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利用X射线衍射技术分析LaNi5氚老化效应 总被引:1,自引:0,他引:1
利用覆膜法对长期贮存氚的LaNi_5进行了XRD分析.经过实验发现,老化后的LaNi_5的谱峰比新鲜的LaNi_5存在明显的展宽,而经过高温除He处理后,又恢复到新鲜的LaNi_5水准,氚衰变形成的~3He在晶格中居留并在其中形成部分位错亚结构,这可能是导致LaNi_5 XRD衍射峰宽化的主要原因. 相似文献
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对He、Ti原子比n(He)/n(Ti)为0.004~0.300的7块氚化钛膜样品在1300K以下进行热解吸分析,以获得它们的热解吸谱。在低于1300K范围内,氚化钛膜共有4种氦的热释放峰,分别对应于贯穿至表面的氦泡、近表面的氦、体相中的氦泡和氦的小团簇。对这4种类型的氦释放峰的解吸温度和解吸量随膜中总氦量的变化分别进行分析,研究观测膜中各种状态存在的氦量随n(He)/n(Ti)增加的变化趋势。实验观测到,升温将导致氚化钛膜可容纳的氦量大幅降低。 相似文献
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在辐射伏特效应同位素电池(辐伏电池)中,器件的辐伏转化性能不仅受限于换能器件所用的半导体材料、结构或加载放射源的种类,还受换能器件表面钝化层结构的影响。为在氚化钛源加载的平面单晶硅PN结辐伏电池(氚辐伏电池)中得到最佳的钝化效果,本文设计了3种不同的钝化层结构,考察其初始输出性能和抗辐射性能,并单独研究了氚化钛源出射的X射线对单晶硅换能器件的辐射损伤。结果显示:在辐伏电池初始输出性能方面,Si/SiO2/Si3N4结构Si/B-Si glass/Si3N4结构Si/Si3N4结构;在抗氚化钛源辐射损伤方面,Si/Si3N4结构Si/B-Si glass/Si3N4结构Si/SiO2/Si3N4结构,Si/B-Si glass/Si3N4结构具有最佳的抗X射线辐射衰减性能。氚化钛源出射的X射线对辐射损伤效应起主要作用,XPS结果显示,X射线长时间辐照造成了单晶硅表面平整性的破坏。 相似文献
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The accelerator production of tritium project will utilize spallation neutrons incident on thousands of 3He gas filled metal tubes to produce tritium by way of the exothermic 3He(n,p)3H reaction. Tritons with energies up to 192 keV and protons with energies up to 576 keV are directly implanted into the tube walls. To minimize tritium retention in the tubes and permeation into the coolant surrounding the tubes, it is desirable to have the implanted tritium migrate back to the inner surface of the tubes and rapidly recombine to be released as T2 and HT. Aluminum alloy (Al 6061-T6) is the primary candidate material for fabrication of the tubes. Aluminum alloy samples implanted with deuterons and protons to fluences as high as 3×1022 D (and p)/m2 were studied. Deuterium retention was measured by mass spectrometry during thermal desorption. Approximately 10% of the implanted deuterium was retained. Copper, nickel and anodized coatings on aluminum alloy were studied as possible methods of reducing retention and permeation of the tritium. In these experiments, the Cu and Ni coatings reduced the retention significantly, whereas retention increased in the anodized coated sample. 相似文献
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压水堆主回路冷却剂流经堆芯时,水中固有及特加核素受中子辐照后会产生氚,氚几乎全部以气体和液体的形式排入环境,造成氚污染。因此,氚是压水堆辐射环境影响评价的主要关注内容之一。本文以AP1000为例,根据压水堆主回路冷却剂中氚的产生途径及其随时间的变化情况建立详细的计算模型,计算压水堆主回路冷却剂中的氚活度并分析各产氚途径对氚产生量的贡献。计算结果表明:主回路冷却剂中的氚主要来源于可溶性硼的中子活化和铀裂变,对氚产生量的贡献达80%以上;在7Li纯度为99.9%时,AP1000主回路中的年产氚量为5.23×1013 Bq,锂产氚量占总量的14.01%,随7Li纯度的增加,锂产氚量的贡献呈线性减小,在7Li纯度为99.99%时,锂产氚量占总量的3.18%。其他途径对氚的产生量贡献很小,可忽略。根据以上结果,可通过控制主回路冷却剂中添加的初始硼浓度、提高燃料包壳质量、增加LiOH中7Li的纯度等多种途径来降低主冷却剂中氚的产生量,从而减少氚对环境的放射性污染。 相似文献
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采用氚化钛源原位辐照和加速器低能电子束加速辐照实验,研究基于氚化钛/单晶硅PN结器件的氚辐伏电池模型和实验室组阵型电池原型样机的长期稳定性。测试电池模型和电池样机的氚辐伏输出随辐照时间的变化,分析辐照对单晶硅PN结型器件的本征暗特性和器件表面层材料缺陷的影响。结果表明,氚化钛源原位辐照电池模型在115 d的辐照中辐伏输出没有明显的衰减,辐照后单晶硅器件的本征暗特性曲线变化微小。电池模型的加速器低能电子束加速辐照实验表明,加速辐照在相同电子注量下对电池造成远大于氚源原位辐照的性能损伤,但损伤仅在辐照最初期快速产生,随后基本保持稳定,电子顺磁能谱(ESR)测试加速辐照60 min单晶硅器件材料的缺陷没有明显增加。组阵型实验室电池原型样机在64个月的室温储存中,基本单元的辐伏输出性能衰减比氚的自发衰变衰减有小幅增大,增大幅度小于11.4%;另外,组阵中单元之间串并联电连接有部分失效,这是后续应重点关注的问题。 相似文献
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Young Zr tritides were investigated for aging times up to about 6 months' using analytical transmission electron microscopy. No isotopic differences between hydrides and tritides were seen as far as precipitation morphology and structures are concerned. Also, no low-temperature phase transitions were observed in the tritides γ and δ. 3He generated by tritium decay was found to precipitate in very small bubbles (1–2 nm in diameter and densities of about 5×1023 m−3) which were first clearly visible after approximately 24 days of aging. In addition to the 3He bubbles, interstitial loop damage was observed. Acoustic emission techniques applied to 5 and 6 months old Zr-T samples did not reveal any above background acoustic activity. 相似文献
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为满足对聚变堆面向等离子体材料中氘氚滞留问题的研究,北京大学4.5 MV静电加速器在原束线基础上新增核反应分析系统,该系统使用能量0.8~3.6 MeV的H+、D+、3He+和4He+粒子束流,可对核反应微分截面和样品中元素浓度的深度分布进行测量分析。本文对核反应分析原理、核反应分析系统的设备布局和实验方法进行了讨论,并以D(3He,p)4He核反应为例,分析了微分截面计算和样品中氘元素浓度深度分布的数据结果,其深度分辨小于1.5 μm,实验误差约为7.5%。 相似文献
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The pulse height distribution in 3He proportional counters has been investigated to accurately quantify the response function to be used in fast neutron spectroscopy. The measurements were performed as a function of the operating voltage, the counting gas mixture, and the incident neutron energy. The special emphasis of this study has been put on the nonlinearity of the pulse height of a recoil helium induced by the 3He(n,n)3He reaction. A distinct deviation of 14% at maximum to lower energies was found in the position of the recoil edge with the energy axis calibrated by the full energy peaks of the 3He(n,p)T reaction produced with neutrons of thermal energy and 2.413 MeV. It was confirmed that the nonlinear effects, such as an initial recombination and a space-charge effect, take place more significantly in the energy loss process of a recoil helium because of its higher linear energy transfer (LET) in the filling gas compared to that of a proton and triton pair emitted from the 3 He(n,p)T reaction. The deviation becomes larger with an increase of the average LET in the gas mixture. The experimental results suggested that the nonlinear effect caused by a higher LET recoil helium is inevitable for the filling gas, even if the operating voltage is changed to an acceptable range 相似文献
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建立了通过制备大气颗粒物中碘样品并采用加速器质谱(AMS)测量颗粒物样品中129I浓度的方法。采用此方法对日本福岛核电站泄漏事故期间北京大气颗粒物样品进行了129I测量,以此探讨129I在环境监测中的作用。北京地区大气颗粒物129I的测量结果显示,2011年3月26日的大气颗粒物中129I浓度已高于正常本底值的数倍,据推测这部分129I来源于福岛核电站泄漏事故。129I是重要的核裂变产物,其来源具有特殊性,较长的半衰期使其在核反应堆中长期积累,核泄漏早期存在区域环境高浓度129I现象,所以129I-AMS测量在辐射安全及应急监测方面具有潜在优势。 相似文献
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为测量聚变堆固态氚增殖剂堆内辐照氚增殖剂的产氚速率,除用常规电离室之外,本研究建立了Ne载气的高精度气相色谱在线检测分析方法,通过测量产氚回路中的氦产生量,验证系统中产生的氚量,从而为聚变堆固态包层产氚包层增殖剂材料辐照产氚性能提供一种新的产氚速率测量验证方法。本工作通过研制含有三个检测器、五个色谱柱的气相色谱分析系统,建立了Ne中微量4He、H2及杂质组分的色谱检测分析方法,并完成了实时在线检测的验证实验。结果表明,研发的色谱分析系统可实现高纯Ne中4He、H2及杂质组分的检测分析,H2、4He检测限可分别达到1.0×10-6、5.9×10-6,各组分含量及峰面积的相对标准偏差(sr)均小于5.0%(n=6),线性相关系数(r2)均大于0.99,说明检测方法重复性好。根据Ne中多组分气体的在线检测验证实验可知,单时段和多时段内的测量重复性均较好,可为辐照产氚考核系统中的产氚速率验证提供分析手段,进而为正式入堆得到辐照数据和氚衡算提供技术支持。 相似文献