Electromigration Separation of Lithium Isotopes: The Effect of Electrode Solutions

Both lithium-6 and lithium-7 with high abundance are indispensable materials in nuclear industry. Here, an aqueous solution│organic solution│aqueous solution system was fabricated to separate lithium isotopes. The effects of species and concentration of electrolytes in the electrode solutions on the lithium ions migration and lithium isotope separation with different voltages and migration time was studied. It was found that lithium-7 was enriched in aqueous solutions on both sides at 0 V and 2 V, while lithium-7 was enriched in anode solution and lithium-6 was enriched in cathode solution at 16 V. The weakening stability of the chelate consisted of crown ether and lithium ion with increasing voltage was believed to the possible reason. Meanwhile, the variation of electrolyte in electrode solution led to notable changes in migration ratio of lithium ions and lithium isotope separation effect, which can be attributed to the different degree of both ionization and hydrolysis for various electrolytes in aqueous solutions and the different ability of H+ and NH4+ to replace Li+ of chelate in organic solutions. This work is of great significance for the selection of electrode solutions in electromigration separation of lithium isotopes and even other electrochemical systems.

Hydrogen Isotopes Permeation in Clean or Unoxidized FeCrAl Alloys: A Review

The US Department of Energy is working with fuel vendors to develop accident tolerant fuels (ATF) for the current fleet of light water reactors (LWRs). The ATF should be more resilient to loss of coolant accident scenarios and help extending the life of the operating LWRs. One of the proposed ATF concepts is to use iron-chromium-aluminum (FeCrAl) alloys for the cladding of the fuel. A concern in using ferritic FeCrAl is that this type of cladding may result in an increase in the concentration of tritium in the coolant. The objective of the current critical review is to collect and assess information from the literature regarding diffusion or permeation of hydrogen (H) and its isotopes deuterium (D) and Tritium (T) across industrial alloys (including FeCrAl) used or intended for the nuclear industry. Over a hundred years of data reviewed shows that the solubility of hydrogen in ferritic alloys is lower than in austenitic alloys but hydrogen permeates faster through a ferritic material than through austenitic materials. The tritium permeation rates in FeCrAl alloys are between those in austenitic stainless steels and in ferritic FeCr steels. The activation energy for hydrogen permeation is approximately 30 pct higher in the austenitic alloys compared with the ferritic (typically ∼ 50 kJ/mol in ferritic vs. ∼ 65 kJ/mol in the austenitic). None of the major elements in FeCrAl alloys react with hydrogen to form detrimental hydride phases. The effect of surface oxides on FeCrAl delaying hydrogen entrance into FeCrAl alloy is not part of this review.

Development of a Risk Classifier as a Stage of Successful Risk Management

The article gives the analysis of approaches to risk classification at industrial enterprise. Based on the findings, conclusions about advantages and disadvantages were drawn up, as well as the possibilities for its application at nuclear enterprises are formulated. The authors propose an original personalized approach to risk classifier development, which takes into account the nuclear industry specifics. An example of an algorithm for risk classifier development based on above-mentioned approach for the enterprise of the Rosatom State Corporation is given. This example can be used in various industries and may be of interest to risk management researchers and specialists.

Nuclear Laws for Peaceful Uses of Nuclear Energy

The development and utilization of nuclear energy is one of the greatest achievements of the 20th century. It has greatly enhanced the ability of humanity to understand and shape the world and had a significant impact on the development of technology and civilization. In the 21st century, the United Nations (UN) has developed the “Millennium Development Goals” and the “2030 Sustainable Development Goals” to promote a comprehensive solution to the world’s social, economic and environmental issues. To this end, nuclear energy offers unique advantages, but the associated risks and challenges of its further development and utilization must be addressed. Nuclear law is a powerful tool for regulating its development and responding to those risks and challenges. The Chinese Government has always developed nuclear energy for peaceful purposes in a safe and innovative way. At the Nuclear Security Summit in 2014, President Xi Jinping proposed adhering to a rational, coordinated and balanced approach to nuclear security and promoting a fair, cooperative and win–win international nuclear security regime. This not only summarizes China’s experience in establishing a nuclear legal framework and developing nuclear industry, but would also strengthen international nuclear governance and promote nuclear energy to better benefit humanity. The international community should fulfil international obligations strictly, implement national responsibilities effectively, and jointly maintain the UN focused international system and international legal order, contributing to the realization of the common goal of “Atoms for Peace and Development”.

Effect of brazing temperatures on microstructure and properties of TC4/Ti57Zr13Cu21Ni9/316L

Titanium alloy is an important metal material with excellent specific strength, which is widely used in aerospace field, nuclear industry, chemical medicine, and military industry. In order to investigate the connection conditions of TC4 titanium alloy and 316L stainless steel at different temperatures, the braze welding measurement with Ti57Zr13Cu21Ni9 filler metal was conducted in vacuum. The microstructure, morphology and phase of the joint were characterized by SEM (scanning electron microscope), EDS (Energy Dispersive Spectrometer) and XRD (X-ray diffraction), respectively. Microhardness and shear strength of the joint at room temperature and the bonding mechanism of TC4 and 316L were also investigated. The obtained results revealed that the main phases in the diffusion layer were Ti-based solid solution and Ti-Fe (TiFe and TiFe2) intermetallic compoundsands (IMCs) the center of the braze was mainly composed of Ti-Fe IMCs, (Ti, Zr)2(Ni, Cu), Ti-based solid solution. Additionally, the increase of brazing temperature firstly increased and then decreased the average shear strength with the maximum value of 133.9 MPa at 960 °C.

Nuclear Liability and Post-Fukushima Developments

The international community has developed a series of conventions on civil liability for nuclear damage, which aim to ensure compensation is available for damage, including transboundary damage, caused by a nuclear incident. Those conventions have struggled to gain universal adherence, and the “global regime” called for in 2011 is at best a patchwork quilt, with a number of treaties with differing memberships, and many States (including States with large and growing nuclear sectors) not party to any convention. However, the principles of the conventions are reflected in national laws in most States which operate nuclear power reactors and associated facilities. This chapter assesses the current global nuclear liability regime and discusses a series of recommendations made by the International Expert Group on Nuclear Liability (INLEX) to allow the international community to respond to the continued evolution of the nuclear industry.

DEVELOPMENT TRENDS OF REGULATORY AND LEGAL REGULATION OF THE IMPLEMENTATION OF NEW TECHNOLOGIES IN THE FIELD OF USE OF ATOMIC ENERGY

Based on the analysis of changes in the atomic legislation of individual foreign countries, the article identifies trends in the development of legal regulation of the introduction of new technologies in the field of atomic energy use and concludes that they go beyond the traditionally conservative culture of nuclear energy and require new incentives and approaches to their regulatory and legal regulation, developed through dialogue between regulators, the nuclear industry and science.

A Novel Method for Measuring the Length of Hot Large Forgings Based on Machine Vision System

Large forgings can be applied to manufacture key parts in large equipment used in petrochemical, shipbuilding, aerospace, nuclear industry. At present, the size of hot large forgings is mainly measured by hand-hold calipers or mechanical gauges through contact measurement method. In order to realize non-contact length measurement of hot large forgings, a novel method for measuring the length of hot large forgings based on machine vision system is proposed. Firstly, the light strips are recognized according to the continuous characteristics of the light stripes in the image acquired by the hot forging dimension measurement system based on machine vision. Secondly, using the sub-pixel edge of light strips acquired by the improved sub-pixel edge detection algorithm, the three-dimension (3D) points of each edge of light strips are calculated, respectively. Lastly, the two-dimensional (2D) points projected from the 3D points onto the fitted plane are used for curve fitting, and the edge of hot part corresponding to each light strip edge is calculated according to the curvature of the fitted curves. The distance between the start point and the edge point on each light strip edge is considered as the length of hot forging at the corresponding edge of each light strip. The length measurement experiment shows that the method can be used to calculate the length of hot large forgings. The measurement error of the length measurement system when measuring part at room temperature is 0.547%. The time for measuring the length of hot forging is 6.8s.