利凡诺法测定HNO3—H2C2O4混合液中的NO∧—2

用利凡诺（Rivanol）法研究并测定HNO3氧去除了TRPO流程Np、Pu反萃液中H2C2O4时产生的NO∧-2。实验在0.48mol/L HCl介质中，利用Rivanol溶液与NO∧-2生成樱红色配合物性质，用分光光度法测定，结果表明，质量比R（NO∧-3/NO∧-2）≤3.6×10∧4和R（C2O∧2-4/NO∧-2)≤4×10∧3时，均对NO∧-2的测定无影响，方法对NO∧-2的检测下限为0.02mg/L，相对标准偏差为3%，重加回收率为97%～105%。     

UO_2C_2O_4·TRPO配合物中有机磷的测定

以H2 SO4 HNO3 H2 O2 作氧化剂 ,采用湿式灰化法将UO2 C2 O4 ·TRPO配合物中的有机磷氧化成磷酸盐 ,并在 0 14mol/LH2 SO4 介质中 ,以水溶性聚乙烯醇为稳定剂 ,用碱性染料乙基紫与磷钼杂多蓝形成较高灵敏度的离子缔合物 ,在波长 6 2 0nm处用分光光度法测定磷含量。结果表明 ,当溶液中质量比Rm(UO2 2 + /P)≤ 1 4× 10 3 ,Rm(C2 O4 2 - /P)≤ 8 8× 10 2 和Rm(C2 O2 2 - /P)≤ 3 6×10 4 (1次湿式灰化 )时 ,可在水相中直接显色测定磷。与聚乙烯醇 罗丹明B 磷钼杂多蓝测定磷的方法进行对照 ,结果符合良好。本法对有机磷转化为无机磷的平均转化率为 99 8%～ 10 1 1% ,磷的检测限为 0 0 2mg/L ,相对标准偏差为 3% ,回收率为 97%～ 10 3%     

HNO3氧化去除Np-Pu反萃液中的H2C2O4

研究了用HNO3 氧化去除TRPO流程反萃Np Pu的H2 C2 O4反萃液中H2 C2 O4的条件。 7 5mol·L-1HNO3 0 .3mol·L-1H2 C2 O4混合液于 90℃下蒸发 1 3 0h和 1 0 0℃下蒸馏回流 6h ,H2 C2 O4可完全分解去除 ;混合液中添加适量催化剂MnCO3 ,于 1 0 0℃下蒸发或蒸馏回流 ,H2 C2 O4分解加速 ,1～ 1 5h内H2 C2 O4完全分解。蒸发或蒸馏回流过程中产生的HNO2 把Np(Ⅳ )氧化为Np(Ⅴ )和Np(Ⅵ ) ,95 %以上的Pu保持Pu(Ⅳ )。     

UO_2C_2O_4·TRPO配合物的制备与分析

制备了UO2 C2 O4与TRPO的配合物 ,测得配合物的摩尔比为n(U)∶n(C2 O42 -)∶n(P) =1 0∶1 0∶1 0。其组分的元素分析结果理论值 (实测值 )为 :U ,33 2 4 % (33 10 % ) ;C2 O2 -4,12 2 9% (12 34% ) ;P ,4 33%(4 35 % )。初步确定该配合物的组成形式为UO2 C2 O4·TRPO。     

Al_2O_3在6MV放疗射线中的吸收剂量比率因子

用EGSnrc/BEAMnrc、DOSXYZnrc、DOSRZnrc模拟计算水体模中Al2O3剂量计的吸收剂量和剂量计对应位置上水的实际吸收剂量,并计算吸收剂量比率因子fmd,讨论Al2O3剂量计的吸收剂量特性.剂量计为φ4mm×1 mm的Al2O3薄片,计算深度0.5-8.0 cm,放疗射线是Varian 600C医用电子直线加速器的6 MV射线和Mohan 6 MV谱线.结果表明:Al2O3剂量计的吸收剂量少于对应位置上水的实际吸收剂量,吸收剂量比率因子fmd与剂量计在体模中的深度有关,在剂量建成区内,fmd对剂量计深度变化敏感;在建成区外fmd受剂量计深度变化的影响很小,用平均值表示不同深度的fmd时偏差不大于1.0%.     

H2O2对Pu(Ⅴ)的还原动力学研究

在0.1 mol/L NaClO4溶液中研究了Pu(Ⅴ)与H2O2反应的动力学。测定了Pu(Ⅴ)与H2O2的反应速率。探讨了温度以及Fe2 ,SO42-,HCO3-,F-等无机离子的存在对反应的影响。实验结果表明,反应对Pu(Ⅴ)与H2O2呈一级,对溶液中H 呈-1级;速率方程可表示为:-dc(Pu(Ⅴ))dt=(3.93±1.93)×10-9c(Pu(Ⅴ))c(H2O2)c(H )。随着温度升高,反应速率明显加快,根据Arrhenius规律,计算出了反应的活化能为Ea=84 kJ/mol。地下水中Fe2 ,SO42-,HCO3-,F-等离子的存在,有利于Pu(Ⅴ)的还原。     

HNO3氧化去除铀反萃液中的C2O42-

研究了用HNO3氧化去除TRPO流程铀的 (NH4 ) 2 CO3反萃液中C2 O4 2 - 的条件。将含铀的(NH4 ) 2 CO3反萃液调节成 0 2～ 0 8mol·L- 1H2 C2 O4 7.5～ 9.5mol·L- 1HNO3溶液 ,在 10 0℃下蒸馏回流 7h ,其中的C2 O4 2 - 被完全分解去除 ,得到UO2 (NO3) 2 NH4 NO3 溶液。蒸馏回流过程中 ,NH4 NO3部分分解 ,在该条件下操作是安全的。     

HNO3介质中H2C2O4电解动力学及电解氧化机理

以Pt-Ti（镀铂钛）为阳极,Ti为阴极,对HNO₃介质中的H₂C₂O₄进行恒电流电解,考察HNO₃介质中H₂C₂O₄电解动力学特性及其影响因素,并初步探讨HNO₃介质中H₂C₂O₄的电解氧化机理。研究结果表明：电流密度控制在25～37mA/cm2、HNO₃浓度为2～3mol/L、温度为30~40℃时,电解效果最佳;微量金属离子（Fe^₃+、MnO-4、Ag+）的存在对H2C2O4的电解起催化作用,能较大提高电解速率;电解氧化法破坏H2C2O4的效率高于KMnO4蒸煮法,在工业中有潜在的应用前景。     

H2O2对Pu(Ⅴ)的还原动力学研究

在0.1 mol/L NaClO4溶液中研究了Pu(Ⅴ)与H2O2反应的动力学。测定了Pu(Ⅴ)与H2O2的反应速率。探讨了温度以及Fe2+，SO2-4，HCO-3，F-等无机离子的存在对反应的影响。实验结果表明，反应对Pu(Ⅴ)与H2O2呈一级，对溶液中H+呈-1级；速率方程可表示为： -dc(Pu(Ⅴ))/dt=(3.93±1.93)×10-9c(Pu(Ⅴ))c(H2O2)/c(H+)。 随着温度升高，反应速率明显加快，根据Arrhenius规律，计算出了反应的活化能为Ea=84 kJ/mol。地下水中Fe2+，SO2-4，HCO-3，F-等离子的存在，有利于Pu(Ⅴ)的还原。     

阴离子交换纯化与浓缩2DW中镎

一、前言核燃料后处理厂Purex流程2 DW溶液的主要组分及其浓度为:HNO_3～1 N;Np,U,Pu,Th分别为0.16,30—90,0.4,0.05 mg/l;Zr-Nb及Ru的比放～4.4×10~(-4)eqRa/l。要求提取的镎产品(硝酸溶液)达到如下指标:Th/Np(重量)≤0.5%,U/Np(重量)≤2.5%,Pu/Np(重量)≤0.1%,比放≤5×10~(-2)meqRa/gNp;镎收率≥90%。     

Vaporization and Surface Ionization of LaC2, CeC2, PrC2, NdC2, ThC2 and UC2

The Langmuir vaporization and the surface ionization of LaC₂, CeC₂, PrC₂, NdC₂, ThC₂ and UC₂ from a heated graphite filament have been studied mass spectrometrically. It was found that there were present small amounts of neutral and ionic metal dicarbide molecules in addition to neutral and ionic metal atoms in the LaC₂, CeC₂, PrC₂, ThC₂ and UC₂-C systems with the exception of NdC₂-C, where neither neutral nor ionic metal dicarbide molecules were observed. The reason for this exceptional behavior of the NdC₂-C system is explained by the very small vaporization coefficients, as estimated from the measurements of neutral MC₂/M ratios and ionic MC₂/M ratios.

From the measurements of the heats of vaporization, it was surmised that the ionization potential of Th measured by the surface ionization comparison technique might be too high.     

Vapor Species over Na2O-B2O3-SiO2-Cs2O Glass

Methods for suppression and control of the axisymmetric vertical positional instability are described on the basis of conceptural design studies with the International Tokamak Reactor (INTOR). The shell effect is well known to be useful for suppression of the fast instability. Here shell structures are presented and their usefulness is assessed. Included in the assessments are required modellings of the plasma current for determination of mutual inductances between the plasma and the inductive components around it. Three kinds of models are described and their features are compared to the shell effect. Two kinds of simplified reactor structures are described and studied by comparing them with some control characteristics of the slow instability by a pair of control coils. Their structures are selected so as to result in different shell effects between them, and are consequently found to produce different capacities of power supply, too.     

Ternary Compounds PuNiC2 and PuCoC2

In order to determine a crack propagation rate of less than 10^-8 mm/s in a 24-hour integrated measurement, major parameters of a coupled system of a constant tension specimen and crack depth measurement, based on potential drop method, have been optimized. Influences of sensor geometry, location for detecting potential drop and data processing of the ratio of signal to noise (S/N) were optimized by applying Taguchi's Method. Then a suitable sensor geometry and data processing method were proposed to get a robust measurement system with higher sensitivity and lower susceptibility for geometrical and procedural fluctuations.

By applying the optimal crack propagation rate measurement system, it was confirmed that a crack propagation rate of lxlO^-8 mm/s can be measured under a low concentration condition of hydrogen peroxide with less than a 20% error by a 24-hour integrated measurement.     

纳米SnO2和SnO2／SiO2材料的正电子湮没研究

采用溶胶一凝胶法制备了纯纳米ＳｎＯ２和掺杂ＳｉＯ２的纳米ＳｎＯ２材料，应用Ｘ射线衍射和正电子湮没寿命谱等手段进行了纳米材料的界面结构和纳米晶粒的生长过程，结果表明，所制备的纳米ＳｎＯ２和ＳｎＯ２／ＳｉＯ２材料中只存在两类缺陷，分别对短寿命τ１和中等寿命τ２，材料中两类缺陷的数量比与粒径有关，纳米ＳｎＯ２晶粒生长随热处理温度升高为分两个阶段，低于晶化临界温度时，晶粒生长缓慢，高于此温度时，则生长迅速     

Thermal Conductivity of ThO2-UO2 System

The thermal diffusivity of the ThO₂-UO₂ system in solid solution was measured by laser pulse method at temperatures ranging from 20° to 500°C. Reproducibility of the data was confirmed to be within 3%. The compositions of the samples were ThO₂, ThO₂-1%UO₂, ThO₂-5%UO₂ and ThO₂-10%UO₂.

The thermal conductivity was calculated from measured thermal diffusivity data and the specific heat data available in literature and corrected to zero porosity by using Loeb's equation, in which the shape factor is unity.

The values on ThO₂ thus obtained agreed very well with the data found in literature, throughout the range of temperature of the experiments. The thermal conductivity of ThO₂, ThO₂-1%UO₂, ThO₂-5%UO₂ and ThO₂-10%UO₂, at 20°C, were 0.0312, 0.0288, 0.247 and 0.0184 cal·cm/sec· °C·cm², respectively.