Erfahrungen bei der zerstörenden Abbrandbestimmung von Reaktorbrennelementen

Es werden zerstörende Abbranduntersuchungen beschrieben, die auf der Analyse des Gehalts der aktiven Spaltprodukte ¹³⁷Cs und ⁹⁰Sr, des stabilen ¹⁴⁸Nd, des Urans sowie auf der Isotopenzusammensetzung des Urans beruhen. Die Erfahrungen bei der Abtrennung und Bestimmung dieser Komponenten unter Anwendung säulenchromalographischer Methoden (lonenaustausch, Extraktionschromatographie; Trennschemata werden angegeben) aus Kernbrennstoff der Reaktoren WWRS und WWER werden mitgeteilt. Die Ergebnisse der einzelnen Methoden, ihre Übereinstimmung sowie ein Vergleich mit theoretischen Berechunungen werden diskutiert.     

Separation of Cerium,Uranium and Plutonium using Silica Gel

Complete adsorption of radiocerium, uranium and plutonium on silica gel surface was attained at pH 5 ± 0.5. Individual separations of the studied radioelements were performed by desorption of the fixed radioelements using 30 ml of 10^?4 M diaminocyclohexanete-traacetic acid (DCTA) at different pH values.     

修水碳硅泥岩型铀矿特征及资源潜力分析

修水碳硅泥岩型铀矿主要有保峰源、董坑、大椿、白土、洞下矿床,矿床集中分布于修水复向斜中,构成修水矿化集中区,该矿化集中区位于修水-宁国-开化碳硅泥岩成矿带西端,是我国重要的碳硅泥岩型铀矿主产地,具有优越的区域铀成矿地质条件.通过铀矿调查评价工作,分析厘定了研究区岩性岩相、构造、岩相古地理、铀源等条件,明确了灯影组、王音铺组碳硅泥岩建造为研究区主要铀源层、赋矿层,新发现了观音堂组中的工业铀矿体.以铀成矿地质条件、铀矿化特征分析为重点,预测铀资源潜力.     

西北某铀矿山强化地浸实践

西北某铀矿山采用酸法地浸对其低渗透性砂岩铀矿床进行开采,但其7#、8#采区投产后浸出效率低。为了提高浸出效率,对采区已有生产数据进行了分析,在两采区开展了“洗孔”、“采区浸出环境优化”、“加压下注”等强化浸出方法的现场实践,结果表明:洗孔后普遍钻孔生产能力恢复;“采区浸出环境优化”后8#采区浸出液量及铀浓度明显增长,产能增加;“加压下注”后8#采区注液量涨幅达25.7%,液固比增长稳定,与采区浸采时间呈线性关系。     

Nature of the Arsonium‐Ylide Ph3As=CH2 and a Uranium(IV) Arsonium–Carbene Complex

Treatment of [Ph₃EMe][I] with [Na{N(SiMe₃)₂}] affords the ylides [Ph₃E=CH₂] (E=As, 1As ; P, 1P ). For 1As this overcomes prior difficulties in the synthesis of this classical arsonium‐ylide that have historically impeded its wider study. The structure of 1As has now been determined, 45 years after it was first convincingly isolated, and compared to 1P , confirming the long‐proposed hypothesis of increasing pyramidalisation of the ylide‐carbon, highlighting the increasing dominance of E⁺?C^? dipolar resonance form (sp³‐C) over the E=C ene π‐bonded form (sp²‐C), as group 15 is descended. The uranium(IV)–cyclometallate complex [U{N(CH₂CH₂NSiPrⁱ₃)₂(CH₂CH₂SiPrⁱ₂CH(Me)CH₂)}] reacts with 1As and 1P by α‐proton abstraction to give [U(Tren^TIPS)(CHEPh₃)] (Tren^TIPS=N(CH₂CH₂NSiPrⁱ₃)₃; E=As, 2As ; P, 2P ), where 2As is an unprecedented structurally characterised arsonium‐carbene complex. The short U?C distances and obtuse U‐C‐E angles suggest significant U=C double bond character. A shorter U?C distance is found for 2As than 2P , consistent with increased uranium‐ and reduced pnictonium‐stabilisation of the carbene as group 15 is descended, which is supported by quantum chemical calculations.     

Synthesis and Structure of Uranium-Silylene Complexes

While carbene complexes of uranium have been known for over a decade, there are no reported examples of complexes between an actinide and a „heavy carbene.“ Herein, we report the syntheses and structures of the first uranium-heavy tetrylene complexes: (CpSiMe₃)₃U-Si[PhC(NR)₂]R’ (R=tBu, R’=NMe₂ 1 ; R=iPr, R’=PhC(NiPr)₂ 2 ). Complex 1 features a kinetically robust uranium-silicon bonding interaction, while the uranium-silicon bond in 2 is easily disrupted thermally or by competing ligands in solution. Calculations reveal polarized σ bonds, but depending on the substituents at silicon a substantial π-bonding interaction is also present. The complexes possess relatively high bond orders which suggests primarily covalent bonding between uranium and silicon. These results comprise a new frontier in actinide-heavy main-group bonding.     

ChemInform Abstract: Structure,Properties, and Theoretical Electronic Structure of UCuOP and NpCuOP.

The title compounds are prepared by solid state reaction of U or Np, Cu and/or CuO, and P at 1073—1273 K (evacuated silica tube, 96 h).     

ChemInform Abstract: Structural Peculiarities of Actinyl Complexation with Monolacunary Polyoxometalates.

K₇H₆ [K(UO₂)(H₂O) (α‐SiW₁₁O₃₉)₂] ·21H₂O (I) is obtained as a byproduct in the crystallization of K_11.5H_0.5 [U(α‐SiW₁₁O₃₉)₂] ·25H₂O by slow evaporation of an aqueous solution of K₈SiW₁₁O₃₉ and U(SO₄)₂ at 22 °C (7 d).     

中新生代盆地砂岩型铀矿床铀矿物类型及赋存状态

中新生代盆地由于其特定的沉积特征,产出大量的砂岩型铀矿床,赋矿载体多为中细砂岩.为了查明砂岩型铀矿中铀矿物类型以及赋存状态,通过电子探针现代分析测试方法对铀矿物类型进行定量、定性分析,根据测试结果显示铀矿物类型主要有铀石、水硅铀矿、沥青铀矿、钛铀矿、菱钙铀矿和铀钍矿,以及铀的碳酸盐,主要与石英、长石、黄铁矿等共生,以及粘土矿物和有机质的吸附形式赋存于砂岩中,铀矿物的沉淀、富集与砂岩地层中pH值和Eh值有着密切关系.