As global demand for nuclear energy and threats to nuclear security increase, the need for verification of the peaceful application of nuclear materials and technology also rises. In accordance with the Nuclear Nonproliferation Treaty, the International Atomic Energy Agency is tasked with verification of the declared enrichment activities of member states. Due to the increased cost of inspection and verification of a globally growing nuclear energy industry, remote process monitoring has been proposed as part of a next-generation, information-driven safeguards program. To further enhance this safeguards approach, it is proposed that process monitoring data may be used to not only verify the past but to anticipate the future via prognostic analysis. While prognostic methods exist for health monitoring of physical processes, the literature is absent of methods to predict the outcome of decision-based events, such as the production of undeclared enriched uranium. This dissertation introduces a method to predict the time at which a significant quantity of unaccounted material is expected to be diverted during an enrichment process. This method utilizes a particle filter to model the data and provide a Type III (degradation-based) prognostic estimate of time to diversion of a significant quantity. Measurement noise for the particle filter is estimated using historical data and may be updated with Bayesian estimates from the analyzed data. Dynamic noise estimates are updated based on observed changes in process data. The reliability of the prognostic model for a given range of data is validated via information complexity scores and goodness of fit statistics. The developed prognostic method is tested using data produced from the Oak Ridge Mock Feed and Withdrawal Facility, a 1:100 scale test platform for developing gas centrifuge remote monitoring techniques. Four case studies are considered: no diversion, slow diversion, fast diversion, and intermittent diversion. All intervals of diversion and non-diversion were correctly identified and significant quantity diversion time was accurately estimated. A diversion of 0.8 kg over 85 minutes was detected after 10 minutes and predicted to be 84 minutes and 10 seconds after 46 minutes and 40 seconds with an uncertainty of 2 minutes and 52 seconds.

Nuclear energy is currently one of the world’s main sources of electricity. Closely connected to the use of nuclear energy are important issues such as the nonproliferation of fissile material that may potentially used in nuclear weapons (safeguards), and the management of the highly radioactive nuclear waste. This thesis addresses both these issues by contributing to the development of new experimental methods for ensuring safe and secure handling of the waste, with focus on methods to be used prior to encapsulation and final storage. The methods rely on high resolution gamma ray spectroscopy (HRGS), involving the measurement and analysis of emitted gamma radiation from the fission products 137Cs, 134Cs and 154Eu. This technique is nondestructive, making it relatively nonintrusive with respect to the normal operation of the nuclear facilities. For the safeguards issue, it is important to experimentally verify the presence and identity of nuclear fuel assemblies and also that the fuel has experienced normal, civilian reactor operation. It has been shown in this thesis that the HRGS method may be used for verifying operator declared fuel parameters such as burnup, cooling time and irradiation history. In the experimental part of the work, the burnup and the cooling time has been determined with an accuracy of 1.6% and 1.5%, respectively (1 σ). A technique has also been demonstrated, utilizing the ratio 134Cs/154Eu, with which it is possible to determine whether a fuel assembly is of MOX or LEU type. This is of interest for safeguards as well as for the safe operation of a final storage facility. As an improvement to the HRGS technique, measuring a part of the fuel assembly length in order to reduce measurement time has been suggested and investigated. A theoretical case for partial defect verification has also been studied as an extension of the HRGS technique. Finally, HRGS has been used for determining the decay heat in spent nuclear fuel assemblies, which is of importance for the safe operation of a final storage facility. This application is based on the radiation from 137Cs, and the accuracy demonstrated was within 3% (1 σ).

It has been shown that neutrons emitted from the same 252Cf fission event are preferentially detected within small angles of each other and at angles around 180 degrees. The distribution of this angular anisotropy is dependent upon the nuclide emitting the neutrons. Coincident neutrons can be detected from a shielded source, so a study of the angular anisotropy between coincident neutrons is useful for this context. This could allow for the dynamic determination of the ratio of the rate of (alpha,n) neutron production to the spontaneous fission neutron production (designated alpha) used in neutron coincidence counting for safeguards. This could also be used to identify neutron emitting isotopes in a homeland security application. An angular frequency distribution for coincident neutrons was produced via experiments using an array of cylindrical liquid scintillators and a 252Cf source. It was found, in accordance with previous experiments, that the angular frequency distribution peaks at small angles and at angles around 180 degrees. A Monte Carlo, physics-based simulation program was created to simulate the distribution of angles between neutrons from the same fission event from 252Cf and 240Pu sources. The resulting distributions were clearly distinguishable from each other. The code was benchmarked to measured results from a 252Cf source at Lawrence Livermore National Laboratory. Knowledge of the unique angular distributions of coincident neutrons from various fissioning sources is useful for identification and verification purposes. Another practical application of angular anisotropy information for coincident neutrons from a given source is determining the ratio of the (alpha,n) to spontaneous fission rates for a source undergoing neutron coincidence counting. The utility of this was verified by using measurements made by faculty and students of the University of Michigan Nuclear Engineering Department for a MOX fuel pin at the Joint Research Center in Ispra, Italy. Good agreement between the predicted and declared values for alpha was found.

Reprocessing nuclear fuel is becoming more viable in the United States due to the anticipated increase in construction of nuclear power plants, the growing stockpile of existing used nuclear fuel, and a public desire to reduce the amount of this fuel. However, a new reprocessing facility in non-weapon states must be safeguarded and new reprocessing facilities in weapon states will likely have safeguards due to political and material accountancy reasons. These facilities will have state of the art controls and monitoring methods to safeguard special nuclear materials, as well as to provide real-time monitoring. The focus of this project is to enable the development of a safeguards strategy that uses well established photon measurement methods to characterize samples from the UREX+3a reprocessing method using a variety of detector types and measurement times. It was determined that the errors from quantitative measurements were too large for traditional safeguards methods; however, a safeguards strategy based on qualitative gamma ray and neutron measurements is proposed. The gamma ray detection equipment used in the safeguard strategy could also be used to improve the real-time process monitoring in a yet-to-be built facility. A facility that had real-time gamma detection equipment could improve product quality control and provide additional benefits, such as waste volume reduction. In addition to the spectral analyses, it was determined by Monte Carlo N Particle (MCNP) simulations that there is no noticeable self shielding for internal pipe diameters less than 2 inches, indicating that no self shielding correction factors are needed. Further, it was determined that HPGe N-type detectors would be suitable for a neutron radiation environment. Finally, the gamma ray spectra for the measured samples were simulated using MCNP and then the model was extended to predict the responses from an actual reprocessing scenario from UREX+3a applied to fuel that had a decay time of three years. The 3-year decayed fuel was more representative of commercially reprocessed fuel than the acquired UREX+3a samples. This research found that the safeguards approach proposed in this paper would be best suited as an addition to existing safeguard strategies. Real-time gamma ray detection for process monitoring would be beneficial to a reprocessing facility and could be done with commercially available detectors.

Made available in DSpace on 2014-10-09T12:28:35Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:02Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IEA/T / Universidade Karlsruhe, Alemanha

Made available in DSpace on 2014-10-09T12:28:35Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:02Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IEA/T / Universidade Karlsruhe, Alemanha

The safeguards verification of spent nuclear fuel is one of the major concern for the safeguards community, as this material represents about 80% of all material placed under safeguards.This PhD thesis described the development of two passive non-destructive assay (NDA) techniques: the Self-Indication Neutron Resonance Densitometry (SINRD) and the Partial Defect Tester (PDET).The NDA methods were investigated with Monte Carlo simulations and the benchmark experiments for SINRD were performed at the GELINA facility of JRC-IRMM in Geel, Belgium.The results for the SINRD technique showed promising results for the direct quantification of 239Pu in spent fuel, and both techniques gave encouraging results for the detection of partial defects. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

The electrorefiner (ER) is the heart of pyroprocessing technology operating at a high-temperature (723 K – 773 K) to separate uranium from Experimental Breeder Reactor-II (EBR-II) used metallic fuel. One of the most common electroanalytical methods for determining the thermodynamic and electrochemical behavior of elemental species in the eutectic molten salt LiCl-KCl inside ER is cyclic voltammetry (CV). Information from CV can possibly be used to estimate diffusion coefficients, apparent standard potentials, transfer coefficients, and numbers of electron transferred. Therefore, predicting the trace of each species from the CV method in an absence of experimental data is important for safeguarding this technology. This work focused on the development an interactive computational design for the CV method by analyzing available uranium chloride data sets (1 to 10 wt%) in a LiCl-KCl molten salt at 773 K under different scan rates to help elucidating, improving, and providing robustness in detection analysis. A principle method and a computational code have been developed by using electrochemical fundamentals and coupling various variables such as: the diffusion coefficients, formal potentials, and process time duration. Although this developed computational model works moderately well with reported uranium data sets, it experiences difficulty in tracing zirconium data sets due to their complex CV structures. Therefore, an artificial neural intelligent (ANI) data analysis has been proposed to resolve this issue and to provide comparative study to the precursor computational modeling development. For this purpose, ANI has been applied on 0.5 to 5 wt% of zirconium chloride in LiCl-KCl eutectic molten salt at 773 K under different scan rates to mimic the system and provide current and potential simulated data sets for the unseen data. In addition, a Graphical User Interface (GUI) through the commercial software Matlab was created to provide a controllable environment for different users. The computational code shows a limitation in high concentration CV prediction, capturing the adsorption peaks, and provides a dissimilarity. However, the model is able to capture the important anodic and cathodic peaks of uranium chloride CV which is the main focus of this study. Furthermore, the developed code is able to calculate the concentration of each species as a function of time. Due to the complexity of the CV of zirconium chloride, the computational model is used to predict the probability reactions occurring at each peak. The resulting study reveals that the reaction at the highest anodic peak is related to the combination of 70% Zr/Zr+4 and 30% Zr/Zr+2 for the 1.07 wt% and 2.49 wt% zirconium chloride and 30% Zr/Zr+4 and 70% Zr/Zr+2 combination for 4.98 wt% ZrCl4. The proposed alternative ANI method has demonstrated its capability in predicting the trend of species in a new situation with a high accuracy on predictions without any dissimilarity. Two final structures from zirconium chloride study which high accuracy (that is, a low error) are related to [9, 15, 10]-18 and [10, 11, 25]-19. These two final structures have been applied on uranium chloride salt experimental data sets to further validate the ANI’s ability and concept. Three different fixed data combinations were considered. The result indicates that by increasing the number of training data sets it does not necessarily help improving the prediction process. ANI implementation outcome on uranium chloride data set illustrates a good prediction with a specific fixed data combination and [9, 15, 10]-18 structure. Thus, it can be concluded that ANI is a promising method for safeguarding pyroprocessing technology due to its robustness in predicting the CV plots with high accuracy.

Privacy entails controlling the use and access to place, location and personal information. In South Africa, the first privacy legislation in the form of the Protection of Personal Information (POPI) Act (Act 4 of 2013) was signed into law on 26 November 2013. The POPI Act promotes the protection of personal information by South African institutions and specifies the minimum requirements in 12 Chapters, which includes 8 Conditions for lawful processing of personal information. Condition 7 of the POPI Act makes specific provision for security safeguards to ensure the confidentiality and integrity of personal information. While the legislative requirements of Condition 7 of the POPI Act are spelt out in Sections 19, 20, 21 and 22, the requirements are not supported by specific guidance in terms of how these should be satisfied. There is also no specific guidance on the security safeguards, as required in Section 19, to ensure the confidentiality and integrity of personal information. Hence, this thesis - which focuses on electronic personal information - proposes a framework that includes a selection of security safeguards that may serve as a frame of reference and be used by South African institutions that store, process and transmit electronic personal information, to achieve and maintain compliance with Condition 7 of the POPI Act. As part of this study, a POPI research survey is used to assess the current state of security safeguards in South African institutions and to validate the selection of security safeguards of the proposed framework. In addition, a model of operation of security safeguards is proposed to guide one on how the selection of security safeguards should be implemented to achieve and maintain confidentiality and integrity of electronic personal information as required by Condition 7 of the POPI Act. Furthermore, this thesis explores the concept and principles of privacy as well as the importance of privacy and provides an overview of the global privacy legislative landscape, including South African privacy legislation. An analysis is also conducted to assess the extent to which the privacy legislation of the European Union (EU) and South Africa addresses the international 2013 Organisation for Economic Co-operation and Development (OECD) guidelines. The POPI research survey is also used to assess the level of compliance with the POPI Act and specifically Condition 7 of the Act. In addition, the POPI research survey is used to assess the financial value associated with electronic personal information and the potential impact of a data breach of electronic personal information. / Thesis (PhD)--University of Pretoria, 2017. / Computer Science / PhD / Unrestricted

Cheating in Online Classes: A Preliminary Investigation, Mirella Baker Bemmel, 2014: Applied Dissertation, Nova Southeastern University, Abraham S. Fischler School of Education. ERIC Descriptors: Cheating, Online, Academic Integrity, Community College, Safeguards This applied dissertation was an inquiry into the phenomenon of cheating among students who take their classes online. There is a common perception that cheating is rampant in online classes and the Southern Association of Colleges and Schools, the accreditation association in the South, implemented policies, which mandate stricter monitoring of students. In turn, colleges have reevaluated or implemented integrity policies, but there is inconsistent enforcement of said policies. Online faculty at three Florida community colleges were invited to complete a modified version of the Academic Integrity Survey, which provided insights into their perception of cheating, their awareness and enforcement of institutional policies regarding cheating and safeguards used or desired. The survey was followed up with an eight-member focus group discussion, and the results were triangulated. An analysis of the data revealed that faculty is uncertain about the extent of cheating at their college, but most take action once they discover an instance of cheating. Their reaction to cheating may not necessarily be in line with the institutional policy although they are aware of the required steps. Different safeguards are used to protect the integrity of their courses, but there is an apparent lack of knowledge about available safeguards and their use.