纯化氢用多孔不锈钢表面的修饰技术

采用浆料涂敷法,将纳米不锈钢粉末沉积在多孔不锈钢载体上,形成孔径依次减小的微孔不锈钢载体,其孔径约为200nm.在压差为0.1MPa时,其干空气渗透率约为200cm3·cm-2·min-1.再经溶胶-凝胶涂敷法,在此载体上沉积TiO2薄膜,其孔径约为100nm,此时的干空气渗透率,在压差为0.1MPa时,约为100cm3·cm-2·min-1.最后经化学镀技术,得到表面较光洁、合金化较完全的钯银合金膜,该膜在压差为0.1MPa、温度为300℃时的渗氢速率在标准状态下达35cm3·cm-2·min-1,氢氦分离因子达500.     

钯催化H2O2分解的机制探讨

高放废物（HLW）处置库近场地下水的辐解能够产生H₂O₂,其被裂变产物合金颗粒（ε-颗粒）的催化分解属于多相表界面反应。本工作选用钯粉模拟ε-颗粒,采用高压反应釜研究体系总压和H₂分压对反应的影响,并按一级动力学模型拟合实验数据。添加HO·的捕获剂和淬灭剂的实验证明无H₂反应过程中存在HO·的生成步骤。钯的催化活性及形态变化与反应时间的关系表明,产物氧吸附在钯的表面对反应具有毒化作用。通过持续监测滤液中H₂O₂浓度的变化,发现溶液中存在类似于Haber-Weiss的反应持续消耗H₂O₂。推导出钯对H₂O₂分解的机制过程和影响因素,为处置库的安全评估提供基础数据。     

氦中痕量杂质气体气相色谱检测分析方法研究

为实现聚变堆氘氚燃料工艺气中痕量杂质气体组分的快速检测分析,需建立特殊的高精度在线气相色谱检测分析方法。以高纯氦作为载气,在不同的色谱柱温度和载气流速控制下,通过分子筛毛细管柱和PLOT-Q柱进行分离,采用放电氦离子化检测器（DID）进行检测,对氦中含量为1、10以及100 ppm的杂质标准气体进行检测分析。结果表明：在柱温为40 ℃、流速为15～20 mL/min实验条件下,分子筛柱在160 s内能够实现H₂、O₂、N₂、CH₄和CO全部分离,且柱效较高,响应值的重复性较好,H₂和O₂之间的分离度高于1.5,实现了完全分离;在柱温为40 ℃、流速为20 mL/min时,PLOT-Q柱分离CO₂组分效果最佳。     

用于氢同位素纯化的Pd-Zr选择渗氢复合膜

为了获得低成本、高渗氢率、长寿命、高强度的选择渗氢膜,耐熔金属锆(zr)被选作复合膜的基体。在真空度为3.0×10-7Pa下,采用离子轰击刻蚀去除其表面氧化层,实验发现在其表面上仍有少量氧化锆的存在。在真空度为6.6×10-6Pa下,采用离子溅射镀膜法,在锆片直径为50 mm、厚度为0.23 mm的双表面上分别镀上了一层厚约400 nm的钯薄膜。采用X射线衍射(XRD)和X射线光电子能谱(XPS)对锆表面及复合膜表面进行了分析。渗氢实验显示这种复合膜的渗氢系数φ为9.917×10-8mol/m·s·Pa1/2(温度623 K,高压侧0.2 MPa,低压侧0.1 MPa),是相同条件下的商用钯银合金膜的6.8倍。研究结果表明,这种Pd-zr选择渗氢复合膜对核燃料和聚变燃料的纯化及反应堆增殖剂中氚的提取具有很大的应用前景。     

碘硫循环中Bunsen反应液-液相分离影响因素的实验研究

Bunsen反应液-液相分离是整个碘硫循环的枢纽,H₂SO₄相与HI_x相分离效果直接影响整个循环系统的热效率。为提高两相分离效果和循环效率,对Bunsen反应平衡时液 液相分离特性进行研究。配制H₂SO₄、HI、I₂、H₂O混合溶液,研究实验条件对溶液分离效果的影响。研究结果表明,当n(H₂O)/n(H₂SO₄)小于18时,分层所需碘量随温度变化不大,之后随着溶液温度升高和水量增大,分层所需碘量明显增加;在提升温度和增加碘量的同时减小水量可有效提高溶液分离效果;增大水量可减小副反应进行程度,随着温度升高,抑制作用越明显。通过实验研究最终得到较好的分离条件。     

Ni掺杂对金属V抗毒化性能的影响

采用磁悬浮感应熔炼法制备VNi_0.01合金,完全活化后,在含0.5%CO₂的1.0 MPa毒化气氛中进行吸氘反应。在反应初期VNi_0.01合金与纯V相比,仍保持较快的吸氘速率,随后合金吸氘速率迅速下降直至为零。样品毒化后经加热除气处理,样品室内再次充入1.0 MPa高纯氘气,VNi_0.01合金吸氘速率已恢复至完全活化时的水平,而纯V的吸氘速率则低于初次活化时的吸氘速率。合金经活化后测得其增压性能在300～400 K范围内均优于纯V,因而合金有望用于增压化学床。这些研究结果将为该材料的应用提供直接依据。     

压水堆大修下行工况冷却剂主要辐解产物计算研究

压水堆大修时活化腐蚀产物源项控制是降低集体剂量最有力的手段，冷却剂辐解的影响必须予以考虑。本文基于水辐解反应动力学原理，构建了冷却剂辐解动力学模型，根据该模型计算得到了主要辐解产物H₂O₂、O₂和H₂在各工况的生成情况，并讨论了微观反应机理。结果表明：(1)在停堆下行过程中，冷却剂温度从310℃逐步下降到60℃，溶解氢浓度逐步降为0，一回路从还原性转为氧化性，H₂O₂和O₂的生成显著上升；(2)温度、B/Li浓度、溶解氢浓度、H₂O₂和O₂初始浓度等多种因素均会影响辐解产物的浓度；(3)H₂O₂和O₂是相互促进生成的关系，H₂可以显著抑制H₂O₂和O₂的生成，但高浓度的H₂O₂     

微型气相色谱法测定H2中杂质气体

为了满足氢同位素分离系统、 等离子体排灰气处理系统和贮存与供给工艺系统对进气品质的要求,需建立准确、快速、高精度的杂质气体分析方法。针对H₂中体积分数为10^-2~10^-3的气体组分He、Ne、N₂、Ar、CH₄、CO和CO₂,本研究首先采用配有1个Pora PLOT U通道和1个MS5- 通道的微型气相色谱仪,以H2为载气,建立H2中杂质气体的分析方法并优化测量参数。结果表明,杂质气体组分测量精密度优于0.2%,-0.5%<测量相对误差<0.5%,分离度>1.5,检出限为1.3×10^-6~8.5×10^-6,定量限为4.5×10^-6~36.3×10^-6,分析时间<2.5 min。在优化后的测量条件下探讨分别以He、Ne和Ar为载气测量H2中杂质气体的可行性,得到了标准气体色谱图。所建立方法能够满足工艺系统对进气的分析要求,并可拓展应用到其他氢同位素气体的杂质组分分析。     

氨水溶液在γ场中的稳态辐射分解行为研究

含氨冷却剂被应用于压水堆中,可以清除冷却剂辐射分解产生的O₂、H₂O₂等氧化性产物,从而减轻结构材料腐蚀。本文研究了氨水在γ辐射场中的辐射分解行为,考察氨浓度、辐射吸收剂量和吸收剂量率、气液体积比和不同饱和气体对氨水辐射分解行为的影响,重点关注辐射分解产物H₂O₂和NO₂-的浓度变化。结果表明,随着体系中氨浓度的增加,H₂O₂的浓度受到明显抑制,NO₂-的浓度则呈现出上升趋势;吸收剂量的增加使得H₂O₂浓度明显升高,NO₂-的浓度则在吸收剂量为8 kGy时达到最大(>100μmol/L),而后降低;吸收剂量率的差异(2.78～25 Gy/min)并未导致H₂O₂和NO₂-浓度产生明显变化;氨水中的O₂是NO₂     

反式二丁烯与氢气流量比对辉光放电等离子体组分与聚合物薄膜表面粗糙度的影响

采用低压等离子体增强化学气相沉积方法（LPPE-CVD）,以反式二丁烯（T₂B）和氢气（H₂）为工作气体,改变T₂B/H₂流量比制备不同条件下的碳氢聚合物（GDP）薄膜。利用质谱诊断技术研究了工作气体流量比对薄膜沉积过程中等离子体组分及离化程度的影响规律。同时结合白光干涉和SEM等技术研究了GDP薄膜的表面粗糙度和表面形貌的变化规律。结果表明,随T₂B/H₂流量比的增加,反应腔室中等离子体的离化率呈现先增大后减小的趋势。当T₂B/H₂流量比为0.8∶10时,反应气体的裂解程度最大,等离子体中离子片段的总量也最多。薄膜的表面粗糙度随T₂B/H₂流量比的增加出现先减小后增大的趋势。在0.6∶10的T₂B/H₂流量比条件下,薄膜的均方根粗糙度R_q达到极小值39.1 nm。     

氚老化对钯钇合金膜氢渗透性能的影响

在聚变堆燃料循环系统中,钯合金膜将被用于氢同位素与杂质气体间的渗透分离以及含氚杂质中氚的催化回收。长期连续的氚操作将使合金膜体内因氚衰变而累积3He,产生氚老化效应。本工作研究了贮氚老化对Pd8.5Y0.19Ru（原子百分数）合金膜的氕、氘渗透性能的影响。研究结果表明：对于膜内体氦浓度He/M为0.042的氚老化膜,在573～723K温度范围内,氕、氘渗透率被严重降低,膜的氕氘渗透分离系数则有所提高。     

PdY合金管束的氢渗透性能

PdY合金膜因其具有良好的透氢性能与机械性能,有望应用于聚变堆氢同位素纯化工艺.基于PdY合金膜的服役参数及氚安全要求,有必要研究在低氢压下PdY合金膜的氢同位素渗透特性,为后续设计氢同位素纯化组件提供数据支撑.本工作基于直管外压式PdY扩散器,研究了低氢压(<50 kPa)、工作温度为350～450℃条件下,厚度为8...     

Effect of water vapor on tritium permeation behavior in the blanket system

It is found that most hydrogen supplied to the purge gas changed to water vapor due to the water formation reaction in the early stage of the blanket operation and that physical or chemical adsorbed water is released in the high concentration into the blanket purge gas when the blanket temperature becomes higher than several hundreds of degrees K if the pre-treatment is not applied to the solid breeder materials. Effect of coexistence of water vapor in the purge gas on permeation behavior of hydrogen through F82H ferritic steel in the breeding part and palladium–silver (Pd–Ag) in the recovery part is discussed because use of them is generally considered for recovery of bred tritium from the solid blanket. Almost no decrease in permeation rate of F82H is observed in this study when water vapor exists in the blanket purge gas. The permeability of hydrogen isotopes through the Pd–Ag pipe gradually decreases when water vapor exists in the blanket purge gas. Properties required in estimation of the hydrogen permeated to the purge gas are experimentally obtained in this study.     

Hydrogen permeation of Hastelloy XR for high-temperature gas-cooled reactors

Hydrogen permeation of Hastelloy XR, which was developed for high-temperature gas-cooled reactors, has been investigated with a simulated gas to the reactor environment, 80% H₂ + 15% CO + 5% CO₂. In this gas environment, Hastelloy XR formed chromium oxide and manganese-spinel oxide on the surface and showed a good quality to prevent hydrogen permeation. The prevention behavior can be interpreted in terms of a hydrogen diffusion model in a uniform oxide layer, and dependences of permeation rate on time and temperature are explained by variation of oxide thickness. The pressure dependence of the permeation rate for the oxidized alloy as well as bare metals obeyed Sieverts' law. The environmental effects on hydrogen permeation are also discussed on the basis of correlation between the characteristics of the surface layer and the permeation behaviors.     

Characteristic of Two-phase Slanting Flow in Rod Bundle

Palladium membrane has been studied for sepration and purification of hydrogen isotopes because of its large permeability. In order to consider permeation of mixture of hydrogen isotopes, solubilities of protium and deuterium in palladium were studied in the temperature range of room temperature to 500°C using breakthrough method. It was observed that solubilities were represented by Sieverts' law and that the separation factor of protium-deuterium binary system was different from the isotope effect ratio. The ideal adsorbed solution theory by Myers and Prausnitz can be applied to estimate the separation factor of protium-deuterium binary system in palladium using the isotope effect ratio observed when protium and deuterium are handled independently. The permeation behavior of multi component hydrogen isotopes through palladium membrane is discussed applying observation on solubilities of this work.     

On the study of catalytic membrane reactor for water detritiation: Membrane characterization

Tritium waste recycling is a real economic and ecological issue. Generally under the non-valuable Q₂O form (Q = H, D or T), waste can be converted into fuel Q₂ for a fusion machine (e.g. JET, ITER) by isotope exchange reaction Q₂O + H₂ = H₂O + Q₂. Such a reaction is carried out over Ni-based catalyst bed packed in a thin wall hydrogen permselective membrane tube. This catalytic membrane reactor can achieve higher conversion ratios than conventional fixed bed reactors by selective removal of reaction product Q₂ by the membrane according to Le Chatelier's Law.This paper presents some preliminary permeation tests performed on a catalytic membrane reactor. Permeabilities of pure hydrogen and deuterium as well as those of binary mixtures of hydrogen, deuterium and nitrogen have been estimated by measuring permeation fluxes at temperatures ranging from 573 to 673 K, and pressure differences up to 1.5 bar. Pure component global fluxes were linked to permeation coefficient by means of Sieverts’ law. The thin membrane (150 μm), made of Pd–Ag alloy (23 wt.%_Ag), showed good permeability and infinite selectivity toward protium and deuterium. Lower permeability values were obtained with mixtures containing non permeable gases highlighting the existence of gas phase resistance. The sensitivity of this concentration polarization phenomenon to the composition and the flow rate of the inlet was evaluated and fitted by a two-dimensional model.     

PdY净化器的氢氦分离性能

对PdY净化器及传统净化器的透氢速率和氢氦分离性能进行了研究,结果表明:PdY净化器透氢速率随压差的增大而增大,压差在0.004~0.04 MPa的范围内,其透氢速率约为传统净化器的3倍;而采用PdY净化器进行氢氦分离时,可显著缩短氢氦分离时间。经过长时间循环分离后,3种组分的氢氦混合气均得到了较好的分离,氦气中氢气体积分数均降至0.03%。     

离心分离大质量数差混合物的实验研究方法

为探究混合物离心分离性能,提出了使用易于分离的气体介质进行实验研究的方法,选取全氟甲基环己烷（C₇F₁₄）/六氟化硫（SF₆）、C₇F₁₄/氙气（Xe）、一氟三氯甲烷（CCl₃F）/乙烯（C₂H₄）气体混合物作为离心分离介质,开展了分离实验。利用分馏装置分别得到了精、贫料中的各组分气体含量,结合质谱分析结果,得到了各组分气体的基本全分离系数与混合物的全净化系数。结果表明：此方法可方便分离轻重气体混合物,针对二元混合物离心分离,能给出全净化系数和各自组分的基本全分离系数,可用于混合物离心分离性能的实验研究。     

Hydrogen cold plasma for synthesizing Pd/C catalysts: the effect of support-metal ion interaction

It has been found that cold plasma is a facile and environmentally benign method for synthesizing supported metal catalysts, and great efforts have been devoted to enlarging its applications. However, little work has been done to disclose the influence mechanism, which is significant for controllable synthesis. In this work, hydrogen cold plasma was adopted to synthesize a palladium catalyst supported on activated carbon(Pd/C-P) using H_2 PdCl_4 as a Pd precursor followed by calcination in hydrogen gas to remove the chlorine ions. The Pd/C-P catalyst was found to be made of larger Pd nanoparticles showing a decreased migration to the support outer surface than that prepared by the conventional thermal hydrogen reduction method(Pd/C-C). Meanwhile, the pore diameter of the activated carbon support is small(~4 nm).Therefore, Pd/C-P exhibits lower CO oxidation activity than Pd/C-C. It was proposed that the strong interaction between the activated carbon and PdCl_4~(2-)and the enhanced metal–support interaction caused by hydrogen cold plasma reduction made it difficult for Pd nanoparticles to migrate to the support outer surface. The larger-sized Pd nanoparticles for Pd/C-P may be due to the Coulomb interaction resulting in the disturbance of the metal–support interaction. This work has important guiding significance for the controllable synthesis of supported metal catalysts by hydrogen cold plasma.     

103Pd-110Agm合金膜制备工艺研究

以103Pd和110Agm 为示踪剂,采用化学镀法制备了103Pd-110Agm合金膜,并优化了制备条件：对制得的103Pd-110Agm合金膜采用γ井型探测器进行定量分析,扫描电镜进行定性分析。结果显示,优化后的镀膜条件为：镀液组成为PdCl2(含放射性103Pd) 、AgNO3、Na2EDTA、NH3 、N2H4;Pd与Ag的摩尔比为9∶1;活化液PdCl2的浓度范围为0.5～2.0 mmol/L;金属离子总浓度为5～7 mmol/L;NH3浓度为2～4 mol/L;pH为10～12;N2H4浓度为10 mmol/L;Na2EDTA浓度为0.15 mol/L;恒温水浴槽保持温度为60 ℃,旋转搅拌器转速为40～60 r/min,反应时间为60 min。在以上镀膜条件下进行化学镀,可得到具有金属光泽的镀层。用载体预处理后,扫描电镜显示,镀层表面有晶粒生长,镀后清晰可见;定性分析结果表明,合金膜中有Pd、Ag元素存在。