ARI; Experimental and Computational Assessment of Unique Trace Elements and Isotope Ratios in Plutonium from Depleted Uranium Irradiated in Fast Reactor Blankets

1140018（Chirayath）。 该项目将利用计算和实验方法，确定是否有可能可靠地预测和测量某些类型反应堆生产的武器级钚的独特固有物理特征。特别令人感兴趣的反应堆是：（a）印度和中国正在开发的快增殖反应堆，其堆芯包层采用贫化铀;（B）以天然铀为燃料的CANDU型反应堆。印度的这两种反应堆今后都可能在无保障的情况下运行。当印度和中国（也许还有其他地方）的开发型FBR在不久的将来开始运行时，它对DNDO会有帮助吗？的全球核探测架构，以了解一个潜在的独特的细节？指纹？与快堆包层中贫化铀产生的钚有关。对CANDU动力反应堆在燃料以低于标准燃耗喷出时产生的钚的潜在独特识别特性有类似的理解也将是有益的。详细了解钚同位素含量、铀的特征、裂变产物和钚分离化学处理后的微量元素残留物等这些独特特征，将有助于开展核法证活动，查明截获的走私钚（爆炸前材料）的来源，并在一定程度上进行爆炸后分析。 该项目的主要重点领域是：[1]快堆和CANDU反应堆的计算建模，以通过使用过的燃料中的核素存量估计生成同位素特征，[2]快速谱中二氧化铀（UO 2）燃料芯块的中子辐照（模拟快堆）和热谱（模拟CANDU）在ORNL-高通量同位素反应堆（HFIR）的实验验证推力区1的计算结果，和[3]通过从裂变产物和铀中化学分离钚对辐照过的二氧化铀芯块进行实验研究，并使用破坏性和非破坏性分析对其进行定性。 该项目的特点包括：（1）对快堆包层和热反应堆低燃燃料产生的武器级钚进行指纹鉴定，（2）对独特核燃料循环产生的武器级钚指纹进行实验验证，（3）发展国家核鉴识能力，以针对外国核燃料循环中低燃燃料组件产生的武器级钚，（4）利用PUREX从裂变产物和铀中分离钚，并通过破坏性和非破坏性分析对其进行表征，这对于向研究生和本科生进行教学和演示将是非常有价值的，（5）指导、教育和支持博士后研究人员、研究生和本科生，（6）通过学生在技术会议上的演讲和学术出版物出版。

1140018 (Chirayath). This project will use computational and experimental methods to determine whether it is possible to reliably predict and measure a unique intrinsic physical signature in weapons-grade plutonium (Pu) produced by certain reactor types. The particular reactors of interest are (a) fast breeder reactors (FBR) of the type under development in India and China, which employ depleted uranium in their core blankets and (b) CANDU-type reactors fueled by natural uranium. Both of these reactor types in India will likely be operating in non-safeguarded circumstances in the future. When the developmental FBRs in India and China (and perhaps elsewhere) begin operating in the near future, it would be useful for the DNDO?s global nuclear detection architecture to understand the details of a potentially unique ?fingerprint? associated with Pu produced from depleted uranium in the FBR blankets. It would also be helpful to have a similar understanding of potentially unique identifying characteristics of Pu generated in CANDU power reactors when the fuel is ejected with lower than standard burn-up. Detailed understanding of these unique characteristics, such as the Pu isotope content, signatures of uranium, fission product, and trace elemental residues after chemical processing of Pu separation would aid nuclear forensics activities aimed at source attribution in the case of interdicted smuggled plutonium (pre-detonation material) as well as to some extent for post-detonation analyses. The main thrust areas of the project are: [1] Computational modeling of FBR and CANDU reactors to generate isotopic signatures through nuclide inventory estimation in used fuel, [2] Neutron irradiation of uranium dioxide (UO2) fuel pellets in fast spectrum (to simulate FBR)and thermal spectrum (to simulate CANDU) at ORNL-high flux isotope reactor (HFIR) for experimental validation of computed results of thrust area 1, and [3] Experimental investigations of irradiated UO2 pellets through chemical separations of plutonium from fission products and uranium and its characterization using destructive and non-destructive analyses. Features of the project include: (1) fingerprinting weapon-grade plutonium produced in fast reactor blankets and thermal reactor low-burned fuel, (2) experimental validation of weapon-grade Pu fingerprint originating from unique nuclear fuel cycles, (3) development of a national nuclear forensics capability for targeting weapon-grade plutonium produced from low burned fuel assemblies in foreign nuclear fuel cycles, (4) plutonium separation from fission products and uranium using PUREX and its characterization by destructive and non-destructive analyses will be highly valuable to teach and demonstrate to graduate and undergraduate students, (5) mentor, educate and support postdoctoral researcher, graduate and undergraduate students, (6) publications through student presentations in technical conferences and scholarlypublications.