The use of ionising radiation to image nuclear fuel:a review

Imaging of nuclear fuel using radiation has been carried out for decades for a variety of reasons. Two important reasons are Physical Inventory Verification (PIV) and Quality Assurance (QA). The work covered in this review focuses on the imaging of nuclear fuel using ionising radiation. The fuels investigated are both fresh and spent, composed of assorted materials, and in various physical forms. The radiations used to characterise the nuclear fuel include γ, α, β, muons, neutrons and X-rays. The research covered in this review, spans the past four decades and show how the technology has developed over that time. The advancement of computing technology has greatly helped with the progression of the images that are produced. The field began with 2D images in black and white showing the density profiles of rays from within an object, culminating in 2013 when a pebble bed fuel element was reproduced in 3D showing each 0.5 mm UO2 globule within it. With the ever increasing computing technology available to the industry, this can only mean an increase in the rate of development of imaging technologies like those covered in this review

McDonald v. Chicago: Which Standard of Scrutiny Should Apply to Gun-Control Laws?

In this debate, Professors Rosenthal and Malcolm debate the standard of scrutiny that the Supreme Court should apply to restrictions on the Second Amendment in the wake of its recent decision, McDonald v. City of Chicago. Professor Rosenthal begins Part I by noting the importance of gun-control laws to police; he considers a lower standard of scrutiny necessary to allow law enforcement officials to protect the community. Turning to the practical consequences of Chicago and Washington, D.C.\u27s recent gun-control laws, which make owning a gun nearly impossible in those cities, Professor Malcolm argues for a standard of strict scrutiny for all gun-control laws in Part II. Finally, in Part III, Professor Rosenthal replies

McDonald v. Chicago: Which Standard of Scrutiny Should Apply to Gun-Control Laws?

In this debate, Professors Rosenthal and Malcolm debate the standard of scrutiny that the Supreme Court should apply to restrictions on the Second Amendment in the wake of its recent decision, McDonald v. City of Chicago. Professor Rosenthal begins Part I by noting the importance of gun-control laws to police; he considers a lower standard of scrutiny necessary to allow law enforcement officials to protect the community. Turning to the practical consequences of Chicago and Washington, D.C.\u27s recent gun-control laws, which make owning a gun nearly impossible in those cities, Professor Malcolm argues for a standard of strict scrutiny for all gun-control laws in Part II. Finally, in Part III, Professor Rosenthal replies

The Decontamination of 137Cs Contaminated Concrete Using Electrokinetic Phenomena and Ionic Salt Washes in Nuclear Energy Contexts

his work describes the first known use of electrokinetic treatments and ionic salt washes to remediate concrete contaminated with 137Cs. A series of experiments were performed on concrete samples, contaminated with K+ and 137Cs, using a bespoke migration cell and an applied electric field (60 V potential gradient and current limit of 35 mA). Additionally, two samples were treated with an ionic salt wash (≤ 400 mol m-3 of KCl) alongside the electrokinetic treatment. The results show that the combined treatment produces removal efficiencies three times higher (>60%) than the electrokinetic treatment alone and that the decontamination efficiency appears to be proportional to the initial degree of contamination. Furthermore, the decontamination efficiencies are equivalent to previous electrokinetic studies that utilised hazardous chemical enhancement agents demonstrating the potential of the technique for use on nuclear licensed site. The results highlight the relationship between the initial contamination concentration within the concrete and achievable removal efficiency of electrokinetic treatment and other treatments. This information would be useful when selecting the most appropriate decontamination techniques for particular contamination scenarios

Reducing sensor complexity for monitoring wind turbine performance using principal component analysis

Availability and reliability are among the priority concerns for deployment of distributed generation (DG) systems, particularly when operating in a harsh environment. Condition monitoring (CM) can meet the requirement but has been challenged by large amounts of data needing to be processed in real time due to the large number of sensors being deployed. This paper proposes an optimal sensor selection method based on principal component analysis (PCA) for condition monitoring of a DG system oriented to wind turbines. The research was motivated by the fact that salient patterns in multivariable datasets can be extracted by PCA in order to identify monitoring parameters that contribute the most to the system variation. The proposed method is able to correlate the particular principal component to the corresponding monitoring variable, and hence facilitate the right sensor selection for the first time for the condition monitoring of wind turbines. The algorithms are examined with simulation data from PSCAD/EMTDC and SCADA data from an operational wind farm in the time, frequency, and instantaneous frequency domains. The results have shown that the proposed technique can reduce the number of monitoring variables whilst still maintaining sufficient information to detect the faults and hence assess the system’s conditions

Radiometric detection of non-radioactive caesium flux using displaced naturally abundant potassium

We report on a method that allows for the radiometric detection of non-radioactive caesium by the measurement of potassium ions displaced from an ion exchange barrier. Electrokinetic transport of K+ and Cs+ through concrete samples was measured using a bespoke scintillation detector to monitor electrolyte concentrations. Results show experimental ionic flux and diffusion parameters of non-active caesium (~1 × 10−5 mol m−3) were consistent with those recorded for potassium and also with values reported in relevant literature. This work demonstrates a novel concept that can be applied to proof-of-concept studies that help develop the next generation of nuclear decommissioning technologies