A Novel Framework for Safeguarding Naval Nuclear Material

ABSTRACT

The present international standard allows non-nuclear weapon states (NNWS) to forego safeguards when nuclear material is used in a “non-proscribed military activity,” though no criteria have been established to determine when NNWS can remove naval nuclear material from safeguards. Though at present, only nuclear-armed states possess nuclear submarines, the global nuclear naval landscape may soon change with the advancement of Brazil's fledgling program and the possible precedent it would set for other NNWS. A framework is needed to shore up nuclear security and prevent nuclear material diversion from the nuclear naval sector. Proposed and existing nonproliferation frameworks, including a Fissile Material Cut-off Treaty and commitments through the nuclear security summits, are insufficient to close this loophole. A Naval Use Safeguards Agreement (NUSA), modeled after the Additional Protocol of the International Atomic Energy Agency, would provide a framework to remove the opacity surrounding nuclear material in the naval sector. Designed for NNWS and encouraged as confidence-building measures for nuclear weapon states, NUSA would explicitly outline those stages in the naval nuclear fuel cycle where safeguards are to be applied and in what context. This viewpoint also further provides direction for targeted research and development in technical naval nuclear safeguards solutions.     

FACILITATING NUCLEAR DISARMAMENT: Verified Declarations of Fissile Material Stocks and Production

Unprecedented interest in seeking progress toward nuclear disarmament exists today; even some nuclear weapon states are looking for new ways to strengthen this process. National declarations of fissile material holdings—highly enriched uranium and plutonium—could play an important role in supporting this effort, facilitating not only transparency but also the irreversibility of the process. This article discusses what kind of content such declarations could have in order to be meaningful and effective, the sequence of data on fissile material holdings that states might release, and some of the challenges to be expected in reconstructing historic fissile material production; it also summarizes current attitudes of weapon states toward making such declarations. Initial declarations can be valuable as confidence-building measures, but better and more background data are necessary if declarations are to serve as the groundwork for deeper cuts in the nuclear arsenals. A robust verification approach would ultimately require inspectors to have access to fissile material production and storage sites. The methods and tools of nuclear forensic analysis—in this context also dubbed nuclear archaeology—would be a key element of this process. This article discusses the capabilities and limitations of potential approaches to verifying declarations of historic production of plutonium and highly enriched uranium; it also identifies and discusses opportunities for further research and development.     

STRATEGY FOR A NEW NUCLEAR AGE

Current U.S. nuclear weapons strategy, force structure, and doctrine contribute to the threat of nuclear terrorism in several ways. First, the U.S. nuclear stockpile presents opportunities for nuclear terrorists to seize the materials they need. Second, U.S. nuclear forces remain a key justification for Russia's maintenance of similar nuclear forces that are less well protected. Third, America's continued embrace of nuclear weapons encourages and legitimizes other states to seek nuclear weapons that they will have difficulty securing from terrorists. The national security interests of the United States would be better served by a strategy to shrink the global footprint of nuclear weapons and provide the highest possible levels of security for the most minimal possible deterrent forces. Given the inability to secure nuclear weapons and materials perfectly or to eliminate terrorism in the foreseeable future, reducing the global inventory of nuclear weapons and materials is the most reliable way to reduce the chances of nuclear terrorism.     

Technical and proliferation‐related aspects of the dismantlement of Russian Alfa‐Class nuclear submarines

When does a state become a “nuclear weapon state”? How we choose to answer this question has significant implications for proliferation assessment, analysis, and policy. Traditionally, the standard demarcation line has been a state's first nuclear test, but in recent years analysts have increasingly focused instead on the accumulation of a significant quantity (SQ) of fissile material. The article argues that although the test/no-test indicator clearly has problems, its replacement by the SQ/no-SQ indicator would be highly counterproductive. The article instead proposes supplementing the traditional test/no-test indicator with a theory-driven approach that focuses on the incentives and disincentives to test.     

伴随掩护进攻分队时雷达干扰机队形研究

针对雷达干扰机伴随掩护任务的需要,通过分析进攻分队进攻队形,对雷达干扰机与进攻分队的协同提出约束,并以干扰效能发挥为依据,建立了队形模型和机队形优化模型。通过仿真分析,得出了不同队形情况下干扰效果随队形倾角变化的情况,并提出了队形选择的建议。     

电离层不规则体对P波段星载SAR成像的影响

电离层不规则体导致星载合成孔径雷达（SAR）信号产生幅度及相位闪烁,严重影响低波段星载SAR的图像分辨性能。推导了具有普遍性的幂律谱对应的双频双点互相关函数。基于此研究了电离层对星载P波段SAR分辨性能的影响及其规律。研究表明,电离层不规则体导致星载P波段SAR两维分辨率恶化,图像峰值增益损失严重。电离层不规则体强度,谱指数,外尺度等参数的增大都会导致星载SAR图像分辨率及峰值增益进一步下降。基于相位屏技术的数值仿真结果验证了本文研究。     

瞬态高强加热条件下含湿多孔介质传热传质模型研究

提出了瞬态高强加热下含湿多孔介质传热传质的新模型,模型包括的水分种类齐全、水分迁移机制全面,假设条件相对较少,考虑了非Fourier传热效应和非Fick传质效应。新模型通过具体的分区分析得到简化并更加实用。     

超磁致伸缩材料特性及其工程应用综述

超磁致伸缩材料是实现电磁能-机械能二者能量和信息高效转换的功能材料。介绍超磁致伸缩材料的特性及器件优异的性能,较全面综述超磁致伸缩材料在各个领域的应用与开发情况,分析开发超磁致伸缩器件需要解决的若干关键技术问题,展望超磁致伸缩材料广阔的应用和发展前景。     

双材料界面裂纹的加料有限元方法

为解决求解双材料界面裂纹应力强度因子等断裂参量的困难,在常规单元位移模式中引入界面裂纹尖端位移场,构建加料界面裂纹单元和过渡单元的位移模式,推出了加料有限元方程。采用不同的加料单元和过渡单元配置方案,建立了方形板中心界面裂纹和矩形板单边斜界面裂纹的加料有限元模型,求解有限元方程直接得到应力强度因子,与解析解的结果对比,表明该方法具有较高的精度,可方便地推广应用于界面裂纹的计算分析中。     

聚氨酯的合成及水声性能

用甲苯-2,4-二异氰酸酯(2,4-TDI)、聚丙二醇(PPG)等原料合成了聚氨酯预聚体,以3,3-二氯-4,4-二氨基二苯甲烷(MOCA)、三羟甲基丙烷(TMP)为扩链剂合成了聚氨酯,在脉冲声管中测试了合成试样的声压反射系数和吸声系数,研究了不同扩链剂及不同含量的2,6-二叔丁基-4-甲基苯酚(BHT)对其水下声学性能的影响。测试结果表明:TDI-PPG-MOCA合成型聚氨酯是一种良好的水下透声材料,TDI-PPG-TMP合成型聚氨酯是一种良好的水下吸声材料;BHT的加入对TDI-PPG-TMP合成型聚氨酯的水下吸声性能有显著提高,因此合理地设计实验工艺参数,可以得到水下声学性能更佳的聚氨酯。