanied by their adsorption and desorption in graphite materials, which are essential to the safety of high temperature gas cooled reactor (HTGR). In order to study this important issue, hydrogen instead of tritium is experimentally used in this work and justified viable by theory. By performing multiple sets of comparative experiments, the features of hydrogen adsorption and desorption behavior changing by adsorption temperature and time in typical graphites used in HTR-PM (High Temperature Gas Cooled Reactor – Pebble Bed Module), i.e. reflective layer, fuel element and boron carbon bricks, have been observed and analyzed. Furthermore, the adsorption rates of hydrogen in the three materials as above at different conditions are also given. Based on the experimental results, tritium behavior in the HTR-PM was inferred and estimated, which is significant for the further study on the mechanism of tritium transport.     

一个基于虚拟技术的幅度谱模拟与处理系统

概述了利用Visual C^ 6．0 Windows设计的一个幅度谱的模拟与处理系统。幅度谱的模拟包括：本底分布、峰分布和谱分布,而谱分析处理包括：谱平滑、寻峰、峰判别、扣本底、峰面积、能量刻度和效率刻度等。     

虚拟技术在核谱仿真与处理系统中的应用

介绍了基于图形化编程环境的LabVIEW平台在核谱仿真和处理系统中的应用,该系统具有核谱分布的模拟、平滑处理、寻峰、感兴趣区的计算等一系列功能。     

Catalytic technology for water treatment by micro arc oxidation on Ti-Al alloy

The feasibility of the formation of a liquid plasma catalysis system through micro arc oxidation (MAO) under AC power with titanium-aluminum alloy electrodes was investigated.In the decolorization of organic dyeing wastewater simulated with Rhodamine B,Ti-Al alloy electrodes were superior over Ti electrodes and A1 electrodes.The optimal molar percentage of Ti in alloy electrodes was 70％ and the optimal decolorization rate was up to 88.9％ if the additive suitable for Al was added into the solution to be treated.The decolorization rates were the same in the case of the alloy-alloy electrodes and alloy-A1 electrodes.The proportion of the effects of plasma,TiO2 catalyzer during MAO and H2O2 after MAO in decolorization has been obtained.With the catalysis of TiO2 formed on the electrodes,the reaction rate was improved by a maximum of 95％ and the decolorization rate was improved by a maximum of 71.6％.Based on the spectral analysis,the plasma catalysis mechanism has been studied.     

Investigation on two-phase critical flow for loss-of-coolant accident of pressurized water reactor

The previous investigations were mainly conducted under the condition of low pressure,however,the steam-water specific volume and the interphase evaporation rate in high pressure are much different from those in low pressure,Therefore,the new experimental and theoretical investigation are performed in Xi‘an Jiaotong University.The investigation results could be directly applied to the analysis of loss-of -coolant accident for pressurized water reacor.The system transition characteristics of cold leg and hot leg break loss-of -coolant tests are described for convective circulation test loop.Two types of loss-of-coolant accident are identified for :hot leg” break,while three types for “cold leg”break and the effect parameters on the break geometries.Tests indicate that the mass flow rate with convergent-divergent nozzle reaches the maximum value among the different break sections at the same inlet fluid condition because the fluid separation does not occur.A wall surface cavity nucleation model is developed for prediction of the critical mass flow rate with water flowing in convergentdivergent nozzles.     

加压贮存和活性炭吸附在核电站放射性废气处理中的应用

加压贮存和活性炭吸附是目前国内处理压水堆核电站放射陛废气最常用的两种方法。以大亚湾核电站和田湾核电站的放射性废气处理系统为例,并结合国内其他核电机组同类系统,分别介绍这两种方法在国内核电站的应用情况,并分析它们各自的优缺点：加压贮存系统结构简单但设备体积庞大,适合处理流量变化较大的放射性废气;活性炭吸附具有安全性高,操作简单的特点,适合于处理流量较小的放射性废气。