Transport Of Radioactive Materials Research Articles

Transfer functions for QA/QB international regulatory limits for the safe transport of radioactive materials.

This paper presents a proposed revision of the International Atomic Energy Agency (IAEA) transport regulations, related to the A1 and A2 limit values used to determine the radioactive transport classification. Based on the "Q system", a novel methodology was introduced to derive QA and QB values related to scenarios involving external exposure from a distant source. These values are key parameters that respectively represent the total effective dose and total equivalent dose to the skin, from all primary and secondary particles contributing to radiation exposure. The International Working Group (WG A1/A2) is established and associated with the TRANSSC Technical Expert Group on Radiation Protection (TTEG-RP). A review of the A1 and A2 values is performed in response to identified limitations within the existing Q system. The followed approach is based on Monte Carlo simulations that enabled the development of transfer functions aimed at reducing computational time and increasing the flexibility of dose evaluations for any radionuclide with known particle emission spectra. This method allows updating the QA and QB values to account for future data evolutions (decay data, fluence-to-dose conversion coefficients) and standardizing the calculation of regulation limits across all referenced radionuclides and scenarios related to external exposure. The transfer functions are established using three Monte Carlo simulation codes - FLUKA, Geant4, and MCNP - and address the previous limitations of the "Q system", reflecting the latest ICRP recommendations and improvements in calculation techniques. The results of the WG show consistent agreement across the codes, with minor discrepancies observed at low primary energies due to statistical uncertainties and different handling of stopping power for electrons/positrons in the codes. This revised approach aligns with current standards and recommendations, ensuring that the radiological consequences of transport accidents are acceptable for the new A1 and A2 limits from a radiological protection perspective.&#xD.

Transport of radioactive materials from terrestrial to marine environments in Fukushima over the past decade

Abstract While 20 % of radionuclides released from the Fukushima Daiichi Nuclear Power Plant accident had been deposited in the terrestrial environment, rivers remain the long-term source for 137Cs, primarily through particulate transfer, from terrestrial to marine ecosystems. In this study, we estimated the suspended 137Cs flux to the ocean at 11 sites in the coastal area between October 2012 and December 2020 to be 17 TBq, based on our long-term monitoring data of concentrations of suspended 137Cs and suspended solids. The cumulative loss of suspended 137Cs from each site to the ocean ranged from 0.1 % to 1.7 % of initial deposition throughout the observation period, depending on the effect of dam lakes and normalized river discharge. The higher loss is also thought to be the large outflow of runoff during the typhoon. The current level of the suspended 137Cs concentrations was lowered to 1/10–1/100 of those immediately after the accident. The average value of the decreasing trend for each site was approximated using the equation: y = a1 e −k 1 t + a2 e −k 2t. The rate constant k 1 is higher in areas with intensive land use, such as pastures, bare land, and water surfaces, and k 2 is lower in urban areas.

Demonstration of the avoidance of brittle fracture of a radioactive material transport package during an impact event

The stress-based assessment described in BS7910:2019 for the demonstration of avoidance of fracture initiation has been applied to a radioactive material transport package. The transport package was designed and manufactured in the early 1990s, predating modern regulatory requirements that are more prescriptive to satisfy the avoidance of brittle fracture. The package design can be usefully re-purposed for the transport of low/intermediate level waste - such as that produced in prototype fission reactors. Current regulations may require demonstration of the avoidance of brittle fracture for this type of package at -40°C in a fault condition -which, for this package, is considered as an impact from a 1.2m drop height. This paper presents an overview of the demonstration of the package, explaining the process of identifying transient stresses throughout the package and then focusses on treatment of high stresses in the base of the package. Stress classification into primary and secondary stresses is discussed. It is demonstrated that such stresses are permissible by extrapolating from solutions in BS7910:2019 Annex N using cracked body models and taking advantage of low constraint conditions at the crack tip.

Detecting Unauthorized Movement of Radioactive Material Packages in Transport with an Adam-Optimized BP Neural Network Model

The rapid expansion of nuclear technology across various sectors due to global economic growth has led to a substantial rise in the transportation of radioactive materials. The International Atomic Energy Agency (IAEA) estimates that approximately 20 million shipments of radioactive materials occur annually. In this context, ensuring the safety and security of radioactive material transportation is of significant importance. IAEA’s “Security of Radioactive Materials in Transport” (Nuclear Security Series No. 9-G) mandates that an effective transport security system should provide immediate detection of any unauthorized removal of the packages. In the present study, an innovative Adam-optimized BP neural network model is developed for detecting unauthorized movements of radioactive material packages. To analyze the performance of the proposed algorithm, numerous experiments were conducted. The results demonstrate that the proposed method achieves a 99.17% accuracy rate in detecting unauthorized movements of radioactive materials, with a missed alarm rate of 0.72% and a false alarm rate of 0.1%. This method also enables real-time detection of unauthorized removal of radioactive materials and effectively enhances the security of radioactive materials during transport to reduce the risks of theft, loss, diversion, or sabotage.

Nuclear material accountancy using momentum-informed muon scattering tomography

Screening cargo and vehicles to prevent proliferation of unauthorized nuclear and radioactive materials is essential to prevent threats to domestic and international security. Cosmic ray muons attracted attention as a potential next-generation radiographic technique to discover illicit transportation of nuclear and radioactive materials at borders or secure facilities. Unique features of cosmic muons—a high energy and deep penetration depth—enable them to be utilized for radiation probes, especially for large and dense materials. In muon scattering tomography, physical characteristics of target materials are estimated by measuring both incoming and outgoing muon trajectories using muon detectors. To reconstruct 3D tomographic images of target objects, a Point of Closest Approach (PoCA) algorithm is typically used to locate a scattering position, and the scattering angle values are used to map material density. However, high-resolution material mapping is often limited due to the absence of muon momentum information because the expected muon scattering angle depends on two variables: material atomic number and muon momentum. Despite the importance of measuring muon momentum, it is still challenging without deploying large and expensive muon spectrometers. Therefore, a mean muon momentum, 3 to 4 GeV/c, is often used to represent the entire cosmic ray muon spectrum. In this paper, we present a new momentum-informed muon scattering tomography (MST) approach for nuclear material accountancy based on a recently devised fieldable muon spectrometer. This approach uses a new imaging algorithm that improves the current PoCA algorithm by encoding momentum into the scattering angle. In our new algorithm, all muon measurements have a categorized momentum level with a scattering angle. We demonstrate the functionality and performance of momentum-informed MST using computational simulations. The results show that the image resolution is significantly improved, and this approach allows for visually differentiating nuclear materials from non-nuclear materials.

Missing steps in the assessment of the local economic impact of nuclear waste: The case of Italy

The risk of adverse effects on local economies originating from the hosting of radioactive waste deep geological repositories and interim storage facilities has been only partially addressed in the literature. Most studies adopt the logic of economic multipliers and focus on benefits rather than potential costs. This may lead policymakers to adopt a biased perspective, as observed in Legislative Decree 31/2010 in Italy, where the process of planning an interim storage facility is underway. The article aims to critically discuss the logic of economic multipliers and contribute to the debate by shifting the focus towards the perspectives of risk perception, hedonic pricing, and willingness to pay. Such approaches, which have been adopted in studies on the effects derived from the transportation of radioactive materials, risks of nuclear incidents, and radiation releases at power plants, should inform citizens and can be useful in arriving at adequate and democratically agreed upon solutions. Their adoption would enable local communities to strengthen their awareness of potential negative socio-economic impacts deriving from such facilities.

The role of the IAEA in establishing international standards for the use of atomic energy (retrospective analysis)

Paradoxically, the peaceful use of nuclear energy and all the prospects it opens up for humanity often coexist with the prospect of nuclear proliferation and nuclear war. This difficult perception is understandable: the materials, knowledge, and expertise needed to produce nuclear weapons are generally no different from those needed to produce nuclear energy and conduct nuclear research.Therefore, ensuring the peaceful and safe use of nuclear energy has always been in the center of attention of the international community. The approach is determined by a complex of national and international measures. It is generally accepted that the primary responsibility for regulating the use of nuclear energy rests with national authorities, but it is also clear that other countries may also be affected. Thus, like many other human activities with potentially transboundary consequences, nuclear energy regulation requires a residual, and in some cases joint, responsibility on the part of the international community to ensure the harmonization of standards, coordination and pooling of resources and services, and regulatory cooperation this activity.In this regard, the IAEA and other international and regional organizations play the role of coordination centers. Article II of the IAEA Statute states that the organization shall seek to accelerate and increase the contribution of atomic energy to world peace, health and prosperity and shall provide, as far as possible, assistance upon request. IAEA supervision or control shall not be used to achieve any military objective.International peration in the field of nuclear energy over the past six decades has resulted in legally binding norms and advisory standards and regulations. This article outlines this global legal framework for the safe and peaceful development of nuclear energy. In particular, it concerns nuclear safety, radiation protection, radioactive waste management, transportation of radioactive materials, emergency assistance and planning, civil liability for nuclear damage, physical protection of nuclear material, armed attack on nuclear facilities, safeguards and controls carried out and provided by the IAEA.

Safety analysis and evaluation of transport and storage container for very Low-Level liquid radioactive waste

Safe temporary storage and transportation of the very low-level liquid radioactive waste generated during the Decommissioning and Decontamination (D&D) of nuclear power plants (NPPs) must be ensured. This study proposes a composite shielding transport container for very low-level liquid radioactive waste, which adheres to the industrial package (IP)-2 technical standards for packaging and transportation of radioactive materials. A shielding container based on barium sulfate (BaSO4) (a shielding material harmless to the human body) and a structurally reinforced frame were developed. Then, to confirm the structural safety of the container according to the regulations on the packaging and transportation of radioactive materials under drop weight and stacking tests, the Abaqus/Explicit program was used and on-site evaluations were performed. The maximum strains of about 8.8% and 2.2% were obtained in the drop-weight and stacking performance tests, respectively. Compared to the strain values of 40% at which high-density polyethylene (HDPE) could break, it was derived to be about 22% and 5.5%, respectively. The test satisfaction standard, that is, no loss or dispersion of radioactive contents and no shielding loss that could increase the radiation dose rate by more than 20% on the outer surface, were satisfied, confirming the safety of the container.

Individual autonomous safety intelligence technology for radioactive material transportation—Multi-sensor fusion early warning technology based on evidence theory

This paper briefly introduces the research project on individual autonomous security intelligence for radioactive materials using radar and microwave-infrared detectors to autonomously sense external threats during railroad transportation and achieve individual autonomous security intelligence. Due to the shortcomings of the single sensor with a false alarm, the project fuses the perception information of each sensor connected to the radar-infrared node to decide the level of danger warning and improve the level of individual autonomous security of radioactive materials. To further improve the accuracy and reduce the false alarm rate of individual autonomous hazard warnings, a reasonable basic probability assignment (BPA) is constructed for each sensor based on a fuzzy set and rough set according to the practical application, and the fusion of individual autonomous perception information is realized by combining Pearson correlation coefficient and D-S evidence theory. The experimental results show that the fused hazard warning accuracy is 91.72% and the false alarm rate is 8.28%, which indicates that individual autonomous safety intelligence can be effectively realized.

The Packaging and Safety Transport of Radioactive Materials

The Packaging and Safety Transport of Radioactive Materials

Comparison of thermal tests before and after the free drop test of a radioactive material transport package

The transport safety of radioactive material is of utmost significance, which is mainly based on the safety of packages. In accordance with the IAEA Regulations for the safe transport of radioactive material, radioactive material transport packages undergo rigorous testing under diverse transport conditions including free drop tests and thermal tests. The determination of the appropriate thickness for the insulation layer poses a challenge, as it necessitates the consideration of factors such as the dissipation of internal heat sources and protection against fire accidents. Finite element simulation is usually used for the design and testing of packages. The requirement of the cumulation effect for the drop test and thermal test makes it harder for the finite element method in testing. In this paper, a method for thickness changing of insulation layer thickness in finite element simulation was developed and verified. A radioactive material transport package is taken as an example for the cumulating effect of the drop test and the thermal test.

Fission Battery transportation and siting aspects

Fission Batteries (FBs) are envisioned to be highly mobile, autonomously operating, and economically competitive small nuclear power reactor systems useable for generating electric power or heat. Such novel systems will face unique challenges pertaining to siting and transportation. This paper presents the findings and recommendations of the 2021 Idaho National Laboratory FB Initiative workshop on the transportation and siting of FBs. Regulatory and technical subject matter experts on the transportation and storage of radioactive materials, licensing of nuclear power plants, innovative sensing technologies, etc., participated in this workshop and shared their professional experiences and perspectives. Based on these conversations, the paper describes the lessons learned from nuclear reactor siting and licensing, as well as from the siting and transportation of radioactive materials such as fresh or spent nuclear fuel. It then explores the applicability of these lessons and practices to FB siting and transportation. In addition, associated regulatory and technological challenges are identified, such as a changing FB source term, criticality safety aspects, neutron activation and embrittlement of structural components, site development, transportation uncertainties, the current regulatory framework, modeling and simulation uncertainties, and limited inspections. Additionally, research and development activities are suggested to address these gaps and challenges, including the development of modeling and simulation tools for FB design, strategies for rapid FB transportation, innovative FB shell materials, procedures for onsite handling of FBs, transportation-accident-proof criticality control mechanisms, self-monitoring and self-testing capabilities, regulatory requirements, and probabilistic risk assessment tools. Carrying out these research initiatives is expected to help accelerate the evolution of FBs and facilitate their design, licensing, and deployment.

Indonesian Legal Perspectives on International Maritime Transport of Ultrahazardous Radioactive Materials at Sea

In 1992, the voyage of the Akatsuki Maru from France to Japan showed the practice in the sea transport of ultrahazardous radioactive materials. The voyage route was nearly around one-half of the planet earth and passed through many countries. Although many countries have openly protested, the vessel has continued because the ship has international navigational rights under UNCLOS 1982. This paper attempts to research international regulations concerning the legal regime governing safety in the sea transport of ultrahazardous radioactive materials in UNCLOS 1982, MARPOL 73/78, SOLAS 1974, PPNM 1980, SCTW 1978, and Indonesia’s national laws and regulations concerning this matter. This research uses normative approach and analysis descriptive methods that is based on international conventions, Indonesia’s national laws and regulations related to the safety of ultrahazardous radioactive materials shipment. The result of this research shows that the legal regime governing safety in the sea transport of ultrahazardous radioactive materials is not yet adequate, because it is partially regulated. However, Indonesia has attempted to harmonize international regulations and Indonesia’s national laws concerning the safety navigation of transport of ultrahazardous radioactive materials.

Safety of Radioactive Materials Transportation and Storing Assisted by Internet of Things

Abstract Nuclear newcomers need to verify the support infrastructure development keeps steady with the power plant construction and radioactive materials transportation. European power reactor's (EPR) spent fuel (SF) had been chosen in this paper for newcomers to determine the SF levels. Radioactive materials are causing harm to the environment, people, and property. These materials may be subject to terrorism, particularly during transportations. Therefore, solutions for the safety of storing and transporting radioactive materials will be proposed in this paper. Recently, the world is suffering from a new type of terrorist—known as “Lone Wolves”—which can attack these materials. Lone wolves harmful attack detection is extremely difficult at any attack stage. Existing surveillance systems are weak to counter the lone wolves, where they respond after the happening of the incident. Therefore, this paper proposed a design for Lone Wolves counter-system (LWCS) based on deep learning and assisted by internet of things to prevent these attacks. Also, an embedded system solution will be proposed based on existing infrastructure networks. The proposed embedded system can monitor and track the radioactive materials during storing and transportation in real-time. Simulation results for the proposed system will show improved performance in the transport of radioactive materials.

Development of an analysis and testing concept for the evaluation of impact targets in the mechanical safety testing of dangerous goods packagings

AbstractThe mechanical and geometrical properties of impact targets greatly influence the outcome of a drop test. The International Agreement concerning the International Carriage of Dangerous Goods by Road (ADR) as well as ISO 2248 describe the characteristics of impact targets for drop tests of dangerous goods packagings. According to these regulations, the impact target's surface needs to be unyielding, under testing conditions non‐deformable, flat and integral with a mass at least 50 times that of the heaviest packaging to be tested. The problem is that many production facilities, especially manufacturers of corrugated fibreboard boxes, do not have their own testing device with the required 50 times mass ratio of the impact target for a regulation compliant drop test during series production. Furthermore, at UN level, it is considered necessary to revise these requirements. In the present paper, the impact target requirements are examined in detail and compared with those in other technical areas (e.g., impact target for container for the transport of radioactive materials). A research method is being developed to investigate the dependency between the mass ratio of the packaging and the target as well as the damage resistance of a drop tested package in relation to specific design characteristics. The results are of high relevance for industry purposes and intended to ensure a uniform level of safety assessment for the mechanical testing of dangerous goods packagings.

A probabilistic, empirical model for permeability of mudstone

Argilaceous rock is being considered for geologic isolation of spent nuclear fuel in various countries. While permeability plays a central role in determination of transport and fate of radioactive material in earth’s crust, most existing models for permeability are deterministic, and relate permeability to Terzaghi effective pressure. Laboratory and field data, however, (i) indicate that other parameters affect permeability of fluid-saturated porous rock and (ii) show significant variability in reported permeability measurements. For example, porosity, pore geometry, and clay size fraction, and the inherent variability of such parameters are important in successful prediction of permeability. This paper first presents a database of permeability measurements determined using laboratory and field tests that includes various rock parameters that affect permeability. A study of relationship of these parameters and permeability is presented. A framework is then presented for development of a probabilistic, empirical model for prediction of permeability of mudstone. The model is unbiased, accounts for the relevant uncertainties, and considers the important parameters affecting permeability.

Evaluation of the permissible 99Mo activity in the KL-15 cask in the design of transportation and process scheme

The demand for the use of radioactive isotopes in medicine is increasing with each coming year necessitating the increased output of radionuclide products. One of the most widely spread radionuclides used in medicine is technetium-99m (99mТс) (Feasibility of producing molybdenum-99 2015, NEA 2012, The Supply of Medical Radioisotopes 2015). The very short 99mТс life (6-hour half-life) requires its production directly on the site of medical treatment. This is achieved using molybdenum-technetium generators (Kodina and Krasikova 2014, Technical Reports No. NF-T-5.4. 2013, Technetium-99 Generator 2021) loaded with molybdenum-99 (99Мо), which uninterruptedly decays (half-life of 66 hours) yielding 99mTc. Close attention must be paid in the course of production of molybdenum-technetium generators to radiation safety during transportation of 99Мо on the territory of the manufacturing facility. The main measure for ensuring radiation safety during transportation of 99Мо is the application of special packaging kits. The Karpov Institute of Physical Chemistry JSC uses a wide range of packaging kits of types A and B for transportation of radioactive materials on the territory of the manufacturer with design features providing the required level of radiation safety. In particular, the KL-15 shipping cask loaded/unloaded from the top is used for onsite transportation of 99Мо for charging molybdenum-technetium generators. The maximum permissible activity of 99Мо is not specified in the passport of the KL-15 cask. Planned construction of a radionuclide production shop in accordance with GMP requirements will require the increase of output of target radionuclides by several times. The above considerations necessitated the evaluation of the maximum permissible activity of 99Мо planned to be transported in KL-15 casks. No other type of standard casks can be used because of their outside dimensions prohibiting the unloading of 99Мо inside the “hot” chamber. Calculation and experimental evaluation of permissible 99Мо activity during transportation inside the KL-15 cask was performed. The paper presents the calculated evaluation of the maximum permissible activity of 99Мо in a KL-15 cask to ensure the radiation exposure of personnel of group A working with the cask not exceeding the established level at the enterprise (80 μSv per shift) and not requiring the use of additional measures and means of protection. The results of the work allow us drawing the conclusion that the KL-15 cask ensures the required level of radiation safety with up to 241 Ki of 99Мо loaded in the cask.

Fluctuation in deep groundwater chemistry and microbial community and their impact on corrosion of stainless-steels

Low and intermediate level radioactive waste produced during the operation and decommissioning of nuclear power plants is disposed of in an underground geological repository. The majority of metallic waste is made of various stainless-steels and carbon steel. Microbial communities and groundwater composition in deep bedrock at repository sites were believed to stay stable over time, allowing the prediction of evolution of the repository environment. However, a two-year survey of chemical components and microbial community composition within deep bedrock revealed changes in both. An in situ corrosion monitoring system was developed to monitor real-time corrosion rates of two stainless-steel grades (AISI 304 and 316) to study the evolution of corrosion, and correlation between environmental changes and corrosion rate. Surprisingly, higher corrosion rates of steel coupons were detected in the higher alloyed stainless-steel grade 316 compared to the lower alloyed grade 304. Pitting was the main corrosion form. Sulphate reducing bacteria and methanogenic archaea were enriched on surfaces of both types of steel coupons. These microbes likely have a role in the corrosion of stainless-steel in this environment. The changes in groundwater conditions and microbial communities within deep bedrock groundwater at this repository site may have implications for the nuclide release and transport of radioactive material and the long-term evolution and safety of this repository and continental repositories in general and thus needs to be thoroughly understood.

The influence of cooling rate on condensation of iron, aluminum, and uranium oxide nanoparticles

Fundamental observations of particle size distributions are needed to develop models that predict the fate and transport of radioactive materials in the atmosphere following a nuclear incident. The extent of material transport is influenced by the time scales of particle formation processes (e.g., condensation, coagulation). In this study, we investigated the influence of cooling time scales on size distributions of uranium, aluminum, and iron oxide particles that are synthesized separately under identical run conditions inside the controlled environment of an argon plasma flow reactor. Two distinct temperature distributions are imposed along the flow reactor by varying the argon flow rate downstream of the plasma torch. The vaporized reactants of uranium, aluminum, and iron are cooled from about 5000 K to 1000 K before they are collected on silicon wafers for ex situ scanning electron microscope analysis. The microscope images show that the sizes of the largest aluminum and iron oxide particles heavily depend on the cooling time scales, whereas significant size variation with cooling rate is not observed for uranium oxide particles. In addition, the size distribution of aluminum oxide particles exhibits the broadest range among all three metal oxides studied. We performed simulations of particle size distributions using a kinetic model that couples gas phase oxidation chemistry with particle formation processes, including nucleation, condensation, and coagulation. The model results demonstrate the strong sensitivity of particle size distribution to different cooling histories (i.e., temperature vs residence time) along the flow reactor. The kinetic model also helps identify directions for future research to improve the predictions.

Operating conditions of container cars in railway trains of special formation

Abstract. The article considers main technical characteristics, indicators of dynamic qualities and parameters of braking effciency of special railway rolling stock of container cars (container transporters) intended for the transportation of radioactive materials — spent nuclear fuel. In accordance with the current regulatory documents of JSC Russian Railways, it is currently allowed forming special trains exclusively from container transporters of any one type, which is associated with the peculiarities of the technology for handling and transporting spent nuclear fuel, which is within the competence of the state corporation Rosatom. However, this signifcantly increases the timing of the delivery of special trains due to the need to wait for the readiness of transporters, due to the non-simultaneous delivery of any one type of assembly kits with spent nuclear fuel. The practice of handling has shown that the transportation of some types of spent nuclear fuel can be carried out with a combination of the transport operation, which implies the combination of various types of container transporters in one echelon, but at the same time it is necessary to correct certain regulatory documents of Russian Railways. For this purpose, at the request of the Rosatom corporation, a necessary set of experimental works was carried out. Authors presented results of control running dynamic, stationary and running braking tests of container transporters of various types, following as part of the same echelon, on the infrastructure of the Test Loop of JSC “VNIIZHT”, including when running along the frst ring track and along various combinations of turnouts along a tangent line (main) and lateral directions. It has been experimentally proved that it is possible to operate container transporters of various types as part of the same echelon in compliance with the conditions for ensuring traffc safety in accordance with the standards of dynamic qualities and braking effciency. Based on the test results, a regulatory document of JSC Russian Railways was developed — the Regulation on the conditions for joint operation of special freight cars (transporters) as part of one echelon, approved by the order of JSC Russian Railways dated July 22, 2021 No. 1591/r. components. Interstate standard, put into effect as nat. standard of the Russian Federation by order of the Federal Agency for Technical Regulation and Metrology dated March 17, 2016 No. 162-st. Moscow, Standartinform Publ., 2016, 54 p. (in Russ.).