Fuel Processing Plant Research Articles

Geochemical and U-Pb isotopic insights into uranium (U) enrichment in the soil around a nuclear fuel element plant, in Southwest China

To assess the impact of nuclear fuel element processing on uranium(U) in the soil environment, a geochemical survey was conducted. The survey provided data on U concentration, speciation, Th/U ratio, and U and Pb isotopic composition in the soil around a nuclear fuel processing plant in Southwest China, which has been operational since 1965, to reveal the enrichment status and sources of U in the soil. The concentrations of Th and Pb in the soil were also compared. The average U concentration was 1.01-1.43 times that of the local background, and U existed primarily as residual U. The enrichment factor value indicates that U is slightly enriched in the soil. The Th/U ratio was higher than the crustal ratio and the world soil average value, indicating that some of the U in the soil has been lost due to surface runoff. The 235U/238U ratio distribution shows that a certain amount of 235U-enriched particles have sedimentation in the downwind direction of the plant soil, which results in a higher 235U/238U ratio in this direction. However, in general, the 235U/238U ratios were observed to be typical natural values. The 207Pb/206Pb ratio indicates that the U in the U ore enters the soil during nuclear fuel processing.

A hydroxy containing, naphthalene-based and imine linked porous organic polymer for rapid iodine uptake

Nuclear energy is turning out to be one of the best alternatives to fossil fuels in order to meet the global electricity demand. Radioactive iodine is a volatile and hazardous component that may be present in aqueous nuclear waste and off-gas streams of a spent fuel processing plant. Iodine species are also quite mobile and their accidental leakage into the environment can adversely affect the health of animals and humans to an alarming extent. Thus, design and development of materials capable of capturing/storing iodine effectively for a long time, is of utmost importance in contemporary research. Herein, facile synthesis of a unique nitrogen rich and thermally stable porous organic polymer (POP_DH) is described that has a porous structure comprising of both micro and mesopores. The POP_DH has a specific surface area (128.3 m2 g-1), and can capture 2.855 g g−1 of iodine (vapours) at 75 °C. The POP_DH can retain the trapped iodine up to seven days without any significant release which makes it a suitable material suitable for storing iodine. The presence of O and N heteroatoms (imine linkages) also enable POP_DH to remove iodine species dissolved in water. Herein, the iodine removal is quite rapid with about 99 % of iodine captured within 2 h. POP_DH samples can be recycled up to five rounds for iodine capture with only small changes in performance as an adsorbent. Overall, POP_DH is promising material for capture of radioactive iodine from various media.

Study on wear morphology of uncoated and MT-CVD TiCN-Al2O3 coated carbide inserts during dry machining of Inconel 825 superalloy

The adoption of the High Speed Machining (HSM) approach by industries to enhance productivity is crucial in order to fulfill the growing demand of the global market. Understanding superalloys' machining behavior is also necessary since they play a significant role in a variety of industries, including the aerospace industry, marine engine parts, biomedical applications, chemical and petrochemical industries, and nuclear fuel processing plants. Hence, dry machining performance of ‘difficult-to-cut’ aerospace superalloy Inconel 825 is studied herein. With uncoated and MT-CVD TiCN-Al2O3 coated carbide inserts, machining experiments are performed at various cutting speeds. Detailed tool wear mechanisms are discussed for each of the cutting inserts with regard to different cutting speeds and hence the performance gain with coated carbide tools is understood as compared to its uncoated counterpart for dry machining of Inconel 825 superalloy.

Comparative Study of Plutonium and Radiocaesium Content in the Muscle of Fish of the Yenisey River.

This work reports the first data on the content of plutonium (239+240Pu) in the muscle tissues of the Northern pike (Esox lucius) and the Siberian dace (Leiciscus baicalensis) inhabiting the middle reaches of the Yenisey River in the vicinity of the radioactive discharge site. An increase in the content of 239+240Pu and radiocaesium (137Cs) in pike muscles followed an increase in the volume of controlled discharges of these radionuclides to the Yenisey in 2018. The content of 239+240Pu in the muscles of pike (2-11 mBq/kg dry weight) and dace (1-4 mBq/kg dry weight) of the Yenisey fall within the range of values obtained by other authors for the ichthyofauna from water bodies contaminated with radioactive discharges from nuclear power plants and spent nuclear fuel processing plants. The ratio of the activity concentrations 239+240Pu/137Cs in fish muscles, compared with the similar ratios in other hydrobionts, indicates a significantly lower bioavailability of plutonium for fish. The obtained preliminary results make it possible to consider the Northern pike as a more prospective indicator of biologically available plutonium in the Yenisey than the dace.

PERFORMANCE OF BARC NEUTRON PERSONAL DOSEMETER IN EURADOS INTERCOMPARISON EXERCISE IC2017N - A LESSON LEARNT.

Bhabha Atomic Research Centre (BARC) conducts fast neutron personnel monitoring service to radiation workers involved in reactors, accelerators, spent fuel processing plants, oil-well industries, etc., using CR-39 detector based dosemeter. In this study, performance of the BARC fast neutron personnel dosemeter has been checked through EURADOS intercomparison exercise for simulated workplace neutron fields. The overall performance of the dosemeter in the lower dose equivalent (≤ 5mSv) was found to be acceptable as per ISO-14146. The performance (ratio of estimated to reference dose equivalent) of the dosemeter in the higher dose equivalent (12mSv) was found to be in the range of 0.48-0.44 and not satisfactory as per the ISO-14146 criteria for any dosimetry service. Based on this performance, a new imaging system was developed and performance of the dosemeters were improved and found to be acceptable (within ±20%) as per ISO.

Maintenance schedules as boundary objects for improved organizational reliability

Organizations that manage complex technologies use planning in various forms to determine priorities and structure work with the goal of controlling both production and system reliability. In addition to this purely functional view of planning, there is a social dimension that also has important system safety implications. Drawing on 53 semi-structured interviews with workers at a nuclear fuel processing plant, this paper addresses the role of the schedule for planned maintenance work. Characterizing the schedule as a boundary object highlights the socio-material dimension of high reliability organizing. It sheds light on the negotiation that takes place at the boundary between five worker groups around the schedule, which allows cooperation without the need for consensus thanks to the interpretive flexibility. Diversity of views is acknowledged, but resolved sufficiently. A ‘reliable’ schedule is one that is accurate enough to facilitate necessary conversations without providing unnecessary constraints. It is a balance between what should be brought to light and what should deliberately be left in the shadows. Yet, the possibility for the schedule to act as a boundary object and to support interdepartmental coordination and organizational reliability depends on organizational and occupational conditions. When managers see the schedule as an object of control, they seek to impose additional standardization. Taken to the extreme, introducing rigidity into the system is aimed at organizational invariance that HRO researchers warn is not the key to reliable operations. The role and legitimacy of planners is also discussed, as a safeguard against the schedule becoming a fantasy plan.

Numerical modeling of an automotive derivative polymer electrolyte membrane fuel cell cogeneration system with selective membranes

Cogeneration power plants based on fuel cells are a promising technology to produce electric and thermal energy with reduced costs and environmental impact. The most mature fuel cell technology for this kind of applications are polymer electrolyte membrane fuel cells, which require high-purity hydrogen.The most common and least expensive way to produce hydrogen within today's energy infrastructure is steam reforming of natural gas. Such a process produces a syngas rich in hydrogen that has to be purified to be properly used in low temperature fuel cells. However, the hydrogen production and purification processes strongly affect the performance, the cost, and the complexity of the energy system.Purification is usually performed through pressure swing adsorption, which is a semi-batch process that increases the plant complexity and incorporates a substantial efficiency penalty. A promising alternative option for hydrogen purification is the use of selective metal membranes that can be integrated in the reactors of the fuel processing plant. Such a membrane separation may improve the thermo-chemical performance of the energy system, while reducing the power plant complexity, and potentially its cost. Herein, we perform a technical analysis, through thermo-chemical models, to evaluate the integration of Pd-based H2-selective membranes in different sections of the fuel processing plant: (i) steam reforming reactor, (ii) water gas shift reactor, (iii) at the outlet of the fuel processor as a separator device. The results show that a drastic fuel processing plant simplification is achievable by integrating the Pd-membranes in the water gas shift and reforming reactors. Moreover, the natural gas reforming membrane reactor yields significant efficiency improvements.

A novel luminescence method for the estimation of uranyl ions using trimesic acid‑cadmium complex

Cadmium ion (Cd2+) with trimesic acid forms water insoluble complex. When uranyl ion (UO22+) is present with Cd2+, the complex shows intense luminescence of UO22+ and it is used for the trace level determination of UO22+ ions. A linear response of luminescence intensity of UO22+ ions was obtained over a concentration range of 1–75 ng mL−1. Analytical data showed that the detection limit of 0.2 ng mL−1 (7.4 × 10−10 M) of UO22+ ion is achieved with a relative standard deviation (RSD) 8.5% (n = 5). The proposed method was successfully applied for quantification of UO22+ ions in natural water and waste water from nuclear fuel processing plant. Furthermore, the estimation of UO22+ ions in cadmium matrix also has been carried out. This study provides a very simple, promising and a novel alternative method for the detection of UO22+ ions in environment.

Dynamic modelling of cut-and-store systems for year-round deliveries of short rotation coppice willow

Short rotation coppice willow (SRCW) is a high-yielding energy crop that can be used to produce solid, liquid or gaseous biofuels. The crop is harvested during the winter, when the leaves have dropped. For economic reasons, however, most fuel processing plants require continuous year-round delivery of raw material. Thus, SRCW should be harvested as stems or in larger pieces in order to be storable, and not chipped directly at harvest for immediate use in large-scale heating plants, which is common practice at present. The aim of the project within which this study was conducted is to find cost-effective whole-stem harvesting and handling systems for year-round deliveries of natural-dried SRCW. A discrete event simulation model for such systems was developed in this study, taking weather, soil trafficability, geographical conditions, natural drying of the material and storage losses into account. The model was applied to a fictitious processing plant in Uppsala, Sweden. Machine performance and costs for a system with one stem harvester and up to three in-field shuttles, together with one chipper truck for chipping and transport, were investigated. The simulations showed that field trafficability had a crucial impact on total quantity harvested. The total cost was € 40 t −1 dry matter. Yield of SRCW and harvest productivity were important factors regarding costs. The model can be used to design cost-effective harvesting and handling systems for year-round deliveries of SRCW.

Dynamic preference revelation and expression of personal frames: how Weibo is used in an anti-nuclear protest in China

This study explores the use of Weibo in a protest against a nuclear fuel processing plant in China. This study argues that social media play an important role in the development of protests in non-democratic societies through the mechanism of preference revelation, which blurs the boundary between offline protests and the individualized expression of preferences on social media. Of Weibo tweets which were posted prior to the occurrence of the offline protest, 11,788 protest-related were examined with the aid of a supervised machine learning technique. The results showed that the revelation of personal preferences in the form of individualized expressions of opposition were more common than mobilization and coordination, and such preferences were legitimized by the personal frames of risk and the distrust in government. The use of Weibo to mobilize potential opponents to the project, primarily by calling for the expression of opposition, was less frequent than the use of Weibo to express personal frames. Furthermore, the prevalence of Weibo usage changed dramatically. In the first few days of the protest, the revelation of personal preferences and personal frames of risk were prominent, whereas personal frames of distrust in government were common in the days leading to the street protest.

Hydrogen Infrastructure Challenges and Solutions

One of the challenges associated with transitioning a transportation economy to any alternative fuel is bringing online fuel production, storage, transportation and end-customer delivery infrastructure at a pace and in the locations relevant to the parallel effort of bringing the related transportation vehicles into the market. In the case of hydrogen as a transportation fuel, the network of fueling stations may include a combination of centralized and de-centralized fuel production. The continuum of centralized to de-centralized production includes massive centralized hydrocarbon fuel processing plants that may number in the tens to hundreds, to neighborhood fueling stations that may number in the tens to hundreds of thousands, to the ultimate de-centralized solution of home fueling stations that may number in the millions. This talk will discuss recent advances in hydrogen fueling demonstrations and lessons learned for the next stage of implementation.

Bridge‐transported bilateral master–slave servo manipulator system for remote manipulation in spent nuclear fuel processing plant

AbstractA bridge‐transported bilateral master–slave servo manipulator system called the Bridge‐Transported Dual‐Arm Servo‐Manipulator (BDSM) was developed for remote manipulation at the Pyroprocess Integrated Inactive Demonstration (PRIDE) facility. Its many innovative design concepts include a motion‐decoupled, cable‐drive mechanism, fully counterbalanced linkage structure, and interface system for easy attachment/detachment of the arms during remote maintenance. In addition, the manipulator is mounted at the end of a novel redundant‐drive extensible telescopic boom with a synchronized compact cabling management system. The BDSM is currently installed in the Remote Handling Evaluation Mock‐up (RHEM), where it has successfully completed operating tests with a remote control system incorporating a bilateral force‐reflection controller. Good tracking performance was confirmed regardless of the payload, allowing highly transparent control. The system is thus expected to achieve its design goals in dexterous remote handling tasks in PRIDE. © 2011 Wiley Periodicals, Inc.

Dynamic modeling of IGCC power plants

Abstract Integrated Gasification Combined Cycle (IGCC) power plants are an effective option to reduce emissions and implement carbon-dioxide sequestration. The combination of a very complex fuel-processing plant and a combined cycle power station leads to challenging problems as far as dynamic operation is concerned. Dynamic performance is extremely relevant because recent developments in the electricity market push toward an ever more flexible and varying operation of power plants. A dynamic model of the entire system and models of its sub-systems are indispensable tools in order to perform computer simulations aimed at process and control design. This paper presents the development of the lumped-parameters dynamic model of an entrained-flow gasifier, with special emphasis on the modeling approach. The model is implemented into software by means of the Modelica language and validated by comparison with one set of data related to the steady operation of the gasifier of the Buggenum power station in the Netherlands. Furthermore, in order to demonstrate the potential of the proposed modeling approach and the use of simulation for control design purposes, a complete model of an exemplary IGCC power plant, including its control system, has been developed, by re-using existing models of combined cycle plant components; the results of a load dispatch ramp simulation are presented and shortly discussed.

Cola soft drinks for evaluating the bioaccessibility of uranium in contaminated mine soils

There is a rising need for scientifically sound and quantitative as well as simple, rapid, cheap and readily available soil testing procedures. The purpose of this study was to explore selected soft drinks (Coca-Cola Classic®, Diet Coke®, Coke Zero®) as indicators of bioaccessible uranium and other trace elements (As, Ce, Cu, La, Mn, Ni, Pb, Th, Y, Zn) in contaminated soils of the Mary Kathleen uranium mine site, Australia. Data of single extraction tests using Coca-Cola Classic®, Diet Coke® and Coke Zero® demonstrate that extractable arsenic, copper, lanthanum, manganese, nickel, yttrium and zinc concentrations correlate significantly with DTPA- and CaCl2-extractable metals. Moreover, the correlation between DTPA-extractable uranium and that extracted using Coca-Cola Classic® is close to unity (+0.98), with reduced correlations for Diet Coke® (+0.66) and Coke Zero® (+0.55). Also, Coca-Cola Classic® extracts uranium concentrations near identical to DTPA, whereas distinctly higher uranium fractions were extracted using Diet Coke® and Coke Zero®. Results of this study demonstrate that the use of Coca-Cola Classic® in single extraction tests provided an excellent indication of bioaccessible uranium in the analysed soils and of uranium uptake into leaves and stems of the Sodom apple (Calotropis procera). Moreover, the unconventional reagent is superior in terms of availability, costs, preparation and disposal compared to traditional chemicals. Contaminated site assessments and rehabilitation of uranium mine sites require a solid understanding of the chemical speciation of environmentally significant elements for estimating their translocation in soils and plant uptake. Therefore, Cola soft drinks have potential applications in single extraction tests of uranium contaminated soils and may be used for environmental impact assessments of uranium mine sites, nuclear fuel processing plants and waste storage and disposal facilities.

Revisiting the NUMEC Affair

It is the story that won’t go away—the possibility that in the 1960s Israel stole bomb-grade uranium from a U.S. nuclear fuel-processing plant. Now two former NRC officials explain what they think happened.

903 火災力学シミュレータ(FDS)を用いた核燃料加工施設内電気ケーブルの燃焼評価(OS11-(1)オーガナイズドセッション《発電機器の材料・構造解析と評価》)

903 火災力学シミュレータ(FDS)を用いた核燃料加工施設内電気ケーブルの燃焼評価(OS11-(1)オーガナイズドセッション《発電機器の材料・構造解析と評価》)

Controlling End-Grain Corrosion of Austenitic Stainless Steels

SS 304L is widely used as a structural material in applications handling nitric acid such as nuclear fuel processing plants and nuclear waste management facilities. Bar, wire, and tubular products of this material are especially susceptible to end-grain corrosion in nitric acid environment. Such an attack takes place on the tubular and forged surfaces that are perpendicular to the hot-working direction and occurs as localized pitting type attack. This study shows that the possible reasons for the directional nature of end-grain attack are the manganese sulfide inclusions aligned along the hot-working direction and/or segregation of chromium along the flow lines during the fabrication stage itself. It has been shown in this study that controlled solution annealing, laser surface remelting, and weld overlay can be used to avoid/minimize end-grain corrosion. Different annealing heat-treatments were carried out on two heats of SS 304L tube and susceptibility to corrosion was measured by ASTM A 262 practice C and electrochemical potentiokinetic reactivation (EPR) test. Solution annealing at 950 °C for 90 min has been shown to increase the resistance to end-grain corrosion. Laser surface remelting using continuous wave CO2 laser under argon shield and weld deposition (overlay) using SS 308L material were done on the end faces of the tubes. These samples were completely resistant to end-grain corrosion in nitric acid environments.

Performance of a personal neutron dosemeter based on direct ion storage at workplace fields in the nuclear industry

In the framework of the EVIDOS project, funded by the EC, measurements were carried out using dosemeters, based on ionisation chambers with direct ion storage (DIS-N), at several workplace fields, namely, at a fuel processing plant, a boiling and a pressurised water reactor, and near transport and storage casks. The measurements and results obtained with the DIS-N in these workplaces, which are representative for the nuclear industry, are described in this study. Different dosemeter configurations of converter and shielding materials were considered. The results are compared with values for personal dose equivalent which were assessed within the EVIDOS project by other partners. The advantages and limitations of the DIS-N dosemeter are discussed.

Evaluation of dose equivalent by the electronic personal dosemeter for neutron 'Saphydose-N' at different workplaces of nuclear facilities

This paper presents the results of measurements made with the electronic personal neutron Saphydose-N during the four campaigns of the European contract EVIDOS (EValuation of Individual DOSimetry in mixed neutron and photon radiation fields). These measurements were performed at Institute for Radiological Protection and Nuclear Safety (IRSN) in France (C0), at the Krümmel Nuclear Power Plant in Germany (C1), at the VENUS Research Reactor and the Belgonucléaire fuel processing plant in Belgium (C2) and at the Ringhals Nuclear Power Plant in Sweden (C3). The results for Saphydose-N are compared with reference values for dose equivalent.

Kinetic modelling of the dispersion of plutonium in the eastern Irish Sea: two approaches

A new model to simulate the dispersion of plutonium in the eastern Irish Sea is presented. The model solves the 3D hydrodynamic equations using normalized σ coordinates in the vertical simultaneously with the suspended matter equation. Pu can be present in three phases: water, suspended matter and bottom sediments. Reduction and oxidation reactions are also included in the model, in terms of reaction rates, since Pu can be present in the marine environment in principally two different oxidation states. Two kinetic models are presented to describe the transfers of radionuclides between the liquid and solid phases: a one-step model consisting of a single reversible reaction and a two-step model consisting of two consecutive reversible reactions. It has been found that both models can properly simulate the contamination of the waters and sediments from the eastern Irish Sea due to the releases from the BNFL Sellafield nuclear fuel processing plant, since the outputs from both models are very similar and in agreement with observations. Also, both models can simulate the speciation of Pu between the reduced and oxidized forms. However, if the dominant source of radionuclides to the water column is redissolution from a contaminated sediment, a process that is actually occurring in the Irish Sea, it has been found that a two-step model must be used. Indeed, a one-step model predicts the redissolution from the sediment to be unrealistically rapid.