Alkali Metal Ion and Lithium Isotope Selectivity of HZr2(PO4)3

HZr₂(PO₄)₃ has been synthesized by the heat treatment of NH₄Zr₂(PO₄)₃ and its properties as an ion exchanger have been examined with the main focus on its alkali metal ion and lithium isotope selectivity. The distribution coefficients for alkali metal ions revealed that HZr₂(PO₄)₃ was lithium ion-specific and showed little affinity toward potassium, rubidium or cesium ion. The lithium and sodium ion uptakes from aqueous solutions were monotonously increasing functions of pH. Isotopically, HZr₂(PO₄)₃ was ⁶Li-specific. Contrary to ion uptake, the lithium isotope effect was a monotonously decreasing function of pH; a larger separation factor was observed at a lower pH. This result was consistent with the existence of two different ion exchange sites formed in lithium ion-inserted HZr₂(PO₄)₃.     

Immobilization of Cs and Sr in aluminosilicate matrices derived from natural zeolites

Three Italian zeolitized volcanoclastic deposits with predominant phillipsite, chabazite or clinoptilolite were selected to investigate their attitude to form ceramized products of the Cs- and Sr-enriched forms and to evaluate the effectiveness of immobilization by means of leaching tests. The mineralogical evolution was carefully followed after thermal treatments at increasing temperatures (800 °C up to 1100 °C) which led to the crystallization of prevailing pollucite for Cs-exchanged phillipsite and chabazite and of a Sr-feldspar (about 35 wt.%) along with cristobalite and amorphous matter for all Sr-exchanged zeolites. Cs-enriched clinoptilolite at the same temperature was almost totally amorphous. Leaching tests confirm the substantial immobilization of the polluting cations in the ceramized materials with slight higher values only for the Cs-enriched clinoptilolite, mostly amorphous. Finally, calorimetric tests account for a hydrolysis process widely decreasing after thermal treatments at 1100 °C for phillipsite and chabazite, both Cs- and Sr-enriched, substantially similar for Sr-enriched clinoptilolite and definitely increased in the prevailing amorphous Cs-enriched clinoptilolite.     

二次自蔓延高温合成钙钛矿固化90Sr

采用二次自蔓延高温合成(SHS)技术制备钙钛矿固化高放废物90Sr,通过XRD, SEM和PCT粉末浸泡法,研究了钙钛矿固化体的微观组织、浸出率以及其对高放废物~(90)Sr的最大包容量.结果表明,固化体样品密度高、孔隙率小,浸出率都小于0.1 g/(m~2·d),对SrO的包容量可达36%(质量分数);表明自蔓延高温合成的钙钛矿人造岩石固化体化学稳定性好、包容量大,是固化高放废物的理想固化体.     

矿物材料对Sr2+、Cs+的竞争吸附性能与表征

采用间歇法研究了相同摩尔浓度Sr²⁺、Cs⁺溶液中,矿物材料对核素Sr²⁺、Cs⁺的竞争吸附性能,用XRD对吸附Cs⁺、Sr²⁺后的矿物材料进行了表征和分析。实验表明：NF、ZF、CA对Cs⁺、Sr²⁺的平衡吸附时间分别约为7、3和14d。ZF对Cs⁺、Sr²⁺的平衡吸附量最大,其次是NF,最后是CA。NF对Cs⁺的吸附具有明显的选择性,CA的选择性较差,ZF最差。ZF对Sr²⁺的去除率基本达100%,对Cs⁺的去除率达72%;NF对Cs⁺的去除率达66%,而对Sr²⁺的去除率仅为15%;CA对Sr²⁺的去除率达29%,而对Cs⁺的去除率仅为16%。矿物材料吸附Sr²⁺、Cs⁺后晶胞体积均变小,晶胞参数c亦变小,其它晶胞参数a、b、β变化不规则。     

Immobilization of Cs and Co in concrete matrix

To assess the safety for disposal of radioactive waste-cement-bentonite composition, the leaching of ¹³⁷Cs and ⁶⁰Co, from a waste composite into a surrounding fluid has been studied [Burns, R.H. Atomic Energy Rev. 9 (1971) 547; Hashimoto, I., Deshpande, K.B. & Thomas, S.H. I & EC Fundamentals 3 (1964) 213]. Leaching tests were carried out in accordance with a method recommended by IAEA [Atomic Energy Rev. 9 (1971) 195]. Determination of retardation factors, K_F and coefficients of distribution, k_d, using a simplified mathematical model for analyzing the migration of radionuclides, has been developed. In our experiment we have achieved the lowest leaching values after 60 days. Results presented in this paper are examples of results obtained in a 20 year mortar and concrete testing project, which will influence the design of the engineered trenches system for a future central Serbian radioactive waste storage center.     

水中锶-90和铯-137分析方法的比对

本文报道了有11个实验室参加的水中锶-90和铯-137分析方法比对的结果,还叙述了供比对用的三种水样的制备和比对的程序。比对结果。各实验室对参考水样中锶-90和铯-137分析结果的总平均值分别为(5.24±0.28)×10~(11)Ci/kg 和(1.05±0.08)×10~(-10)Ci/kg,与参考值5.24×10~(-11)Ci/kg 和1.03×10~(-10)Ci/kg 很接近。用统一发放的标准溶液和各实验室的原刻度源刻度β计数器,所得结果的准确度无显著性差异,但前者比后者的精密度好一些。通过单总体 t检验和 X~2检验表明,有些实验室可能存在系统误差,或者对偶然误差估计偏低。     

土壤中^90Sr和生物灰中^137Cs测量比对

介绍了浙江省辐射环境监测站组织实施的2009年全国辐射环境监测系统土壤中^90Sr和生物灰中^137Cs测量比对情况及其结果分析。比对结果表明,90%的测量值为满意结果,5%的测量值为有问题结果,5%的测量值为离群值。通过此次比对,基本上了解了全国辐射环境监测系统土壤中^90Sr和生物灰中^137Cs测量水平,为今后进一步开展系统内的质保工作提供了依据。     

Migration Behavior of Radionuclides (60Co, 85Sr and 137Cs) in Aquifer

The migration behavior of radionuclides (⁶⁰Co, ⁸⁵Sr and ¹³⁷Cs) in aquifer has been studied under a steady flow of water by using aquifer model apparatus.

In the portion of high concentration (≧ 10^?3 μCi/g), water flow has slight influence on migration of these radionuclides. On the other hand, in the portion of low concentration (10^?4 μCi/g), ⁶⁰Co and ¹³⁷Cs are particularly influenced by the flow, but the migration of ⁸⁵Sr is relatively small. Such phenomena support that the migration of ⁸⁵Sr is subject to the ion exchange reaction, and the migration of ⁶⁰Co and ¹³⁷Cs may be due to both ion exchange reaction and particulate moving mechanism.

The concentration distribution observed is compared with that of the calculation by predicting equation based on ion exchange reaction. In the distribution of high concentration portion, the observed on each radionuclide is almost same as to the calculated, but in the distribution of low concentration portion, both observed on ⁶⁰Co and ¹³⁷Cs are very different from the calculated. Since migration behavior of ⁶⁰Co and ¹³⁷Cs cannot be described by predicting equation only based on ion exchange reaction, it is, therefore, necessary to predict those migration by the equation consisting of ion exchange reaction and particulate moving mechanism.     

上海市环境中^9^0Sr,^1^3^7Cs和^3H放射性水平调查及评价

本文报道了1989—1991年上海市环境(包括大气、水体、土壤和生物)中~(90)Sr、~(131)Cs 和~3H 放射性水平调查的方法和主要结果。本次调查在市区和郊县共设11个点,采集气溶胶样品;以黄浦江为重点对各类水体(长江上海段、苏州河、宝钢水库、淀山湖及自来水)共设15个调查点,采集枯、丰两水期水样45个;在全市范围内按20 km×10 km 网格布设陆地土壤调查点32个,并在长江、黄浦江及其支流淀山湖水体调查断面处采集河底泥样品10个。与沉降物调查点同位采集生物样品(大米、青菜、牛奶、羊肉及鱼等);测量项目为~(90)Sr、~(137)Cs 和总β放射性浓度或含量;对于水体,还测量了~3H 浓度;对于气溶胶,所测总β放射性浓度为长寿命核素。调查结果表明,上海市环境中~(90)Sr、~(137)Cs 和~3H 放射性均属正常本底;由饮食摄入~(90)Sr、~(137)Cs 和~3H 所致的人均年有效剂量为1μSv,由土壤中~(137)Cs 外照射引起的居民人均年有效剂量为0.92μSv,分别为全国天然贯穿辐射所致我国居民人均年有效剂量的0.12%和0.11%。     

Leaching Rate Test of Nuclei Cs and Sr

A novel material-resemble verifiable cement for disposal of spent nuclear fuel reprocessing mediate-level waste has been developed. Waste form has been characterized for their compressive strength, phase composition. The cement formulation has been patented. In this experiment, the cement was mixed with simulated wastes for each composition 5 min at least. Ratio of waste to the cement is 0.45-0.55. After being packed into cylindrical molds, the grouts were cured for a period 28 days in a room temperature curing chamber at atmospheric pressure. The wasteform then     

植物激素对油菜植株富集133Cs和88Sr的影响

通过水培试验,研究外源植物激素(生长素IAA、赤霉素GA、水杨酸SA)对油菜吸收和累积133Cs、88Sr的影响.以西南地区普遍种植的甘蓝型油菜为试验材料,利用火焰原子吸收光谱法对油菜苗进行88Sr和133Cs含量的测定.结果表明:在三种植物激素处理下,油菜地上部和根部的生物量显著高于对照(未加激素),油菜中133Cs...     

Oxygen Potential of Cs2U4O12/Cs2U4O13 Equilibrium

A batch distillation of tritiated water (～10 nCi/cm³) has been performed in a packed column 1.6cm inner diameter x 100 cm high. Packings were Dixon rings made of SUS. Time variations of tritium activity were measured by changing vapor flow rate within the column, and then the separative performances, such as the separation factors and the separative power per unit charge, were obtained. The maximum values of the total separation factor and the separative power per unit charge were 1.45 and 2.0x10^?2, respectively. The vapor flow rate from the reboiler decreases as the batch operation proceeds, so that a simulation with a fixed stage-number, the usual case, could not sufficiently predict the experimental values. We have therefore developed a simulation procedure where the number of hypothetical stages can be changed during the batch operation in order to predict the dynamic column behavior obtained from the experiments. The simulation result with the variable stage-number agreed with the experimental one.     

从高放废液中除去(回收)~(137)Cs和~(90)Sr

在较早的方法的基础上,结合最近几年进展的情况,从沉淀、离子交换和溶剂萃取3个方面综述了从高放废液中除去(回收)~(137)Cs和~(90)Sr的方法,并进行了讨论.     

芦苇和茶叶样品中锶-90和铯-137分析方法的比对

本文报道了有9个实验室参加的芦苇和茶叶样品中锶-90和铯-137分析比对的结果。比对结果表明,各实验室芦苇中锶-90和茶叶中铯-137的分析结果可比性良好,遵从正态分布规律;少数实验室芦苇中铯-137的分析结果偏低;茶叶中锶-90的分析结果可比性差。本文讨论了分析结果差异的原因,估计了样品中锶-90和铯-137含量的95%置信区间。     

Simultaneous separation and recovery of Cs(I) and Sr(II) using a hybrid macrocyclic compounds loaded adsorbent. Kinetic,equilibrium and dynamic adsorption studies

In this study, simultaneous separation and recovery of Cs(I) and Sr(II) from nitric acid solution was investigated using a silica-based hybrid adsorbent. The adsorbent was prepared by successive impregnation and fixing of two supramolecular recognition agents namely, 1,3-[(2,4-diethylheptylethoxy)oxy]-2,4-crown-6-Calix[4]-arene(Calix[4]arene-R14) and 4',4' (5")-di(tert-butylcyclohexano)-18-crown-6, onto a silica-based polymer support(SiO₂-P). Uptake properties, characterization, equilibrium kinetics, and dynamic adsorption properties of Cs(I) and Sr(II) were then assessed. Distribution coefficients (K_d) higher than 10² cm³/g for Cs(I) and Sr(II) were obtained using 3 M HNO₃ at 298 K, and the K_d values decreased with increasing temperature. Adsorption kinetics and equilibrium studies fitted well with pseudo-second-order model and Redlich–Peterson isotherm model, respectively. The constant total organic carbon values in the aqueous phase were obtained after adding 10^?3 ～ 4 M HNO₃. Results of the dynamic adsorption/elution test indicated that Cs(I) and Sr(II) were efficiently and simultaneously captured and eluted even under a flow rate of 1.5 cm³/min.     

(Sr0.1Th0.2Nd0.3La0.2Gd0.2)2Zr2O7高熵烧绿石固化体的制备及化学稳定性

以金属硝酸盐为原材料,通过溶胶-喷雾热解-高温烧结法制备了(Sr_0.1Th_0.2Nd_0.3La_0.2Gd_0.2)₂Zr₂O₇高熵烧绿石固化体。利用X射线衍射(XRD)、扫描电镜(SEM)、Raman光谱对固化体结构进行表征,通过MCC-1浸出实验方法分析了固化体化学稳定性。研究结果表明：高熵烧绿石固化体为纯相高熵烧绿石结构,最佳烧结温度为1 500℃。随着烧结温度增加,固化体晶粒和密度明显增加。浸出实验结果显示：La、Gd、Zr、Nd元素42 d归一化浸出率为10^-6 g/(m²·d)量级,Sr、Th元素的42 d归一化浸出率分别为10^-5 g/(m²·d)和10^-3 g/(m²·d)量级,固化体表现出良好的化学稳定性。     

~(133)Cs和~(88)Sr在蚕豆苗中的蓄积及其辐射损伤效应

通过水培试验研究了蚕豆苗对不同浓度133Cs和88Sr的蓄积及其辐射损伤效应。本实验利用原子吸收方法测定蚕豆苗对133Cs和88Sr的蓄积量,研究了133Cs和88Sr在蚕豆苗各部位的分布及对其生理影响。结果表明:在133Cs和88Sr所设不同浓度下,蚕豆苗地上部和根部的133Cs和88Sr蓄积量均随浓度梯度升高而增加,表现出根部含量地上部含量,133Cs含量88Sr含量。随着时间的推移,蚕豆苗对溶液中133Cs和88Sr蓄积量表现出先骤升后趋于平稳的趋势;随核素浓度的上升,根系活力均表现为先增强后减弱的趋势;蚕豆苗叶片中的丙二醛含量增加,叶片中丙二醛含量变化均较根系的大。88Sr处理组中的可溶性糖含量高于133Cs处理组。     

空气条件下合成的CaBPO5:Eu、SrB4O7:Eu和Ba3(PO4)2:Eu的XANES和发光性质

测定了采用高温固相反应在空气条件下合成的发光体CaBPO5：Eu、SrB4O7：Eu和Ba3(PO4）2：Eu的Eu-L3边的X射线吸收近边结构(XANES)谱和发光光谱。从发光体的Eu—L3边XANES可见，Eu^3 -L3边能量比Eu^2 -L3边能量高7—8eV；3个发光体的激发光谱和发射光谱均可看到Eu^2 的4f-5d跃迁和Eu^3 的4f-4f跃迁。发光体的Eu—L3边的XANES和发光光谱说明空气条件下合成的发光体中Eu^3 可部分还原为Eu^2 。     

Behavior of cesium molybdate,Cs2MoO4, in severe accident conditions. (1) Partitioning of Cs and Mo among gaseous species

In order to better understand the behavior of cesium in severe accident of Light Water Reactor (LWR), the high-temperature chemistry of Cs₂MoO₄ in H₂O + H₂ gas was studied. The pseudo–binary system, Cs₂MoO₄–MoO₃, was thermochemically modeled with Redlich–Kister formulation to form a basis to analyze the high-temperature behavior of Cs₂MoO₄. The model prediction was compared with the thermogravimetric measurements of Cs₂MoO₄ in dry and humid argon, which revealed that the mass-loss rate was enhanced in humid atmosphere. The thermochemical model was further applied to predict the partitioning of cesium and molybdenum among gaseous species in the boiling water reactor-core degradation condition typical of short-term station blackout. Effects of the total pressure (3.5–75 bar) as well as the H₂/H₂O ratio (1/4000–2) were examined. CsOH(g) is the predominant cesium species, when the damaged fuel temperature is higher than 2000 K at higher steam pressures, but Cs₂MoO₄(g) would become more important as the steam cools toward the steam dome. The condensation of Cs₂MoO₄ occurs below ～1900 and ～1550 K at 75 and 3.5 bar, respectively. Besides, the ideal mixing of complex component model has also been examined for its simplicity. The latter gave satisfactory prediction as far as the condensed phase composition is concerned.     

Sr，Cs在不同产地黏土中的吸附

采用批式法对不同产地的18种黏土材料进行了⁹⁰Sr，¹³⁷Cs的吸附分配系数测定，比较了不同材料的吸附性能。结果表明，在吸附达平衡时，浙江沸石对Sr的吸附分配系数为2 112.0 mL/g；内蒙古赤峰沸石对Cs的吸附分配系数为3 495.0 mL/g；均位于所有样品之首。产地不同的黏土样品其吸附分配系数差异很大，Sr的吸附分配系数分布在22.4～2 112.0 mL/g，Cs的吸附分配系数分布在43.5～3 495.0 mL/g；大部分样品对Cs的吸附大于对Sr的吸附；相同样品对Sr，Cs的吸附性能趋势基本一致。