Nuclear Material Control Research Articles

A Proposed Non-Intrusive System for the Verification of Sensitive Nuclear Material

One of the primary challenges in negotiating treaties related to the control of Nuclear Materials (NM) is the verification process, particularly when dealing with sensitive information. Normally, in this process, the inspector utilizes a suitable measuring system to verify the declared information. The difficulty may arise whenever sensitive information related to the NM should not be released to an inspector. Simultaneously, the NM owner (operator) should remain unaware of the measuring system employed by the inspector to prevent any probable manipulation. To address this issue, a neutral third party is assumed to act as an intermediary, who matches the data declared by the operator with the results obtained by the inspector, without exchanging any information between them. In this work, a Non-Intrusive System (NIS) is proposed and tested to play this role. The system receives data and information from both the operator and the inspector in the form of CAD or Monte Carlo (MC) input files, in addition to the results of measurements performed by the inspector. Then the system performs calculations and combines the results of these calculations with the inspector's measurement result to estimate the mass of the NM. The only information automatically conveyed to the inspector is the final conclusion regarding whether the declared and the estimated masses of NM are matched or not. The proposed NIS concept is tested using samples of NMs, and the results are presented.

The transformation of the nuclear law of the Russian Federation into an independent public complex branch of law as a way to strengthen global nuclear security in the world

This article considers the process of transformation of the Russian Federation nuclear law into an independent public complex branch of law and its important role in improving global nuclear safety. Since it is well known that the criteria of distinguishing branches of law are usually the subject and method of legal regulation as well as the existence of their own codification, the authors are confident of such a need. The results of the analysis of the state corporation Rosatom activities serve as the basis for the proposed theses and only confirm this confidence. The main idea of the article is to assert the need for changes in the Russian legal system structure in order to increase the effectiveness of regulation in the field of nuclear safety. The paper examines the evolution of nuclear law in Russia, identifies the basic principles and norms of this area of law as well as the need to make changes to adapt to modern challenges and threats. Supporting its position by analyzing the current state of the Russian nuclear industry and world standards in the field of nuclear safety, the article suggests practical steps to strengthen legal regulation to ensure safety in the nuclear field. Special attention is paid to the importance of strengthening international nuclear safety through the modernization of the national nuclear legal system, its compliance with international norms and standards. The article discusses current issues, including the development of nuclear doctrine, control of nuclear materials, responsibility for violation of international nuclear obligations and other aspects affecting global nuclear security. The study is an important contribution to understanding the problems of nuclear law in the context of global safety, and also substantiates the need for independent development of this branch of law to ensure stability and security on the world stage. The authors of the article offer specific recommendations for improving legislation and practice in the field of nuclear law in order to strengthen global nuclear safety

Electrochemical Identification of Metal Chlorides in Eutectic LiCl-KCl Without Prior Knowledge of Analyte Identities

The identities of unknown analytes within four eutectic LiCl-KCl melts were determined using electrochemical methods, simulating the uncertainty of electrochemically probing an electrorefiner salt bath or molten salt nuclear reactor. With a variety of electrochemical methods (e.g. cyclic voltammetry, chronopotentiometry, and square-wave voltammetry), and electroanalytical techniques (e.g. semi-differentiation), every analyte was positively identified, although one false positive occurred because of an unexpected chemical interaction. This study highlights some remaining challenges for the use of electrochemical sensors in nuclear material control and accountability in molten salts: (1) quantification of analytes without the use of calibration curves (e.g. error in property values, such as diffusion coefficient) and (2) additional and interfering electrochemical signals due to interaction and alloying of multiple species.

Characterization and verification of low-enriched uranium plate using a non-destructive methodology

Non-destructive methods play a crucial role in evaluating the integrity of nuclear materials. During the production of low-enriched mini-uranium plates, some destructive tests were initially employed to assess parameters such as uranium meat density, homogeneity, 235U enrichment, and meat distribution within the clad. While these destructive methods provide precise measurements during the manufacturing process, they become impractical and costly post-fabrication. Consequently, non-destructive tests are employed for quality control, verification, and inspection of nuclear materials. Laboratories and factories are developing non-destructive methods that yield results closely aligned with destructive measurements. The present research focuses on creating non-destructive measurements for verifying 235U enrichment and meat distribution in mini-uranium plates. This innovative approach involves utilizing 235U gamma emission as input to calculate enrichment and meat distribution. High purity germanium (HPGe) and sodium iodide (NaI) detectors alongside MCNPX code for efficiency correction were used in the proposed non-destructive measurements, respectively. The obtained results were validated and verified against certified measurements and x-ray images of mini-uranium plate. The enrichment measurement exhibited consistency with certified measurements, with about 0.8% difference. Similarly, the meat distribution measurement aligned with the x-ray image of the plate. This research proposes a practical application for nuclear material control during mini-uranium plate fabrication and for ensuring accountability and verification of inventory in storage facilities.

The Contribution of Latin America and the Caribbean to Multilateral Nuclear Nonproliferation and Disarmament

This article addresses the developments and interconnections between regional and global-level negotiations to prohibit nuclear weapons. Ambassador Sergio Duarte, who has been one of the leading negotiators on nuclear weapons disarmament and nonproliferation since the 1960s and is the current president of the Pugwash movement, traces the history of Latin American and Caribbean efforts to forge stronger ties and foster regional cooperation. He goes back to the first quarter of the nineteenth century to show how those ties laid the ground for the conception of the Treaty of Tlatelolco, the first Nuclear-Weapons-Free Zone in a populated area, and facilitated the region’s active role in nuclear affairs. He also dives into other successful arrangements, such as the creation of a binational agency (ABACC) that ensures control of nuclear materials in cooperation with the International Atomic Energy Agency (IAEA) to build confidence and increase cooperation in the nuclear field, and he describes the region’s key role in enabling the Treaty on the Prohibition of Nuclear Weapons (TPNW).

METHODS AND MEANS OF CONTROL OF NUCLEAR MATERIALS AND STATUS OF PROTECTIVE BARRIERS AT NPP IN WARTIME CONDITIONS

METHODS AND MEANS OF CONTROL OF NUCLEAR MATERIALS AND STATUS OF PROTECTIVE BARRIERS AT NPP IN WARTIME CONDITIONS

Gamma-ray spectra of post-irradiated uranium salt for total mass accounting with sodium-22 tracer

In order to meet the safeguard requirements for Nuclear Material Control and Accountability (MC&A) in liquid-fueled molten salt reactors, fuel salt transportation, and fuel cycle processes, it is important to develop effective methods for measuring and monitoring the mass of molten fuel salt or coolant salt. This paper seeks to validate the radioactive tracer dilution (RTD) method used for determining the mass of irradiated uranium-bearing molten salt. Small scale testing was conducted for this method by irradiating 6.065 g of MgCl–KCl–UCl3 salt mixture with 1.21 mg of 235U at The Ohio State University, resulting in a neutron fluence of 4.0 × 1016 n/cm2. Gamma spectra were acquired over the course of a 42-day period starting in March 2023 to assess fission products and activity levels of the 22Na tracer that was added before irradiation. No additional interference peaks were observed to overlap with the 1274.54 keV energy peak from 22Na, aside from the known 154Eu peaks, which can be corrected based on prior studies. By placing a thin piece of lead between the source and detector, deadtime was effectively reduced while still allowing observation of the higher-energy peaks, most notably around the 154Eu peak at 1004.76 keV used for interference correction. Overall, the uranium salt irradiation techniques applied in this experiment demonstrate the potential of the RTD method to effectively measure small irradiated samples for large scale molten fuel salt applications.

Demonstration of INCC6 for advanced list-mode data acquisition and analysis using ALMM

The International Neutron Coincidence Counting (INCC) software plays an important role in nuclear safeguards and nuclear material control and accounting (NMC&A) measurements. While the current version, INCC5, represents the traditional standard utilized by inspectorates as well as facilities and practitioners alongside shift register hardware, LANL has recently developed an upgraded version of the software, INCC6. INCC6 offers the same analysis tools as INCC5 while adding new capabilities including acquisition and analysis of list-mode data, recording and storage of list-mode data files, and an expanded set of advanced analysis tools that make use of the additional information available from list-mode data. This paper presents the first demonstration of data acquisition and analysis using INCC6 and the Advanced List Mode Multiplicity Module (ALMM). The capability of INCC6 to perform live list-mode data acquisition and analysis is demonstrated for a variety of neutron sources with a range of neutron emission rates relevant for practical applications and validated against the results obtained with INCC5 and traditional shift register hardware. Advanced list-mode analysis tools introduced by INCC6, such as time-interval and coincidence matrix analysis, are also demonstrated. Finally, the capability of INCC6 to analyze list-mode data files is tested and validated against traditional shift register results using INCC5.

Nuclear security in public events

Nuclear and radioactive materials provide a great benefit to humanity through the production of vast amounts of energy to meet critical development needs and mitigate the threat of climate change. These materials also have a vital role in primary life fields such as medicine, industry, agriculture, research, and education. They are used in safe environments and with firm and sufficient security conditions. However, there is a high probability of some breaches that include some radioactive materials getting out of control, which may lead to harmful consequences. For example, terrorist groups may obtain radioactive sources with high radioactivity to use them for terrorist purposes. These threats have led to a global trend towards increasing the control, inventory, and security of nuclear and radioactive materials to prevent their use for any illegal purpose causing harm to individuals or polluting the environment. Such a situation constitutes a huge complication of the safety scope, presenting security issues that must be addressed effectively. In an environment where terrorist groups could use nuclear materials to attack, organizing a large public event poses significant security challenges for security officials whose duty is to prevent the use of nuclear and other radioactive materials for criminal or terrorist purposes. These nuclear and other radioactive materials pose serious health, social, psychological, economic, and political threats.Consequently, this review paper aims to describe the procedures that lead to preventing hostilities related to nuclear and radioactive materials, detecting, and responding to such actions, and helping to prevent the loss of control over these materials by describing nuclear security systems and appropriate measures to enhance the effectiveness and efficiency of comprehensive security for a large public event.

Neutron and gamma-ray signatures for the control of alpha-emitting materials in uranium production: A Nedis2m-MCNP6 simulation

The radiations emitted via 19F(α,nγ), 19F(α,pγ), and 19F(α,α′γ) reactions in compounds containing alpha-emitting elements and fluorine are used for non-destructive neutron and gamma-ray analyses in monitoring the contents of nuclear fissile materials during the manufacture, processing, and storage of nuclear fuels. As far as the literature survey confirms, the data available on the yield of (α,n) reaction on fluorine, which depends on alpha particle energy, have significant dispersion. For the accompanying gamma-rays, on the other hand, no reliable absolute data exist for the production yield of gamma-rays per number of interacting alpha particles or emitted nucleons as a function of alpha particle energy. Therefore, to improve the monitoring and control of nuclear materials and to ensure the safety of production processes, the present study was undertaken, where the neutron yields and energy spectra were calculated using the Nedis-2m program taking into account the updated values of the total cross-section for (α,n) reactions on 19F. The resulting Nedis-2m input datasets were used in the MCNP6 code to calculate the leakage multiplication factor and neutron energy spectrum.

BARRIERS TO NUCLEAR PROLIFERATION IN THE EXPORT OF THE RUSSIAN FAST REACTORS WITH CLOSED NFC (USING EXAMPLE BREST-OD-300)

In the coming decades, it is possible to start exporting fast reactors with a closed nuclear fuel cycle to non-nuclear-weapon countries, which will require strengthening the nuclear non-proliferation regime and increasing the effectiveness of IAEA safeguards. This can be achieved both by creating technical barriers and by improving the system of accounting and control of nuclear materials and ensuring their reliable physical protection. Using the example of the BREST-OD-300 reactor under construction as part of a pilot demonstration power complex, the analysis of design and technological features that prevent or seriously hinder the switching of nuclear materials or the use of technologies by the importing State in violation of its international obligations to produce nuclear weapons or other nuclear explosive devices has been carried out.

Use of nuclear material accounting and control for augmenting nuclear security: a logical step but challenges remain

A cornerstone of both nuclear safeguards and the State system of accounting for and control of nuclear material (SSAC) is nuclear material accountancy of which nuclear material accounting is a key component. In 2008, the International Atomic Energy Agency (IAEA) published Nuclear Material Accounting Handbook for use by States and their organisations in their application of nuclear material accounting. Recognising the important role of Nuclear Material Accounting and Control (NMAC) in nuclear security, in 2015 the IAEA published an implementation guide 'Use of nuclear material accounting and control for nuclear security purposes at facilities'. The aim of this paper is to bring out important features of both the publications; one for safeguards and another for nuclear security. This paper also highlights some of the challenges that member States may come across in applying NMAC as we understand from safeguards directed to nuclear security.

МОДЕЛЮВАННЯ ДЕТЕКТОРА З ВИКОРИСТАННЯМ ТВЕРДОГО РОЗЧИНУ CA-ZN-TE ДЛЯ СИСТЕМ РАДІАЦІЙНОГО КОНТРОЛЮ

The article created a model of the primary converter - a gamma radiation sensor. It is based on the following properties of a semiconductor crystal: maximum quantum efficiency; maximum mobility of charge carriers; minimum density of structural defects; maximum values of resistivity and density. The combination of these properties provides a significant sensitivity of sensor with the minimum size of crystal. The inconsistency of such a combination must be eliminated both in the process of manufacturing a crystal (for example, a high-resistance crystal can be obtained by the simultaneous use of cleaning, components, and compensating doping) and subsequent processing by the methods proposed in this work (thermal field method, ionization annealing). Among the known materials for gamma radiation sensors, single crystals of Cdx-Zn1-xTe solid solutions have the optimal combination of the above properties and possibilities of their preparation. The advent of modern semiconductor sensors for the first time linked nuclear instrumentation and electronics into a single complex - a semiconductor detector. It combines a semiconductor primary converter of ionizing radiation (sensor), a secondary converter of information from the sensor (electronics) and software for processing this information, interconnected in terms of problem being solved and parameters. However, the development of nuclear energy and the spread of nuclear technologies have put forward new requirements for the control and metrology of ionizing radiation. The current level of nuclear instrumentation cannot fully satisfy them. The solution to this problem can be provided by the development of: methods for choosing the optimal type of semiconductor materials and controlling their properties to create uncooled detectors; sensors with higher resolution; electronics with lower noise level; computer methods and information processing programs with lower estimated costs; control systems for nuclear materials and the state of AES protective barriers that meet the requirements of the existing automatic control of radiation safety (ARS). This article is devoted to the solution of such problems, which ensures the relevance of its topic. The main principle of solving the named scientific problem was results of nuclear-physical studies of the interaction of ionizing radiation with semiconductors, the development and experimental verification of physical-mathematical models of technological processes dosimetry and control of nuclear materials.

Belarusian software for nuclear material accounting at the level of the regulatory body

A review of the information system for nuclear material accounting and control at the level of the Belarusian regulatory body in the field of nuclear and radiation safety is presented. This system is developed in accordance with International Atomic Energy Agency (IAEA) requirements depicted in Code 10 of the State subsidiary arrangements. The system provides automatic generation of the following accounting reports: physical inventory listing, inventory change report, material balance report, and textual report for each material balance area as well as the corresponding General Ledger. It provides all necessary calculations and pre-calculations, based on input data, to produce accurate accounting reports. The system implements the import/export of data to/from the system using Code 10 (labelled and fixed formats), as well as making adjustments to accounting documents in accordance with IAEA rules. There are two possibilities of nuclear material accounting in the system. The first consists of importing into the system of all reporting documents from the material balance areas of facilities and the subsequent possibility of checking the received data using an independent recalculation tool in the system. The second one includes the registration of all necessary information on nuclear material batches at locations outside facilities and their movement in the material balance area and then automatic generation of all required reports and General Ledger.

Characteristics of X-ray and gamma radiation detectors 
 based on polycrystalline CdTe and CdZnTe films

Based on CdTe and CdZnTe detectors a number of promising devices were created, which found their application in metallurgy, in solving the problems of customs control and control of nuclear materials, as well as matrix detectors created for the manufacture of medical devices and devices for space research. Detectors, created on the basis of polycrystalline semiconductor CdTe and CdZnTe films with a columnar structure on a molybdenum substrate with a thickness d = 30150 μm, had a specific resistance p > 10^5 10^8 W-cm. The energy resolution of the CdTe and CdZnTe detectors at room temperature reached ~ 5 keV on the 59.6 keV 241Am line.

Information system for nuclear material accounting and control

A brief description of information system for nuclear material accounting developed for the national regulator in the field of nuclear and radiation safety - the Department for Nuclear and Radiation Safety of the Ministry of Emergency Situations of the Republic of Belarus (Gosatomnadzor) is given. The information system is a part of the Intellectual information system of a Gosatomnadzor employee to ensure control (supervision) in the field of nuclear and radiation safety. It is developed on the basis of free software. The system has been implemented in Gosatomnadzor and at present in the Republic of Belarus all nuclear material accounting with reporting to the IAEA is carried out with its help. The system, in full compliance with the IAEA requirements, provides automatic generation with all the necessary calculations based on the input data of the following reporting documents: physical inventory listing, inventory change report, material balance report, textual report, General Ledger. All reports are fully consistent each with other. An efficient mechanism has been developed for importing and exporting data from / to the system according to formats of fixed and labelled Code 10 required by the IAEA. All logs of the system describing reports contain a field “IAEA approved” (yes / no). If it set to “yes”, they are closed for editing and correction. A special tool has been developed for making adjustments to these documents in accordance with the IAEA rules. The system contains fully completed reference books (small journals referenced by all major journals in the database) with the necessary reference data in accordance with Code 10. The information system meets all the IAEA requirements for such systems of national regulators in the field of accounting, control and supervision of nuclear material. It can be easily translated into other languages and adapted for the needs of accounting and control of nuclear material in operating organizations.

Застосування сучасних технологій навчання з підвищення кваліфікації з фізичного захисту

Two training technologies, developed and implemented by the George Kuzmich Training Center for Physical Protection, Accounting and Control of Nuclear Material of the Institute for Nuclear Research of the National Academy of Sciences of Ukraine in the training process for advanced training in physical protection, are considered. The first is a training technology based on the use of the Training ground "Complex of engineering and technical means of a physical protection system", which enables students to acquire practical skills in operational management and technical operation of a complex engineering and technical means of a physical protection system. The second is a technology based on the use of the Interactive training complex "Nuclear Power Plant with elements of the physical protection system", which allows interactively checking the configurations of the nuclear power plant physical protection system proposed by the students for the presence of vulnerable routes to the targets of adversaries. The effectiveness of using these technologies in the training process is discussed, as well as the development and implementation of other modern training technologies by the Training Center.

Knowledge Management in the Decommissioning of Nuclear Facilities in Brazil

In the second half of the twentieth century in Brazil, several nuclear facilities were built for the most varied objectives. The largest number of such facilities is at the Nuclear and Energy Research Institute in São Paulo (IPEN-CNEN/SP). For different reasons, some of these facilities had their projects finalized and were deactivated. Some of the equipment was then dismantled, but the respective nuclear and radioactive material remained isolated in the original sites awaiting the proper decommissioning procedures. The Celeste Project is an example of a facility where the nuclear material has been kept, and is subject to Argentine-Brazilian Agency for Accounting and Control of Nuclear Materials (ABACC) periodic inspections. Because of a number of interests, including financial and/or budgeting situations at the institutions, decades have passed without any further action, and the people who withold information and knowledge about these facilities have already moved away from the area or are in the process of. Therefore, because of the absence of knowledge management techniques in force at the time of establishing and operating these installations, this work proposes an analysis about the possible consequences in case of loss of perhaps the only one remaining knowledge, the one from the people who designed those departments and worked there.

Nuclear Materials Ownership in the Russian Federation

In response to the challenges of the epoch, “nuclear” laws currently regulate safety issues related to handling of nuclear materials, nuclear facilities operation, related transactions, nuclear waste processing and disposal, state control over the nuclear energy use, and international cooperation in the nuclear sphere. One of the most important institutions of the “nuclear” regulation system in Russian law is the institution of ownership of nuclear materials, understood by the modern legislator as materials containing, or capable of reproducing, fissile (fissionable) nuclear substances. Consolidating the rules of nuclear materials ownership, the legislator further formulates requirements for nuclear materials control and accounting, transactions procedure, and safe operation of nuclear facilities, as well as introduces liability for violation of such requirements. Today, many aspects related to the legal status of nuclear materials owners and the notion of handling nuclear materials deserve a deep legal analysis, since the current legal regulation has gaps and contradictions. The legal writing method used to word such norms, structures, and basic notions must meet the criteria of clarity, unambiguous interpretation, and absence of regulatory gaps, that is why the system of legal regulation of the institution of nuclear materials ownership needs further improvement.

Право собственности на ядерные материалы в Российской Федерации

In response to the challenges of the epoch, “nuclear” laws currently regulate safety issues related to handling of nuclear materials, nuclear facilities operation, related transactions, nuclear waste processing and disposal, state control over the nuclear energy use, and international cooperation in the nuclear sphere. One of the most important institutions of the “nuclear” regulation system in Russian law is the institution of ownership of nuclear materials, understood by the modern legislator as materials containing, or capable of reproducing, fissile (fissionable) nuclear substances. Consolidating the rules of nuclear materials ownership, the legislator further formulates requirements for nuclear materials control and accounting, transactions procedure, and safe operation of nuclear facilities, as well as introduces liability for violation of such requirements. Today, many aspects related to the legal status of nuclear materials owners and the notion of handling nuclear materials deserve a deep legal analysis, since the current legal regulation has gaps and contradictions. The legal writing method used to word such norms, structures, and basic notions must meet the criteria of clarity, unambiguous interpretation, and absence of regulatory gaps, that is why the system of legal regulation of the institution of nuclear materials ownership needs further improvement.