Theses and Dissertations from UMD
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Item U.S. NUCLEAR ENERGY COOPERATION AND PARTNER COUNTRY NONPROLIFERATION: CASE STUDIES FROM EAST ASIA(2022) Siegel, Jonas Elliott; Gallagher, Nancy; Public Policy; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)U.S. policy makers are promoting U.S. civilian nuclear exports as a means of influencing the nonproliferation policies of foreign governments and of achieving U.S. nuclear nonproliferation objectives. This approach to nonproliferation policy making assumes that engaging in international civilian nuclear cooperation is effective at influencing partner country nonproliferation commitments and behavior, and that it is more efficient and effective than other means of achieving similar nonproliferation goals. This dissertation tests these assumptions by examining the historical nonproliferation impact of U.S. civilian nuclear cooperation on three countries who sought to build civilian nuclear power programs with U.S. assistance: Japan, South Korea, and China. These case studies place U.S. civilian nuclear energy cooperation in the context of broader U.S. security and economic relations with these countries, and provide a nuanced understanding of each countries’ rationales for engaging in nuclear cooperation and nonproliferation in the first place. This dissertation also develops a novel approach to measuring nonproliferation that focuses on a country’s nonproliferation behavior in addition to its policy commitments. It also assesses whether particular types and stages of U.S. civilian nuclear cooperation and/or the characteristics of U.S. partners affect the strength and direction of the relationship between nuclear cooperation and nonproliferation. In examining multiple periods of U.S. civilian nuclear cooperation with each country, this dissertation finds that U.S. civilian nuclear energy cooperation—and more specifically, the process of negotiating and renegotiating the terms of nuclear cooperation—can be effective ways to induce U.S. partner countries to adopt nonproliferation commitments. This is particularly the case when U.S. partners are energy insecure and rely predominantly (or exclusively) on foreign assistance in developing their civilian nuclear programs. U.S. civilian nuclear cooperation coupled with U.S. security cooperation (including nuclear security guarantees) can often win U.S. policy makers additional, detailed nonproliferation commitments from partner countries that are not possible with security cooperation alone. The dissertation also finds that U.S. civilian nuclear cooperation has limited impact on the nonproliferation behaviors of U.S. partners in the short run once they formally make nonproliferation commitments. In all three cases, U.S. partners’ nonproliferation behaviors improve over time, but these improvements are due to the partners’ internalization of global nonproliferation norms and partners’ development of their own nonproliferation logic, rather than the influence of U.S. civilian nuclear cooperation. Frequent changes in U.S. nonproliferation preferences and, in particular, the divergence of U.S. nonproliferation preferences from the baseline tenets of the multilateral nonproliferation regime make it costly and difficult for the United States to maintain influence on partner countries’ nonproliferation commitments and behaviors over time with civilian nuclear cooperation. On account of these findings, this dissertation argues that in many situations, U.S. civilian nuclear cooperation is not an effective means of achieving U.S. nonproliferation objectives. Compared to other possible courses of action, such as reinforcing multilateral nonproliferation agreements and norms, or engaging in nonproliferation capacity building, U.S. civilian nuclear cooperation is also not efficient in achieving U.S. aims. Should U.S. policy makers continue to pursue civilian nuclear cooperation as a means of achieving U.S. nonproliferation objectives, they should be aware of the conditions that are most conducive to U.S. nonproliferation influence, and they should be realistic about the challenges and costs associated with maintaining that influence over time.Item THE ISOTOPIC ABUNDANCE OF CESIUM IN TRINITITE: IMPLICATIONS FOR POST-DETONATION ANALYSIS OF NUCLEAR MATERIALS(2013) Borg, Dana Tamara; McDonough, William F; Geology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Currently, there are few studies of post-detonation materials due to their extremely complex nature. The cesium isotopic composition of trinitite, the product of the first nuclear detonation, was determined using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) to evaluate the relationship between the time since the detonation of nuclear materials and their cumulative fission yields. The ratio of 137Cs/135Cs in trinitite was found on average to be 0.31±0.06, with abundances of 137Cs (t1/2=30.07a) and 135Cs (t1/2=2.3x106a) equal to 21.8±0.6pg/g and 68±12pg/g, respectively. These values result in an under-calculation of the amount of time that has passed since detonation. It is recommended that an initial 137Cs/135Cs ratio of 1.5±0.3 be used, instead of the proportion that they are produced during fission of 239Pu 0.87±0.02, due to the fractionation of 137Cs and 135Cs before their deposition in trinitite due to the approximately 200 times longer cumulative half-life of the precursors to 135Cs.Item Reliability-Based Design Of Piping: Internal Pressure, Gravity, Earthquake, and Thermal Expansion(2007-08-09) Avrithi, Kleio; Ayyub, Bilal M.; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Although reliability theory has offered the means for reasonably accounting for the design uncertainties of structural components, limited effort has been made to estimate and control the probability of failure for mechanical components, such as piping. The ASME B&PV Code, Section III, used today for the design of safety piping in nuclear plants is based on the traditional Allowable Stress Design (ASD) method. This dissertation can be considered as a primary step towards the reliability-based design of nuclear safety piping. Design equations are developed according to the Load and Resistance Factor Design (LRFD) method. The loads addressed are the sustained weight, internal pressure, and dynamic loading (e.g., earthquake). The dissertation provides load combinations, and a database of statistical information on basic variables (strength of steel, geometry, and loads). Uncertainties associated with selected ultimate strength prediction models -burst or yielding due to internal pressure and the ultimate bending moment capacity- are quantified for piping. The procedure is based on evaluation of experimental results cited in literature. Partial load and resistance factors are computed for the load combinations and for selected values of the target reliability index, β. Moreover, design examples demonstrate the procedure of the computations. A probabilistic-based method especially for Class 2 and 3 piping is proposed by considering only cycling moment loading (e.g., thermal expansion). Conclusions of the study and provided suggestions can be used for future research.